Identical versus compatible blood typing: investigating best practices in lung transplantation

This study investigated acute rejection in ABO-compatible versus ABO-identical lung transplants from 2005-2023, with a secondary objective of comparing 5-year survival. Lung transplantation improves quality of life and survival; however, organ scarcity remains a major challenge. While ABO-identical matching has traditionally been preferred, evolving allocation policies and research have increased the use of ABO-compatible transplants to expand the donor pool. A retrospective cohort study using the UNOS database included adult recipients (n = 32,761). Comparisons were made between ABO-identical (n = 30,347) and ABO-compatible (n = 2,414) groups. Logistic regression assessed acute rejection, and Kaplan-Meier and Cox proportional hazards models evaluated 5-year survival. There was no significant difference in acute rejection (p = 0.99; OR = 1.03, 95% CI 0.86-1.21). ABO-identical transplants showed improved 5-year survival (p = 0.019; HR = 0.91, 95% CI 0.85-0.98), with benefits limited to recipients with obstructive lung disease (p = 0.043) and those in the highest LAS quartile (p = 0.014). The differential benefit of this modest association between ABO-identical matching and survival in this subpopulation remains unclear. Overall, ABO-compatible transplantation safely expands donor availability without increasing rejection risk.