Petersdorf summarized the rich history of studies investigating the importance of HLA matching in haematopoietic stem cell tranplant either unrelated donor transplantation or cord blood transplantation. In unrelated donor hematopoietic stem cells transplantation, there are five major concepts regarding the role of donor HLA mismatching and graft versus host disease :
- Type and match at high resolution
- Consider HLA-DP especially HLA-A, C, B, DR, DQ-mathced donors are available
- When matched donors are not available, limit the total number of HLA mismatches
- When selecting among HLA-mismatched donors, distinguish allele from antigen mismatches
- Consider KIR ligands, KIR alleles, and KIR haplotypes
In cord blood transplantation, there is strong evidence that fewer mismatches are associated with overall improved outcome and that HLA-associated effects are influenced by the cell dose of the cord blood unit. Like unrelated donor hamatopoeitic stem cell transplantation, there is emerging evidence that matching the cord blood unit for HLA-C will lower post-transplant complication.