Interleukin-17-producing T helper (Th17) CD4 + T cells are highly susceptible to HIV infection and are depleted early in people living with HIV. Here, we investigated whether systemic Th17 cell levels prior to HIV infection are associated with subsequent HIV disease progression. We analyzed archived cryopreserved peripheral blood mononuclear cells (PBMCs) collected within one year prior to HIV acquisition from participants enrolled in a South African cohort (HIV Vaccine Trials Network [HVTN] 503