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

Summary 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)‐γ‐, 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‐γ were increased significantly following mycobacterial antigens stimulation in both latent and actively infected patients. Interestingly, proinflammatory IFN‐γ and tumour necrosis factor (TNF)‐α were increased following antigen stimulation in latent infection. Similarly, IL‐1β, IL‐4, IL‐8, IL‐22 and TNF‐α were increased in the serum of latently infected individuals, whereas IL‐6 and TNF‐α were increased significantly in actively infected patients. Overall, we observed differential induction of IL‐17‐, IL‐22‐ and IFN‐γ‐expressing CD4 + T cells, IL‐22‐expressing granulocytes and proinflammatory cytokines in circulation and following antigenic stimulation in latent and active tuberculosis.