No Impact of KIR‐Ligand Mismatch on Allograft Outcome in HLA‐Compatible Kidney Transplantation

Natural killer (NK) cell function can be modulated by the killer cell immunoglobulin‐like receptors (KIR) which interact with human leukocyte antigen (HLA) class I molecules on target cells. KIR‐ligand mismatching has recently been shown by van Bergen et al. (American Journal of Transplantation 2011; 11(9): 1959–1964) to be a significant risk factor for long‐term graft loss in HLA‐A, ‐B and ‐DR compatible kidney transplants. To verify this potentially important finding, we performed genotyping of 608 deceased‐donor kidney graft recipients and their HLA‐A, ‐B and ‐DR compatible donors for KIR and HLA, using samples and clinical data provided by the Collaborative Transplant Study. Graft survival of KIR‐ligand‐matched and ‐mismatched transplants was compared. We found no impact of KIR‐ligand mismatching on 10‐year graft survival in HLA‐A, ‐B, ‐DR compatible kidney transplants. Further analysis did not reveal a significant effect of recipient activating/inhibitory KIR or KIR genotypes on graft survival. Our data do not support the concept that KIR‐HLA matching might serve as a tool to improve long‐term renal allograft survival.