Dynamics of tuberculin tests. Mantoux reaction technique, evaluation of results

Naimanov A.Kh. - Head of the laboratory of mycobacteriosis, doctor of veterinary sciences, professor.

Ovdienko N.P. – leading researcher of the laboratory of mycobacteriosis, doctor of veterinary sciences, professor.

GNU VIEV (Moscow, Russian Federation)

Measures for the prevention and control of animal tuberculosis in our country are carried out in accordance with the sanitary and veterinary rules "Prevention and control of infectious diseases common to humans and animals", approved by the State Committee for Sanitary and Epidemiological Supervision and the Department of Veterinary Medicine of the Ministry of Agriculture of the Russian Federation on June 18, 1996, and "Manual for the diagnosis of animal tuberculosis", approved by the Department of Veterinary Medicine of the Ministry of Agriculture of the Russian Federation on November 18, 2002.

The sanitary and veterinary rules state that when the herds are cured from tuberculosis by the method of systematic studies with the slaughter of sick animals, all animals from the age of two months are examined every 45-60 days by a double intradermal tuberculin test.

In the "Manual for the Diagnosis of Animal Tuberculosis" we read: "In points that are unfavorable for tuberculosis of cattle, the use of a double tuberculin test is allowed."

The Manual of Standards for Diagnostic Tests and Vaccines (Office International des Epizooties Manual of Standards for Diagnostic Tests and Vaccines, 2000) states that the standard method for detecting bovine tuberculosis is the intradermal tuberculin test with PPD tuberculin and determination of thickening skin fold three days after the introduction of the allergen, that is, the use of a single intradermal tuberculin test is regulated, taking into account allergic reactions 72 hours after the introduction of tuberculin.

It should be noted that at present the double or double test is not used in any country in the world. In all countries, only a single intradermal test is used, and this issue is not discussed anywhere and no one doubts it. In our country in 1978, the double test was also canceled. However, later, due to discrepancies in the use of a double tuberculin test in the diagnosis of tuberculosis in disadvantaged farms, the Instructions of 1988 stated that in disadvantaged farms it was allowed to examine animals with double intradermal and eye tests, and since 1996 a double test has been legalized as diagnostic method research in disadvantaged farms.

The question of the diagnostic value of a double intradermal test is debatable only in our country. So, some authors believe that when using a double test in disadvantaged farms, animals that respond to tuberculin are detected, while tuberculosis is confirmed among them up to 40% of cases.

Others believe that when using a double test, only reacting animals with non-specific reactions are detected in mass quantities.

Therefore, the purpose of our work is to present the results of our studies on the comparative study of the diagnostic value of single and double methods of using the intradermal tuberculin test.

Materials and methods

Studies were carried out on 72 experimentally sensitized various types mycobacteria in calves (11 - M. bovis, 3 - M. tuberculosis, 12 - M. avium, 20 - M. fortuitum, 6 - M. intracellularae, 12 - M. paratuberculosis, 8 - control), on 56 artificially infected M. bovis calves, on 1639 heads of cattle in three tuberculosis-free farms, on 2142 cows in three tuberculosis-free farms, where sensitization of animals with atypical mycobacteria and avian mycobacteria was established, on 6403 cattle in seven disadvantaged farms with different epizootic tuberculosis situation.

In farms unfavorable for tuberculosis, in order to determine the diagnostic value of repeated administration of tuberculin, animals responsive to single and double administration and non-responders to double administration of tuberculin were slaughtered. Biomaterial from slaughtered animals was tested for tuberculosis by laboratory methods.

Accounting for allergic reactions was carried out 72 hours after the first injection and 24 hours after the re-introduction of tuberculin. Animals with an increase in the thickness of the skin fold by 3 mm or more were considered to be responding.

Research results

Study of experimentally sensitized and infected calves

In a study of 72 experimentally sensitized calves, it was found that all 11 M. bovis sensitized calves responded to the first intradermal administration of tuberculin, and repeated administration of tuberculin only increased the intensity of allergic reactions. Calves sensitized by Mycobacterium tuberculosis of the human species also reacted to the first injection of tuberculin, but their allergic reactions were less intense.

Of the 50 calves sensitized with avian mycobacteria, paratuberculosis mycobacteria and atypical mycobacteria, 39 (78%) responded to the first, 3 (16%) - to the repeated administration of tuberculin. Control calves did not respond to the first injection of tuberculin, and two calves (25%) responded to the second injection of tuberculin.

Of the 56 experimentally infected M. bovis calves, 54 (96.4%) responded to the first tuberculin injection, 2 (3.5%) calves did not respond to the first and second tuberculin injections.

The obtained research results show that experimentally sensitized and infected with M. bovis calves respond to the first intradermal injection of tuberculin from 96.4% to 100% of cases.

Research in prosperous farms

In tuberculosis-free farms, up to 15.3% of the studied healthy animals reacted to the two-time administration of tuberculin PPD for mammals, with an increase in the thickness of the skin fold by 3-5 mm.

In tuberculosis-free farms, where sensitization of animals with atypical mycobacteria and mycobacteria of avian tuberculosis has been established, it has been established that 2-3 times more tuberculin-responsive animals are detected after a double injection of tuberculin than after a single injection of tuberculin.

So, in farm No. 1, in the study of 694 cows, 29 (4.1%) animals reacted to the first injection, 75 (10.8%) animals reacted to the repeated administration of tuberculin, in farm No. 2, in the study of 177 animals of cattle that previously reacted to the first injection 93 (52.5%) reacted, 84 (47.4%) animals reacted to the second; in farm No. 3, in the study of 1271 heads of cattle, 96 (7.5%) animals reacted to the first injection, 166 (13.0%) animals reacted to the second injection.

The results of the studies show that in tuberculosis-free farms, up to 15.3% of healthy animals can respond to the repeated introduction of tuberculin. In prosperous farms, where the sensitization of animals with atypical mycobacteria and M. Avium is established, with the repeated introduction of tuberculin, twice as many reacting animals are detected.

Research in disadvantaged farms with different epizootic situation of tuberculosis

1286 heads of cattle were examined in four farms with tuberculosis problems. At the same time, 94 (7.3%) cattle reacted to the first injection of tuberculin, and 112 (8.7%) cattle reacted to repeated administration.

During the selective diagnostic slaughter of 21 cows that responded only to the repeated administration of tuberculin, changes characteristic of tuberculosis were not found in any case. Histological, bacteriological and biological examination of the pathological material from slaughtered animals did not confirm tuberculosis.

In the study of cattle in the overexposure groups of patients with tuberculosis in three long-term disadvantaged this disease farms, it was found that in some groups of animals, up to 100% of individuals react to the first intradermal injection of tuberculin (in cases where overexposure groups were completed with animals from disadvantaged herds that had previously reacted to tuberculin).

In long-term tuberculosis-prone farms, during selective diagnostic slaughter of ten animals that responded only to a double injection of tuberculin, changes characteristic of the disease were found in two (20%) cases. In these farms, during the selective slaughter of ten cows that did not respond to the first and second injections of tuberculin, changes characteristic of tuberculosis were also found in two (20%) cases.

The presented results of the studies show that in long-term tuberculosis-prone farms, the two-time intradermal administration of tuberculin also does not detect sick animals.

Studies in tuberculosis-prone farms where chemoprophylaxis with tubazid was used

The studies were carried out in four farms in one region, where recreational activities were carried out using the chemoprevention of tuberculosis by the method subcutaneous injection suspensions of tubazid.

In the same area, studies were conducted in four farms, where rehabilitation was carried out by the method of systematic research and slaughter of reacting animals without the use of chemoprophylaxis.

At the Rassvet state farm, on 200 heads of cattle of one farm, health-improving measures were carried out using chemoprophylaxis, on the other farm (544 heads), in order to control, health-improving measures were carried out without the use of chemoprophylaxis.

The research results are presented in table No. 1.

Table 1

The value of the multiplicity of the introduction of tuberculin in the households disadvantaged by tuberculosis, being rehabilitated different methods

From the data of the table it can be seen that in farms where rehabilitation is carried out with the use of tubazid, a large number of tuberculosis-infected cows with disease-specific changes. Thus, during the slaughter of 52 animals responding to the first injection of tuberculin, characteristic changes were found in 20 (38.4%) animals. At the slaughter of 81 cows that responded to the repeated administration of tuberculin, changes characteristic of tuberculosis were found in 32 (39.5%) cases.

It should be noted that at the Mikhailovsky state farm we slaughtered 82 animals, of which 19 were those that responded to the first injection of tuberculin, 58 to the second injection, and 5 did not respond to the double injection of tuberculin. During the pathoanatomical examination of slaughtered cows, changes characteristic of tuberculosis were found in 9 (47.3%) that responded to the first injection, in 26 (44.8%) - to the second injection, and in one individual that did not respond to the double injection of tuberculin. The obtained results of the research show that in farms that are unfavorable for tuberculosis, where chemoprophylaxis with tubazide is carried out, with a relatively small detection of animals responding to tuberculin, up to 47.3% of slaughtered animals showed changes characteristic of the disease. Moreover, these changes were found in those who responded to the first and second injections of tuberculin, as well as in those who did not respond to the double injection of tuberculin.

In disadvantaged farms, where recreational activities are carried out by the method of systematic research and slaughter of those reacting to the double administration of tuberculin, tuberculosis is confirmed in isolated cases. Thus, during the slaughter of 23 animals that responded to the second tuberculin injection, changes characteristic of tuberculosis were found only in two (8.6%) cases.

The results of the studies indicate that when using tubazide in cattle, the sensitivity to the intradermal administration of tuberculin decreases, that is, the manifestation of allergic reactions is suppressed.

Conclusion

Long-term TB-prone farms should be rehabilitated by a complete replacement of the livestock or with the use of additional studies on the disease. In disadvantaged farms, allergic tests for tuberculosis should be carried out with a single intradermal tuberculin test.

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Diagnosis of tuberculosis is the main measure that becomes not only the key to successful treatment, but also a way to prevent an epidemic, since in fact one sick person can infect a whole team. For this reason, it is worth regularly diagnosing for preventive purposes. It is for this purpose that tuberculin tests are carried out in children's institutions. About what a tuberculin test is, how informative it is and what consequences it can have, is described in this article.

What is a tuberculin test?

Children regularly undergo tuberculin test, this right is enshrined at the legislative level. What it is? This test, carried out in most cases, is a subcutaneous injection of a tuberculin preparation of natural or synthetic origin, depending on the type of test. Usually, the drug is injected under the skin in the area of ​​​​the wrist, but it can also be in other places, for example, in newborns.

The action of this drug causes a local reaction on the skin - first, redness appears and swelling forms, after a day a papule begins to form. By the size of this papule, the doctor concludes whether the patient is sick. What kinds of reactions can there be?

• A positive reaction is observed when, after 72 hours, a large papule has formed. This suggests that the causative agent of tuberculosis is present in the body. The patient is sent for a mandatory examination;
• Doubtful. There is a papule, but its size is insufficient to diagnose the presence of tuberculosis. May appear if a natural vaccine against this disease was introduced not so long ago. With this result, the patient is most often referred for examination;
• A negative reaction is one in which there are no changes in skin. She speaks of the absence of a pathological process. But it can also say that the patient is not vaccinated against the disease or the vaccine "did not work", that is, immunity was not formed.

Thus, deciphering the results of the study does not cause significant difficulties.

By itself, the reaction develops because the injected drug causes a reaction immune system and in the presence of tuberculosis pathogens, the immune response will be stronger, that is, the volume of the papule will become larger. Whereas, if there is no pathogen in the body, then the immune system has not developed the appropriate antibodies and does not react in any way to the pathogen entering the blood as part of the sample. Of course, such a small volume of an inactive pathogen cannot cause infection.

The history of the appearance of tuberculin

Tuberculin tests are carried out with the substance tuberculin of natural or artificial origin. How did it come about? Tuberculin was discovered by the same scientist who discovered the "Koch's wand" - Robert Koch. It happened in 1890. At the very beginning of the 20th century, the pediatrician Clemens Pirke from Austria introduced the concept of allergy into medicine and substantiated the information content of the tuberculin test. He proposed to carry it out by a scarifying skin method - this was the first such test, but it was not widely used due to the inappropriateness of the method used.

Very soon, in 1908, Charles Mantoux, on the one hand, improved, and on the other hand, only slightly modified the Pirquet test, proposing to inject a tuberculin solution intradermally. This diagnostic method has become much more widespread, as it has proven its maximum accuracy and efficiency. In this unchanged form, the Mantoux test is carried out in kindergartens and schools to this day.

Until recently, natural tuberculin was used, which includes the waste products of pathogenic bacteria. But such a composition is very allergic, therefore, at the injection site, in addition to immune response allergic is also manifested, which significantly reduces the information content of the test, since the result can be regarded as a false positive.

Therefore, such a drug is gradually being replaced by purified tuberculin (PPD). Such tuberculin was discovered back in 1934, approved by the World Health Organization in the 1950s, but it has become widespread relatively recently. The advantage of the new drug is not only in its higher specificity and accuracy of the test with it, but also in the fact that the drugs used are more sterile.

Types of tuberculin samples

At present, the Mantoux test is widespread, however, in addition to it, there are alternative methods of administering the drug and evaluating the results of the reaction, since the symptoms also differ. In addition to the Mantoux method, the Koch and Pirquet methods are also implemented. These approaches have different contraindications and indications, features, and therefore can be interchanged in different conditions.

Subcutaneous Koch test

The indication for such a study is the need to clarify the diagnosis of tuberculosis. The test is very highly sensitive, has greater accuracy than the Mantoux test, but is also more expensive. It is usually performed when the Mantoux reaction is not informative enough.

The drug is administered subcutaneously. The difference is in the dosages and the sampling scheme. First, the drug is injected under the skin in a volume of m10-120TE. If no result followed, then another 50 or 100 TU is introduced. After such a volume of the drug, both general and local focal reactions are detected. Such tests are also used in gynecology for suspected urogenital tuberculosis.

The test result is decoded as follows:

1. Lack of reaction after administration of 100 TU of the drug - no tuberculosis;
2. The general reaction (fever, deterioration of health, increase in leukocytes in the blood and ESR, etc.) - there is tuberculosis;
3. Focal reaction (observed in the lesion) is established by means of radiography, sputum examination, etc. - there is tuberculosis, even despite the absence of a general reaction;
4. Local reaction - a papule in the injection zone with a diameter of 1.5-2 cm is not informative if there are no other symptoms, that is, if there is a papule, but there are no symptoms, then there is no tuberculosis.

This is a fairly informative and effective test, more effective than the Mantoux test. But it is complex, more expensive, and may be worse tolerated by the patient.

Pirquet skin test

It is carried out if necessary to confirm the diagnosis of tuberculosis. It is used quite rarely, as it is less informative than the Mantoux reaction. It is impossible to carry out such testing in the presence of bronchial asthma, an allergic reaction, a local skin reaction, a rash and skin injuries in the injection area, with bronchitis, acute respiratory infections, acute respiratory viral infections, etc.

Such a test is done for both children and adults and is performed by the scarification method, that is, just like the traditional allergy test, which it is. The place of application of the drug is disinfected with carbolic acid, usually the agent is applied to the forearms. With the help of a scarifier, small notches are made on the skin, and then the drug is applied to them.

Within 5-6 minutes, the drug is absorbed into the skin, then its residues are wiped off with a paper towel. The patient is under observation for 48 hours, during which the reaction of his body to the sample is monitored.

As a result, several papules are formed. They, as in all other methods, are differentiated by size.

• A papule up to 3 mm indicates that it is necessary to re-vaccinate, and then repeat the test itself;
• A papule 3-5 mm in diameter indicates the absence of tuberculosis and the normal effectiveness of the vaccination;
• A 4-10 mm papule indicates that there may be an infection, or there was contact with an infected person;
• Papule 10-15 mm, sores, etc. indicate the presence of the disease.

Since several papules are formed, it is possible that they can vary quite a lot in size. In this case, they are evaluated together, depending on which area of ​​what concentration the solution was applied to.

Mantoux test with 2TE PPD-L

The Mantoux tuberculin test is mandatory for all children under the age of 15 years. These events are organized on the basis of schools and kindergartens. Its purpose is diagnostic and prophylactic. The advantages are that it is as simple as possible, fast, cheap, and also well tolerated by patients (and therefore it can be put on stream). Among the shortcomings is a rather low (compared to other methods) information content, in addition, it is quite difficult for a child to handle it.

Such a test cannot be carried out with ARVI, acute respiratory infections, inflammatory and infectious processes in the body. The interpretation of the results also occurs by assessing the size of the formed papule. But as a result of an allergic reaction, such a test can often give a false positive result.

Conclusion

Tuberculin reaction is the main way to guess or determine for sure whether a person is infected with tuberculosis. Such timely diagnosis at an early stage is not only the guarantor of successful treatment, but also does not allow the pathology to spread. For this reason, a mandatory Mantoux test is carried out for all children, starting from the maternity hospital and up to the age of 15 years, because it is the children who are most vulnerable to this disease. However, an adult can also carry out this test at will - the assessment of his reaction will have the same principles.

In Russia, PPD-L - domestic dry purified tuberculin, is purified and dried in a vacuum from a frozen state filtrate of a heat-killed culture of mycobacterium tuberculosis of the human and bovine types.

Tuberculin is a hapten, it is not able to sensitize the body (infect), but it causes a response allergic reaction in a previously sensitized (with spontaneous infection with Mycobacterium tuberculosis or immunization with BCG vaccine) organism.

PPD-L is produced in three forms. Dry purified tuberculin- in ampoules of 50000TE. The drug is used for diagnostic purposes, mainly in individual tuberculin diagnostics, is used for tuberculin therapy.

Purified Tuberculin- in a standard dilution with 2TE activity (in 1TE it is contained in 0.00006 mg of dry preparation) in 0.1 ml. Ready-to-use tuberculin solution in 3 ml ampoules or 5 ml vials is intended for Mantoux test with 2TE, used in mass tuberculin diagnostics.

Reactions to the introduction of tuberculin. AT The response to the introduction of tuberculin in the body of infected and TB patients can develop prick, general and focal reactions.

Prick reaction characterized by the appearance at the injection site of tuberculin papule (infiltrate) and hyperemia. With hyperergic reactions, the formation of vesicles, bulls, lymphangitis, necrosis is possible.

General reaction infected organism to the effects of tuberculin is manifested by deterioration general condition, headaches, arthralgia, fever, etc.

Focal reaction characterized by increased perifocal inflammation around the tuberculous focus, depending on the localization of the process.

Tuberculin tests- These are skin tests with tuberculin to detect sensitization of the body to Mycobacterium tuberculosis. The most famous tests are Pirque (skin), Mantoux (intradermal), Koch (subcutaneous). The most sensitive is Koch's test.

For mass diagnostics, only a single intradermal Mantoux test with 2TE is used.

Goals of mass tuberculin diagnostics:

Early detection of MBT infection (turn) and tuberculosis;

Selection of contingents for BCG revaccination (negative tests at 7, 14, 21 years of age), as well as before primary vaccination of children aged 2 months or more, not vaccinated at maternity hospital;

Study of the level of infection of the population with tuberculosis (samples are positive, but the examined are not sick);

Differential Diagnosis tuberculosis;

Identification of individuals with hyperergic reactions to tuberculin with an increased risk of the disease (the task is in adults).

In order to early detection tuberculosis Mantoux test with 2TE for children and adolescents put annually, starting from the age of 12 months (under the age of one year - according to indications), regardless of the previous result. With the systematic formulation of this test, it is possible to identify the transition of a previously negative reaction to a positive one, an increase in sensitivity to tuberculin. In kindergartens and schools, mass Tuberculin diagnostics is carried out by a team method, Mantoux tests are performed for unorganized children of early and preschool age in a children's clinic. In rural areas, tubd-ku is carried out by district rural district hospitals and FAPs.

The method of setting and evaluating the Mantoux test. The instruction provides for the setting of a sample by an individual special tuberculin a syringe into which two doses of tuberculin are collected - 0.2 ml (available in 0.1 ml ampoules).

The skin is pretreated with 70% alcohol. Strictly intradermally on the inner surface of the middle third of the forearm, 0.1 ml of tuberculin solution is injected. An indicator of the correct technique for administering the drug is the formation in the skin "lemon peel" - papules white color with a diameter of 6 - 7 mm.

The sample is evaluated after 72 hours by measuring the size of the infiltrate in millimeters perpendicular to the axis of the forearm. Hyperemia is taken into account only in cases where there is no infiltration. The reaction is considered negative in the absence of infiltration and hyperemia, doubtful with an infiltrate of 2-4 mm in size, or only with hyperemia without infiltration, positive in the presence of an infiltrate of 5 mm or more. hyperergic reactions are considered: in children and adolescents - in the presence of an infiltrate of the size 17 mm or more, in adults - 21 mm or more, and also regardless of the size of the infiltrate, with the appearance of vesicles, bullae, lymphangitis, regional lymphadenitis, herpetic reaction.

Relative contraindications for tube testing:

· skin diseases,

· acute diseases, chronic infectious and somatic diseases during an exacerbation

allergic conditions, bronchial asthma,

epilepsy,

idiosyncrasy,

quarantine in the children's team.

Prof. vaccinations can affect the level of sensitivity to tuberculin, so tuberculin is carried out before prof. vaccinations against various infections or not earlier than 4 weeks after vaccination.

Individual tuberculin diagnostics. It is used for differential diagnosis of post-vaccination and infectious tuberculosis allergy with non-specific diseases in children under dispensary observation.

The skin graduated scarification test of N. N. Grinchar and D. A. Karpilovsky, which is a modification of the Pirquet test, has been widely used.

For setting this sample, 100, 25, 5 and 1% dilutions of tuberculin concentration are used (dry PPD-L is used). The skin of the forearm is pulled from below with the left hand, then the integrity of the surface layers of the skin is violated with a smallpox lancet in the form of scratches 5 mm long, first through a drop of solvent, then through drops of 1, 5, 25 and 100% tuberculin solutions along the axis upper limb. Tuberculin is rubbed with the flat side of the lancet. For penetration of tuberculin into the skin, the scarified area is left open for 5 minutes. At the site of scarification, a white roller should appear, indicating the absorption of tuberculin. After that, the remnants of tuberculin can be removed with sterile cotton.

Skin results graduated scarification test is taken into account through 48 and 72 hours. At the site of application of each concentration of tuberculin, the largest size of the infiltrate is measured transversely to the scratch with a transparent millimeter ruler. negative the result is absence of hyperemia and papules; dubious - papule 1 - 2 mm or only hyperemia; positive - papule 3 mm or more; hyperergic result - papule 10 mm or more, vesiculo-necrotic reactions. Hyperemia is taken into account only in cases where there is no papule.

The graded scarification test is evaluated according to Shmelev. There are the following variants of graduated scarification test:

• non-specific reaction - slight redness at the site of application of a 100% tuberculin solution;
• average specific reaction (normergic) - moderate sensitivity to high concentrations of tuberculin, no reactions to 1%, 5% and even 25% tuberculin concentrations;
• hyperergic reaction - an increase in the size of the infiltrate as the concentration of tuberculin increases, ranging from 1% to 100%, while there may be vesiculo-necrotic changes, lymphangitis, etc .; such tests are often found in active forms of primary tuberculosis;
• equalizing reaction - approximately the same intensity of reaction to different (for example, 100% and 25%) concentrations of tuberculin, large concentrations of tuberculin do not cause an adequate response;
• paradoxical reaction - a lower intensity of the reaction to a large concentration of tuberculin than to a weak one.

For post-vaccination allergies, normergic adequate reactions to 100% and 25% concentrations are characteristic; on 5%, 1% and control - negative reactions. Positive results for 100%, 25%, 5% and 1%, as well as equalizing, paradoxical, hyperergic tests are characteristic of infectious allergies.

Tuberculin diagnostics - a set of diagnostic tests to determine the specific sensitization of the body to MBT using tuberculin. Since the creation of tuberculin to the present day, tuberculin diagnostics has not lost its significance and remains an important method for examining children, adolescents and young people. When meeting with mycobacteria (infection or vaccination with BCG), the body responds with a certain immunological reaction and becomes sensitive to the subsequent introduction of antigens from mycobacteria, i.e. sensitized to them. This sensitivity, which is of a delayed nature, i.e. a specific reaction manifests itself after a certain time (24-72 hours), called delayed hypersensitivity(GZT). Tuberculin has a high specificity, acting even in very large dilutions. Intradermal administration of tuberculin to a person whose body is previously sensitized both by spontaneous infection and as a result of BCG vaccination causes a specific response that has diagnostic value.

Tuberculin is a preparation obtained from culture filtrates or MBT microbial bodies. Tuberculin is an incomplete antigen - a hapten, i.e., when administered, it does not sensitize the human body, but only causes a specific delayed-type hypersensitivity response (DTH). The occurrence of a specific reaction to tuberculin is possible only under the condition of preliminary sensitization of the organism by mycobacteria.

6.1. DEVELOPMENT OF TUBERCULIN DIAGNOSIS

For the first time, tuberculin was obtained by Koch more than 100 years ago from 6-8-week cultures of MBT of human and bovine species grown in meat-peptone broth with the addition of glycerin, killed by heating with steam for 1 hour, released by filtration from microbial bodies and condensed at a temperature of 90 ° From up to 1/10 of the original volume. This drug is named old tuberculin Koch (Alt Tuberculin Koch), or alttuberculin Koch- ATK. A significant disadvantage ATK was the presence in its composition, along with specific active

nymi substances - waste products of the MBT ballast substances (protein components of the meat-peptone nutrient medium on which the MBT were grown). Ballast protein substances can cause a non-specific reaction of the body, which makes diagnosis difficult, therefore, in the future, many tuberculin manufacturers replaced meat broth with a synthetic nutrient medium. Tuberculin is named after old tuberculin- old tuberculin. At present, ATC and OT are of limited use in the world, and in our country they are not produced and are not used.

In the 30s of the last century, a more purified preparation, freed from ballast substances, was created for the first time. From purified tuberculin PPD obtained in 1939 by F. Seibert and S. Glenn (Purified protein derivative- purified protein derivative) an international standard for purified tuberculin has been prepared, which exists and has been successfully used to date, i.e. almost 70 years old. Freeze-dried international standard contains 5000 TU per ampoule (tuberculin units). The international tuberculin unit is such an amount of tuberculin that in 80-90% of spontaneously infected with MBT individuals reveals sensitivity to tuberculin, i.e., causes a positive HRT reaction.

To obtain tuberculin PPD, protein from culture filtrates of mycobacterium tuberculosis, previously killed by heating, concentrated and purified by ultrafiltration or supercentrifugation, is isolated using ammonium sulfate followed by dialysis and (or) trichloroacetic acid. Other methods of salting out or protein precipitation have been used, but they are not widely used. In domestic literature, purified tuberculin was abbreviated not as PPD (purified protein derivative), but as PPD (PPD). In the same years, under the leadership of M.A. Linnikova at the Leningrad Research Institute of Vaccines and Serums developed domestic purified tuberculin - PPD-L, and since 1954 purified tuberculin began to be produced by the production enterprise of this institute.

In terms of its chemical composition, tuberculin is a complex preparation containing tuberculoproteins (at least 80% in the ERD), polysaccharides, lipids, and nucleic acids. The composition of tuberculin, including its antigenic spectrum and specificity, depends on the strains used and the nutrient medium, the timing of cultivation

of mycobacteria, a method for obtaining tuberculoprotein protein. For example, the specificity of tuberculins from 6-week culture filtrates is significantly higher than from 14-week culture filtrates, and the protein yield of the drug is lower. In view of the foregoing, in order to be able to compare tuberculin diagnostic data and interpret them correctly, tuberculin series should not differ in activity and specificity from each other. The biological activity of tuberculin, which tuberculoprotein provides, is measured in tuberculin units (TU) and standardized against the industry standard sample - the national standard. In 1963, the first national standard for domestic tuberculin PPD was approved, and in 1986, the second national standard for this drug. The national standard, in turn, must be compared with the international standard. First, this comparison is carried out on animals (usually on guinea pigs) sensitized by various strains or species of mycobacteria. Then the established activity is confirmed in the clinic.

One of effective methods production of tuberculin, the activity of which is the same from series to series, is the accumulation of a large amount of semi-finished powder, which is a mixture of separate sediments of cultural filtrates. It is prepared for 20-30 years, standardized and controlled according to all indicators provided by national and international requirements. The first digit in the tuberculin commercial batch number is the number of such semi-finished powder. Despite the fact that the semi-finished powder is standardized, the specific activity of each batch of purified tuberculin made from it is in turn controlled against the national standard.

At present, the following forms of PPD-L are issued in the country.

1. Tuberculosis allergen purified liquid standard dilution (purified tuberculin standard dilution)- in ampoules of 3 ml (2 TU in 0.1 ml). This is ready-to-use tuberculin. The drug is a transparent colorless liquid, contains tween-80 as a stabilizer (a polyoxyethylene derivative of sorbitan monooleic acid - a surfactant that prevents the adsorption of tuberculin by glass and ensures the stabilization of the biological activity of the drug) and phenol as a preservative. The shelf life of the drug is a year. This drug is used for mass and individual

tuberculin diagnostics both in the general medical network and in anti-tuberculosis institutions.

2. Tuberculosis allergen purified dry for cutaneous, subcutaneous and intradermal use (dry purified tuberculin)- in ampoules of 50,000 IU. It is a lyophilized (frozen) dried, purified tuberculin dissolved in phosphate buffer with sucrose. The drug is a dry compact mass or powder of a slightly grayish or cream color, easily soluble in the supplied solvent - 0.25% carbolized isotonic sodium chloride solution. The shelf life of the drug is 5 years. This drug is used for individual tuberculin diagnostics and for tuberculin therapy only in anti-tuberculosis institutions.

Each box with tuberculins contains instructions for the use of drugs with their detailed characteristics and methods for setting up and evaluating various tuberculin samples. Familiarization with the instructions of the doctor and nurse before conducting tuberculin diagnostics is mandatory.

Tuberculin preparations PPD-L are injected into the human body cutaneously, intradermally and subcutaneously. The route of administration depends on the type of tuberculin test. If the human body is previously sensitized by MBT (spontaneous infection or as a result of BCG vaccination), then a specific response develops in response to the introduction of tuberculin. This reaction is based on the mechanism of delayed-type hypersensitivity (DTH). The reaction begins to develop 6-8 hours after tuberculin administration in the form of an inflammatory infiltrate of varying severity, the cellular basis of which is lymphocytes, monocytes, macrophages, epithelioid and giant cells. The trigger mechanism for the DTH reaction is the interaction of the antigen (tuberculin) with receptors on the surface of effector lymphocytes, resulting in the release of cellular immunity mediators that involve macrophages in the process of antigen destruction. Some cells die, releasing proteolytic enzymes that have a damaging effect on tissues. Other cells accumulate around the foci of a specific lesion. An inflammatory reaction occurs not only at the site of tuberculin application, but also around the tuberculous foci. When sensitized cells are destroyed, active substances with pyrogenic properties. The time of development and the morphology of reactions with any methods of tuberculin application are fundamentally not

different from those for intradermal administration. The peak of the DTH reaction falls on 48-72 hours, when its non-specific component is reduced to a minimum, and the specific component reaches a maximum.

The intensity of the tuberculin reaction depends on many factors (specific sensitization of the body, its reactivity, etc.). In apparently healthy children infected with MBT, tuberculin reactions are usually less pronounced than in patients active forms tuberculosis. In children with tuberculosis, sensitivity to tuberculin is higher than in adults with tuberculosis. In severe forms of tuberculosis (meningitis, miliary tuberculosis, caseous pneumonia), there is often a low sensitivity to tuberculin due to a pronounced inhibition of the body's reactivity. Some forms of tuberculosis (tuberculosis of the eyes, skin), on the contrary, are more often accompanied by high sensitivity to tuberculin.

In response to the introduction of tuberculin in the body of a previously sensitized person, a local, general and / or focal reaction develops.

Local reaction formed at the injection site of tuberculin, may manifest as hyperemia, papule (infiltrate), vesicles, bulla, lymphangitis, necrosis. The local reaction is of diagnostic value for cutaneous and intradermal administration of tuberculin.

General reaction characterized by general changes in the human body and can manifest itself in the form of deterioration of health, fever, headaches, arthralgia, changes in blood tests (monocytopenia, dysproteinemia, slight acceleration of ESR, etc.). The general reaction often develops with subcutaneous administration of tuberculin.

Focal reaction occurs in patients in the focus of a specific lesion - in tuberculous foci of various localization. A focal reaction is clinically manifested (with pulmonary tuberculosis, hemoptysis, increased coughing, an increase in the amount of sputum discharge, the appearance of pain in the chest, increased catarrhal phenomena during a physical examination of the patient; with extrapulmonary tuberculosis, increased inflammatory changes in the area of ​​​​tuberculous lesions); x-ray increase in perifocal inflammation around tuberculous foci. The focal reaction is more pronounced with subcutaneous administration of tuberculin.

Tuberculin diagnostics is divided into mass and individual.

6.2. MASS TUBERCULIN DIAGNOSIS

Mass tuberculin diagnostics is used for mass screening of the population for tuberculosis. Tasks of mass tuberculin diagnostics:

Identification of children and adolescents with tuberculosis;

Identification of persons at risk of tuberculosis for subsequent observation by a phthisiatrician, if necessary - for preventive treatment(persons newly infected with MBT - "turn" of tuberculin tests, people with an increase in tuberculin tests, people with hyperergic tuberculin tests, people with tuberculin tests that are at a moderate and high level for a long time);

Selection of children and adolescents for BCG revaccination;

Determination of epidemiological indicators for tuberculosis (infection of the population with MBT, annual risk of infection with MBT).

For mass tuberculin diagnostics, only one tuberculin test is used - Mantoux with 2 tuberculin units.

Mantoux test with 2 tuberculin units carried out for all children and adolescents vaccinated with BCG, regardless of the previous result, once a year. The child should receive the first Mantoux test at 12 months of age. For children who are not vaccinated with BCG, the Mantoux test is carried out from the age of 6 months once every six months until the child receives a BCG vaccination, in the future - according to the generally accepted method once a year.

For the Mantoux test, special disposable tuberculin syringes with thin short needles and a short oblique cut are used. Do not use syringes with expired suitability and insulin syringes.

For mass tuberculin diagnostics, only purified tuberculin in standard dilution is used. The ampoule with tuberculin is carefully wiped with gauze moistened with 70 ° ethyl alcohol, then the neck of the ampoule is filed with a knife to open the ampoules and broken off. Tuberculin is taken from the ampoule with a syringe and a needle, which then carry out the Mantoux test. 0.2 ml of the drug is drawn into the syringe (i.e. 2 doses), then the solution is released to the 0.1 ml mark into a sterile cotton swab, it is unacceptable to release the solution into the protective cap of the needle or into the air, as this can lead to

to allergization of the body of vaccinators. Ampoule with tuberculin after opening is suitable for use for no more than 2 hours, while maintaining it under aseptic conditions.

The intradermal test is performed only in the treatment room. The patient is in a sitting position, as in emotionally labile individuals, the injection can cause fainting.

On the inner surface of the middle third of the forearm, a skin area is treated with 70 ° ethyl alcohol, dried with sterile cotton wool. Tuberculin is injected strictly intradermally, for which the needle is directed with the cut up into the upper layers of the stretched skin parallel to its surface. After inserting the needle hole into the skin, 0.1 ml of tuberculin solution is injected from the syringe, i.e. 1 dose. With the right technique, a papule is formed in the skin in the form of a "lemon crust" with a diameter of at least 7-9 mm in a whitish color, which soon disappears.

A Mantoux test, as prescribed by a doctor, is performed by a specially trained nurse. The response is taken into account after 72 hours, it is evaluated by a doctor or a trained nurse. The results are recorded in the accounting forms: 063/y (vaccination card), ? 026/y ( medical card child), 112/y (child development history). At the same time, the manufacturer, the batch number, the expiration date of the tuberculin, the date of the test, the introduction of the drug into the right or left forearm, the result of the test is the size of the infiltrate (papules) in millimeters; in the absence of infiltration indicate the size of hyperemia, if any.

With proper organization, tuberculin diagnostics should cover 90-95% of the child and adolescent population of the administrative territory every year. In organized groups, mass tuberculin diagnostics is carried out in institutions either by specially trained medical personnel or by a team method, which is preferable. With the team method, teams are formed - 2 nurses and a doctor. The formation of teams is assigned to children's clinics. For unorganized children, the Mantoux test is carried out in a children's clinic. In rural areas, tuberculin diagnostics is carried out by district rural district hospitals and feldsher-obstetric stations. The methodical guidance of tuberculin diagnostics is carried out by the pediatrician of the anti-tuberculosis dispensary (office). In the absence of an anti-tuberculosis dispensary (office), the work is carried out by the head

by the outpatient department for childhood (district pediatrician) together with the district phthisiatrician.

Contraindications to PM with 2 TEs:

Skin diseases, acute and chronic infectious and somatic diseases (including epilepsy) during the period of exacerbation;

Allergic conditions, rheumatism in the acute and subacute phases, bronchial asthma in the acute stage, idiosyncrasy with severe skin manifestations during the acute period;

It is not allowed to conduct tuberculin tests in children's groups where there is a quarantine for childhood infections;

The Mantoux test is not given within a month after other preventive vaccinations (DTP, measles vaccinations, etc.).

Mantoux test is carried out 1 month after the disappearance clinical symptoms or immediately after the quarantine is lifted.

In order to identify contraindications, the doctor (nurse) examines the medical documentation, interrogates and examines the persons subjected to the sample.

Evaluation of the results of the intradermal Mantoux test. The result is evaluated after 72 hours. The diameter of the papule (hyperemia) in millimeters is measured with a transparent ruler, the ruler is placed perpendicular to the axis of the forearm. For the correct interpretation of the results, not only a visual assessment of the reaction is required, but also palpation of the tuberculin injection site, since with a mild papule (slightly rising above the skin level), in the absence of hyperemia, the reaction can be visually regarded as negative. If the flat papule is hyperemic, then visual assessment may give a result as doubtful or positive. Palpation of the injection site of tuberculin allows you to fairly accurately determine the presence or absence of an infiltrate (papules), and only after a palpation examination, a measurement is made using a ruler. With hyperemia that goes beyond the papule, light pressure with the thumb on the reaction area allows you to briefly remove the hyperemia and measure only the papule.

The results of the test can be regarded as follows:

Negative reaction - the complete absence of infiltration (papules) and hyperemia, a prick reaction of 0-1 mm is allowed;

Doubtful reaction - infiltrate (papule) 2-4 mm in size or the presence of hyperemia of any size without infiltration;

A positive reaction is an infiltrate (papule) measuring 5 mm or more, this includes the presence of vesicles, lymphangitis, screenings (a few more papules of any size form around the papule at the injection site of tuberculin).

Among positive reactions allocate:

Weakly positive - the size of the papule is 5-9 mm;

Medium intensity - papule size 10-14 mm;

Expressed - the size of the papule is 15-16 mm;

Hyperergic - in children and adolescents, the size of the papule is 17 mm and above, in adults - 21 mm and above; hyperergic reactions include vesiculonecrotic reactions, the presence of lymphangitis, screenings, regardless of the size of the papule.

Studies conducted by various authors confirm the need to study the reactions to the Mantoux test with 2 TU in dynamics based on the results of the annual mass tuberculin diagnostics. In our country, according to the vaccination schedule, the entire child population is subject to vaccination against tuberculosis at a certain time. After the introduction of the BCG vaccine, HRT also develops in the body, as a result of which reactions to 2 TU of purified tuberculin in a standard dilution become positive - the so-called post-vaccination allergy (PVA) develops. The appearance of a positive reaction to the Mantoux test with 2 TU as a result of spontaneous infection of the body with MBT is regarded as an infectious allergy (AI). Differential diagnosis between post-vaccination and infectious allergies is often quite difficult. The study of the results of Mantoux testing in dynamics, combined with data on the timing and frequency of BCG vaccinations, as a rule, in the vast majority of cases, allows for differential diagnosis between PVA and IA.

Positive results for a Mantoux test with 2 TU is regarded as a post-vaccination allergy in the following cases:

There is an association of positive and questionable reactions to 2 TU with a previous vaccination or BCG revaccination (i.e. positive or questionable reactions appear in the first 2 years after vaccination or BCG revaccination);

There is a correlation between the size of reactions (papules) to tuberculin and the size of the post-vaccination BCG sign (scar): a papule up to 7 mm corresponds to BCG scars up to 9 mm, and up to 11 mm corresponds to scars more than 9 mm;

The largest response to the Mantoux test is detected in the first 2 years after vaccination or BCG revaccination, in the next 5-7 years post-vaccination sensitivity to tuberculin fades.

A reaction to 2 TU PPD-L is regarded as the result of an infectious allergy (TET) in the following cases:

The transition of a negative reaction to 2 TU tuberculin into a positive one, not associated with vaccination or BCG revaccination; an increase in the size of the papule by 6 mm or more after a previous post-vaccination allergy - an early period of primary tuberculosis infection - a "turn";

A sharp increase in sensitivity to tuberculin (by 6 mm or more) during the year (in tuberculin-positive children and adolescents after a previous infectious allergy);

Gradual, over several years, increased sensitivity to tuberculin with the formation of reactions to 2 TU of moderate intensity or severe reactions;

5-7 years after vaccination or BCG revaccination, persistently (for 3 years or more) remaining sensitivity to tuberculin at the same level without a tendency to fade - monotonous sensitivity to tuberculin;

Extinction of sensitivity to tuberculin after a previous infectious allergy (as a rule, in children and adolescents who were previously observed by a phthisiopediatrician and received a full course of preventive treatment).

The study of the results of tuberculin diagnostics carried out in children and adolescents showed the dependence of the intensity of responses to 2 TU PPD-L on many factors, which should also be taken into account when examining patients.

It is known that the intensity of the reaction to 2 TU depends on the frequency and frequency of revaccinations against tuberculosis. Each subsequent revaccination entails an increase in sensitivity to tuberculin. In turn, a decrease in the frequency of BCG revaccinations leads to a decrease in the number of positive results for the Mantoux test by 2 times, hyperergic - by 7 times. Thus, the cancellation of revaccinations helps to reveal the true level of MBT infection in children and adolescents, which in turn allows for full coverage of BCG revaccination of adolescents in the required time frame. It is possible that in epidemiologically favorable conditions

It is expedient to carry out only one revaccination at the age of 14, and in epidemiologically unfavorable conditions, two - at 7 and 14 years. It was shown that the average size of the papule per 2 TU with the "turn" was 12.3±2.6 mm. According to E.B. Meve (1982), in unvaccinated healthy children, the size of the papule per 2 units of PPD-L does not exceed 10 mm.

The intensity of DTH reactions to 2 TU is affected by a number of factors. Many authors confirmed the dependence of the intensity of the Mantoux reaction on the magnitude of the post-vaccination sign of BCG. The larger the post-vaccination scar, the higher the sensitivity to tuberculin. With age, the frequency of positive reactions increases. In children born with a body weight of 4 kg or more, sensitivity to tuberculin is higher; breast-feeding over 11 months also entails high reactions to 2 TU (possibly due to low iron content in milk). worm infestation, food allergy, acute respiratory diseases increase sensitivity to tuberculin. With high sensitivity to tuberculin, blood group II (A) is more often recorded, which correlates with a predisposition to the exudative type of morphological reactions in patients with pulmonary tuberculosis with the same blood group.

In conditions of exogenous superinfection, with hyperthyroidism, allergies, viral hepatitis, influenza, obesity, concomitant infectious diseases, chronic foci of infection, against the background of the introduction of certain protein drugs, taking thyroidin, tuberculin reactions are intensified.

The study of sensitivity to tuberculin in children of early and preschool age showed a decrease in the frequency of negative reactions in children aged 3 and 7 years. These periods coincide with the vaccination of children against childhood infections (DTP, DTP-M, ADS-M, measles, mumps vaccines). An increase in sensitivity to tuberculin is observed when the Mantoux test with 2 TU is performed from 1 day to 10 months after the above vaccinations. Previously, negative reactions become doubtful and positive, and after 1-2 years they again become negative, therefore, tuberculin diagnostics are planned either before preventive vaccinations against childhood infections, or not earlier than 1 month after vaccinations. When staging a Mantoux test before vaccination against childhood infections, they can be carried out on the day of recording the reaction to the Mantoux test, if the size of the response to tuberculin does not require the intervention of specialists.

Evaluation of tuberculin test results can be difficult in areas with a significant prevalence of mild tuberculin sensitivity due to atypical mycobacteria. The mechanism of skin tuberculin reactions is the same during infection various types mycobacteria, but differences in the antigenic structure of the latter cause different degrees of severity of skin reactions when using different antigens. When conducting a differentiated test with preparations from various types of non-tuberculous (atypical) mycobacteria, the most pronounced reactions are caused by "tuberculin" prepared from the type of mycobacteria with which the body is infected. Such "tuberculins" are called sensitins.

It has been established that the domestic BCG substrain, from which the vaccine preparation is prepared, contains specific antigens, which made it possible to obtain more specific tuberculin (PPD-BCG) from it. This drug turned out to be more specific for vaccinated individuals than purified tuberculin PPD-L from virulent MBT strains. For example, in children examined 3.5-6 years after immunization with the BCG vaccine, the proportion of doubtful and positive reactions to PPD-BCG was 35.3% higher than to PPD-L. Thus, 30% fewer children were subject to the first revaccination against tuberculosis. However, the advantage of PPD-BCG tuberculin for the selection of contingents for the second revaccination was insignificant, since with age, children are more likely to encounter virulent mycobacteria and become sensitized by their antigens. Currently, a number of antigens have been identified in virulent Mycobacterium tuberculosis, which are absent in the vaccine strain. Domestic researchers have proposed new drug- recombinant tuberculosis allergen diaskintest, created on the basis of ESAT-6 and SBR-10 proteins, which are present only in virulent Mycobacterium tuberculosis. Diaskintest does not cause HRT responses in vaccinated guinea pigs, and animals infected with virulent strains of human or bovine Mycobacterium tuberculosis react to its intradermal administration in the same way as to PPD-L tuberculin. Diaskintest is currently being clinically studied.

A number of authors believe that the repetition of tuberculin tests in children vaccinated with BCG leads to increased sensitivity to tuberculin, i.e. under the condition of mass BCG vaccination and annual Mantoux testing, almost all children are sensitized by tuberculin. However, this is not true, since tuberculin does not have sensitizing properties, and the so-called booster effect the previous setting of the tuberculin test for the next one manifests itself with a short interval between samples. Therefore, the repetition of the tuberculin test (especially in case of negative reactions), if necessary, is carried out, as a rule, not earlier than after 1-2 months.

A negative reaction to tuberculin is called tuberculin anergy. Possible primary energy- failure to respond to tuberculin in uninfected individuals and secondary energy, developing in infected individuals. Secondary anergy, in turn, can be positive representing a variant of a biological cure for a tuberculosis infection or a state of immunoanergy, as seen, for example, in the case of "latent microbism", and negative which develops in severe forms of tuberculosis. The works of many authors indicate the possibility of the appearance of negative anergy with unfavorable course of the disease which can make diagnosis difficult.

There are reports that in 3.4% of children and adolescents with tuberculosis, against the background of tuberculin anergy, severe forms tuberculosis, and in young children from contact with adults with tuberculosis in 14% of cases, tuberculosis was accompanied by tuberculin anergy.

Secondary anergy also occurs in lymphogranulomatosis, sarcoidosis, many acute infectious diseases (measles, rubella, mononucleosis, whooping cough, scarlet fever, typhoid fever, etc.), vitamin deficiency, cachexia, neoplasms.

Mass tuberculin diagnostics often reveals hyperergic reactions. Most authors have shown that the presence of hyperergic sensitivity to tuberculin is most often associated with the development of local forms of tuberculosis. It is known that in the presence of tuberculin hyperergy, the risk of tuberculosis is several times higher than in the presence of normergic reactions to tuberculin tests. In 75% of children and adolescents with hyperergic reactions to tuberculin tests, small forms of intrathoracic tuberculosis are detected. In 27% of children and under-

sprouts with active forms of tuberculosis also showed hyperergic reactions to 2 TU tuberculin. Hyperergic and high reactions to 2 TU were also noted in children and adolescents from social risk groups for tuberculosis.

Among adults with hyperergic reactions to the Mantoux test with 2 TU, residual tuberculous changes were detected in 86% of cases, while among those examined with normergic reactions, such changes were noted in 14% of cases, and with negative reactions - in 4% of cases.

Thus, MBT-infected children, children and adolescents from contact with adult tuberculosis patients who have hyperergic reactions to 2 TU, adolescents with hyperergic sensitivity to tuberculin, according to the results of mass tuberculin diagnostics, are the group most threatened by tuberculosis, and require the most thorough examination in phthisiatrician.

In some cases, the development of hyperergy to tuberculin in children may be associated with other factors. Thus, revaccination against tuberculosis and subsequent infection with mycobacterium tuberculosis lead to an increase in sensitivity to tuberculin, and the frequency of hyperergic reactions to 2 TU increases.

In addition, hypersensitivity to tuberculin may be associated with the influence on the body of various paraspecific factors that increase the sensitization of an infected organism. The use of penicillin, norsulfazol, streptomycin in children, the presence of occupational hazards, allergies, acute and chronic inflammatory nonspecific diseases can lead to the development of hyperergic sensitivity to tuberculin. .

A particularly careful approach to the examination of children and adolescents with hyperergic reactions to purified tuberculin in a standard dilution is necessary if patients have allergic dermatoses.

In persons with hyperergic reactions to tuberculin (patients with active tuberculosis, nonspecific diseases and practically healthy people) observed quantitative and functional disorders in the T- and B-systems of lymphocytes, pronounced cellular and humoral reactions to tuberculin and significant sensitization to nonspecific bacterial antigens. In this case, hyperergic reactions are due not only to an active specific infection, but also to paraallergic reactions.

In each individual case, it is necessary to study all the factors influencing sensitivity to tuberculin, which has great importance for making a diagnosis, choosing the right medical tactics, the method of managing the patient and his treatment.

In modern conditions, many authors note a pronounced decrease in sensitivity to tuberculin both in practically healthy infected individuals and in patients with tuberculosis. In past years, high sensitivity to tuberculin was considered characteristic of primary tuberculosis; hyperergic reactions were noted in most patients. However, in those years, 5 units of purified tuberculin were used for mass tuberculin diagnostics. Since 1970, with the transition to the Mantoux test with 2 TU of purified tuberculin in a standard dilution, the frequency of hyperergic reactions has decreased and the frequency of weak reactions has increased in mass tuberculin diagnostics.

Many researchers have associated a decrease in sensitivity to tuberculin also with increased resistance of the body, favorable changes in the epidemiological situation, a decrease in the massiveness and virulence of infection, the frequency of superinfection under antibiotic therapy, the pathomorphosis of tuberculosis, which manifested itself, in particular, in favorable outcomes of primary infection, not accompanied by the development of extensive caseous lung injury and lymph nodes, which served in the past as a source of hypersensitization. Currently, however, the epidemiological situation of tuberculosis has deteriorated significantly.

The results of mass tuberculin diagnostics in dynamics make it possible to distinguish the following contingents among children and adolescents:

Children and adolescents not infected with MBT are children and adolescents with annual negative PM with 2 TUs, children and adolescents with PVA;

Children and adolescents infected with MBT.

For early detection of tuberculosis and its timely prevention, it is important to register the moment of primary infection of the body with MBT as a result of systematic staging of intradermal tests with 2 TU. This does not cause difficulties in the transition of negative reactions to 2 TU into positive ones, which is not associated with vaccination or BCG revaccination, the so-called "turn" of tuberculin tests. Such children and adolescents should

be referred to a phthisiatrician for timely examination and preventive treatment. Before the introduction of preventive treatment into medical practice, children with "turn" were the most threatened group in terms of tuberculosis. The main part of tuberculosis in children and adolescents was detected in the period of "turn" - in the early period of primary tuberculosis infection (within a year from the moment of primary infection of the MBT body).

Many authors have studied the possibility of preventing the disease; it has been proven that specific prophylactic treatment for 3 months (chemoprophylaxis) in the early period of primary infection prevents the development of local forms of tuberculosis. As a result of the widespread use of preventive treatment, the number of children and adolescents who fall ill in the early period of primary infection has significantly decreased. To date, the proportion of tuberculosis in children and adolescents, detected in the period of "turn", is from 15 to 43%. There is evidence of the development of tuberculosis in children and adolescents from new risk groups: this is a group of children and adolescents who have been infected with mycobacterium tuberculosis for a long time (2 years or more), and a group of children with increasing sensitivity to tuberculin (by 6 mm or more per year). Increased sensitivity to tuberculin in long-infected is accompanied by the onset of the disease in 70% of cases. It was proposed to treat such children and adolescents also prophylactically for 3 months.

The next group threatened by the disease of tuberculosis are obviously infected children and adolescents with hyperergic reactions to tuberculin. An increase in sensitivity to tuberculin in an infected child to hyperergy indicates a high risk of developing local tuberculosis. These patients are also subject to consultation with a phthisiatrician with an in-depth examination for tuberculosis and a decision on the appointment of preventive treatment.

The development of tuberculosis was also noted in children and adolescents who had been infected with MBT for a long time, who had long-term sensitivity to tuberculin at the same level - monotonous sensitivity to tuberculin. In 36% of children and adolescents, in whom the reactions to tuberculin 2 TE for 3 years or more were at the same level without a tendency to increase or decrease,

tuberculosis was diagnosed. All of these patients had risk factors for developing tuberculosis. These data were the basis for the fact that children and adolescents with monotonous reactions to tuberculin in combination with two or more risk factors for developing tuberculosis should also be consulted by a phthisiatrician with an in-depth examination for tuberculosis.

When evaluating the results of mass tuberculin diagnostics, for the correct interpretation of sensitivity to tuberculin for each patient, an individual approach is required, taking into account all the data of the anamnesis, objective examination, laboratory and instrumental examination. The first positive reaction to tuberculin in a 2-3-year-old child may be a manifestation of a post-vaccination allergy. An objective assessment of the child's condition, an epidemiological history, as well as dynamic monitoring of the child in the "zero" group of dispensary registration with repeated tuberculin diagnostics after 3 months allows avoiding cases of under- and overdiagnosis when deciding on the need for observation in the TB dispensary. Inspection of these children is carried out in institutions of the general medical network.

Increased sensitivity to tuberculin, including hyperergy in children and adolescents with somatic pathology, bacterial infection, allergic, frequent colds, sometimes associated not with MBT infection, but with the influence of the nonspecific factors listed above. If it is difficult to interpret the nature of sensitivity to tuberculin, children are also subject to preliminary observation in the "zero" group of dispensary registration with the obligatory conduct of therapeutic and preventive measures in the pediatric area (hyposensitization, sanitation of foci of infection, deworming, achievement of a period of remission in case of chronic diseases) under the supervision of a pediatric TB specialist. Re-examination in the dispensary is carried out after 1-3 months. Decreased sensitivity to tuberculin after non-specific treatment indicates the non-specific nature of the allergy. Children with frequent clinical manifestations non-specific allergies, the Mantoux test with 2 TU is recommended to be taken while taking desensitizing agents for 7 days (5 days before the test and 2 days after it). Preservation of sensitivity to tuberculin at the same level or its further increase,

despite therapeutic and preventive measures, confirms the infectious nature of the allergy and requires subsequent dispensary observation child.

Thus, at present, mass tuberculin diagnostics is still the only method that makes it possible to screen the entire child population for tuberculosis quite simply and in a short time. But due to objective difficulties (often overlaying of IA on PVA, the influence of various factors on the results of the Mantoux test, a decrease in the intensity of tuberculin reactions both in infected MBT and in patients with tuberculosis recently), the effectiveness of mass tuberculin diagnostics is insufficient. According to various authors, from 36 to 79% of cases of tuberculosis in children and adolescents are detected using tuberculin diagnostics.

Studies have shown that more than half of the cases of tuberculosis of the intrathoracic lymph nodes are detected late, in the phase of incipient compaction. The disease coincided with early period primary MBT infection in 15.1% of cases, accompanied by hyperergic reactions in 27.2% of cases, detected against the background of increasing sensitivity to tuberculin in 18.1% of cases, against the background of monotonous reactions - in 36.2% of cases. Thus, long-term MBT-infected patients (for 3 years or more) prevailed among those with tuberculosis - with increasing and monotonous reactions (54.3%). One third of the patients were children and adolescents, in whom monitoring of skin HRT in dynamics showed that sensitivity to tuberculin remained at the same level without a tendency to increase or decrease. This nature of reactions to 2 TU is explained by the stratification of infectious allergy on the post-vaccination one, as a result of which there are objective difficulties in the timely detection of tuberculosis. This group of children and adolescents differed significantly from patients with a different nature of sensitivity to tuberculin. The disease was less frequently detected using tuberculin diagnostics (33.3 and 63.1%, p<0,01), преобладало выявление туберкулеза при обследовании по контакту с больными туберкулезом взрослыми (40,6 и 15,6%, p<0,001). В подростковом возрасте выявить заболевание у таких пациентов помогала флюорография (72,2%). У давно инфицированных МБТ (при нарастающих и монотонных реакциях) заболевание чаще выявлялось поздно - в фазе начинающегося уплотнения (55,3%), в связи с чем в исходах туберкулеза орга-

new breath in these patients was dominated by the formation of residual changes (62.6%) over complete resorption (37.4%). The average size of the papule in response to the Mantoux test with 2 TU in patients with tuberculosis at the time of detection of the disease was 12.8±0.37 mm.

The study of sensitivity to tuberculin according to the results of annual tuberculin diagnostics in dynamics in children and adolescents of school age infected with MBT showed the presence of fading reactions to 2 TU in 44.2%, monotonous - in 30.1%, "turn" - in 7.0% , increasing - in 18.5% of cases and hyperergic - in 0.2% of cases. In general, in children and adolescents infected with MBT, low sensitivity to tuberculin prevailed with an average papule size of 8.0 ± 0.18 mm.

The second task of mass tuberculin diagnostics is the selection of children and adolescents for BCG revaccination. To do this, a Mantoux test with 2 TEs according to the preventive vaccination calendar is placed in the decreed age groups: 7 years old (0-1 grades of high school) and 14 years old (8-9 grades). Revaccination is carried out by previously uninfected MBT, clinically healthy individuals with a negative reaction to the Mantoux test.

The third task of mass tuberculin diagnostics is to determine the epidemiological indicators of tuberculosis. MBT infection is more often established retrospectively when comparing tuberculin reactions over a number of years, taking into account the timing of vaccination and BCG revaccinations.

6.3. INDIVIDUAL TUBERCULIN DIAGNOSIS

Individual tuberculin diagnostics is used for individual examinations. The goals of individual tuberculin diagnostics are:

Differential diagnosis of post-vaccination and infectious allergies (HRT);

Diagnosis and differential diagnosis of tuberculosis and other diseases;

Determination of the "threshold" of individual sensitivity to tuberculin;

Determination of the activity of the tuberculosis process;

Evaluation of the effectiveness of treatment.

When conducting individual tuberculin diagnostics, various tuberculin tests are used with cutaneous, intradermal, subcutaneous administration of tuberculin. For various tuberculin samples, both purified tuberculin in a standard dilution (tuberculosis allergen purified in a standard dilution) and dry purified tuberculin (tuberculosis allergen purified dry) are used. Purified tuberculin in standard dilution can be used in anti-tuberculosis institutions, children's clinics, somatic and infectious diseases hospitals. Dry purified tuberculin is allowed to be used only in anti-tuberculosis institutions (anti-tuberculosis dispensary, tuberculosis hospital and sanatorium).

Skin tuberculin tests(plaster, ointment) currently have more historical significance, are rarely used, more often for the diagnosis of skin tuberculosis or in cases where, for some reason, it is impossible to use the more common skin and intradermal tuberculin tests.

Pirquet test also rarely used. It is a skin application of dry purified tuberculin, diluted to a content of 100,000 IU per 1 ml. Through a drop of this solution of tuberculin applied to the skin, the skin is scarified. The result is evaluated after 48 hours.

Graduated skin test of Grinchar and Karpilovsky(GKP)

is a skin tuberculin test with 100%, 25%, 5% and 1% tuberculin.

The method of setting the GKP. To obtain a 100% solution of tuberculin, 2 ampoules of dry purified tuberculin PPD-L are successively diluted in 1 ml of a solvent, thus obtaining 100,000 TU PPD-L in 1 ml. From the obtained 100% solution (the sample replaces the cutaneous graduated test with ATK, which contained 90,000-100,000 IU in 1 ml), subsequent solutions of tuberculin are prepared. To obtain a 25% solution from an ampoule with a 100% solution, 1 ml is collected with a sterile syringe and poured into a sterile dry vial. Another sterile syringe add 3 ml of solvent - carbolized solution of 0.9% sodium chloride. Shake the vial thoroughly, get 4 ml of 25% tuberculin solution (vial? 1). To obtain a 5% tuberculin solution from a vial? 1 ml of solution is drawn up with 1 sterile syringe

and transferred to another sterile dry vial, then add

4 ml of solvent, shake up and get 5 ml of 5% tuberculin solution (vial? 2). Likewise in a bottle? 3 mix 1 ml of 5% tuberculin solution and 4 ml of solvent, get 5 ml of 1% tuberculin solution.

On the dry skin of the inner surface of the forearm, previously treated with 70% ethyl alcohol, a drop of tuberculin of various concentrations (100%, 25%, 5%, 1%) is applied with sterile pipettes. The tuberculin concentration should decrease distally from the antecubital crease. Below a drop of 1% tuberculin solution, a drop of 0.25% carbolized sodium chloride solution is applied as a control. Separate labeled pipettes are used for each tuberculin solution and for control. The skin of the forearm is pulled from below with the left hand, then the integrity of the surface layers of the skin is violated with a smallpox feather in the form of a long scratch.

5 mm through each drop in the direction of the longitudinal axis of the arm. Scarification is carried out first through a drop of solvent, then sequentially through 1%, 5%, 25% and 100% tuberculin, rubbing tuberculin 2-3 times with the flat side of the pen after each scarification to penetrate the drug into the skin. The forearm is left open for 5 minutes to dry tuberculin drops. A separate sterile pen is used for each subject. At the site of scarification, a white roller should appear, indicating sufficient time for the absorption of tuberculin. After that, the remnants of tuberculin are removed with sterile cotton wool.

Evaluation of the results of the PCU. GKP is evaluated by N.A. Shmelev after 48 hours. The following reactions to HCP are distinguished:

Anergic reaction - lack of response to all tuberculin solutions;

Nonspecific reaction - slight redness at the site of application of 100% tuberculin (very rare);

Normergic reaction - moderate sensitivity to high concentrations of tuberculin, no response to 1% and 5% tuberculin. There may also be no reaction to 25% tuberculin;

Hyperergic reaction - responses are observed to all concentrations of tuberculin, the size of infiltrates increases with increasing concentration of tuberculin, vesiculo-necrotic changes, lymphangitis, screenings are possible;

Equalizing reaction - approximately the same size of the infiltrate for all concentrations of tuberculin, large concentrations of tuberculin do not cause an adequate response;

Paradoxical reaction - less intensity of reaction to high concentrations of tuberculin, more intense reactions to low concentrations of tuberculin.

Equalizing and paradoxical reactions are also called inadequate reactions to HCP. Some authors classify inadequate reactions to HCP as hyperergic reactions.

HCP has a differential diagnostic value in elucidating the nature of tuberculin allergy. Post-vaccination HRT is characterized by normergic adequate reactions, while in case of infectious allergy, the reaction to HCP may have a hyperergic, egalitarian or paradoxical character. In the early period of primary MBT infection (“turn”), which proceeds with functional changes, paradoxical leveling reactions are observed.

In practically healthy children who have had a favorable primary tuberculosis infection, HKP also happens to be normergically adequate.

GKP is of great importance for the differential diagnosis of tuberculosis and other diseases, for determining the activity of the tuberculosis process. Hyperergic, leveling and paradoxical reactions are more common in patients with active tuberculosis. Severe tuberculosis may be accompanied by anergic reactions.

There are data on the diagnosis of initial mild manifestations of tuberculosis infection in children.

According to our data, hyperergic and inadequate reactions to HCP were observed in 33.9% of children and adolescents with active tuberculosis.

Normalization of sensitivity to tuberculin according to HKP data (transition from hyperergic to normergic, from inadequate to adequate, from anergic to positive normergic) in patients with tuberculosis against the background of antibacterial treatment indicates a normalization of the body's reactivity and is one of the indicators of the effectiveness of therapy.

Intradermal tuberculin tests.Mantoux test with 2 TU of purified tuberculin in standard dilution can also be used for individual tuberculin diagnostics.

It can be carried out in a children's clinic, somatic and infectious diseases hospitals for the differential diagnosis of tuberculosis and other diseases, in the presence of chronic diseases of various organs and systems with a torpid, undulating course, with the ineffectiveness of traditional methods of treatment and the presence of additional risk factors for MBT infection and tuberculosis ( contact with a patient with tuberculosis, lack of vaccination against tuberculosis, social risk factors, etc.).

In addition, there are groups of children and adolescents, subject to Mantoux test with 2 TU 2 times a year in a general medical network(Order of the Ministry of Health of the Russian Federation? 109 of March 21, 2003):

Patients with diabetes mellitus, peptic ulcer of the stomach and duodenum, blood diseases, systemic diseases, HIV-infected, receiving long-term hormonal therapy (more than 1 month);

With chronic nonspecific diseases (pneumonia, bronchitis, tonsillitis), subfebrile condition of unclear etiology;

Not vaccinated against tuberculosis, regardless of the age of the child;

Children and adolescents from social risk groups who are in institutions (shelters, centers, reception centers) who do not have medical documentation are examined using PM with 2 TU upon admission to the institution, then 2 times a year for 2 years.

When conducting individual tuberculin diagnostics, the definition is used threshold of sensitivity to tuberculin - the lowest concentration of tuberculin, to which the body responds with a positive reaction. To determine the threshold of sensitivity to tuberculin use intradermal Mantoux test with various dilutions of dry purified tuberculin.

In children with suspected specific eye damage, in order to avoid a focal reaction, it is advisable to start tuberculin diagnostics by performing skin or intradermal tests with 0.01 and 0.1 TU.

Intradermal test with various dilutions of tuberculin.

The initial solution of tuberculin is prepared by mixing an ampoule of dry purified tuberculin PPD-L (50,000 TU) with an ampoule of a solvent,

get the main dilution of tuberculin - 50,000 TU in 1 ml. The drug should dissolve within 1 min, be transparent and colorless.

The first dilution of tuberculin is prepared by adding 4 ml of a solvent, a carbolic sodium chloride solution, to the ampoule with the main dilution. Get 1000 IU in 0.1 ml of solution. The second dilution of tuberculin is prepared by adding 9 ml of solvent to 1 ml of the first dilution, 100 IU in 0.1 ml of solution are obtained.

All subsequent dilutions of tuberculin (up to the 8th) are prepared in the same way, adding 9 ml of the solvent to 1 ml of the previous dilution. Thus, dilutions of tuberculin correspond to the following doses of tuberculin in 0.1 ml of solution: first dilution - 1000 IU, 2nd - 100 IU, 3rd - 10 IU, 4th - 1 IU, 5th - 0.1 TE, 6th - 0.01 TE, 7th - 0.001 TE, 8th - 0.0001 TE.

Mantoux tests with different dilutions of tuberculin are carried out in the same way as a test with 2 TU. A separate syringe and needle is used for each subject and for each dilution. On one forearm, a Mantoux test is placed with two dilutions of tuberculin at a distance of 6-7 cm from each other. At the same time, you can put a third on the other forearm with another dilution of tuberculin.

Evaluation of the results of samples with different dilutions of tuberculin. Evaluate the sample after 72 hours. The reaction is considered negative in the absence of papule and hyperemia, the presence of only a prick reaction (0-1 mm). Doubtful reaction - papule less than 5 mm or hyperemia of any size. Positive reaction - papule 5 mm or more.

Titration (determination of the threshold of sensitivity to tuberculin) is completed when a positive reaction to the smallest dilution of tuberculin is reached.

Positive reactions to high dilutions of tuberculin with doses of 0.1 TU; 0.01 TU, etc. indicate a high degree of sensitization of the body and usually accompany active tuberculosis.

Thus, a positive reaction to the 5th or more dilution of tuberculin is important in the differential diagnosis of tuberculosis with other diseases, as well as in determining the activity of the tuberculosis process. In this case, the totality of the results of all tuberculin tests (Mantoux tests with 2 TU, GKP, Mantoux tests with various dilutions of tuberculin) should be taken into account.

For example, the combination of a positive reaction to 2 TU with a normergic GPC and a 6th threshold dilution excludes the post-vaccination nature of the allergy and indicates the activity of a tuberculosis infection. The combination of a positive reaction to 2 TU with hyperergic HKP and with the 4th threshold dilution of tuberculin also indicates an infectious allergy.

The presence of etiologically unclear functional disorders in a child, clinical and radiological changes characteristic of tuberculosis, in combination with a negative response to the Mantoux test with 2 TU and with the 5th threshold dilution of tuberculin, also indicates the tuberculous nature of the disease and indicates the activity of the process.

In some cases, it becomes necessary to bring the titration to high doses of tuberculin - 10 and 100 IU (3rd and 2nd dilutions, respectively). A negative reaction to 100 TU in the vast majority of patients with a probability of 97-98% makes it possible to reject the diagnosis of tuberculosis or exclude the infectious nature of the allergy.

A number of authors described only a few cases when tuberculosis, confirmed histologically or bacteriologically, proceeded against the background of negative reactions to 100 TU. In some of these patients, this could not be explained by the severity of the condition; anergy persisted even after clinical cure.

According to our data (2003), in children and adolescents with active tuberculosis, in 76.3% of cases, threshold reactions to 5-7 dilutions of tuberculin were detected.

In the vast majority of sick and infected individuals, skin and intradermal tuberculin tests reveal only a local reaction to tuberculin. In isolated cases, general reactions are noted on the Mantoux test with 2 TU. Such patients are subject to a thorough clinical and radiological examination. Focal reactions are even less common.

Subcutaneous tuberculin Koch test is the subcutaneous injection of tuberculin.

Koch's test procedure. Regarding the dose for the Koch test, there is no consensus. In pediatric practice, Koch's test often starts with 20 TU. To do this, 1 ml of purified tuberculin in a standard dilution or 0.2 ml of the third dilution of dry purified tuberculin is injected subcutaneously without taking into account a preliminary study of the tuberculin sensitivity threshold.

A number of authors recommend the first dose of 20 TU for the Koch test with the normergic nature of the Mantoux test with 2 TU and a negative or weakly positive reaction to 100% tuberculin GKP. With a negative reaction to the Koch test with 20 IU, the dose is increased to 50 IU, and then to 100 IU. In children with hyperergic reactions to the Mantoux test with 2 TU, the Koch test begins with the introduction of 10 TU.

It is recommended to preliminarily determine the threshold of sensitivity to tuberculin using Mantoux tests with various dilutions of tuberculin; depending on the sensitivity threshold, use suprathreshold, threshold and subthreshold doses of tuberculin for the Koch test. For differential diagnostic purposes, suprathreshold doses should be used, for example, at the 4th threshold dilution of tuberculin, 20-50 TUs are injected subcutaneously (0.2-0.5 ml of the 3rd dilution of tuberculin). To determine the activity of small forms of tuberculosis, threshold doses are used, i.e. subcutaneously injected dose of tuberculin 2-4 times higher than that established when determining the intradermal titer. To judge the dynamics of functional changes during treatment, subthreshold doses of tuberculin are used - 0.2-0.4 ml of tuberculin is injected subcutaneously at a dilution 10 times less than the threshold.

Evaluation of the results of the Koch test. In response to the Koch test, reactions develop - local, general and focal. A local reaction develops at the injection site of tuberculin. The reaction is regarded as positive when the size of the infiltrate is 15-20 mm. Without a general and focal reaction, it is uninformative.

Focal reaction is a change after the introduction of tuberculin in the focus of tuberculous lesions. Along with clinical and radiological signs, it is advisable to examine sputum, bronchial washings before and after the introduction of tuberculin. A positive focal reaction (an increase in clinical symptoms, an increase in perifocal inflammation on x-ray examination, the appearance of bacterial excretion) is important both in the differential diagnosis of tuberculosis with other diseases, and in determining the activity of the tuberculosis process.

The general reaction is manifested in the general deterioration of the body. The temperature reaction is considered positive if the body temperature rises by 0.5 ° C compared with the maximum before the subcutaneous injection of tuberculin (thermometry is advisable

figuratively carried out after 3 hours 6 times a day for 7 days: 2 days before the test and 5 days against the background of the test), in the vast majority of patients, an increase in temperature is observed on the 2nd day, although a later increase is possible - on days 4-5 .

When conducting a Koch test, it is advisable to determine various other tests: hemogram indicators, proteinograms, serum immunoglobulins, etc.

30 minutes or 1 hour after the subcutaneous injection of tuberculin, the absolute number of eosinophils decreases (F.A. Mikhailov's test), after 24-48 hours the ESR increases by 5 mm/h, the number of stab neutrophils by 6% or more, the content of lymphocytes decreases by 10 % and platelets - by 20% or more (N.N. Bobrov's test).

24-48 hours after subcutaneous administration of tuberculin, the albumin-globulin coefficient decreases due to a decrease in the content of albumins and an increase in α1-, α2- and 7-globulins (protein-tuberculin test by A.E. Rabukhin and R.A. Ioffe). This test is considered positive when the change in indicators is not less than 10% from the initial level.

The information content of individual indicators of the content of sialic acids, C-reactive protein, lipoproteins, hyaluronidase, haptoglobin lactate dehydrogenase against the background of subcutaneous administration of tuberculin is small, but in combination they increase the diagnostic capabilities of determining the activity of the tuberculosis process and differentiating it from nonspecific diseases.

According to published data, among tuberculin-provoking tests that allow detecting the latent activity of tuberculosis, such cellular and humoral reactions as RTBL, RTML, indicators of neutrophil damage, and rosette formation are highly informative.

The study of sensitivity to tuberculin in children and adolescents with active forms of tuberculosis, as well as in children and adolescents infected with MBT, according to the data of mass and individual tuberculin diagnostics in combination with clinical and radiological data, made it possible to propose an algorithm for monitoring children and adolescents, depending on the nature sensitivity to tuberculin, the presence of risk factors for tuberculosis (Scheme 2).

Scheme 2. Algorithm of the stages of observation of children and adolescents with different sensitivity to tuberculin

Note:

*** Indications for consultation with a phthisiatrician.

In addition to tuberculins used in vivo, There are also drugs used in vitro, for the manufacture of which tuberculins or various antigens of mycobacteria are used.

To detect antibodies to MBT, a diagnosticum erythrocyte tuberculosis antigenic dry- Sheep erythrocytes sensitized with MBT phosphatide antigen. The drug is a porous mass or powder of reddish-brown color. Diagnosticum is intended for carrying out an indirect hemagglutination test (RIHA) in order to detect specific antibodies to MBT antigens. This immunological test is used to determine the activity of the tuberculosis process and to monitor the effectiveness of treatment. To determine antibodies to MBT in the blood serum of patients, an enzyme immunoassay test system is also intended - a set of ingredients for enzyme immunoassay (ELISA) on a solid-phase carrier on which tuberculin or antigens from mycobacteria are fixed. ELISA is used for laboratory confirmation of the diagnosis of tuberculosis of various localization, evaluation of the effectiveness of treatment, and decision on the appointment of specific immunocorrection. The sensitivity of enzyme immunoassay for tuberculosis is low, it is 50-70%, specificity is less than 90%, which limits its use and does not allow the use of a test system for screening tuberculosis infection.

This is the most important method for studying the infection with Mycobacterium tuberculosis, as well as the reactivity of infected or vaccinated people, based on the use of tuberculin tests. The role and importance of this method has not diminished since R. Koch received tuberculin in 1890.

Tuberculin. Koch's old tuberculin (ATK - Alt-tuberculinum Koch) is a water-glycerin extract of tuberculous cultures obtained from a 6-8-week culture of mycobacterium tuberculosis grown in meat-peptone 4% glycerin broth, sterilized for 1 hour with steam, released by filtration from bacterial bodies and condensed at a temperature of 90 ° C to 1/10 of the original volume.

ATK, along with specific active substances, waste products, mycobacteria toxins, also contains a lot of ballast substances (peptones, glycerin, salts, etc.) of the nutrient medium on which Mycobacterium tuberculosis was cultivated.

The presence of protein products of the medium in the preparation is associated with the possibility of non-specific reactions (in particular, severe hyperemia) during tuberculin skin tests, which can be a certain hindrance in diagnosis, especially in people with a non-specific allergic mood of the body.

Due to these shortcomings, the drug has found limited use in recent years. ATK is available (as of 1987) in 1 ml ampoules, representing a dark brown liquid. 1 ml of ATK contains 100,000 tuberculin units (TU).

The task of creating more specific preparations freed from ballast proteins and devoid of sensitizing properties was first solved by F. Seibert and S. Gleen (1934), who obtained dry purified tuberculin - PPD (Purified protein derivate-purified protein derivative).

In the USSR, PPD-L - domestic dry purified tuberculin - was manufactured in 1939 under the direction of M.A. Linnikova at the Leningrad Research Institute of Vaccines and Serums, and since 1954 its mass production has been established.

This preparation is a purified by ultrafiltration or ultracentrifugation, precipitated with trichloroacetic acid, washed with alcohol and ether and dried in vacuum from a frozen state, a filtrate of a heat-killed culture of mycobacterium tuberculosis of human and bovine types.

Tuberculin in its biochemical composition is a complex compound, including proteins (tuberculoproteins A, B, C), polysaccharides (polysaccharide I, II), lipid fractions and nucleic acid. Biologically, proteins are the most active part, lipids act as a protective substance for proteins.

From an immunological point of view, tuberculin is a hapten, it is not able to sensitize the body, cause the production of specific antibodies in it, but it causes an allergic response in a previously sensitized (with spontaneous infection with Mycobacterium tuberculosis or immunization with BCG vaccine) organism. The absence of sensitizing properties in tuberculins is one of the main requirements for preparations, a valuable quality that allows them to be widely used in diagnostics.

To a lesser extent, tuberculin can be spoken of as a toxin. This property is manifested only when using large doses of tuberculin. One of the features that bring together tuberculin with allergens and distinguish it from toxins is the fact that the effect of its action is determined not so much by the dose of the drug as by the degree of sensitization of the body.

PPD-L is produced in three forms.

Dry purified tuberculin - in ampoules of 50,000 TU. A 0.25% carbolized isotonic NaCl solution is used as a solvent. The drug is used for diagnostic purposes, mainly in individual tuberculin diagnostics, used for tuberculin therapy.

Purified tuberculin - in a standard dilution with an activity of 2 TU in 0.1 ml with 0.005% tween-80. Tween-80 is a surfactant (detergent) that prevents the adsorption of tuberculin on glass and ensures the stabilization of the biological activity of the drug. Sterility is achieved by the presence of 0.01% quinosol in the solution. Ready-to-use tuberculin solution in 3 ml ampoules or 5 ml vials is intended for Mantoux test with 2 TU ( order of the Ministry of Health of the Russian Federation of March 21, 2003 N 109 "On the improvement of anti-tuberculosis measures in the Russian Federation"), is used in individual and mass tuberculin diagnostics.

Ready-to-use solutions of purified tuberculin with an activity of 5 and 100 TU in 0.1 ml with the addition of 0.005% tween-80 and 0.01% chinosol. The preparations are intended for clinical diagnostics. The national standard for domestic tuberculin PPD-L was approved in 1963 and 1 TU is contained in 0.00006 mg of dry preparation.

Reactions to the introduction of tuberculin.

In response to the introduction of tuberculin in the body of patients with tuberculosis, prick, general and focal reactions can develop.

Prick reaction characterized by the appearance at the injection site of tuberculin papule (infiltrate) and hyperemia. With hyperergic reactions, the formation of vesicles, bulls, lymphangitis, necrosis is possible. Histologically, in this place, at the first stages, expansion of capillaries, sweating of tissue fluid, and accumulation of neutrophils are noted. Subsequently, mononuclear infiltration appears with involvement of histiocytes in inflammation. In the long term, epithelioid and giant cells are found.

General reaction of an infected organism on the effect of tuberculin is manifested by a deterioration in the general condition, headaches, arthralgia, fever; may be accompanied by a change in hemogram, proteinogram, etc.

Focal reaction characterized by increased perifocal inflammation around the tuberculous focus. With pulmonary processes, a focal reaction may manifest itself as an increase in chest pain, cough; an increase in the amount of sputum discharge, hemoptysis; strengthening of the catarrhal phenomena listened to in the lungs; radiographically - an increase in inflammatory changes in the area of ​​a specific lesion.

Tuberculin tests - These are skin tests with tuberculin to detect sensitization of the body to Mycobacterium tuberculosis.

They are manifested by delayed-type allergic reactions resulting from the interaction of tuberculin with antibodies fixed on lymphocytes and mononuclear cells. At the same time, part of the cells - carriers of antibodies - dies, releasing proteolytic enzymes that cause a damaging effect on tissues. Other cells accumulate around the foci of a specific lesion. An inflammatory reaction occurs not only at the site of tuberculin application, but also around the tuberculous foci. During the destruction of sensitized cells, active substances with pyrogenic properties are released.

The intensity of the tuberculin reaction is determined by the degree of specific sensitization of the body, its reactivity and many other factors that increase or, conversely, weaken specific allergies.

In practically healthy children infected with mycobacterium tuberculosis, tuberculin allergy is usually less pronounced than in patients with active forms of the process. Children with active TB are generally more sensitive to tuberculin than adults. In severe forms of tuberculosis (meningitis, miliary, advanced fibro-cavernous tuberculosis), accompanied by a pronounced inhibition of the body's reactivity, there is often a low sensitivity to tuberculin. Some forms of extrapulmonary tuberculosis (tuberculosis of the eyes, skin) are often accompanied by high sensitivity to tuberculin.

According to the intensity of tuberculin allergy in tuberculosis, it is customary to distinguish hypoergic (weak), normergic (moderate), hyperergic (strong) reactions.

In addition, a variant of infratuberculin allergy is distinguished, which can be detected only when a complete antigen (live or killed microbial bodies) is introduced into the body, for example, when performing a BCG test.

There is also anergy (lack of reaction to tuberculin), which is divided into primary, or absolute, - negative tuberculin tests in persons not infected with mycobacterium tuberculosis, and secondary - conditions accompanied by loss of sensitivity to tuberculin in patients with tuberculosis or in persons who have previously had tuberculosis. infection.

A distinction is made between passive, or negative secondary, anergy, which occurs in severe forms of tuberculosis, and active, or positive, anergy, which is a biological cure for tuberculosis infection or a state of immunoanergy, which occurs, for example, in cases of "latent microbism".

Secondary anergy occurs in lymphogranulomatosis, sarcoidosis, many acute infections (measles, rubella, mononucleosis, whooping cough, scarlet fever, typhoid fever, etc.), vitamin deficiency, cachexia, neoplasms.

Tuberculin test intensity may decrease in febrile conditions, pregnancy, during menstruation; in the treatment of glucocorticoids, antihistamines.

On the contrary, under conditions of exogenous superinfection, with hyperthyroidism, allergic concomitant diseases, chronic foci of infection, against the background of the introduction of certain protein preparations, taking thyroidin, tuberculin reactions are enhanced.

In children, in some cases, the development of hypersensitivity to tuberculin is associated precisely with the influence on the body of various paraspecific factors that enhance the sensitization of the infected organism.

In the autumn-winter period, a weakening of sensitivity to tuberculin is usually noted, and in the spring-summer time - an increase. The latter circumstance is taken into account by the instruction on tuberculin diagnostics, which recommends tuberculin tests for early detection of tuberculosis in children and adolescents at the same time of the year, mainly in autumn.

Thus, various factors, both endogenous and exogenous, can influence the nature and intensity of tuberculin allergy and should be taken into account in diagnostic practice.

Tuberculin tests, being one of the manifestations of delayed-type hypersensitivity and in this respect being an indispensable diagnostic test, do not allow in all cases to judge the intensity of anti-tuberculosis immunity, the severity and prevalence of the disease, the nature of the specific sensitization of the body.

It is impossible in all cases to draw a parallelism between the sensitivity of the skin and the allergic state of the internal organs.

However, the identification of one or another type of tuberculin reactions has a certain diagnostic and prognostic value. The decrease in the frequency of hyperergic reactions to tuberculin during mass examinations of the population allows us to judge, to a certain extent, the improvement of the epidemiological situation in tuberculosis.

Under conditions of mass intradermal vaccination and BCG revaccination, the identification of children and adolescents with hyperergic tuberculin reactions is of great importance, since the latter are extremely rarely associated with post-vaccination allergies and, as a rule, reflect a true infectious allergy.

Many authors indicate that persons with high sensitivity to tuberculin fall ill with tuberculosis several times more often than persons with moderate and weak reactions to tuberculin; among the former, residual changes after suffering tuberculosis are also more often detected, in the anamnesis there is often an indication of contact with patients with tuberculosis.

L. V. Lebedeva et al. (1979), who studied tuberculin sensitivity in children depending on the nature of the reaction to intradermal tuberculin administration in healthy adults within the family, found that the rate of infection and disease in children with tuberculosis in families in which adults had positive tuberculin tests (especially hyperergic ), many times more than in families in which adults had negative reactions. These facts prove the focality of tuberculosis infection. At the same time, chronic foci of infection and allergic diseases often play a decisive role in the development of hyperergy in children.

Identification of the causes leading to increased sensitivity to tuberculin is important for determining the doctor's further tactics and choosing the method of therapy.

In modern conditions, there is a pronounced decrease in sensitivity to tuberculin both in infected practically healthy individuals and in patients with tuberculosis. Many researchers attribute the decrease in sensitivity to tuberculin to the increased resistance of the body, with favorable changes in the epidemiological situation, a decrease in the massiveness and virulence of infection, the frequency of superinfection under conditions of antibiotic therapy; pathomorphism of tuberculosis, which manifested itself, in particular, in favorable outcomes of primary infection, not accompanied by the development of extensive caseous lesions of the lungs and lymph nodes, which served as a source of hypersensitization in the past.

Methods for introducing and evaluating tuberculin samples.

Skin, skin, intradermal and subcutaneous injections are used. In mass tuberculin diagnostics, the Mantoux test with 2 TEs of PPD-L is used for the timely detection of infection and tuberculosis, persons with an increased risk of the disease (for the first time infected and with hyperergic reactions to tuberculin), for the selection of contingents for BCG revaccination, to study the level of infection of the population with tuberculosis.

For the purpose of early detection of tuberculosis, the Mantoux test with 2 TEs is given to children and adolescents annually, starting from the age of 12 months (under the age of one year - according to indications), regardless of the previous result. With the systematic formulation of this test, it is possible to identify the transition of a previously negative reaction to a positive one, an increase in sensitivity to tuberculin, and the development of hyperergy.

The method of setting and evaluating the Mantoux test.

The instruction provides for the staging of the sample with an individual special tuberculin syringe, into which two doses of tuberculin - 0.2 ml are collected, on the inner surface of the middle third of the forearm. The skin is pretreated with 70% alcohol. Strictly intradermally injected 0.1 ml of tuberculin solution.

indicator correct technique the introduction of the drug is the formation of a "lemon crust" in the skin - white papules with a diameter of 6-7 mm.

The sample is evaluated after 72 hours by measuring the size of the infiltrate in millimeters perpendicular to the axis of the forearm. Hyperemia is taken into account only in cases where there is no infiltration.

The reaction is considered negative in the absence of infiltrate and hyperemia, doubtful with an infiltrate of 4-5 mm in size, or only with hyperemia without infiltration, positive in the presence of an infiltrate of 5 mm or more.

Hyperergic reactions are considered in children and adolescents in the presence of an infiltrate of 17 mm or more, in adults - 21 mm or more, and also, regardless of the size of the infiltrate, with the appearance of vesicles, bulls, lymphangitis, regional lymphadenitis, herpetic reaction.

In recent years, needle-free injectors (BI-1M, BI-3) have been widely used in mass tuberculin diagnostics, the use of which has revealed a number of advantages compared to the needle-syringe method: a significant increase in labor productivity, cost-effectiveness, accuracy of tuberculin dosage with its strictly intradermal administration, ensuring sterility procedures.

It should be borne in mind that, according to the approved instructions of the Ministry of Health of the RSFSR and methodological recommendations for the use of the needleless injector BI-1M for the mass setting of tuberculin samples (1982), the reaction is considered positive if there is an infiltrate of 3 mm or more, hyperergic - with a papule size of 15 mm or more, or the presence of vesicle-necrotic changes, regardless of the size of the infiltrate; doubtful - with a papule of 2 mm or hyperemia without a papule; negative - in the presence of only a prick reaction - up to 1 mm. On average, the size of the reaction to the Mantoux test with 2 TU using a needle-free injector is 2 mm smaller than to the test delivered by the needle-syringe method. The documents must clearly indicate by what method the tuberculin test was delivered to the child. For dynamic monitoring of sensitivity to tuberculin, the same method of tuberculin diagnostics should be used.

Literature data [Maslauskene T.P., 1978; Charykova G. P., Kaplan F. V., 1978; Preslova I. A., Slotskaya L. V., 1979] indicate that it is most rational to carry out mass tuberculin diagnostics in children's groups (especially for the needleless method) by the brigade method. This ensures high productivity and quality of the ongoing work on tuberculin diagnostics and BCG revaccination.

Individual tuberculin diagnostics used for differential diagnosis of post-vaccination and infectious allergies, tuberculosis with non-specific diseases, determining the activity of specific changes, studying the dynamics of tuberculin tests in children under dispensary observation.

For individual diagnostics, along with intradermal tuberculin tests with various diagnostic dilutions, skin, skin and subcutaneous tests can be used. The skin graduated scarification test of N. N. Grinchar and D. A. Karpilovsky, which is a modification of the Pirquet test, has been widely used. For this test, 100, 25, 5 and 1% tuberculin concentrations are used.

Method for setting and evaluating a skin graduated scarification test

The initial 100% solution is prepared by successively diluting 2 ampoules of dry tuberculin in 1 ml of a solvent (sterile 0.25% carbolized isotonic NaCl solution). Tuberculin solutions of 25, 5 and 1% concentrations are prepared as follows: 1 ml of a 100% tuberculin solution is poured into a glass bottle (preferably dark glass) with a sterile syringe and 3 ml of solvent is added with another sterile syringe. After thorough shaking, 4 ml of a 25% solution are obtained (bottle No. 1). With a sterile syringe, transfer 1 ml of the solution from vial No. 1 into a sterile vial No. 2 and add 4 ml of the solvent, shake it up and get 5 ml of a 5% tuberculin solution. In the same way, 1 ml of a 5% tuberculin solution is mixed with 4 ml of a solvent in vial No. 3 to obtain 5 ml of a 1% solution.

On dry skin pre-treated with ether (you can use 2% chloramine solution or 70% alcohol) of the inner surface of the forearm below the elbow crease at a distance of 2-3 cm from each other, tuberculin is applied in a decreasing distally concentration drop by drop of tuberculin. Below a drop with a 1% tuberculin solution, a drop of 0.25% carbolized isotonic NaCl solution is applied as a control.

Separate labeled pipettes are used for each solution of tuberculin and solvent. The skin of the forearm is pulled from below with the left hand, then the integrity of the surface layers of the skin is violated with a smallpox lancet in the form of scratches 5 mm long, first through a drop of solvent, then through drops of 1, 5, 25 and 100% tuberculin solutions along the axis of the upper limb.

Tuberculin is rubbed with the flat side of the lancet. For penetration of tuberculin into the skin, the scarified area is left open for 5 minutes. At the site of scarification, a white roller should appear, indicating the absorption of tuberculin. After that, the remnants of tuberculin can be removed with sterile cotton. Before each use, the lancet is sterilized by calcining in the flame of an alcohol burner or by prolonged boiling.

Graduated scarification test can also be done with ATK. In this case, the original 100% solution is available in ready-made form in ampoules, and the remaining dilutions are obtained according to the above method.

The results of the skin graduated scarification test are taken into account after 48 and 72 hours. In clinical conditions, it is checked after 24, 48 and 72 hours; this allows you to evaluate the intensity and nature of the sample in dynamics. After 24 hours, the nonspecific component of inflammation usually subsides, and an increase in the reaction after 48 hours, which occurs in isolated cases, may, however, be of great diagnostic value in pediatric practice. This, for example, never occurs with post-vaccination allergies.

At the site of application of each concentration of tuberculin, the largest size of the infiltrate is measured with a transparent millimeter ruler transversely to the scratch. Hyperemia is taken into account only in cases where there is no papule. The reaction is considered negative if there is no infiltrate and hyperemia, but there must be a scab at the site of the scarification. Cases where there is no trace of scarification at the site of tuberculin application are considered as a technical error.

Evaluation of a graduated scratch test carried out according to N. A. Shmelev. There are the following variants of graduated scarification test:

• non-specific reaction - slight redness at the site of application of a 100% tuberculin solution (more common when using ATK);
• average specific reaction (normergic) - moderate sensitivity to high concentrations of tuberculin, no reactions to 1, sometimes 5 and even 25% tuberculin concentration;
• hyperergic reaction - an increase in the size of the infiltrate as the concentration of tuberculin increases, ranging from 1 to 100%, while there may be vesiculo-necrotic changes, lymphangitis, etc .; such tests are often found in active forms of primary tuberculosis;
• equalizing reaction - approximately the same intensity of reaction to different (for example, 100 and 25%) concentrations of tuberculin, large concentrations of tuberculin do not cause an adequate response;
• paradoxical reaction - a lower intensity of the reaction to a large concentration of tuberculin than to a weak one; a weakened immune system does not respond to a high concentration of antigen; a sharper reaction comes to light at a low concentration. The paradoxical phase is more often distinguished when comparing the size of the infiltrate to 100 and 25% tuberculin concentration, rarely large reactions develop to 5 and 1% tuberculin solution;

  paradoxical and equalizing reactions of a graduated scarification test can occur both at high and at low levels of tuberculin allergy;

• anergic reaction - the absence of a response to all dilutions of tuberculin with complete parabiotic inhibition, which usually accompanies the severe course of tuberculosis.

Identification of one or another type of skin graduated scarification test has a differential diagnostic and prognostic value. Its role in the diagnosis of primary tuberculosis is especially great. All authors who studied the issues of differential diagnosis of post-vaccination and infectious allergies noted that the former is characterized by adequate, normergic reactions.

In the early period of primary tuberculosis infection, which occurs with functional disorders, there are perverted, inverted reactions. In practically healthy children who have successfully survived a primary tuberculosis infection, a graduated test is also adequate, while in patients with tuberculosis it can have an equalizing and paradoxical character.

Functional disorders that are not clear in terms of etiology can be more likely to be associated with tuberculosis with inverted reactions to a graduated scratch test.

Normalization of sensitivity to tuberculin (transition from hyperergic to normergic, from inverted to adequate, from anergic to positive normergic) in patients with tuberculosis against the background of antibacterial treatment indicates the normalization of the body's reactivity and is one of the indicators of the effectiveness of therapy.

Pirquet test with 100% ATK or PPD-L, which was used in previous years in pediatric practice for the early detection of tuberculosis, in modern conditions is of limited use. The study of intradermal titer and the determination of the threshold of sensitivity to tuberculin are more widely used.

Mantoux test .

Method for preparing dilutions of tuberculin:

When working with ATK, dilution 1 is obtained by mixing (diluting) 1 ml of the original preparation with 9 ml of 0.25% carbolized isotonic NaCl solution. Thus, diluting 10 times with 1 ml of tuberculin dilution 1, dilution 2 (1:100) is obtained. In this case, 0.1 ml tuberculin dilution 2 contains 100 IU.

To obtain the appropriate concentration of PPD-L, an ampoule of dry tuberculin (50,000 IU) is diluted in 1 ml of the supplied solvent. Then the contents of this ampoule to obtain a dilution of 1 tuberculin, corresponding to a dose of 1000 IU in 0.1 ml, are mixed with 4 ml of solvent and a dilution of 1:5 is obtained. All subsequent dilutions are prepared, as well as ATK dilutions, in a ratio of 1:10, i.e., to obtain the 2nd dilution, 1 ml of tuberculin dilution 1 is mixed with 9 ml of the solvent (Table 1).

In modern conditions, to identify the threshold of sensitivity to tuberculin, it is enough to use dilutions of 4, 5 or 6 tuberculin (doses of 0.01 ... 0.1 ... 1 TU). At the same time, three samples can be placed simultaneously, preferably on different forearms, on one - samples with tuberculin of the 6th and 5th dilution, on the other - with the 4th dilution. If the samples are placed on one forearm, then the distance between them should be 6...7 cm. The detection of a positive reaction to large dilutions of tuberculin (0.01...0.1 TU) indicates a high degree of sensitization of the body, which may accompany active tuberculosis.

In some cases, you can resort to the accelerated titration method - setting a Mantoux test with 2 TU on one forearm, and on the other with 0.01 TU.

The evaluation of the results of intradermal titration is carried out, in essence, according to the method of graduated samples and has a certain differential diagnostic value. The combination, for example, of positive Mantoux tests with 2 TU and with 0.01 TU excludes the post-vaccination nature of the allergy and may be an indirect sign of the activity of a tuberculosis infection. The presence of clinical and radiological signs characteristic of tuberculosis, functional disorders that are not specified in etiological terms, a combination of a negative Mantoux test with 2 TU with a positive test for 0.01 TU may testify in favor of the specific nature of the disease and indicate the activity of the process.

In some cases, if children have clinical and radiological signs that do not allow to exclude the tuberculosis nature of the disease, despite the negative Mantoux test with 2 TU, it becomes necessary to deepen the study of sensitivity to tuberculin by staging intradermal tests with 5, 10 and 100 TU.

A negative reaction to the Mantoux test with 100 TU in the vast majority of patients, with a probability of 97-98%, makes it possible to reject the diagnosis of tuberculosis.

In some cases, situations are possible when tuberculosis, confirmed by clinical and radiological methods, histologically or by the isolation of mycobacteria, occurs against the background of a negative Mantoux test with 100 TU. In some patients, this could not be explained by the severity of the condition; anergy persisted even after treatment.

Skin tests (plaster, ointment) are used relatively rarely, more often for the diagnosis of skin tuberculosis or in cases where, for some reason, it is impossible to use more common intradermal and skin tests.

In the vast majority of patients and infected when setting up skin tests and Mantoux test with 2 TU, only a prick reaction is detected at the site of tuberculin injection. Only in isolated cases on the Mantoux test with 2 TU are general and temperature reactions observed (these persons are subject to a thorough clinical and radiological examination) and even less often - focal.

In most cases, to speed up the examination of patients in a hospital, they practice the simultaneous application of a graduated skin prick test and a Mantoux test with 2 TU on different forearms. In children with suspected specific eye damage, in order to avoid a focal reaction, it is advisable to start tuberculin diagnosis with skin tests or intradermal tests with 0.01 and 0.1 TU.

Subcutaneous tuberculin Koch test is set with a differential diagnostic goal, to determine the activity of the tuberculosis process, to monitor the effectiveness of treatment.

There is no consensus in the literature regarding the choice of dose of tuberculin for subcutaneous administration. The most commonly used dose is 20 IU (1 ml of purified tuberculin in a standard dilution or 0.2 ml of a dilution of 3 ATK) without taking into account a preliminary study of the tuberculin sensitivity threshold.

In children, a number of authors inject 20 TU under the skin if the Mantoux test with 2 TU is not hyperergic in nature, and the graduated scarification test is negative or slightly positive for 100% tuberculin concentration. If the result is negative for the Koch test with 20 IU, the dose is increased to 50 IU, and then to 100 IU.

With a negative Mantoux test with 2 TU, a dose of 50 ... 100 TU is used for subcutaneous administration. In children with hyperergic reactions to the Mantoux test with 2 TU, the Koch test begins with the introduction of 10 TU.

Above-threshold doses should be used in cases where the Koch test is given for differential diagnostic purposes. For example, at a sensitivity threshold for a Mantoux test with a dilution of 4 (1 TU), depending on its intensity, 0.2 ... 0.5 ml of tuberculin dilution 3 (20 ... 50 TU) is injected under the skin.

Threshold doses of tuberculin for subcutaneous administration are used to determine the activity of small forms of tuberculosis. In this variant, a dose of tuberculin is injected subcutaneously, 2...4 times more than that established when determining the intradermal titer.

Subthreshold doses are used to judge the dynamics of functional changes under the influence of treatment. In such cases, 0.2 ... 0.4 ml of tuberculin is injected subcutaneously, 10 times less than the threshold dilution.

In response to the Koch test, there may be reactions: prick, general and temperature, focal. To take into account the focal reaction in pulmonary tuberculosis, along with clinical and radiological signs, it is advisable to examine bronchial washings and sputum for Mycobacterium tuberculosis. At the same time, in patients with active tuberculosis, the percentage of findings of Mycobacterium tuberculosis by methods of both bacterioscopy and culture increases.

The prick reaction is considered positive when the infiltrate is 15-20 ml or more; in isolation from the general, temperature, focal reactions and other tests of information, it gives little.

To take into account the temperature reaction, it is advisable to carry out thermometry at intervals of 3 hours - 6 times a day - for 7 days (2 days before the sample and 5 days against the background of the sample). Late rises in temperature are possible - on the 4th - 5th day, although in the vast majority of patients an increase is noted on the 2nd day.

The temperature reaction is considered to be positive if there is an increase of 0.5 °C in comparison with the maximum before the subcutaneous injection of tuberculin. The temperature reaction may be accompanied by symptoms of general intoxication, although not always.

A manifestation of the general reaction of the body to the introduction of tuberculin are changes in the parameters of the hemogram, proteinogram and other tests. 30 minutes or an hour after the subcutaneous injection of tuberculin, a decrease in the absolute number of eosinophils is noted (F. A. Mikhailov's test), after 24 ... neutrophils by 6% or more, a decrease in the content of lymphocytes by 10% and platelets - by 20% or more (N. I. Bobrov's test).

When studying the proteinogram 24-48 hours after the subcutaneous injection of tuberculin, a decrease in the albumin-globulin coefficient may be noted due to a decrease in the content of albumins and an increase in alpha1, alpha2 and gamma globulins (protein-tuberculin test by A. E. Rabukhin and R. A. Ioffe) . This test is considered positive when the change in indicators is not less than 10% from the initial level.

Higher diagnostic informativity was noted by A. E. Rabukhin et al. (1980) when studying the content of serum immunoglobulins after subcutaneous administration of 20 TU. Immunoglobulin-tuberculin test - an increase in the content of immunoglobulins of all classes after 72 hours (mostly IgA) - turned out to be positive in 97% of patients with active tuberculosis and negative - with an inactive process and other respiratory diseases.

The information content of individual indicators of the content of sialic acids, C-reactive protein, lipoproteins, hyaluronidase, haptoglobin, lactate dehydrogenase against the background of parenteral administration of tuberculin is small, but in combination they increase the diagnostic capabilities of determining the activity of the tuberculosis process and differentiating it from nonspecific diseases.

According to the literature, among the tuberculin provocative tests that allow revealing the hidden activity of tuberculosis, highly informative are such cellular and humoral reactions as RTBL, RTML, an indicator of neutrophil damage, rosette formation [Averbakh M. M. et al., 1977; Kogosova A. S. et al., 1981, etc.].