Antiretroviral initiation at ≥800 CD4+ cells/ mm 3 associated with lower HIV reservoir size

BACKGROUND: Identifying factors that determine the frequency of latently infected CD4+ T-cells on antiretroviral therapy (ART) may inform strategies for HIV cure. We investigated the role of CD4 count at ART initiation for HIV persistence on ART. METHODS: Among participants of the Strategic Timing of Antiretroviral Treatment (START) Study, we enrolled people with HIV (PWH) who initiated ART with CD4+ T-cell counts of 500-599, 600-799 or ≥800 cells/mm 3. After 36-44 months on ART, we quantified levels of total HIV-DNA, cell-associated unspliced HIV-RNA (CA-US HIV-RNA) and 2-long terminal repeat HIV-DNA in CD4+ T-cells and measured plasma HIV-RNA by single-copy assay. We measured T-cell expression of HLA-DR, programmed death-1, phosphorylated signal transducer and activator of transcription-5 (pSTAT5). Virological and immunological measures were compared across CD4+ strata. RESULTS: We enrolled 146 PWH, 36 in the 500-599, 60 in the 600-799 and 50 in the ≥800 CD4 strata. After 36-44 months of ART, total HIV-DNA, plasma HIV-RNA and HLA-DR expression were significantly lower in PWH with CD4+ T-cell count ≥800 cells/mm 3 at ART initiation compared to 600-799 or 500-599 cells/mm 3. The median level of HIV-DNA after 36-44 months of ART was lower by 75% in participants initiating ART with ≥800 vs. 500-599 cells/mm 3 [median (IQR): 16.3 (7.0-117.6) vs. 68.4 (13.7-213.1) copies/million cells, respectively). Higher pSTAT5 expression significantly correlated with lower levels of HIV-DNA and CA-US HIV-RNA. Virological measures were significantly lower in females.. CONCLUSION: Initiating ART with a CD4+ count ≥800 cells/mm 3 compared to 600-799 or 500-599 cells/mm 3 was associated with achieving a substantially smaller HIV reservoir on ART.