Insights in tuberculosis immunology: Role of NKT and T regulatory cells.

Background: Tuberculosis (TB) control is challenging due to poor drug compliance and emerging resistance. The need of the hour is to determine the prediction of disease cure and relapse. Patients' immune response is crucial to the disease outcome. This study was designed to study the immune profile of TB patients during treatment and cure.

Methods: The cross-sectional study included newly diagnosed pulmonary TB patients and healthy controls. Levels of serum cytokines/chemokines (Th1/Th2/Th17) were measured by BD cytometric bead array. The cell surface markers assessed in the study were CD3, CD4, CD8, CD16, CD56, and BD human regulatory T cell cocktail (CD4/CD25/CD127).

Results: Data analysis observed statistically significant differences in CD3dim/CD56 + natural killer T (NKT) among TB patients with significantly low levels in healthy controls and after treatment completion (P < 0.0001). The analysis also revealed a high percentage of CD3dim/CD56 + NKT in fast responders. The percentage of T regulatory was found to be high in patients when compared with healthy controls; the values were statistically significant (0.0002). Interleukin-6 was significantly associated with the disease (P < 0.0485).

Discussion: A comprehensive understanding of role of CD3dim/CD56+ NKT in antimycobacterial immunity may enable new possibilities for NK cell-based prophylactic and/or therapeutic strategies against TB.