CD4 and HIV infectious disease: Since in macaque models of HIV infection, especially in pilot studies, it is not always possible to treat macaques with cART for prolonged periods of time due to cost constrains and technical challenges, we asked if the frequency of CD4+ T cells producing tat/rev msRNA right after cART initiation could be indicative of response to treatment and predict the magnitude of viral rebound after cART interruption.