Anatomopathologie du rejet de greffe humoral en transplantation rénale et cardiaque

Humoral rejection (antibody-mediated rejection, ABMR) is a major concern in solid organ transplantation, playing a key role in late allograft losses. ABMR is mediated by anti HLA antibodies found in the serum of the recipient and directed against the donor (donor specific antibodies - DSA). Activation of the classical pathway of the complement cascade triggered by the fixation of the antibodies on endothelial cells is the main pathogenic feature of ABMR, responsible for the histological lesions. Diagnostic criteria are well established in kidney and cardiac transplantation based on the presence of histological criteria, mainly inflammation of the microcirculation, DSA and positivity of C4d. In other solid organ transplantations, ABMR is a more recent entity and diagnostic criteria are less clear.