IL-2–induced decreases in proliferation were observed in naive and recall memory CD4⁺ T cells. Median values of percent Ki67 expression in naive and memory subsets of CD4⁺ (A) and CD8⁺ (B) T cells at baseline (□) and month 12 (▪) from the IL-2 group are shown. Statistically significant decreases of Ki67 expression were noted in the naive (P = .004) and recall memory (P < .001) CD4⁺ T-cell subsets. Trends were noted in the effector CD4⁺ (P = .06) and CD8⁺ T cell pools (P = .05).