Natural killer cells in allogeneic transplantation: effect on engraftment, graft- versus-tumor, and graft-versus-host responses.
Natural killer (NK) cells are effectors of the innate immune system and recognize cells transformed by viruses or neoplasia. Their response to "missing self" signals was described 3 decades ago, but the recent discovery of a panoply of activating receptors has made it clear that NK cell reactivity arises from a combination of inhibitory and activating signals. Successful clinical exploitation of NK cell reactivity was demonstrated in allogeneic transplantation for acute myelogenous leukemia from HLA-haploidentical donors when matched donors were not available. Multiple clinical studies have since attempted to use NK reactivity in the setting of both HLA-matched and -mismatched transplantation, with varying results. This review summarizes the heterogeneous clinical results and explains them based on a succinct description of NK cell biology.
Gill
Saar
S
Department of Medicine, Division of Blood and Marrow Transplantation, Stanford University, Stanford, CA 94305, USA.
Olson
Janelle A
JA
Negrin
Robert S
RS
D000818:Animals; D006085:Graft Survival / Q000276:immunology*; D006086:Graft vs Host Disease / Q000276:immunology*; D020544:Graft vs Leukemia Effect / Q000276:immunology*; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D007113:Immunity, Innate; D007694:Killer Cells, Natural / Q000276:immunology*; D015470:Leukemia, Myeloid, Acute / Q000276:immunology* / Q000628:therapy; D014184:Transplantation, Homologous