Specific von Willebrand factor-cleaving protease in thrombotic microangiopathies: a study of 111 cases.

Abstract

Retrospective studies of patients with thrombotic microangiopathies (TMAs) have shown that a deficient activity of von Willebrand factor (vWF)-cleaving protease is involved in thrombotic thrombocytopenic purpura (TTP) but not in the hemolytic-uremic syndrome (HUS). To further analyze the relevance of this enzymatic activity in TMA diagnosis, a 20-month multicenter study of vWF-cleaving protease activity was conducted in adult patients prospectively enrolled in the acute phase of TMA. Patients with sporadic (n = 85), intermittent (n = 21), or familial recurrent (n = 5) forms of TMA (66 manifesting as TTP and 45 as HUS) were included. TMA was either idiopathic (n = 42) or secondary to an identified clinical context (n = 69). vWF-cleaving protease activity was normal in 46 cases (7 TTP and 39 HUS) and decreased in 65 cases (59 TTP and 6 HUS). A protease inhibitor was detected in 31 cases and was observed only in patients manifesting TTP with a total absence of protease activity. Among the 111 patients, mean vWF antigen levels were increased and the multimeric distribution of vWF was very heterogeneous, showing either a defect of the high-molecular-weight forms (n = 40), a normal pattern (n = 21), or the presence of unusually large multimers (n = 50). Statistical analysis showed that vWF-protease deficiency was associated with the severity of thrombocytopenia (P <.01). This study emphasizes that vWF-cleaving protease deficiency specifically concerns a subgroup of TMA corresponding to the TTP entity.

• Authors: A Veyradier, B Obert, A Houllier, D Meyer, J P Girma
• Journal: Blood (Blood) Vol. 98 Issue 6 Pg. 1765-72 (Sep 15 2001) ISSN: 0006-4971 [Print] United States
• PMID: 11535510 (Publication Type: Case Reports, Journal Article, Multicenter Study)

Chemical References

• Protease Inhibitors
• ADAM Proteins
• Metalloendopeptidases
• ADAMTS13 Protein
• ADAMTS13 protein, human

Topics

• ADAM Proteins
• ADAMTS13 Protein
• Adult
• Female
• Follow-Up Studies
• Hemolytic-Uremic Syndrome (blood, diagnosis, therapy)
• Humans
• Male
• Metalloendopeptidases (antagonists & inhibitors, metabolism)
• Prospective Studies
• Protease Inhibitors (metabolism)
• Purpura, Thrombotic Thrombocytopenic (blood, diagnosis, therapy)
• Remission Induction