F8 and hemophilia A: Acquired hemophilia A (AHA) is a rare condition triggered by an autoantibody targeting factor VIII (FVIII). In congenital hemophilia A, FVIII-neutralizing inhibitors are alloantibodies that arise after FVIII replacement therapy, whereas in AHA, these inhibitors are autoantibodies. Evaluations of various populations have estimated an annual incidence of acquired hemophilia A to be roughly one to two cases per million [1,2].