KIR3DL1 and acute myeloid leukemia: In related HLA-matched HSCT, the absence of KIR ligands in the recipient (missing KIR ligand, i.e., the absence of Bw4, C1 or C2) for the donor’s inhibitory KIRs was found to either be a beneficial prognostic factor by increasing OS and disease-free survival (DFS) and/or by decreasing relapse incidence for AML patients [137,138] or have no effect [101].