Acquired factor VIII inhibitor in patients with hepatitis C virus infection and the role of interferon-alpha: a case report.

A patient with HIV and hepatitis C virus (HCV) co-infection developed an autoantibody to factor VIII after 8.7 months of treatment with pegylated interferon-alpha and ribavirin. Three previous cases of the development of factor VIII autoantibody in patients infected with the hepatitis C virus have been reported. Only one of these patients was treated with interferon-alpha, and this patient had hemophilia A, a condition prone to development of factor VIII autoantibody, even without interferon treatment. It is possible that chronic HCV infection itself, which has been associated with immunological disorders, is responsible for this phenomenon, but the immunomodulatory properties of interferon-alpha may also contribute to this rare occurrence. No previous case of factor VIII inhibitor in a patient infected with HIV has been reported. (c) 2005 Wiley-Liss, Inc.