HIV-1–infected patients treated with ART and IL-2 have lower basal proliferation of CD4⁺ T cells compared to patients treated with ART alone. The correlation between plasma HIV-RNA and CD4⁺ T cells positive for BrdU is shown for participants treated with ART alone (open blue circles) and for IL-2 recipients (red circles). The significant difference in CD4⁺ T cell proliferation over the range of viral load in the IL-2 and control groups (P < .001) was not observed following adjustment for CD4⁺ T cell counts (P = .15).