Little evidence for anti-endothelial cell antibodies in microscopic polyarteritis and Wegener's granulomatosis

We studied sera from patients with vasculitis and controls for the presence of anti-endothelial cell antibodies (AECA) and correlated these with disease type, anti-neutrophil cytoplasmic antibodies (ANCA) and anti-myeloperoxidase (MPO) antibodies. AECA were detected by a cellular ELISA on cultured human umbilical vein endothelium. AECA were found in the sera of one of 43 patients with microscopic polyarteritis (2%), five of 27 patients with Wegener's granulomatosis (19%), three of 23 patients with an idiopathic glomerulonephritis (13%), none of eight patients with rheumatoid arthritis and three of 12 patients with rheumatoid vasculitis (25%). In patients with a vasculitis AECA titres were higher in sera with a positive ANCA as compared with ANCA negative sera although the difference was not significant (P = 0.0702) and there was no correlation between AECA and anti-MPO titres (r = 0.1171 P = 0.114). AECA binding was not enhanced following upregulation of endothelial ICAM-1 and ELAM-1 by TNF alpha. This study shows that AECA occur infrequently in microscopic polyarteritis and Wegener's granulomatosis, and are not a major antibody system in these vasculitides.