CD4 and HIV-1 infection: We investigated the effect of HIV-1 infection and timing of ART initiation on CD4+ T cell metabolism and function.<h4>Methods</h4>Longitudinal blood samples from people living with HIV who initiated ART during hyperacute HIV-1 infection (HHI; before peak viremia) or chronic HIV-1 infection (CHI) were assessed for the metabolic and immune functions of CD4+ T cells.