Five-year relapse estimates after allogeneic hematopoietic stem cell transplantation. Estimates are shown after HSCT from HLA-identical donors (dotted line; n = 237), HLA class I–disparate, inhibitory KIR ligand–compatible donors (dashed line; n = 89), and HLA class I–disparate, inhibitory KIR ligand–incompatible donors (solid line; n = 48). Significance for the heterogeneity between the 3 study groups tested by log-rank statistics.