Reviews on mysterious vascular endothelial cells in renal allografts.

Endothelial cells (ECs) are involved in allograft rejection and are prime targets, but also key players. HLA antigens are the most prominent targets of alloantibodies in transplantation. Alloantibodies against other antigens such as ABO blood group antigens and non-HLA antigens could also be demonstrated. Alloantibodies undoubtedly cause allograft rejection. Activation of ECs by anti-EC antibodies and direct antibody- or complement mediated EC damage may be suggested. However, the mechanisms underlying acute antibody-mediated rejection (AAMR) and chronic rejection (CR) remain unclear. In this review, the relationship between vascular endothelium and rejection is discussed mainly from our reports, and the mechanism and pathogenesis of CR are discussed.