Fibrinolytic activity and d-dimer levels in Behçet's syndrome

Thrombophlebitis occurs in a third of patients with Behçet's syndrome (BS). The thrombotic tendency in BS has been studied with inconclusive results perhaps due to the inadequate numbers of patients studied during the acute phase of the thrombosis as well as the lack of appropriate diseased controls. We have studied tissue-type plasminogen activator (t-PA) and its inhibitor (PAI-1), and d-dimer levels in BS patients with and without thrombosis both in the acute and chronic phases along with suitable diseased and healthy controls. t-PA and PAI-1 were studied by ELISA and d-dimer by semiquantitative latex agglutination slide test in 30 BS patients without deep vein thrombosis (DVT), 10 BS with acute DVT (ADVT), 25 BS with chronic DVT, 27 with ankylosing spondylitis, 26 diffuse systemic sclerosis, 15 patients with ADVT due to other causes, 10 patients with sepsis, and 23 healthy controls. The t-PA levels in BS with ADVT were significantly lower than those in patients with ADVT due to other causes (7.4 +/- 6.2 vs. 13.4 +/- 6.3, P = 0.027) while PAI-1 levels did not show significant differences between the groups (P = 0.60). The numbers of patients with d-dimer levels of > or = 0.5 microg/ml in BS with ADVT were similar to those found in patients with ADVT due to other causes (9/10 vs. 14/14). The relatively low t-PA levels point to a defect in fibrinolysis in BS. d-dimer levels are increased in the acute phase of thrombosis in BS.