“…In allogeneic HSCT, donor NK cells attack the allogeneic cells if the recipient HLA class I ligands do not sufficiently engage their inhibitory receptors. Alloreactive donor-derived NK cells are thought to promote engraftment [3][4][5][6], reduce GVHD [7,8], mediate a graft-versus-leukemia effect, and decrease leukemic relapse [4,9,10], resulting in an antileukemic response with lower relapse rates, fewer graft failures, and less GVHD, ultimately leading to improved overall survival (OS) [11,12]. Some recent studies have indicated that KIR interactions of donor and recipient can influence the outcomes of haploidentical [13][14][15], matched-unrelated donor [3,16,17], and matched-related donor [2,5,[18][19][20][21][22] allogeneic HSCT, particularly in patients with acute myeloid leukemia (AML).…”