1. From the Thrombosis and Haemostasis Laboratory (C.W., J.A., P.G.d.G., T.L.), Department of Haematology, University Medical Centre Utrecht, the Netherlands; the Institute of Biomembranes (C.W., P.G.d.G., T.L.), Utrecht University, Utrecht, the Netherlands; and the Division of Hematology (T.M.), Department of Medicine, Stanford University School of Medicine, Stanford, Calif.