title: Factor VIII procoagulant antigen in human tissues.
abstract: The localization of factor VIII procoagulant antigen (VIII:Ag) and factor VIII von Willebrand antigen (VWF:Ag) was investigated in human liver, lung, spleen, placenta and umbilical cord, by an immunoperoxidase technique using an avidin biotin complex (ABC). Positive staining for VIII:Ag was observed in the endothelial cells of liver sinusoids, veins and arteries, as well as in the endothelial cells of placenta, lung and spleen. VWF:Ag was detected in the vascular endothelial cells of all the organs explored. The staining intensity of both VIII:Ag and VWF:Ag varied in the different tissues and showed a distinctive pattern of distribution in the liver. VIII:Ag was also observed in the cytoplasm of dysplastic, foetal-like hepatocytes which infiltrated one liver specimen. Our results agree with the view that liver endothelial cells are a major site of Factor VIII (F VIII) storage and secondary release into the circulation. However, the bright staining intensity of VIII:Ag and VWF:Ag in the lung and placenta suggests that these two tissues might also be a substantial source of F VIII.
mesh_terms: D000941:Antigens / Q000302:isolation & purification*; D005169:Factor VIII / Q000276:immunology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008099:Liver / Q000276:immunology; D008168:Lung / Q000276:immunology; D010920:Placenta / Q000276:immunology; D011247:Pregnancy; D013154:Spleen / Q000276:immunology; D014018:Tissue Distribution; D014470:Umbilical Cord / Q000276:immunology; D014841:von Willebrand Factor / Q000276:immunology
chemical_list: D000941:Antigens; C029417:Von Willebrand antigen; D014841:von Willebrand Factor; D005169:Factor VIII