Comparison of interferon-γ-, interleukin (IL)-17- and IL-22-expressing CD4 T cells, IL-22-expressing granulocytes and proinflammatory cytokines during latent and active tuberculosis infection

In this study, we investigated the role and expression of T helper type 17 (Th17) cells and Th17 cytokines in human tuberculosis. We show that the basal proportion of interferon (IFN)-gamma-, interleukin (IL)-17- and IL-22-expressing CD4(+) T cells and IL-22-expressing granulocytes in peripheral blood were significantly lower in latently infected healthy individuals and active tuberculosis patients compared to healthy controls. In contrast, CD4(+) T cells expressing IL-17, IL-22 and IFN-? were increased significantly following mycobacterial antigens stimulation in both latent and actively infected patients. Interestingly, proinflammatory IFN-? and tumour necrosis factor (TNF)-a were increased following antigen stimulation in latent infection. Similarly, IL-1 beta, IL-4, IL-8, IL-22 and TNF-alpha were increased in the serum of latently infected individuals, whereas IL-6 and TNF-a were increased significantly in actively infected patients. Overall, we observed differential induction of IL-17-, IL-22- and IFN-gamma-expressing CD4(+) T cells, IL-22-expressing granulocytes and proinflammatory cytokines in circulation and following antigenic stimulation in latent and active tuberculosis.