膠原病における von Willebrand 因子特異的切断酵素と
抗リン脂質抗体との関連

山　崎　　　哲*1　瀧　　　正　志*2　安　室　洋　子*3　高　山　成　伸*4
三　宅　良　彦*5　藤　村　吉　博*6　鈴　木　康　夫*7　　　　　　　　　　
　　　　　　　　　　　　　　　　　　　　　　
Von Willebrand Factor-Cleaving Protease Activity in Patients of Collagen Disease
with Antiphospholipid Antibodies

Satoshi YAMAZAKI*1, Masashi TAKI, MD*2, Yoko YASUMURO*3, Shigenobu TAKAYAMA, PhD*4,
Fumihiko MIYAKE, MD*5, Yoshihiro FUJIMURA, MD*6 and Yasuo SUZUKI, MD*7

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.
[Rinsho Byori 50 : 301〜307, 2002]

*1Department of Clinical Laboratory, St. Marianna University School of Medicine Hospital, Kawasaki 216-8511

【Key Words】Von Willebrand factor cleaving protease：VWF-CPase(フォンビレブランド因子切断酵素)，antiphospholipid antibodies：APA(抗リン脂質抗体)，Thrombotic thrombocytopenic purpura：TTP(血栓性血小板減少性紫斑病)

受付2001年9月7日・受理2001年12月13日
*1,3聖マリアンナ医科大学病院臨床検査部，*2同　小児科，*5同　循環器内科，
*7同　リウマチ・アレルギー内科(〒216-8511 川崎市宮前区菅生2-16-7)
*4同　横浜市西部病院特殊検査室(〒241-0811 横浜市旭区矢指町1197-1)
*6奈良県立医科大学輸血部(〒634-8521 橿原市四条町840)

E-mail :syamazak@marianna-u.ac.jp