CD4 and immunodeficiency disease: HIV infects and replicates in CD4 T cells, resulting in death of the infected cells and immunodeficiency, whereas in schistosomiasis, CD4 T cells play a role in host resistance to infection34 and excretion of parasite eggs.35 In this study, we report that the frequency of HIV-specific IFN-γ+ IL-2− TNF-α+ CD4 T cells and IFN-γ+ IL-2− TNF-α− CD8 T cells in response to Gag PTE pools 1 and 2 was significantly higher in the HIV+SM+ individuals compared with HIV+SM− individuals, suggesting that S. mansoni infection enhanced HIV-specific Th1 and CD8 T-cell responses.