Antiendothelial cell antibodies (AECA) have been detected by flow cytometry analysis in 23 out of 80 patients with connective tissue diseases. Ten out of 19 serum samples from patients with systemic lupus erythematosus (SLE) were positive. These antibodies were not detectable in healthy donors. We examined the capacity of serum samples to induce endothelial cell activation by modulating cell adhesion molecule expression on human umbilical vein endothelial cells. We found that sera from both AECA-positive and AECA-negative patient groups induced a significantly higher expression of E-selectin compared to healthy controls (P<0.05). There were no differences in the ICAM-1 on VCAM-1 expression. Our data suggest that increased E-selectin expression in activated endothelium in patients with various connective tissue disorders is not related to the production of AECA., M. Horváthová, E. Jahnová, Š. Nyulassy., and Obsahuje bibliografii