Immunochemistry of factor VIII:C inhibitor antibodies

Factor VIII:C (FVIII:C) inhibitors are pathologic circulating antibodies that reduce FVIII:C activity. They can arise either as alloantibodies in some congenital hemophiliacs, or as autoantibodies in nonhemophilic patients with acquired inhibitors. The reason for development of such antibodies is not known, but their basic biochemical and clinical characteristics have been reviewed extensively in the past several years. This article surveys recent immunochemical studies to characterize the FVIII:C molecule and antibodies against it. For instance, epitope (antigenic site) mapping investigations conducted to date suggest that binding sites for most inhibitory antibodies can be localized to limited regions of the FVIII:C molecule. Further progress in the understanding of immune responses against FVIII:C is likely to provide a sound basis for the design of new therapeutic approaches to patients suffering the sequelae of FVIII:C inhibitor antibodies.