Characterization of human anti factor VIII antibodies purified by immune complex formation

Abstract

Anti factor VIII antibodies from three hemophilia A patients were selectively isolated by immune complex formation and secondary precipitation with polyethylene glycol. These antibodies were characterized as IgG, with only one type of light chains (kappa) and a mixture of IgG3 and IgG4 heavy chains. This finding indicated that stable complexes of factor VIII and homologous anti factor VIII antibodies could be obtained, and that the immunologic response to the infusion of homologous factor VIII was oligoclonal rather than monoclonal in these patients.