Evolution of naive T-cell subsets during chronic HIV-1 infection. Naive T-cell (CD45RA⁺, CD27⁺) frequencies (A) and numbers (B) were quantified in CD4⁺ and CD8⁺ peripheral T cells from HIV-1–infected patients. Slow progressor (SLP, n = 6) as well as progressor (P, n = 9) patients are compared with healthy control persons (Ctl, n = 9). Statistical differences between groups are shown on top (*P < .05; **P < .01). The subgroups of patients analyzed are representative of their respective patient population described in Table 1 with respect to age, CD4 counts, and viral load.