Their role in HIV infection is not clearly understood; on the one hand, the expansion of Tregs has been shown to be associated with the suppression of HIV-specific CD4+ T-cell responses and disease progression (36, 37) while on the other hand, Tregs have been associated with protection from productive infection, CD4+ T-cell activation and disease progressions in both humans (38, 39) and non-human primates (40). The gene discussed is CD4; the disease is HIV infectious disease.