title: In vivo interactions of autoantibodies to factor VIII with the factor VIII complex.
abstract: Two non-haemophilic elderly patients who had developed autoantibodies to factor VIII were studied over a period of 9 months to 5 years. Sequential measurements of antibody to factor VIII (anti-VII:C), factor VIII coagulant activity (VIII:C), factor VIII coagulant antigen (VIII:CAg), factor VIII-related antigen (VIIIR:Ag), and factor VIII ristocetin cofactor (VIII:WF) were performed. Before treatment, low VIII:C, normal or increased VIII:CAg and high VIIIR:Ag levels were found and were indicative of the presence of circulating immune complexes. Immunosuppressive therapy induced progressive correction of VIII:C and VIIIR:Ag values. High levels of VIII:CAg subsided in the patient who relapsed. It is suggested that antibodies to factor VIII bind and remove VIII:C from the circulation thereby inducing an increased synthesis of VIII:CAg which may be associated with an augmented release or production of VIIIR:Ag.
mesh_terms: D000368:Aged; D000941:Antigens / Q000276:immunology*; D001323:Autoantibodies / Q000032:analysis / Q000096:biosynthesis*; D001778:Blood Coagulation Disorders / Q000188:drug therapy / Q000276:immunology; D005169:Factor VIII / Q000032:analysis / Q000276:immunology*; D005260:Female; D006801:Humans; D007123:Immunoelectrophoresis, Two-Dimensional; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008297:Male; D014841:von Willebrand Factor / Q000032:analysis
chemical_list: D000941:Antigens; D001323:Autoantibodies; D007166:Immunosuppressive Agents; D014841:von Willebrand Factor; D005169:Factor VIII