Antiendothelial cell antibodies in vascular inflammation

Endothelium is one of the main targets of the immune-mediated inflammatory process in systemic autoimmune vasculitis. Endothelial cells (EC) are now considered as a dynamic, heterogeneous tissue that plays key roles in haemostatic balance and vessel tone regulation and that secretes a wide panel of pro-inflammatory cytokines, chemokines and growth factors. The availability of EC culture techniques led to the formal demonstration of anti-endothelial cell antibodies (AECA) in a variety of disorders that have in common an immune-mediated damage of the vessel wall. More interestingly, AECA have been shown to mediate different effects that can be pivotal in autoimmune vasculitis: cytotoxicity, release of endothelial mediators (vWF, arachidonic acid metabolites, Endothelin-1) and the induction of a pro-inflammatory and a pro-coagulant phenotype. Altogether these findings suggest that EC might act as active players in the pathogenesis of autoimmune vasculitis being at the same time the target for autoantibodies (and cell-mediated immune responses) and the source of mediators of the immune-mediated inflammation.