PD-1 [23]–[25], CTLA-4 [26] and Tim-3 [27]–[28] have also been associated to HCV and HIV-specific CD4 and CD8 T cell dysfunction as the expression levels of these molecules correlated positively with plasma viral load and negatively with absolute CD4 T cell counts while there expression declined in subjects treated with highly active antiretroviral therapy (HAART) [23], [26]–[27].More recently, studies have shown in cancer [29] and HIV [30]–[31] that the co-expression of several immune inhibitory molecules on antigen-specific CD8 T cells leads to a more severe dysfunction. The gene discussed is CD4; the disease is cancer.