ristocetin and Thrombophilia

The thrombopoietin receptor agonist romiplostim is used for the long-term treatment of chronic immune thrombocytopenia (ITP). ITP patients have an increased thrombotic risk, which could be exacerbated if romiplostim increased platelet hyperreactivity or caused spontaneous platelet aggregation. To investigate this possibility, this study examined platelet function in romiplostim-treated ITP patients and healthy subjects. Light transmission platelet aggregometry utilizing arachidonic acid, collagen, epinephrine, ristocetin, ADP, and saline (to assess spontaneous aggregation) was performed for each subject. In addition, the ADP AC

Topics: Adenosine Diphosphate; Adult; Aged; Arachidonic Acid; Blood Platelet Disorders; Collagen; Epinephrine; Female; Humans; Male; Middle Aged; Platelet Aggregation; Purpura, Thrombocytopenic, Idiopathic; Receptors, Fc; Receptors, Thrombopoietin; Recombinant Fusion Proteins; Ristocetin; Thrombophilia; Thrombopoietin; Young Adult

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.

Topics: Activated Protein C Resistance; Adult; Antigens; Antithrombin III; Behcet Syndrome; Cross-Sectional Studies; Endothelium, Vascular; Factor VIII; Female; Fibrinogen; Humans; Male; Middle Aged; Prospective Studies; Protein C; Protein S; Ristocetin; Thrombophilia; Venous Thrombosis; von Willebrand Factor