Endothelial cell activation and hypercoagulability in ocular Behçet's disease

To investigate the presence of a hypercoagulable state and vascular endothelial dysfunction in patients with ocular Behçet's disease and relate the results to the activity of ocular and systemic involvement.

Cross-sectional laboratory and clinical study.

Prospective study of blood samples of 24 patients diagnosed with ocular Behçet's disease, which were analyzed for factor VIII, factor XI, von Willebrand factor antigen and ristocetin (vWF ag and risto), antithrombin III (ATIII), protein C and S, fibrinogen and activated protein C (APC) resistance. The results were compared with 40 healthy controls and analyzed for association with ocular and systemic clinical features.

The mean values of factor VIII, factor XI, vWF ag, vWF risto, ATIII, and fibrinogen were significantly raised compared to healthy population (for all: P <.001). Most striking were factor VIII activity levels above 130% in 79% (19 of 24) of our patients. 67% (16 of 24) had levels of factor VIII above 150%, which correlates with a fivefold increase in risk of thrombosis. Other prothrombogenic factors were negative in all but 2 patients (1 protein C deficiency, 1 factor V Leiden mutation). Endothelial cell activation, measured by vWF activity, revealed elevated levels in 42% (10/24). Complete/incomplete Behçet's disease patients with present or previous macular edema had significantly higher FVIII levels than complete/incomplete Behçet's disease patients who had never shown any signs of macular edema (P =.04). Further correlations between the laboratory results and clinical symptoms were not found.

We found a generalized hypercoagulable state with endothelial cell activation in ocular Behçet's disease, irrespectively of current ocular disease activity.