IL17A and infection: During infections, the cytokine milieu modulates the differentiation and polarization of CD4+ T cells into distinct effector phenotypes, including interferon γ (IFNγ) producing-T-helper 1 (Th1) cells that mediate the clearance of infected cells, interleukin 4 (IL4)- and IL13-producing Th2 cells that play a role in parasite expulsion and driving allergic response, and IL17-producing Th17 cells that mediate anti-fungal response and promote autoimmunity [3,4].