Back
For best output, select "Paper Size" as "A4" and "Margin" as "0" or "None".
To save or print to PDF, please select Print Destination > Save as PDF, enable Background Graphics under "More Settings", then click "Save".
During the congress, E-Posters will be accessible to all participants on the congress website 24/7, as well as in the E-poster stations in the congress center.
Preparing your E-Poster
Please review the E-Poster format requirements carefully when preparing your E-Poster. Should your E-Poster not meet the mentioned requirements, it may not be displayed as described above.
E-Poster Submission Deadline
Please prepare and upload your E-Poster no later than March 14, 2026 11.59PM CET. After this date, you will no longer be able to prepare and upload your E-poster and it will not be displayed and accessible on the congress website.
Please follow the instructions below to input your abstract title.
Abstract titles should be brief and reflect the content of the abstract.
Kidney retransplantation provides a survival advantage over dialysis after graft failure but is challenged by immunologic memory induced by prior HLA exposure. Conventional antigen-level assessments do not fully reflect the molecular determinants of antibody binding. Eplet analysis quantifies the amino acid configurations that form functional epitopes, providing a refined measure of histocompatibility. In the setting of retransplantation, repeated eplet mismatches (REM)—re-exposure in the second graft to eplets mismatched in the first—may amplify anamnestic immune responses; however, their clinical impact has not been established. This study examined whether REM burden is associated with biopsy-proven acute rejection (BPAR) within one year after kidney retransplantation.
We performed a retrospective cohort study that included all adult recipients of a second kidney transplant at a tertiary university center between January 2008 and July 2024. Patients with early graft loss (≤1 month), multiorgan transplantation, incomplete HLA data, or loss to follow-up were excluded. High-resolution HLA typing (A, B, C, DR, and DQ loci) was performed, and eplet mismatches were computed using the HLAMatchmaker database. REM was defined as donor–recipient eplets shared by both grafts and quantified separately for class I and class II loci. The primary endpoint was BPAR within 12 months, classified per Banff 2022. Associations between REM burden and outcomes were analyzed using Kaplan–Meier and multivariable Cox regression models.
Among 158 retransplant candidates, 132 met the inclusion criteria (mean age 44.3 ± 12.5 years; 36% female; median cPRA 52.6). Within the first year, 19 patients (14.4%) developed BPAR. Higher total eplet mismatch load (54.3 ± 18.7 vs. 43.4 ± 20.1, p = 0.030) and higher class I (ABC) eplet mismatches (30.2±14.4 vs. 23.5±12.0, p=0.031) were associated with rejection, whereas allelic-level mismatches were not predictive. Repeated class I eplet mismatches were more frequent in patients with rejection (median 10 vs. 7.5, p=0.029). Rejection-free survival differed across the tertiles of repeated class I mismatches (log-rank p=0.037), with early failures clustering in the high-REM group.In the multivariable Cox analysis, each 5-eplet increase in repeated class I mismatches independently increased the rejection risk (adjusted HR 1.06 per eplet, 95% CI 1.01–1.12, p = 0.016) after adjustment for recipient age and cPRA. No significant associations were observed for repeated class-II REM.
This study provides the first evidence that repeated class I eplet mismatches independently predict early acute rejection after kidney retransplantation. By quantifying re-exposure to identical molecular HLA targets, REM captures the cumulative immunologic memory driving early graft rejection. The integration of eplet mismatches into immunologic risk assessment may refine recipient evaluation and donor selection, improving precision in retransplant management while maintaining equitable organ access. Prospective validation is required to establish clinically actionable REM thresholds.
