The CD38+ HLA-DR+ PD-1+ CD4 T cell population represents a short-lived part of the viral reservoir and predicts poor immunologic recovery upon initiation of ART

The activated PD-1+ CD4 T cell population is associated with disease progression in untreated HIV-1 infection, and with residual viral replication in individuals on ART. Few studies have examined cell associated viral load (CAVL) in phenotypically different activated CD4 T cell populations to define the HIV reservoir. We followed 32 HIV-1 chronically infected individuals, from Kampala, Uganda, and determined their CD4 T cell counts, and viral load at baseline, 6, and 12 months after the initiation of ART. Peripheral blood T cell populations were sorted based on activation profiles and gag DNA was measured to determine CAVL within these populations. Soluble inflammatory factors were measured in plasma using a multiplexed platform. The median HIV-1 viral load declined from 95,315 copies/ml at baseline to below detection for all patients after 12 months of ART, whereas CD4 T cells counts averaged 204 cells/μl at baseline and increased to 373 cells/μl by month 12. Median levels of the activated PD-1+ CD4 T cell population contracted from 4.5% of CD4 T cells at baseline to 2.3% of CD4 T cells after 12 months of ART. Baseline levels of activated PD-1+ CD4 T cells positively correlated with plasma levels of IP-10 (R2=0.362, P