Changes in subsets of MDSCs and expression of LOX-1 before and after transplantation. Gated MDSCs were analyzed for percentages of CD14⁺ monocytic MDSCs (A), CD15⁺ pmn MDSCs (B), and CD14⁻CD15⁻ double-negative MDSCs (C). MDSC subsets were also enumerated to determine the absolute cell number of CD14⁺ monocytic MDSCs (D), CD15⁺ pmn MDSCs (E), and CD14⁻CD15⁻ double-negative MDSCs (F) in blood. Percentage of LOX-1⁺CD15⁺ pmn MDSCs in a normal subject (G) and in an HLA-mismatched recipient pretransplant (H) and at 3 months (3m) posttransplant (I). (J) Mean LOX-1⁺ cells among CD15⁺ pmn MDSCs from normal individuals and recipients at pretransplant vs 1.5 to 4 months posttransplant vs 6 to 12 months posttransplant vs 13 to 24 months posttransplant. *P < .05, **P < .01, ***P < .001, Mann-Whitney U test of independent means; significance was subsequently determined by 1-way ANOVA, multicomparison analysis with Holm-Sidak correction. ns, not significant (P > .05). The data from the fully HLA-matched patients (circles), as well as HLA-mismatched patients (squares) who were mixed chimeric (closed symbols, >5% donor type cells in whole blood) or nonchimeric (open symbols), were combined.