Platelet ultrastructural abnormalities in three patients with type 2B von Willebrand disease.

摘要: Several reports have described the presence of giant platelets in patients with type 2B von Willebrand disease (VWD). We now characterized ultrastructural changes from three unrelated VWD and different mutations within exon 28 factor (VWF) gene. Electron microscopy showed that each these subjects had an increased proportion large when compared those a patient 2A or control subjects. Immunogold labelling for VWF was performed. Large masses detected by anti-VWF antibody were seen not only on platelet surface, but also inside surface-connected canalicular system (SCCS) ultrathin sections labelled. This suggested translocation abnormally bound surface. Labelling α-granules eccentric as normal platelets. glycoprotein (GP) Ib surface SCCS, suggesting co-localization VWF. However, there no evidence endosomes other endocytic vesicles. The platelet-bound accompanied high levels activation, electron microscopy, using monoclonal antibodies against P-selectin activation-dependent determinants GP IIb-IIIa flow cytometry. Intriguingly, ultrastructure often resembled congenital thrombocytopathies characteristic syndromes.