Anti-Endothelial Cell Antibodies In Antineutrophil Cytoplasmic Antibodies Negative Pauci-Immune Crescentic Glomerrulonephritis

Purpose Patients with pauci-immune crescentic glomerulonephritis (CrGN) are frequently associated with antineutrophil cytoplasmic antibodies (ANCA). However, in patients with ANCA-negative pauci-immune CrGN, the pathogenesis is not clear. Anti-endothelial cell antibodies (AECA) have been implicated in the pathogenesis of various vasculitis. The purpose of this study is to investigate the prevalence of AECA and their possible clinical significance in ANCA-negative pauci-immune CrGN. Methods Sera from 19 patients with ANCA-negative pauci-immune CrGN and 26 patients with ANCA-positive pauci-immune CrGN were collected. Soluble proteins extracted from cultured human umbilical vein endothelial cells were used as antigens and Western blot analysis was performed to detect AECA.Results In patients with ANCA-negative pauci-immune CrGN, 10 of the 19 patients were serum IgG-AECA positive and seven protein bands of endothelial antigens could be blotted. The prevalence of skin rash and thrombocytosis was significantly higher in patients with anti-76kD and anti-123kD autoantibodies than those without respectively; the average Birmingham Vasculitis Activity Score of patients with anti-200kD AECA was significantly higher than those without. While in the sera of 26 ANCA-positive cases, 23 of them were AECA positive and 11 bands could be recognized. The prevalence of total AECA and anti-90kD AECA was significantly lower in patients with ANCA-negative pauci-immune CrGN than that in patients with ANCA-positive pauci-immune CrGN. Conclusions AECA could be found in the sera from patients with ANCA-negative pauci-immune CrGN, some AECA might have some clinical significance. The differences of AECA might contribute to the differences on clinical manifestations between ANCA-negative and ANCA-positive pauci-immune CrGN.