[Anti-endothelial cell antibodies]

Abstract

Anti-endothelial cell antibodies (AECA) are demonstrated in connective tissue diseases (CTD) such as systemic lupus erythematosus (SLE) and progressive systemic sclerosis (PSS), but their role in the pathogenesis of CTD is unknown. Sera from 33 patients with SLE, 10 patients with PSS, 10 patients with polymyositis/dermatomyositis, 10 patients with mixed connective tissue diseases, 6 patients with rheumatoid arthritis (RA), 6 patients with malignant RA and 22 normal controls were examined for IgG-AECA and IgM-AECA by cellular ELISA method using cultured human umbilical vein endothelial cells. Each patient group except RA had significantly elevated levels of both IgG-AECA and IgM-AECA compared with that of normal controls. Furthermore, the possible relationship of AECA to clinical and laboratory findings in 28 patients with active SLE was analysed. The levels of both IgG-AECA and IgM-AECA in patients with either pulmonary hypertension (PH) or digital ulcer were significantly increased compared with those in patients without such abnormalities. IgG-AECA levels in patients with Raynaud's phenomenon and IgM-AECA levels in patients with serositis were significantly increased compared with those in patients without such abnormalities. PH and digital ulcer result from vasculitis and PH in SLE is reported to be associated with Raynaud's phenomenon, digital ulcer and serositis. These results suggest that AECA might play an important role in the pathogenesis of vasculitis and vascular injury in these organs. Further studies are required to characterize the nature of endothelial cell antigens with which AECA react and the role of AECA in vascular injury.