HLA Compatibility and Graft Survival Rates Among Related and Unrelated Donors in Renal Transplantation

Abstract

Human leukocyte antigen (HLA) compatibility between donors and recipients plays a critical role in graft survival in renal transplantation. This study evaluates the impact of HLA mismatching on graft survival and rejection among renal transplant recipients with related and unrelated donors, considering factors such as age, sex, ABO blood type, and anti-HLA antibodies. We investigated the graft survival rates between related and unrelated donors in a prospective cohort study conducted from 2018 to 2020 at Cho Ray Hospital and People's Hospital 115 in Vietnam, involving 126 related and 82 unrelated donor–recipient pairs. Over 32 months of follow-up, there was no significant difference in the rates of suspected graft rejection (P = .75) or graft loss (P = .095) between the 2 groups. However, related donors exhibited significantly higher overall survival (P = .0086) and better event-free survival (P = .0025) compared with unrelated donors. HLA matching and ABO type did not show any association with suspected graft rejection in either group. Notably, unrelated donors older than 5 years increased the risk of suspected graft rejection (hazard ratio, 4.22), and positive anti-HLA antibodies also increased this risk (hazard ratio, 4.5). Conversely, male–male donor–recipient pairs significantly decreased the risk of graft rejection by 88% compared with female–female pairs. The study concludes that although HLA matching is not different for related and unrelated donor groups, factors such as donor age, same-sex pairs, and the presence of anti-HLA antibodies are significant risk factors for graft rejection in unrelated donors. Enhancing monitoring and developing strategies for unrelated donors are essential to improve graft survival outcomes in renal transplantation.