Article: article from journal or magazin.
von Willebrand factor-cleaving protease (ADAMTS-13) activity determination in the diagnosis of thrombotic microangiopathies: the Swiss experience.
Seminars in Hematology
Publication types: Journal Article ; Research Support, Non-U.S. Gov't Publication Status: ppublish
Severe deficiency of von Willebrand factor (VWF)-cleaving protease (ADAMTS-13) activity (<5% of normal) is a specific finding for acute idiopathic thrombotic thrombocytopenic purpura (TTP), a disorder that presents as thrombocytopenia, microangiopathic hemolytic anemia, and often organ dysfunction such as neurological disturbances or renal failure, and fever. Between January 2001 and July 2003, ADAMTS-13 activity was determined in plasma samples of 396 consecutive patients referred to our laboratory for diagnostic purposes. Plasma samples with ADAMTS-13 activity less than 5% were in addition tested for the presence of inhibitory antibodies. Patients were assigned to 10 predefined clinical categories according to information provided by the referring clinician: thrombotic microangiopathy (TMA) not further specified; neoplasia- or chemotherapy-associated TMA; TMA following hematopoietic stem cell transplantation; TMA with additional/alternative disorder; idiopathic TTP; hemolytic-uremic syndrome (HUS) not specified; HUS with diarrhea prodrome (D+HUS); atypical HUS; other hematological disorder; and no clinical information available. Severe ADAMTS-13 deficiency was found in 69 (17%) patients, including 42 with acquired idiopathic TTP, either at initial presentation or at relapse, 14 with confirmed or suspected hereditary TTP, 10 with TMA not further specified, two with neoplasia- or chemotherapy-associated TMA, and one in continued clinical remission 3.4 years after splenectomy for plasma-refractory TTP. Forty-three (62%) patients with ADAMTS-13 activity less than 5% displayed inhibitory antibodies. Severe ADAMTS-13 deficiency was found in 60% of patients diagnosed with acute idiopathic TTP, but in none of 130 patients diagnosed with HUS or in any of the 14 patients with hematopoietic stem cell transplantation-associated TMA. Thus, plasma ADAMTS-13 activity less than 5% does not identify all patients clinically diagnosed with TTP, and severe ADAMTS-13 deficiency is not invariably associated with clinical manifestations of microvascular platelet clumping.
ADAM Proteins, Adolescent, Adult, Aged, Aged, 80 and over, Anemia, Hemolytic/blood, Anemia, Hemolytic/diagnosis, Child, Child, Preschool, Humans, Infant, Metalloendopeptidases/blood, Metalloendopeptidases/deficiency, Middle Aged, Protease Inhibitors/pharmacology, hic" UI="D013557">Switzerland/epidemiology, Thrombosis/blood, Thrombosis/diagnosis
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