AUTHOR=Roufosse Candice , Becker Jan Ulrich , Rabant Marion , Seron Daniel , Bellini Maria Irene , Böhmig Georg A. , Budde Klemens , Diekmann Fritz , Glotz Denis , Hilbrands Luuk , Loupy Alexandre , Oberbauer Rainer , Pengel Liset , Schneeberger Stefan , Naesens Maarten TITLE=Proposed Definitions of Antibody-Mediated Rejection for Use as a Clinical Trial Endpoint in Kidney Transplantation JOURNAL=Transplant International VOLUME=35 YEAR=2022 URL=https://www.frontierspartnerships.org/journals/transplant-international/articles/10.3389/ti.2022.10140 DOI=10.3389/ti.2022.10140 ISSN=1432-2277 ABSTRACT=

Antibody-mediated rejection (AMR) is caused by antibodies that recognize donor human leukocyte antigen (HLA) or other targets. As knowledge of AMR pathophysiology has increased, a combination of factors is necessary to confirm the diagnosis and phenotype. However, frequent modifications to the AMR definition have made it difficult to compare data and evaluate associations between AMR and graft outcome. The present paper was developed following a Broad Scientific Advice request from the European Society for Organ Transplantation (ESOT) to the European Medicines Agency (EMA), which explored whether updating guidelines on clinical trial endpoints would encourage innovations in kidney transplantation research. ESOT considers that an AMR diagnosis must be based on a combination of histopathological factors and presence of donor-specific HLA antibodies in the recipient. Evidence for associations between individual features of AMR and impaired graft outcome is noted for microvascular inflammation scores ≥2 and glomerular basement membrane splitting of >10% of the entire tuft in the most severely affected glomerulus. Together, these should form the basis for AMR-related endpoints in clinical trials of kidney transplantation, although modifications and restrictions to the Banff diagnostic definition of AMR are proposed for this purpose. The EMA provided recommendations based on this Broad Scientific Advice request in December 2020; further discussion, and consensus on the restricted definition of the AMR endpoint, is required.