OR8 Killer cell immunoglobulin-like receptor genotype BX1 and centromeric gene-content motifs influences survival after 3-models of allogeneic hematopoietic stem cell transplantation

Abstract

Aim To investigate the role of donor killer cell immunoglobulin-like receptor (KIR) in allogeneic hematopoietic stem cell transplantation (allo-HSCT) and to develop a donor selection strategy for Chinese population. Methods In this 5-year retrospective study, we performed KIR genotyping on a total of 626 donor and recipient pairs by PCR-SSP. All patients underwent HSCT, comprising 219 HLA-identical sibling HSCT, 210 HLA-identical unrelated donor (URD) HSCT, and 197 HLA haplo-identical HSCT, for treatment of myeloid and lymphoid leukemia. Results Donor KIR genotypes and KIR gene motifs influenced transplantation outcomes for AML/MDS but not ALL/NHL patients in 3 models of transplants. In sibling HSCT for AML/MDS patients (n = 128), KIR mismatch between patient and donor had a better overall survival (OS; 87.3% versus 69.3%; P = 0.027) and reduced grade III to IV acute graft-versus-host disease (aGVHD; 4.6% versus 13.6%; P = 0.029). However, the effect was not observed in URD (n = 122) and haplo-identical HSCT (n = 108) for AML/MDS patients. Multivariate analysis indicated that centromeric B motifs contributed to improved survival in all models of transplants: (1) In sibling HSCT, donors’ haplotype cB-tA/tB were associated with improved OS compared with cA-tB (96.6% versus 71.2%; P = 0.021) or cA-tA (96.6% versus 72.1%; P = 0.017); (2) In URD-HSCT, donors with Cen -B were associated with a significantly improved OS (HR = 0.256; 95% CI, 0.084 to 0.774; P = 0.016) and RFS (HR = 0.252; 95% CI, 0.084 to 0.758; P = 0.014); (3) In haplo-identical HSCT, the same effect of Cen -B was observed on OS (HR, 0.335; 95% CI, 0.164 to 0.667; P = 0.002), RFS (HR, 0.331; 95% CI, 0.167 to 0.657; P = 0.002), and NRM (HR, 0.286; 95% CI, 0.120 to 0.683; P = 0.005). Regarding the KIR genotypes, compared with other donor KIR B/x genotypes: (1) In sibling HSCT, genotype Bx1 was a risk factor for lower OS (HR, 8.667; 95% CI, 2.321 to 32.37; P = 0.001) and RFS (HR, 9.207; 95% CI, 2.631 to 32.22; P = 0.001); (2) The same negative effect of Bx1 was also found in URD-HSCT (OS: P = 0.047; RFS: P = 0.041) and haplo-identical HSCT (OS: P = 0.002; RFS: P = 0.002). Conclusions Avoiding the selection of Bx1 donors is strongly advisable for AML/MDS patients undergoing both related and unrelated HSCT whereas the presence of the Cen -B motifs was rather recommended in donor selection.