CD4 and HIV infectious disease: Moreover, we found that the proportions of FOXP3+, as well as FOXP3negative IL-17A+ and IFN-γ+ effector CD4+ populations, are decreased in HIV-infected tonsils (Fig. 3B and Supplementary Fig. 7A, B), showing that CD4+ cells are also highly susceptible to cell death during acute HIV infection (Fig. 3C).