Factor VIII inhibitor associated with peginterferon.

We present a case of a 53-year-old black male who developed a factor VIII inhibitor during his treatment for hepatitis C virus infection with peginterferon. The development of inhibitors against factor VIII during peginterferon therapy has been rarely reported. We have reviewed the current literature and the following case presentation provides the first demonstration, to our knowledge, in which chronic exposure to peginterferon is associated with an acquired factor VIII inhibitor.