[KIRs on human NK cells and in relation with HLA class I antigen--review]

The interaction of killer cell immunoglobin-like receptors (KIR) with HLA molecules has particular relevance to the genetics, immune responses and allogeneic stem cell transplantation. The genes of KIR and HLA are located in different chromosomes and segregate independently. The repertoire of KIR molecules varies among NK cells and is determined by the KIR genotype. The HLA genotype has only subtle impact on the KIR phenotype. Three major HLA specificity groups are recognized by KIRs. Donor versus recipient NK-cell alloreactivity, when recipients lack HLA ligand for their donor inhibitory KIR, can benefit allogeneic stem cell transplantation, especially the HLA haploidentical hematopoietic stem cell transplantation. The outcome of stem cell transplantation can be best predicted by the presence of KIRs on the donor's NK cells and the absence of corresponding KIR ligand in the recipient's HLA repertoire-a receptor-ligand model. In this paper the interaction of KIR and HLA in hematopoietic stem transplantation, the genetic basis of KIR and HLA, the relation of KIR expression on NK cells with HLA and the role of KIR and HLA in immune responses were reviewed.