NKG2D mediates an important costimulatory pathway in CD8 T cells. In HIV infection, the authors found that NKG2D expression on both total CD8 and HIV-specific CD8 T cells was significantly lower in viremic patients than in HIV controllers. Antiretroviral therapy partially restored NKG2D expression on HIV-specific CD8 T cells. The authors observed a negative correlation between the respective expression levels of CD38 and NKG2D on total CD8 and HIV-specific CD8 T cells. The maintenance of NKG2D expression on CD8 T cells in HIV controllers may contribute to better cell function.