Pathogenic role of anti-endothelial cell antibodies in systemic vasculitis

Antiendothelial cell antibodies (AECA), a heterogeneous group of antibodies quite distinct from the ANCA family, have been detected in variety of diseases which share a varying degree of vessel wall damage. This review is mainly focused on Wegener's granulomatosis, Takayasu's arteritis and Kawasaki syndrome, which provide the best examples to evaluate the pathogenic and prognostic value of AECA. There is increasing evidence to show that AECA might be pathogenic in inducing autoimmune vascular disease. It is relevant to note that the presence and titre of AECA has been correlated with disease activity in systemic vasculitis. Experimental in vitro and in vivo models support a potential pathogenic role for AECA in sustaining immune-mediated vessel inflammation. Rather than being cytotoxic to endothelial cells, AECA are able to up-regulate the expression of adhesion molecules (E-selectin, intercellular adhesion molecule-1 and vascular cell adhesion molecule-1) and to induce the secretion of cytokine and chemokine which, in turn, cause leukocyte recruitment and adhesion. A recent idiotypic animal model has provided further evidence that AECA can be pathogenic.