Casonato A, De Marco L, Mazzucato M, De Angelis V, De Roia D, Fabris F, Ruggeri Z M, Girolami A
Centro Immunotrasfusionale e Chimica Clinica, Universita di Padov.
Blood. 1989 Nov 1;74(6):2028-33.
A case is reported of a 49-year-old woman with a mild bleeding tendency. Her bleeding time, platelet count and size, plasma ristocetin cofactor activity, von Willebrand factor (vWF) antigen, and vWF multimeric pattern are all within normal limits. Spontaneous platelet aggregation is observed when citrated platelet-rich plasma (PRP) is stirred in an aggregometer cuvette. This aggregation is completely is only slightly diminished by an antiglycoprotein (GP) IIb/IIIa or by an anti GPIb monoclonal antibody. The patient's PRP shows increased sensitivity to ristocetin. The distinct feature of this patient, also present in two family members studied, is that platelet aggregation is initiated by purified vWF in the absence of any other agonist. The vWF-induced platelet aggregation is abolished by anti-GPIb and anti-GPIIb/IIIa monoclonal antibodies and by EDTA (5 mmol/L). Apyrase inhibits the second wave of aggregation. Patient's platelets in PRP are four to six times more reactive to asialo vWF-induced platelet aggregation than normal platelets. The amount of radiolabeled vWF bound to platelets in the presence of either low concentration of ristocetin or asialo vWF was increased 30% compared with normal. The patient's platelet GPIb was analyzed by SDS page and immunoblotting and by binding studies with anti-GPIb monoclonal antibodies showed one band with slightly increased migration pattern and a normal number of GPIb molecules. Unlike the previously reported patients with pseudo or platelet-type von Willebrand disease, this patient has normal vWF parameters.
报告了一例49岁有轻度出血倾向的女性病例。她的出血时间、血小板计数及大小、血浆瑞斯托霉素辅因子活性、血管性血友病因子（vWF）抗原和vWF多聚体模式均在正常范围内。当在凝聚仪比色杯中搅拌枸橼酸化富血小板血浆（PRP）时，可观察到自发血小板聚集。这种聚集完全或仅略有减少，分别是通过抗糖蛋白（GP）IIb/IIIa或抗GPIb单克隆抗体实现的。该患者的PRP对瑞斯托霉素敏感性增加。该患者以及所研究的两名家庭成员的独特特征是，在没有任何其他激动剂的情况下，纯化的vWF可引发血小板聚集。vWF诱导的血小板聚集可被抗GPIb和抗GPIIb/IIIa单克隆抗体以及EDTA（5 mmol/L）消除。腺苷三磷酸双磷酸酶抑制第二波聚集。与正常血小板相比，该患者PRP中的血小板对脱唾液酸vWF诱导的血小板聚集反应性高4至6倍。与正常情况相比，在低浓度瑞斯托霉素或脱唾液酸vWF存在下，与血小板结合的放射性标记vWF量增加了30%。通过SDS电泳和免疫印迹分析该患者的血小板GPIb，并用抗GPIb单克隆抗体进行结合研究，结果显示一条迁移模式略有增加的条带和正常数量的GPIb分子。与先前报道的假性或血小板型血管性血友病患者不同，该患者的vWF参数正常。
