[Changes of ADAMTS13 activity and endothelial cell markers in TMA cases].

Severe deficiency of ADAMTS13 activity was recently found in patients with thrombotic thrombocytopenic purpura (TTP). The great advance associated with these basic and clinical studies on ADAMTS13 is the possible elucidation of the pathogenesis of TMA (thrombotic microangiopathy). However, the exact pathogenetic mechanism in TMA without severe deficiency of ADAMTS13 activity remains unknown due to heterogeneity of the disease.

Predicting response to plasma exchange in patients with thrombotic thrombocytopenic purpura with measurement of vWF-cleaving protease activity.

Background: Severe deficiency of vWF-cleaving protease (vWF-CPase) activity was recently found in patients with thrombotic thrombocytopenic purpura (TTP). Although the survival of patients with TTP has been dramatically improved with plasma exchange (PE), there are still many patients who are refractory to PE and immunosuppressive therapy.

Study Design And Methods: The activities of vWF-CPase and its inhibitor were measured in 27 patients with nonfamilial TTP and hemolytic-uremic syndrome (HUS) to examine the relationship between the clinical variables and vWF-CPase activity.

Increased plasma thrombomodulin as a vascular endothelial cell marker in patients with thrombotic thrombocytopenic purpura and hemolytic uremic syndrome.

Several hemostatic and vascular endothelial cell markers were measured in 39 patients with thrombotic thrombocytopenic purpura (TTP)/hemolytic uremic syndrome (HUS) and in 20 healthy volunteers to examine the relationship between the occurrence of hemostatic abnormality or vascular endothelial cell injury and patient outcome. The plasma levels of von Willebrand factor, tissue plasminogen activator (TPA), plasminogen activator inhibitor (PAI-1), and the TPA-PAI-1 complex were significantly increased in TTP/HUS patients; however, the levels of these markers were not significantly different between TTP/HUS patients who survived and those who died, suggesting that these markers might not be directly related to outcome. The plasma levels of soluble granule membrane protein (GMP)-140 were significantly higher in TTP/HUS patients than in healthy volunteers, suggesting that platelets and vascular endothelial cells are activated or injured in TTP/HUS.