Incidence, risk factors, treatment, and consequences of antibody-mediated kidney transplant rejection: A systematic review.

Background Antibody-mediated rejection (AMR) is a leading cause of kidney allograft failure, but its incidence, risk factors, and outcomes are not well understood. Methods We searched Ovid MEDLINE, Cochrane, EMBASE, and Scopus from January 2000-January 2020 to identify published cohorts of ≥ 500 incident adult or 75 pediatric kidney transplant recipients followed for ≥ 1 year posttransplant. Results At least two reviewers screened 5061 articles and abstracts; 28 met inclusion criteria. Incidence of acute AMR was 1.1%-21.5%; most studies reported 3%-12% incidence, usually within the first year posttransplant. Few studies reported chronic AMR incidence, from 7.5%-20.1% up to 10 years. Almost all patients with acute or chronic AMR received corticosteroids and intravenous immunoglobulin; most received plasmapheresis, and approximately half with rituximab. Most studies examining death-censored graft failure identified AMR as an independent risk factor. Few reported refractory AMR rates or outcomes, and none examined costs. Most studies were single-center and varied greatly in design. Conclusions Cohort studies of kidney transplant recipients demonstrate that AMR is common and associated with increased risk of death-censored graft failure, but studies vary widely regarding populations, definitions, and reported incidence. Gaps remain in our understanding of refractory AMR, its costs, and resulting quality of life.