T-cell compartment in recipients without aGVHD after HCT. Shown are results for donor/recipient couples without aGVHD from cohort 1. (A) Frequency of CD3⁺ T cells within the lymphocyte population (left panel) and frequencies of CD4⁺ (middle panel) and CD8⁺ (right panel) T cells within CD3⁺ T cells. (B) Ratio of CD4^+/CD8⁺ T cells in recipients (R) at day 90 post-HCT compared with their respective sibling donors (D). (C) Gating strategy used to identify naive and memory subsets within the CD4⁺ and CD8⁺ T-cell compartments in donors and recipients after transplantation by polychromatic flow cytometry. (D) Frequencies of T_Naive, T_SCM-like, T_CM, T_EM, and T_EMRA cells within the CD4⁺ (upper panels) and CD8⁺ (lower panels) T-cell compartments in recipients (R) at day 90 post-HCT compared with their respective sibling donors (D). (E) Frequency of proliferating Ki-67⁺ cells in total CD4⁺ and CD8⁺ T cells and in the different naive and memory subsets in CD4⁺ (left panel) and CD8⁺ (right panel) compartments in donors and recipients. The frequency of Ki-67⁺ cells is represented as the percentage of Ki-67–expressing cells within total CD4⁺ or CD8⁺ T cells and as the percentage Ki-67–expressing cells within the parent gate for T_Naive, T_CM, T_EM, and T_EMRA cell subsets. Horizontal lines indicate the median. P values were calculated using the Wilcoxon matched-pairs Student t test (donor vs respective recipient). Differences are considered significant for P < .05.