CTLA-4 expression on T cells, T-regs and NK cells in patients with CML and in healthy donors. (A) PD-1 expression on T cells was significantly higher in patients in the MolR group compared with healthy donors (HD). Expression in the TFR group was not different to patients in the MolR group or HD. (B) Absolute counts of CTLA-4⁺ T cells were not different between MolR and TFR patients. (C) CTLA-4 as a percentage of CD4⁺ T cells was higher in patients in the MolR group compared with the HD group. (D) There was no difference in the absolute counts of CTLA-4⁺CD4⁺ T cells between MolR and TFR patients. CTLA-4 expression on CD8⁺ T cells was not different either (E) as a percentage of CD8⁺ T cells or (F) absolute counts of CTLA-4⁺CD8⁺ T cells. (G) CTLA-4 expression as a percentage of T-regs was not different between the groups. (H) However, the absolute count of CTLA-4⁺ T-regs was significantly higher in patients in the MolR group compared with patients in the TFR group. There was no difference in CTLA-4 expression on NK cells either (I) as a percentage of NK cells or (J) absolute counts. The Mann-Whitney test was used to compare 2 groups, whereas multiple comparisons were made using the Kruskal-Wallis test; alpha was set at 0.05 (adjusted for multiple comparisons).