Background: Despite ubiquitous exposure to sensitizing events, most Fontan PLE patients have low panel reactive antibodies (PRA). To assess whether they are at risk for donor-specific antibody (DSA) memory response following heart transplantation (HT) when their PLE resolves, DSA profiles, incidence of rejection, and graft outcomes in Fontan recipients with and without PLE were compared.
Methods: Patient characteristics, appearance of newly detected DSA (nDSA), and graft outcomes were compared between patients with and without PLE using Wilcoxon rank-sum and Chi-squared tests. DSA burden was quantified using titers and time to nDSA, incidence of rejection, and graft outcomes were compared using Kaplan-Meier curves and the log-rank test.
Results: Characteristics of patients with and without PLE were similar. Lymphocyte and albumin levels were lower in the PLE group, and flow PRA were comparable. Graft failure, CAV, and ACR were similar between the two groups, but AMR occurred more frequently in the PLE group (p = .03). Nearly 50% of PLE patients experienced class II nDSA by 1-year post-HT, compared to 30% of non-PLE patients, but this difference was statistically not significant. Antibody burden did not differ between groups.
Conclusions: In this cohort, PLE was associated with AMR within the first-year post-HT, despite no significant difference in nDSA. Small patient numbers limited statistical comparison of nDSA in this cohort. PLE may be a risk factor for AMR post-HT, and the possibility of a clinically important DSA memory response remains. Larger studies are necessary to better understand these preliminary findings.
Keywords: Fontan; antibody mediated rejection; donor specific antibody; protein losing enteropathy.
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