[SENSITIVITY OF THE NEW SKIN TEST DIASKINTEST® FOR THE DIAGNOSIS OF TUBERCULOSIS INFECTION IN CHILDREN AND ADOLESCENTS].

Abstract

In Russia, an intradermal Diaskintest® drug has been designed, which is a recombinant tuberculosis allergen based on M. tuberculosis-- specific proteins: ESAT-6 and CFP-10 produced by a genetically modified Escherichia coli culture. Diaskintest® test and Mantoux test with 2TE PPD-L were concurrently carried out in 300 children and adolescents with tuberculosis and followed up in risk groups at a tuberculosis dispensary to determine the sensitivity of the new skin test in active tuberculosis infection. Diaskintest® showed a high sensitivity not only in active tuberculosis, but also in occult, the so-called latent, tuberculosis infection. This is suggested by the following evidence. The high percentage (83.8%) of positive responses to Diaskintest® is noted in children and adolescents with tuberculosis, receiving an intensive course of chemotherapy. Negative tests were observed only in minor forms at the resolution stage. In the children who had completed treatment, positive tests were seen in 78.3%, moreover in those with prior tuberculosis of intrathoracic lymph nodes; negative tests were observed not earlier than 18 months after start of treatment. The highest sensitivity of Diaskintest® was shown in children with early primary tuberculosis infection and through family contact with bacteria-excreting subjects (91.7%). These children may be judged with the highest assurance to have latent tuberculosis infection, the population of which is in an active state at the moment of the study. The children with early primary tuberculosis infection, but in no family contact with bacteria-excreting individuals, showed a lower percentage of positive responses to Diaskintest® both before (37.5%) and after (10%) treatment, which suggests that there must be a lower bacterial burden in the child. A high percentage of positive responses to Diaskintest® (76.2%) were found in subjects with hyperergic reactions to tuberculin. These were in only 16.7% in the group of patients receiving preventive therapy. In children and adolescents with a persistent positive Mantoux test (for more than 3 years), the response to Diaskintest® was negative in most cases since in early infection when mycobacteria propagated, the reaction to the drug was positive, but as 3 years pass the probability of the infection transition to the persistence stage is high--at that time the response to Diaskintest® becomes negative. Diaskintest® induces no delayed hypersensitivity associated with BCG vaccination, suggesting its high specificity. There were no positive reactions in patients with nonspecific lung diseases.