Indeed, detecting functional TH17 cells and production of protective IL-17 during the early phase of the immune response [33–35] and the activation of TH17 that even precedes the differentiation of TH1 cells [33], together with the later contribution of TH17 [36], highlight the crucial importance of IL-17 and other TH17-related cytokines in the early, as well as, the late phase of infection. The gene discussed is IL17A; the disease is infection.