The importance of CD4+ T lymphocytes producing IFN-γ and IL-17 to control fungal infection was observed, for instance, in models of infection by Pneumocystis, H. capsulatum, Cryptococcus neoformans, P. brasiliensis, Candida albicans, and A. fumigatus [7,31,32,33,34]. The gene discussed is IL17A; the disease is infection.