HLA-C2 homozygous patients receiving a CB graft with the combined HLA-C2-KIR2DL1/S1 genotype have a lower 1-year cumulative incidence of relapse and better probability of OS. We combined HLA-C2 homozygous patients in the discovery and validation cohorts (n = 40) for this analysis. The 19 HLA-C1/x patients receiving at least one CB unit with the combined HLA-C2-KIR2DL1/S1 genotype (green line) have a significantly lower incidence of relapse (A) and a better OS (B) compared with the 21 patients receiving CB grafts that were either KIR2DS1-negative or predicted to be unlicensed (HLA-C2-negative) (blue line). Tick marks on the lines indicate censored patients.