ANTIENDOTHELIAL CELL ANTIBODIES IN TAKAYASU-ARTERITIS

Background Although a specific etiology for Takayasu arteritis has not been found, the bulk of evidence favors an autoimmune mechanism. We e xamined the sera of 19 patients with Takayasu arteritis for antineutro phil cytoplasmic antibodies (ANCA), antinuclear antibodies (ANA), anti -DNA antibodies, antibodies to extractable nuclear antigens (ENA), ant i-Ro antibodies, anticardiolipin antibodies. circulating immune comple xes, and anti-endothelial cell antibodies (AECA). Methods and Results We used enzyme-linked immunoassays, immunofluorescence, counterimmunoe lectrophoresis, fluorescent-activated cell sorter (FACS) analysis, and confocal microscopy. We found that although no patient had positive A NCA, ANA, anti-DNA antibodies, ENA antibodies, anti-Ro antibodies, or anticardiolipin antibodies, 18 of the 19 patients had AECA. The AECA t iters of the patients were 2561+/-1458 compared with 126+/-15 arbitrar y units in a normal group of control subjects (P<.001). To verify the specificity of AECA, we performed cytofluorimetry on human endothelial cells with the sera from patients and control subjects. Two entirely separate patterns of fluorescence intensity were identified. We next p erformed immunocytochemistry and confocal microscopy with human endoth elial cells subjected to patients' sera and to sera from normal subjec ts. The cells subjected to sera from patients with Takayasu arteritis demonstrated specific immunofluorescent staining of their plasma membr ane and cytosol. Conclusions AECA are frequently present in patients w ith Takayasu arteritis. They may play a role in the pathogenesis. Furt hermore, they may be useful as an additional diagnostic tool.