Expansion of CD100⁻CD8⁺ T cells coexpressing CD57 and PD-1 in HIV-1–infected individuals. Correlation of the number of CD100⁻CD8⁺ T cells with (A) immune activation as assessed by percentage of CD38⁺HLA-DR⁺CD8⁺ T cells of all untreated subject groups (n = 84), or (B) viral loads of all untreated subject groups (black line; n = 84) or only untreated viremic patients (gray line; n = 65). (C) Correlation of the number of CD100⁻CD8⁺ T cells during the first year of infection and the AUC for viral loads over time (n = 12). D) Frequency of CD100 coexpression with CD57 and PD-1 in the total CD8⁺ T cell population of ECs (n = 20) and untreated, chronically infected NCs (n = 60) compared with HCs. Shaded bars represent minimum-maximum range and the black middle bar indicates the median. (E) Frequency of CD100, CD57, and PD-1 coexpression in HIV (lightest gray) and CMV (medium gray) pentamer-specific CD8⁺ T-cell population of HIV-1–infected subjects and CMV pentamer-specific CD8⁺ T cell population of healthy controls (darkest gray). Open bars represent mean and symbols represent individual subjects. Statistical analysis: (A-C) Correlations were determined by 2-tailed nonparametric Spearman correlations; (D-E) Student t tests (*P < .05, **P < .01, and ***P < .001).