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 to January 2020 to identify published cohorts of >= 500 incident adult or 75 pediatric kidney transplant recipients followed for >= 1 year post-transplant. 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 post-transplant. 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.