Antibody-mediated rejection (AMR) is a relatively rare but severe complication in transplantation surgery associated with increased risk of graft loss. Diagnosis of acute and chronic AMR is based on typical histological hallmarks. Antibody-mediated rejection (AMR) defines all allograft rejection caused by antibodies directed against donor-specific HLA molecules, blood group antigen (ABO)-isoagglutinins, or endothelial cell antigens.