Chad A Witt, Ramsey R Hachem Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, Saint Louis, MO, USA: The role of donor-specific antibodies to human leukocyte antigens and the burden of antibody-mediated rejection in lung transplantation remain enigmatic. Over the past several years, evidence has been emerging that humoral immunity plays an important role in the development of both acute and chronic lung allograft dysfunction. Multiple case reports and case series have (...) identified lung allograft recipients with clinical findings consistent with acute AMR. However, there is currently no widely accepted definition for AMR in lung transplantation, and this has been a significant barrier to furthering our understanding of this form of rejection. Nonetheless, the development of DSA after transplantation has consistently been identified as an independent risk factor for persistent and high-grade acute cellular rejection and CLAD. This has raised the possibility that chronic AMR may be a distinct phenotype of CLAD although evidence supporting this paradigm is still lacking. Additionally, antibodies to lung-restricted self-antigens have been associated with primary graft dysfunction early and the development of CLAD late after transplantation, and emerging evidence underscores significant interactions between autoimmunity and alloimmunity after transplantation. There is currently an active International Society for Heart and Lung Transplantation working group that is developing an operational definition for AMR in lung transplantation. This will be critical to improve our understanding of this form of rejection and conduct clinical trials to identify optimal treatment strategies. This review will summarize the literature on DSA and AMR in lung transplantation and discuss the impact of antibodies to self-antigens on lung allograft dysfunction. Keywords: antibody-mediated rejection, donor-specific antibodies, lung transplantation. (shrink)