International Society for Heart and Lung Transplantation Scientific Statement on pulmonary antibody-mediated rejection and proposed graft, antibody, and pathology (GAP) definition.

Antibody-mediated rejection (AMR) is an increasingly recognized form of rejection and cause of graft failure after lung transplantation. AMR has been the focus of extensive research over the past decade. Despite growing awareness and recent advances in our understanding of AMR, outcomes remain dismal with a 2-year survival of only 20%. The International Society for Heart and Lung Transplantation convened a multidisciplinary workgroup of experts in AMR to review the most up-to-date research and clinical experience and to update the 2016 definition. The workgroup was divided into 9 subgroups covering a broad range of topics pertaining to AMR and used the modified Delphi method to synthesize a cohesive summary of the literature. A multidimensional definition was developed to enhance precision by reporting the specific presenting features. This Graft, Antibody, and Pathology (GAP) definition is based on the presence of Graft dysfunction, the presence and characteristics of Antibodies, and Pathological findings. The workgroup emphasized that identifying better treatments for AMR is a critical unmet need and proposed that a more precise definition might allow better management by providing a platform for testing and developing new therapies.