Single nucleotide polymorphisms within HLA region are associated with disease relapse for patients with unrelated cord blood transplantation
Similar to hematopoietic stem cell transplantation (HSCT), disease relapse occurs in unrelated cord blood transplantation (CBT) even the human leukocyte antigen (HLA) alleles are fully matched between donor and recipient. A total of fourteen single nucleotide polymorphisms (SNPs) within the region of major histocompatibility complex (MHC) have been reported previously by Petersdorf et al. (Blood 2013;121:1896-1905) and Piras et al . ( Bone Marrow Transplant. 2014;49:1400-1404) to associate with transplantation determinants post-HSCT. The genomic sequences within 500 base pairs upstream and downstream of the fourteen HSCT-related SNPs were analyzed in this study to investigate whether geneticvariants within the MHC region are associated with disease relapse of unrelated HLA-matched CBT. A panel of seven SNPs was revealed to associate with the risk of relapse after unrelated CBT after analysis of fifty-three donor-recipient pairs. These SNPs included the donor type SNPs of rs2523675 and rs2518028 at the telomeric end of HCP5 gene, rs 2071479 in the intron of HLA-DOB gene, and rs 2523958 in the MICD gene; and the recipient type SNPs of rs 9276982 in the HLA-DOA gene and rs435766 and rs 380924 in the MICD gene. These SNPs have not yet been reported to associate with the transplant outcome of HSCT, implying that different SNPs were associated with the effectiveness of unrelated HSCT and CBT. As measured by pair-wise linkage disequilibrium (LD), the SNP of rs2523675 had high LD with the SNPs of rs4713466 (D’ = 0.86) and rs2523676 (D’ = 0.91) in the HCP5 gene. The SNP of rs2518028 had no LD with all other SNPs except rs2523675. This study provides a basis to meliorate strategies of searching and selecting better candidate donors for unrelated CBT.