Beyond Criteria and Definitions: Outcome of a Standardized Antibody-Mediated Rejection Protocol with a Diagnostic Schema Different from the Banff 2009 Criteria.

A new clinical diagnostic schema is needed for the diagnosis of antibody-mediated rejection (AMR) in kidney transplant recipients due to the limited utility of C4d staining, lack of standardized quantitative tests for donor specific antibodies, and potential new diagnostic markers. The treatment of AMR remains controversial because previous studies included heterogeneous treatment modalities, small sample sizes, and short follow-up time. At the University of Michigan Transplant Center, 26 patients were diagnosed with AMR based on our diagnostic protocol including C4d-negative AMR in thesetting of graft dysfunction and Banff tissue injury type II (capillaritis) or type III (arteritis). After diagnosis, these patients received six sessions of plasmapheresis (PP) and IVIG (100 mg/kg after the first to fifth PP and 500 mg/kg with the last PP). Our novel finding in this analysis was the association between persistent C1q detection and graft loss. We confirmed that C4d positivity at diagnosis is associated with worse outcomes. Also, we found that response to our treatment protocol is dependent on C4d staining and Banff tissue injury type.