Impact of Donor Characteristics and HLA Matching on Survival of Chinese Patients with Hematologic Malignancies Undergoing Unrelated Hematopoietic Stem Cell Transplantation

We retrospectively analyzed the impact of donor characteristics and HLA matching on outcomes in Chinese patients undergoing unrelated hematopoietic stem cell transplantation (HSCT). A total of 693 patients with hematologic malignancies who underwent HSCT between 2005 and 2010 had available survival data at 100 days or 1 year posttransplantation in the Buddhist Tzu-Chi Stem Cell Center database. The overall survival rates at 100 days and 1 year were 83.3% and 65.2%, respectively. Mismatches of HLA-A, -B, and -DRB1 at the antigen or allele level, along with inadequate cell dose, were associated with a significant risk of mortality (hazard ratio [HR] = 2.36, P < .001; HR = 1.44, P = .005; and HR = 2.20, P = .009, respectively). In 107 donors with matched HLA-A, -B and -DRB1 and known HLA-C match status, 22.4% had an HLA-C antigen mismatch, resulting in an HR of 2.87 for mortality relative to complete 8/8 matches (P = .005). Recipients with unknown HLA-C match status also had a significantly worse outcome (HR = 1.73; P = .039). Multivariate analysis revealed that cell dose and HLA-A, -B, -C, and -DRB1 antigen match status significantly affected the final outcome of survival (P = .012 and <.001, respectively). Our data indicate that HLA-C match status should be confirmed before HSCT from an unrelated donor. Inadequate cell dose remains an important determinant of poor transplantation survival. Further studies to elucidate the importance of matching of specific HLA loci are needed to better understand the risk of HSCT and improve patient outcomes.