HLA-DR+ CD38+ CD4+ T lymphocytes have elevated CCR5 expression and produce the majority of R5-tropic HIV-1 RNA in vivo.

Percentages of activated T cells correlate with HIV-1 disease progression, but the underlying mechanisms are not fully understood. We hypothesized that HLA-DR(+) CD38(+) (DR(+) 38(+)) CD4(+) T cells produce the majority of HIV-1 due to elevated expression of CCR5 and CXCR4. In phytohemagglutinin (PHA)-stimulated CD8-depleted peripheral blood mononuclear cells (PBMC) infected with HIV-1 green fluorescent protein (GFP) reporter viruses, DR(-) 38(+) T cells constituted the majority of CCR5 (R5)-tropic (median, 62%) and CXCR4 (X4)-tropic HIV-1-producing cells (median, 61%), although cell surface CCR5 and CXCR4 were not elevated in this subset of cells.