CD4 and HIV-1 infection: Furthermore, it is well described that in HIV+ subjects commencing ART, either during primary or chronic HIV-1 infection, CD4+ and CD8+ T cell activation is progressively reduced [46,47], but this occurs in the absence of any reconstitution of CD73+ CD4+ T cells, as previously described for ART commenced during CHI [12], and confirmed prospectively in this study for ART commenced in both CHI and PHI.