Diagnostics of the latent TBC infection (LTBI) activity in children

Material and methods: Under observation there were 118 children with LTBI and 129 diseased children with local forms of lung tuberculosis. The concentration of key cytokines IFNr, IL4, IL10, IL18 in blood serum was identified with immunoferment method. Results: To comparatively study the correlation of functioning of Th1 and Th2 cells in the immune response, we introduced the notion of “Cytokine index”. Accordingly, the secretorious activity of T-helpers of the 1 and 2 type we determined by quantitative correlation of the key cytokines IFNr/IL4 and IL18/IL10. It was determined that in comparison with a control group (30 noninfectious children) average values of IFNr content increased in diseased children in 2,4 times, in healthy with LTBI – in 3,6 times. By analogy, the values of IL18 increased in the diseased in 2,9 and in healthy children with LTBI – in 4,5 times. The obtained results underline the oneway direction of the immune response to TBC infection, appeared in organism. In diseased children the quantitative index of correlation of the key cytokines IFNr/IL4 lessened to 1,4 times (in a control group – to 2,3). In infectious children this index was equal to 1,9. The correlation of the other two nonetheless important cytokines IL18/IL10 in the differentiating of T-lymphocites in very indicative: in both groups the cytokine index appeared to be lowered to 1,4 and 1,9, which was caused by the increase of IL10 almost in 5 times as compared with the control group (2,3). Conclusion: The IL18/IL10 obtained results allow of IL18/IL10 introducing into clinical practice quantitative evaluation of correlation of Th1 and Th2 hence to diagnose the LTBI progress.