Humoral theory of transplantation: some hot topics

Antibody is a major cause of allograft injury. However, it has not been routinely tested post-transplant. A literature search was performed using PubMed on the topics of antibody monitoring, autoantibody and allograft dysfunction and prevention and treatment of antibody-mediated rejection (AMR). Donor-specific antibody (DSA) monitoring not only helps to identify patients at risk of AMR, but also serves as a biomarker to personalize patients maintenance immunosuppression. Development of autoantibody is a secondary response following primary tissue injury. Some autoantibodies are directly involved in allograft injury, while others only serve as biomarkers of tissue injury. It remains controversial whether DSA-positive patients without symptoms need to be treated. In addition, given the variation in study designs and patients characteristics, there is discrepancy regarding which treatment regimens provide optimal clinical outcome in preventing/treating AMR. Efficacy of B-cell and/or antibody-targeted therapies in treating or preventing AMR would be better measured by the incorporation of antibody monitoring into current functional and pathological assays. Research in B-cell targeted therapies to prevent and treat AMR is rapidly growing, which includes monoclonal antibodies against B-cell markers CD20, CD40, CD19, BlyS, etc. It requires extensive clinical research to determine the best approach to inhibit or delete antibody and how to balance the drug efficacy with safety.