d'Alessio P, Zwaginga J J, de Boer H C, Federici A B, Rodeghiero F, Castaman G, Mariani G, Mannucci P M, de Groot P G, Sixma J J
Department of Haematology, University Hospital Utrecht, The Netherlands.
Thromb Haemost. 1990 Oct 22;64(2):227-31.
Von Willebrand's disease type I, characterized by low levels of factor VIII coagulant activity (VIII: C), von Willebrand factor antigen (vWF:Ag) and ristocetin cofactor activity (RiCof) (1), can be subdivided on the basis of platelet von Willebrand factor into subtype platelet normal, platelet discordant, and platelet low (2). We have investigated the contribution of platelet von Willebrand factor in these various subtypes to platelet adhesion using the rectangular perfusion chamber of Sakariassen et al. (3) with fibrillar collagen or a fibroblast matrix as adhesive surfaces. Platelet adhesion to fibrillar collagen was decreased in all subtypes of von Willebrand's disease, but not as low as in severe von Willebrand's disease. A close correlation was observed between platelet adhesion to collagen and plasma vWF:Ag in severe von Willebrand's disease, subtype platelet low, subtype platelet discordant, and normal controls. The platelet adhesion in subtype platelet normal was higher than expected from the plasma vWF:Ag level. Perfusions in which washed platelets were added to a human albumin solution together with red blood cells gave similar adhesion values in subtype platelet normal and normal controls; adhesion was decreased in subtype platelet discordant, and the lowest values were found in subtype platelet low and in severe von Willebrand's disease. These data indicate that platelet von Willebrand factor may contribute to platelet adhesion, when plasma von Willebrand factor is low. Perfusion studies over a fibroblast matrix gave similar low adhesion values for subtype platelet low and platelet normal, indicating that the contribution of platelet von Willebrand factor can only be observed on a strongly activating surface such as fibrillar collagen.
I型血管性血友病的特征是凝血因子VIII促凝活性（VIII:C）、血管性血友病因子抗原（vWF:Ag）和瑞斯托霉素辅因子活性（RiCof）水平较低（1），根据血小板血管性血友病因子可细分为血小板正常亚型、血小板不一致亚型和血小板低亚型（2）。我们使用Sakariassen等人的矩形灌注室（3），以纤维状胶原蛋白或成纤维细胞基质作为黏附表面，研究了这些不同亚型中血小板血管性血友病因子对血小板黏附的作用。在血管性血友病的所有亚型中，血小板与纤维状胶原蛋白的黏附均降低，但不像重型血管性血友病那样低。在重型血管性血友病、血小板低亚型、血小板不一致亚型和正常对照中，观察到血小板与胶原蛋白的黏附与血浆vWF:Ag之间存在密切相关性。血小板正常亚型中的血小板黏附高于根据血浆vWF:Ag水平预期的值。在将洗涤后的血小板与红细胞一起加入人白蛋白溶液的灌注实验中，血小板正常亚型和正常对照的黏附值相似；血小板不一致亚型中的黏附降低，而在血小板低亚型和重型血管性血友病中黏附值最低。这些数据表明，当血浆血管性血友病因子水平较低时，血小板血管性血友病因子可能有助于血小板黏附。在成纤维细胞基质上进行的灌注研究显示，血小板低亚型和血小板正常亚型的黏附值同样较低，这表明只有在如纤维状胶原蛋白这样的强激活表面上才能观察到血小板血管性血友病因子的作用。
