OBJECTIVETo evaluate the prognostic implication of the killer-immunoglobulin like receptor (KIR) ligand mismatch in HLA mismatched hematopoietic stem cell transplantation (HSCT).

METHODSNinety-four leukemia patients undergoing unmanipulated HLA-mismatched/haploidentical blood and marrow HSCT enrolled this study.

RESULTSMultivariate analysis showed that both KIR ligand mismatch (HR 2.833, CI, 1.286 - 6.241, P = 0.01) and doses of T cells (HR 3.059, CI, 1.292 - 7.246, P = 0.011) were independent risk factors for the acute graft versus host disease (aGVHD). In addition, compared to those without KIR ligand mismatch, patients with KIR ligand mismatch had the more adverse effect of 'high' dose T cells (> 1.48 x 10(5)/kg) on aGVHD (100% vs 63.3%, P = 0.036), and had more incidence of aGVHD with HLA-C mismatch (80.0% vs 57.4%, P = 0.056). Since multivariate analysis demonstrated that high risk leukemia was the only predictor for transplant related mortality (TRM), relapse and overall survival (OS), the effect of KIR ligand mismatch on prognosis in standard and high risk patients was further analyzed. The differences in TRM (50.0% vs 7.6%, P = 0.005) and OS (50.0% vs 88.4%, P = 0.014) between patients with and without KIR ligand mismatch were most striking for standard risk patients.

CONCLUSIONKIR ligand mismatch is a poor prognosis factor for patients underwent HLA mismatched HSCT, and is a useful parameter for donor selection.