Immunological host responses as surveillance and prognostic markers in tubercular infections

Tuberculosis (TB) control is challenging due to failure of drug compliance and resistance. Mycobacterial antigen-induced cytokine secretions are helpful in detecting Mycobacterium tuberculosis infection and to determine prediction for the fate of TB infection and its cure. Considering immunological response to be a crucial factor in pathogenesis and cure of TB, it can be explored to determine clinical prospects in different categorical tubercular infections. This study was designed to compare serum levels of inflammatory (tumor necrosis factor [TNF]-alpha and interferon [IFN]-gamma) and anti-inflammatory cytokines/chemokines (interleukin [IL]-10 and IL-8) among different TB groups (freshly diagnosed, relapse, cases on antitubercular treatment [ATT], and healthy controls).

This cross-sectional study included total 100 subjects. The study subjects were further divided into four study groups with 25 cases in each of freshly diagnosed TB, TB relapse cases, cases on ATT, and 25 healthy controls. Levels of serum cytokines/chemokines (TNF-alpha, IFN-gamma, IL-10, and IL-8) were measured by flow cytometry.

Data analysis observed statistically significant differences in serum levels of TNF-alpha and IFN-gamma among the studied groups with significantly low levels in subjects on ATT and markedly high levels in TB relapse subjects. No statistically significant difference was observed in IL-10 and IL-8 levels. However, subjects with relapse revealed low IL-8 and high IL-10 levels.

TNF-alpha and IFN-gamma have important roles in immune response and might be considered as indicators for response to ATT. However, high levels of IL-10 with low IL-8 appear to be associated with poor outcome and possibility of relapse.