Selection of donors with KIR B–content scores of 2 of greater has significant potential to improve the outcome of HLA-matched and HLA-mismatched HCT. For patients transplanted for AML, the incidence of relapse (A-B), the probability of DFS (C-D) and the probability of overall survival (E-F) are shown. Panels A, C, and E show the data from HLA-matched transplants, and panels B, D, and F show the data from HLA-mismatched transplants. Comparison is made between donors with a KIR B–content score of 0 or 1 (374 matched and 374 mismatched) and donors with a KIR B–content score of 2 or greater (162 matched and 165 mismatched).