Anti-endothelial cell antibodies in inflammatory bowel disease.

Antibodies to endothelial cells may be involved in the pathogenesis of vasculitic disorders. In view of recent evidence implicating intestinal vascular injury in the pathogenesis of inflammatory bowel disease, we have sought anti-endothelial cell antibodies in affected patients, examined their relationship to vascular injury, and tested their ability to mediate endothelial cell cytotoxicity in vitro. Anti-endothelial cell antibody levels were elevated in ulcerative colitis (P < 0.0001) and Crohn's disease (P < 0.05) compared with healthy controls. In ulcerative colitis, anti-endothelial cell antibody levels were related to disease activity and correlated with circulating levels of von Willebrand factor (r = 0.58, P < 0.01), a marker of vascular injury. Anti-endothelial cell antibodies, however, were not directly cytotoxic to endothelial cells in vitro. These data indicate, for the first time, an association between anti-endothelial cell antibody levels and vascular injury in vivo and suggest that they may be important in the pathogenesis of inflammatory bowel disease, particularly ulcerative colitis.