Antiendothelial cell antibodies in systemic lupus erythematosus

Abstract

Objective: Anti-endothelial cell antibodies (AECAs) are a heterogeneous group of antibodies against a variety of antigenic determinants on endothelial cells (EC). AECAs are known to play an immunopathogenic role in triggering EC activation, leading to vascular damage. The purpose of this study was to assess: (i) the incidence of AECAs in systemic lupus erythematosus (SLE) patients with nephritis (LN) and to compare this with SLE patients without clinical evidence of nephritis; and (ii) to understand the association of AECAs with disease severity based on renal histopathological findings. Method: Fifty-three clinically and histopathologically proven cases of LN were studied along with 20 patients without evidence of nephritis. AECAs were detected by immunofluorescence using cultured human umbilical vein endothelial cells (HUVECs). The titres and immunoglobulin subclass of AECAs were also identified. Other autoantibodies were also detected. Results: In the LN group, 21 (39.6%) were AECA positive and 19 (35.8%) were antineutrophil cytoplasmic antibody (ANCA) positive. Autoantibodies to double-stranded DNA (anti-dsDNA) were present in 49 (92.4%) cases. In patients without nephritis, seven (35%) tested positive for AECA, five for ANCA and all were antinuclear antibody (ANA) positive. Anti-dsDNA was detected in 16 patients (80%), higher incidence of AECAs was noted in diffuse proliferative glomerulonephritis (41.2%) as compared to focal proliferative glomerulonephritis (37.5%) and membranoproliferative glomerulonephritis (33.3%). IgG-AECA subclass was noted in 85.7% patients, IgM-AECA and IgG + M AECA subclasses of AECA were detected in 7.1% cases. AECAs were also found to be associated with other autoantibodies such as ANA, anti-dsDNA and ANCA. Conclusion: No significant differences in AECA positivity was found between SLE with and without nephritis. © 2008 Asia Pacific League of Associations for Rheumatology and Blackwell Publishing Asia Pty Ltd.