[Von Willebrand factor-cleaving protease activity in patients of collagen disease with antiphospholipid antibodies].
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.
Yamazaki
Satoshi
S
Department of Clinical Laboratory, St. Marianna University School of Medicine Hospital, Kawasaki 216-8511.
Taki
Masashi
M
Yasumuro
Yoko
Y
Takayama
Shigenobu
S
Miyake
Fumihiko
F
Fujimura
Yoshihiro
Y
Suzuki
Yasuo
Y
D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; D000328:Adult; D017152:Antibodies, Antiphospholipid / Q000378:metabolism*; D016736:Antiphospholipid Syndrome / Q000150:complications; D003095:Collagen Diseases / Q000201:enzymology*; D006801:Humans; D008666:Metalloendopeptidases / Q000378:metabolism*; D011697:Purpura, Thrombotic Thrombocytopenic / Q000201:enzymology
D017152:Antibodies, Antiphospholipid; D051722:ADAM Proteins; D008666:Metalloendopeptidases; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human