Behcet's disease sera containing antiendothelial cell antibodies promote adhesion of T lymphocytes to cultured human dermal microvascular endothelialcells

Antiendothelial cell antibodies (AECA) have been detected in the sera of pa tients of autoimmune diseases showing vasculitis. Using IgM-ELISA, we found AECA in 42 (56%) of 75 sera samples from patients with Behcet's disease in a previous study. All of the 15 AECA-positive sera of Behcet's disease pat ients had an increased expression of the intercellular cell adhesion molecu le-1 (ICAM-1), 93.3% of the sera induced the vascular cell adhesion molecul e-1 (VCAM-1), and 100% of the serum induced the E-selectin molecule on huma n dermal microvascular endothelial cells (HDMEC). After stimulation of HDME C with AECA-positive sera of Behcet's disease patients, the expression of I CAM-1 and VCAM-1 on HDMEC increased significantly at 4 hours, reaching a pe ak at 16 hours. Expression of E-selectin was induced at 1 hour after stimul ation with a peak at 4 hours and it decreased thereafter. Adherence of T ly mphocytes to HDMEC increased significantly after stimulation with AECA-posi tive sera from Behcet's disease patients. Also, the adherence of T lymphocy tes to HDMEC increased at 4 hours and returned to its normal level at 48 ho urs. These results show that AECA-positive sera of Behcet's disease patient s are capable of activating HDMEC to promote the adherence of T lymphocytes to increase the expression of ICAM-1, VCAM-1, and E-selectin on the cell s urfaces. The whole process may play an important rule in the pathogenesis o f vasculitis in Behcet's disease.