[Influence of donor activating or inhibitory KIR on prognosis of unmanipulated allogeneic hematopoietic stem cell transplantation].

This study was purposed to investigate the role of NK-alloreactivity and donor-inhibiting or activating KIR gene in predicting prognosis under unmanipulated allogeneic blood and marrow transplantation. A modified polymerase chain reaction sequence specific primers (PCR-SSP) method was used to typing KIR and HLA genotype of donors and recipients. The relationship between donor activating or inhibitory KIR and recipient HLA genotypes on event free survival (EFS), cumulative incidence of malignant relapse and transplant-related mortality (TRM) were investigated retrospectively in 67 patients undergoing hematopoietic stem cell transplantation. The results showed that no effect of 'KIR/HLA mismatched' was detected on acute graft-versus-host disease (aGVHD) and relapse. The EFS of KIR/HLA mismatched group was lower, especially KIR2DL1/HLA-C2 mismatched group (44.8% vs 69.2%, P = 0.043). However, EFS was better for the presence of donor-activating KIR2DS2 (81.3% vs 52.6%, P = 0.052), and the relapse rate was significantly lower for the presence of this genotype (7.7% vs 34.2%, P = 0.05). EFS was worse in patients homozygous for group 1 HLA-C (C1) when donor carries the activating KIR2DS1 (KIR2DS1 positive/HLA-C2-negative group, P = 0.028), and the incidence of aGVHD in this group was significantly higher than that in any other groups (P = 0.028). In multivariate analysis, advanced disease stage, more than two donor-activating KIR, donor KIR2DS2-negative genotype were associated with an reduced disease-free survival (HR = 3.34, 2.19, 3.18;and P = 0.005, 0.053, 0.066). Donor KIR2DS2-negative genotype were also associated with an increased risk of relapse (HR = 6.72, 9.43; and P = 0.019, 0.047). And donor KIR2DS1 positive/recipient HLA-C2 negative group was the only risk factor of TRM (HR = 3.27, 95% CI 1.78 - 9.06, P = 0.023). It is concluded that missing ligand for the donor inhibitory KIR has weak effect on the outcome of unmanipulated HSCT. The activating KIR play an important role in the EFS, relapse and TRM after HSCT. Donor KIR2DS1-positive/recipient HLA-C2-negative group and donor KIR2DS1 gene negative predict poor prognosis. Analysis of KIR genotype and its ligand is important for the selection of best donor and prognostic evaluation in unmanipulated allogeneic HSCT.