Analysis of KIR genes in HLA-identical sibling hematopoietic stem cell transplantation in Thai patients with leukemia.

BACKGROUND Killer cell immunoglobulin-like receptors (KIRs) are members of a group of regulatory molecules found on the natural killer (NK) cells that regulate NK cells function by interacting with the human leukocyte antigen (HLA) class I molecules or ligands. The effects of KIR genes on the outcome of hematopoietic stem cell transplantation (HSCT) are still controversial. OBJECTIVE To investigate the distribution of KIR genes in HLA-identical sibling and the effect of KIR genes on the outcome of HSCT. MATERIAL AND METHOD The present study included 74 patients and their HLA-identical sibling donors. KIR genes and HLA ligands typing were determined by polymerase chain reaction-sequence specific primer (PCR-SSP). A retrospective study was carried out to analyze the outcomes of the recipients. RESULTS There was no effect of KIR gene mismatch and missing ligand on the outcome regarding graft-versus host disease (GVHD), relapse, and overall survival (OS) (p > 0.05). However the presence of donor activating KIR2DS5 was associated with decreased aGVHD (p = 0.01). CONCLUSION Our findings suggest an important role of donor activating KIR in identical sibling HSCT.