The importance of non-HLA antibodies in transplantation

Abstract

The development of post-transplant antibodies against non-HLA autoantigens is associated with rejection and decreased long-term graft survival. Although our knowledge of non-HLA antibodies is incomplete, recent studies provide compelling experimental and clinical findings demonstrating that antibodies directed against autoantigens contribute to the process of antibody-mediated acute and chronic rejection. Important areas for investigation remain understanding the mechanisms underlying the production of autoantibodies in the setting of organ transplantation. Ischaemia-reperfusion injury, surgical trauma and/or alloimmune responses can result in the release of organ-derived autoantigens in the form of soluble antigens, extracellular vesicles or apoptotic bodies that are presented in context of the transplant recipient’s antigen presenting cells to stimulate autoantibody production. Th17 cells are essential in the orchestrating autoantibody production by supporting the proliferation and maturation of autoreactive B cells within ectopic tertiary lymphoid tissue. Conversely, autoantibody-mediated graft damage can trigger alloimmunity and the development of donor-specific HLA antibodies that can act in synergy to promoteallograft rejection. Identification of the immunologic phenotypes of transplant recipients at risk of non-HLA antibody-mediated rejection and the development of targeted therapies to treat these rejections are sorely needed to improve both transplant and patient survival.