The Role of HLA-Directed Antibodies in Cardiac Transplant Immunology

Over the last few years heart transplant physicians have encounted more allograft rejection episodes that are not responsive to conventional treatment. The role of B cells and alloantibodies in organ transplant outcome becomes more apparent. More centers recognize the role of humoral rejection and the involvement of HLA-directed antibodies specifically. In fact, new guidelines to diagnose antibody mediated rejection have just recently been published and are reviewed in this context. This review summarizes our data as well as other published manuscripts related to the involvement of pre-formed as well as de-novo HLA-directed antibodies in determining allograft outcome. Special emphasis is given to the rapid advancements in antibody detection methodologies and the use of solid phase based techniques. We further discuss cutting edge opportunities to overcome prior sensitization of patients awaiting heart transplantation ("Desensitization protocols"). Utilizing recent advances in HLA-directed antibody detection methods and progress in immunosuppression protocols, patients previously not considered to be transplant candidates now have an opportunity to receive a life-saving allograft.