Possibilities of Immunogenetic Methods in Testing the Activity of Tuberculosis Infection in Children

The objective: to test the TREC/KREC DNA levels in children with various manifestations of tuberculosis infection. Subjects and Methods. A prospective, cross-sectional study was conducted in 2022-2024. Observation Group consisted of 115 children aged 6 (5; 7) years, of them 25 were diagnosed with tuberculosis, 63 were diagnosed with latent tuberculosis infection, 27 were not infected with Mycobacterium tuberculosis (conditionally healthy). Results. Findings of the study were as follows: among children with LTBI and a positive response to TRA, only 18.2% had the high TREC DNA concentration which corresponded to the level in the children ill with tuberculosis ( t = 0.971; p = 0.342), there was a direct relationship between the TREC DNA and KREC DNA levels in children with LTBI; in 21.2% of children the level was low and indicative of immunodeficiency. If the positive response to TRA persisted in children for two years or more, there was a decrease in the average TREC DNA level, which was statistically significant compared to that in children with TRA+ for less than 2 years. Taking into account the results obtained, the TREC DNA level in children with LTBI can be considered as an additional criterion to assess activity of tuberculosis infection and can be an evidence to justify preventive anti-tuberculosis therapy if studied further. We also found a direct correlation between the TREC and KREC DNA levels in children with LTBI, r = 0.48 (by Spearman). When the positive response to TRA persisted for more than two years, a statistically significant decrease in the TREC DNA level was noted versus the results in children with the first positive response to TRA ( t = 2.965; p = 0.005). Conclusion. Taking into account the results obtained, the TREC DNA level in patients with various manifestations of tuberculosis infection can be considered as an additional criterion of infection activity, which will allow differentiated approach to preventive treatment being an important evidence to justify anti-tuberculosis therapy.