Abstract 14400: Human Leukocyte Antigen Mismatching and Graft Survival in Pediatric Heart Transplant Recipients
Background: Studies suggest that mismatched human leukocyte antigen (HLA) alleles between donors and recipients are associated with graft failure in adult heart transplant recipients, but this has not been studied adequately in pediatric patients. This study is the first to measure the association between HLA mismatches and long-term graft survival in a large national database of pediatric heart transplant recipients.
Methods: We conducted a retrospective cohort study of primary heart transplant recipients under 21 years of age using the Scientific Registry of Transplant Recipients from 1987-2012. We used Kaplan-Meier method and Cox proportional hazards regression to compare rates of death or re-transplantation in 778 recipients with 0-3 total donor-recipient mismatches at HLA-A, -B, and -DR loci to both the combined group of 4687 recipients with 4-6 total mismatches, and to the smaller groups of recipients with 4, 5, and 6 mismatches separately. We also compared graft survival separately by number of class I (HLA-A and -B) and class II (HLA-DR) mismatches.
Results: Recipients with 0-3 total mismatches were more likely to be Caucasian, to have received a graft from a Caucasian donor, and to have a negative cross-match result. Recipients with 4-6 mismatches had an increased long-term risk of death or re-transplantation over 25 years of follow-up as compared to those with 0-3 mismatches (HR: 1.17 [95% CI: 1.03-1.33, p=0.02]). This association was not confounded by conventional risk factors for post-transplant outcomes. Separate HRs for those with 4, 5, and 6 mismatches were 1.17 (95% CI: 1.01-1.35), 1.15 (95% CI: 1.00-1.32), and 1.21 (95% CI: 1.04-1.41). Median times to death or re-transplantation were 10.6 (95% CI: 10.0-11.2) and 13.2 (95% CI: 11.2-15.8) years in the groups with 4-6 vs. 0-3 mismatches, respectively. Mismatching at class I loci was associated with a HR of up to 1.36 (95% CI: 1.06-1.73) while mismatching at the class II locus was associated with a HR of up to 1.11 (95% CI: 0.90-1.37).
Conclusions: Having more HLA mismatches was associated with increased risk of death or re-transplantation in pediatric heart transplant recipients. The association was strongest with mismatched class I alleles.
- © 2013 by American Heart Association, Inc.