A CIBMTR (Center for International Blood and Marrow Transplant Research) study found that single HLA mismatches at HLA-A, -B, -C, or -DRB1 are associated with increased hazard for mortality as observed in earlier studies of unrelated donor hematopoietic cell transplantation. There have been many advances in supportive care and treatment regimens following earlier studies from 1988 -early 2000s. Dr. Pidala and colleagues evaluated 8,003 unrelated donor transplants for AML, ALL, CML, and MDS facilitated by the National Marrow Donor Program (NMDP)/Be The Match from 1999-2011, with outcomes reported to the NMDP's research program, CIBMTR. Based on single HLA mismatches and an increased hazard for mortality, Dr. Pidala recommends that unrelated donor allogeneic transplantation should proceed with the best available 8/8 or 7/8 donor as quickly as possible to avoid disease progression, because outcomes in advanced disease are poor regardless of the degree of HLA match.
A Contemporary Analysis of the Impact of HLA Mismatch on HCT Outcomes