Frequency and phenotype of CD70⁺ T cells in blood after allo-SCT. (A-B) Frequency of circulating CD70⁺ (dark blue) and CD27⁺ (light blue) T cells in the blood at 2-week intervals after allo-HSCT during early immune reconstitution until 14 weeks (3 months, n = 14) within the CD4⁺ (A) and CD8⁺ (B) T-cell compartments. Distribution of naïve (N), central memory (CM), effector memory (EM), and EM-like CD45RA⁺ EMRA cells within the CD4⁺CD70⁺ (n = 11) (C) and CD8⁺CD70⁺ (n = 11) (D) T cells, identified using cell surface expression of CD45RA and CCR7. (E-F) Cell surface expression of PD-1 (n = 6), CD95 (n = 6) and LAG-3 (n = 6), ICOS (n = 13), CTLA-4 (n = 13), CD28 (n = 13), and CD154 (n = 13) on CD70⁺ and CD70^– population as percentages within the CD4⁺ (E) and CD8⁺ (F) T-cell populations in blood at 2 weeks (day 14) after allo-HSCT. Statistical comparisons were performed using 1-way analysis of variance (ANOVA) with Dunn multiple comparison test (A-D) or Wilcoxon matched-pairs signed-rank test (E-F): ns, not significant; ∗P < .05; ∗∗P < .01; ∗∗∗P < .005. CTLA-4, Cytotoxic T-lymphocyte associated protein 4; EMRA, Terminally differentiated effector memory cells re-expressing CD45RA.