Antiallograft antibodies: Relevance, detection, and monitoring

Purpose of review: Solid-phase immunoassays increase the accuracy of assessing pretransplant immunologic risk and facilitate posttransplant prediction and diagnosis of antibody-mediated rejection (AMR). This review will describe methods available for antibody analyses, discuss the types of targets of AMR and the characteristics of pathogenic alloantibodies, and provide guidelines for the application of antibody tests in the prediction of rejection risk and diagnosis of rejection. Recent findings: The presence of human leukocyte antigen-specific antibodies increases the risk of AMR, but the clinical relevance of low antibody levels is questioned with reports of stable graft function in their presence. Posttransplant monitoring has been shown to provide early diagnosis of AMR permitting preemptive intervention. Antibodies to other alloantigens and autoantigens are being implicated as potential targets for both acute and chronic AMR. Certain limitations and interfering factors have also been recognized that should be recognized in the interpretation of solid-phase antibody assay results. Summary: Contemporary technology is clearly advancing the detection of various antibodies that can contribute to AMR, but continued work is needed to elucidate the relevance of very low levels of human leukocyte antigen-specific antibody and the importance of antibodies to other alloantigens and autoantigens.