Early donor-specific antibodies in pediatric patients with Fontan circulation after heart transplant

De novo donor specific antibodies (DSA) are associated with increased morbidity and mortality in adults after heart transplant (HT). We describe our experience with pediatric patients undergoing HT for Fontan circulatory failure (FCF) who developed early DSA.

This is a retrospective case series of patients who received HT for FCF at a single center between April 2017 and May 2024. The inclusion criteria were age < 18 years, receiving HT for FCF, and positive DSA within 35 days of HT. Data collected included demographics, pre-transplant anatomy and FCF phenotype, pre- and post-transplant human leukocyte antigen (HLA) antibodies, induction therapy and DSA and AMR treatments. Outcomes of DSA, and antibody-mediated rejection (AMR) within the first year were noted.

Of 24 patients with FCF who received HT during the study period, eight (33%) developed early DSA. Antibodies were a combination of newly formed antibodies after a negative virtual cross match (VXM) and memory antibodies as some had positive VXM. Most had AMR within the first year (N = 5, 63%). All AMR resolved with treatment. Follow up ranged from 42 days to 5 years with a median of ∼2 years.

Early DSA were a combination of memory and newly formed antibodies. More than half of the patients developed AMR within the first year. Further research is needed to identify the implications of early DSA on graft dysfunction and long-term outcomes in patients with Fontan post heart-transplant.