Naive T-cell cycling and thymic function during chronic HIV-1 infection. Naive T-cell cycling was quantified through Ki-67 expression on CD45RA⁺, CD27⁺ cells in the CD4⁺ (A) and CD8⁺ (B) T-cell compartments. Slow progressor (SLP, n = 6) as well as progressor (P, n = 9) patients are compared with healthy control persons (Ctl, n = 9). 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. For panels A and B, horizontal lines represent median values. Statistical differences between groups are shown on top (*P < .05; **P < .01). (C) Thymic function was estimated through the calculation of the sj/βTREC ratio in the 3 groups of individuals (group P, n = 10; group SLP, n = 12; controls, n = 38). Horizontal lines represent maximal values, third quartiles, medians, first quartiles, and minimal values, from top to bottom. sj/βTREC ratio (D), sjTREC (E), and DJβTREC (F) frequencies are presented as a function of age for group P (close symbols) and group SLP (open symbols). The lines represent the linear regressions for the control group.