Tuesday March 29, 2022 - 14:00 to 15:10
Epitopic mismatch and risk of developing DSA in pediatric kidney transplantation
Gwenaelle Roussey1, Laure Trottier1, Nicolas Vince2, Florent Delbos3, Hortense Langlois d'Estaintot1, Sophie Limou2, Alexandra Bruel1, Emma Allain Launay1, Georges Karam1, Fleur Lorton1, Amélie Ryckewaert4.
1Pediatric Departement, University Hospital of Nantes, NANTES, France; 2Centre de Recherche en Transplantation et Immunologie, UMR 1064, INSERM, University of Nantes, NANTES, France; 3HLA department, Etablissement Français du Sang, NANTES, France; 4Pediatric department, University Hospital of Rennes, Rennes, France
Introduction: In kidney transplantation, the appearance of donor specific antibodies (DSA) is linked to the risk of graft rejection. HLA matching at the epitope level could limit the risk of DSA and graft rejection. The aim of this study was to evaluate the correlation between the number of HLA mismatches (MM) at the epitope level and the risk of developing DSA in a pediatric cohort.
Methods: This monocentric retrospective study included all patients under 18 years-old who had received a kidney transplant between March 2003 and March 2018. Patients were followed up once a year with an HLA antibody screening. HLA epitopic MM were analyzed with Easy HLA and PIRCHE II softwares. Statistic analysis were performed with logistic regression models. P<0.05 was considered as signifiant.
Results: One hundred and sixteen donor/recipients pairs were included. Twenty-nine of them (25%) had pre-transplant anti-HLA antibodies. Post-transplant anti-HLA antibodies appeared in 57.7% of patients, de novo DSA in 23.3% of patients. De novo DSA were anti class-I DSA in 47.4%, anti class-II DSA in 76.5%, and both class-I and II DSA in 23.8% of the cases. The mean time to onset of DSA was 4.3 +/-3.4 years. Graft rejection was observed in 21% patients (N=25). Graft survival at 5 and 10 years was respectively 94.6% and 84%.
According to Easy-HLA software, mean class-I and class-II epitopic MM were 40.6+/-14.6 and 20.5+/-10.3 respectively. The mean PIRCH II score was 77.3+/-40.2. There was no correlation between the number of HLA MM at the epitopic level and the occurrence of DSA, either according to the EASY-HLA method or to PIRCHE II.
Conclusion: In this retrospective monocentric cohort, no correlation between the number of epitopic HLA mismatches and the risk of developing DSA was observed. Further studies are necessary to investigate the impact of HLA mismatching at epitopic level in pediatric patients.