Disorders associated with antibodies to endothelial cells.

Antibodies that bind to endothelial cells have been identified in patients with diverse forms of vasculitis and thrombosis. Sera from patients with systemic lupus erythematosus contain both complement-fixing antibodies and immune complexes that bind to cultured endothelial cells. Sera from patients with heparin-associated thrombocytopenia and thrombosis contain antibodies that react with heparin bound to the endothelium and cross-react with heparan sulfate synthesized by endothelial cells. Children with Kawasaki syndrome may develop cytolytic IgM antibodies that recognize surface antigens induced on endothelial cells by interferon-gamma, interleukin 1, and tumor necrosis factor. The presence of alloantibodies to tissue-restricted polymorphic antigens expressed by endothelial cells is frequently associated with thrombotic microvascular injury and hyperacute allograft rejection. Binding of antibodies and immune complexes to endothelial cells in vitro initiates platelet adherence, production of tissue factor, and secretion of plasminogen activator inhibitor. Antibody-mediated endothelial cell injury may play a role in other vascular disorders of unknown cause.