Ruggeri Z M, Lombardi R, Gatti L, Bader R, Valsecchi C, Zimmerman T S
Blood. 1982 Dec;60(6):1453-6.
The abnormal multimeric composition of plasma von Willebrand factor in type IIB von Willebrand's disease is transiently corrected after infusion of 1-deamino-[8-D-arginine]-vasopressin. However, the larger multimers released into the circulation disappear more rapidly in these patients than in type I von Willebrand's disease or normals. We demonstrate that the larger multimers of normal von Willebrand factor transfused into a type IIB patient are cleared from the circulation more slowly than multimers of similar size endogenously released from tissue stores. The rate of disappearance of large von Willebrand factor multimers after infusion of cryoprecipitate is similar in IIB, IIA, and severe homozygous-like von Willebrand's disease. Platelets from the IIB patient exhibited normal ristocetin-induced binding of normal von Willebrand factor. However, like normal platelets, they bound IIB von Willebrand factor at lower ristocetin concentrations than required for normal von Willebrand factor. These findings provide evidence that absence of the larger multimers from IIB plasma is related to a molecular abnormality of von Willebrand factor rather than to enhanced affinity of abnormal tissue or cellular binding sites, as is the case in the recently described "pseudo" von Willebrand's disease and "platelet-type" von Willebrand's disease.
在输注1-去氨基-[8-D-精氨酸]-血管加压素后，IIB型血管性血友病患者血浆中血管性血友病因子异常的多聚体组成会得到短暂纠正。然而，与I型血管性血友病患者或正常人相比，这些患者释放到循环中的较大多聚体消失得更快。我们证明，输注到IIB型患者体内的正常血管性血友病因子的较大多聚体从循环中清除的速度比从组织储存中内源性释放的类似大小的多聚体更慢。在IIB型、IIA型和严重的纯合子样血管性血友病中，输注冷沉淀后大的血管性血友病因子多聚体的消失速率相似。IIB型患者的血小板对正常血管性血友病因子表现出正常的瑞斯托霉素诱导的结合。然而，与正常血小板一样，它们在低于正常血管性血友病因子所需的瑞斯托霉素浓度下结合IIB型血管性血友病因子。这些发现提供了证据，表明IIB型血浆中缺乏较大的多聚体与血管性血友病因子的分子异常有关，而不是与异常组织或细胞结合位点的亲和力增强有关，就像最近描述的“假性”血管性血友病和“血小板型”血管性血友病那样。
