title: The combined use of monoclonal antibody-based enzyme-linked immunosorbent assays (ELISA) for factor VIII antigen (VIII:Ag) and von Willebrand factor antigen (vWF:Ag) for the detection of carriers of haemophilia A.
abstract: Enzyme-linked immunosorbent assays (ELISA) for factor VIII antigen (VIII:Ag) and von Willebrand factor antigen (vWF:Ag) have been developed, each employing monoclonal antibodies. In the majority of severe haemophilic plasmas tested, VIII:Ag was undetectable by ELISA and also by immunoradiometric assay (IRMA) using haemophilic VIII:C antibodies. In haemophilic plasmas with mild/moderate deficiency of coagulant factor VIII (VIII:C), there was no significant difference between the two immunoassays although there was a general trend for ELISA VIII:Ag results to be higher. Assay of von Willebrand's disease (vWd) plasmas with the ELISA for vWF:Ag demonstrated reduced levels of this antigen in type I vWd, normal levels in type IIA, and a severe reduction of vWF:Ag in type III vWd. The discrimination of obligate carriers of haemophilia from normal was determined using ratios of factor VIII/vWF. Factor VIII antigen/von Willebrand factor antigen measured by IRMA and Laurell immunoelectrophoresis respectively, gave a superior discriminant to that of VIII:C/vWF:Ag (Laurell), but optimal discrimination was obtained with the combination of ELISAs for VIII:Ag and vWF:Ag.
mesh_terms: D000911:Antibodies, Monoclonal; D000941:Antigens / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D005169:Factor VIII / Q000032:analysis / Q000276:immunology*; D005260:Female; D006580:Genetic Carrier Screening / Q000379:methods*; D006467:Hemophilia A / Q000097:blood / Q000235:genetics* / Q000276:immunology; D006801:Humans; D014841:von Willebrand Factor / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000941:Antigens; C029417:Von Willebrand antigen; D014841:von Willebrand Factor; D005169:Factor VIII