Elevated serum anti-endothelial cell autoantibodies titer is associated with lupus nephritis in patients with systemic lupus erythematosus.

BACKGROUND AND PURPOSE: Systemic lupus erythematosus (SLE) is an autoimmune connective tissue disease associated with endothelial dysfunction and the existence of multiple species of autoantibodies. However, the association between endothelial dysfunction and renal manifestations remains unclear in Taiwanese SLE patients. METHODS: Serum samples were collected from SLE patients with biopsy-proven lupus nephritis (n = 32), stable SLE patients (n = 32) and healthy controls (n = 32). The SLE Disease Activity Index (SLEDAI) of SLE patients was scored, and levels of anti-endothelial cell antibodies (AECA) and anti-endothelial activities in serum samples were measured by cell-enzyme-linked immunosorbent assay and crystal violet assay, respectively, using cultured human endothelial EA.hy926 cells. RESULTS: Significantly higher AECA (p<0.001) and anti-endothelial activities (p<0.001) were found in sera from patients with lupus nephritis compared with that from stable SLE patients or controls. Moreover, AECA titers (p<0.001) and anti-endothelial activities (p<0.001) were strongly correlated with SLEDAI scores in these patients. CONCLUSION: The strong correlations of AECA and anti-endothelial activity with lupus nephritis activity support an endothelial origin for renal complications in Taiwanese SLE patients.