[Von Willebrand factor-cleaving protease activity in patients of collagen disease with antiphospholipid antibodies]

Rinsho Byori. 2002 Mar;50(3):301-7.
[Article in Japanese]


Acquired thrombotic thrombocytopenic purpura (TTP), characterized by widespread thrombus formation in the microcirculation, is a ponderous complication of antiphospholipid syndrome. Recently, von Willebrand factor-cleaving protease (VWF-CPase) activity has been reported as a possible determinant for the occurrence of TTP. To clarify the role of VWF-CPase in the thrombus formation associated with antiphospholipid syndrome, we investigated plasma VWF-CPase activity in patients of collagen diseases with lupus anticoagulant (LA). Decreased plasma VWF-CPase activity less than 50% of the normal activity was observed in 25.7% (n = 18) in 70 patients with collagen diseases and 7 (10%) cases of them showed more lower VWF-CPase activity less than 25%. The IgG fractions obtained from 2 patients with the low VWF-CPase activity strongly inhibited the proteolytic reaction of normal VWF-CPase. There was no significant relationship between LA and plasma VWF-CPase activity. Thrombotic episodes, especially arterial thrombosis, were more frequently observed in LA-positive patients with low VWF-CPase activity. These results suggest that decreased activity of VWF-CPase, partly due to IgG type inhibitor to the enzyme activity may be an additional risk factor for arterial thrombosis in collagen disease patients with antiphospholipid antibodies.

MeSH terms

  • ADAM Proteins
  • ADAMTS13 Protein
  • Adult
  • Antibodies, Antiphospholipid / metabolism*
  • Antiphospholipid Syndrome / complications
  • Collagen Diseases / enzymology*
  • Humans
  • Metalloendopeptidases / metabolism*
  • Purpura, Thrombotic Thrombocytopenic / enzymology


  • Antibodies, Antiphospholipid
  • ADAM Proteins
  • Metalloendopeptidases
  • ADAMTS13 Protein
  • ADAMTS13 protein, human