Parker R I, Bray G L, McKeown L P, White J G
Clinical Pathology Department, National Institutes of Health, Bethesda.
J Lab Clin Med. 1993 Oct;122(4):441-9.
We report a mother and son who were found to have macrothrombocytopenia, prolonged bleeding time, and abnormal platelet responses to thrombin. Transmission electron microscopy performed on the son's platelets demonstrated an unusual arrangement of membrane complexes formed by association of the open canalicular and dense tubular systems. Number and appearance of platelet alpha-granules, dense bodies, and mitochondria were normal. These platelets demonstrated normal agonist-induced Ca2+ flux in response to collagen and supranormal responses to arachidonic acid but displayed no increase in intracellular free Ca2+ in response to thrombin. Platelet surface glycoproteins IIb-IIIa, Ib, and granular membrane protein-140 measured by fluorescence-activated flow cytometry, along with platelet content of von Willebrand factor and fibrinogen, were normal. The von Willebrand factor binding function of GP-Ib on these platelets was also normal. We believe that this family demonstrates a unique macrothrombocytopenia syndrome characterized by deficient Ca2+ mobilization in response to thrombin that is not related to a defect in GP-Ib.
我们报告了一位母亲和她的儿子，他们被发现患有大血小板减少症、出血时间延长以及血小板对凝血酶的反应异常。对儿子的血小板进行透射电子显微镜检查显示，开放小管系统和致密管状系统联合形成的膜复合物排列异常。血小板α颗粒、致密体和线粒体的数量及外观正常。这些血小板对胶原的反应显示出正常的激动剂诱导的Ca2+通量，对花生四烯酸的反应超常，但对凝血酶的反应未显示细胞内游离Ca2+增加。通过荧光激活流式细胞术测量的血小板表面糖蛋白IIb-IIIa、Ib和颗粒膜蛋白-140，以及血小板中血管性血友病因子和纤维蛋白原的含量均正常。这些血小板上GP-Ib的血管性血友病因子结合功能也正常。我们认为，这个家族表现出一种独特的大血小板减少症综合征，其特征是对凝血酶的Ca2+动员不足，且与GP-Ib缺陷无关。
