Characterization of an Anti-Factor VIII Inhibitor Related To P.Arg2178Cys Mutation in A Patient with Mild Haemophilia A

Abstract

In patients with inherited mild haemophilia treated with clotting factor concentrates, the risk of inhibitor development is lower than in severe haemophilia. We report the observation of a 38-year-old man, with mild haemophilia A, previously treated for mucosal bleeding, who presented no major immunization risk factors except an exon 23 missense mutation p.Arg2178Cys in the F8 gene in the C1 domain. He developed an inhibitor against Octocog alfa. The implication of the mutation in this particular immunization process is well known. Characterization of this inhibitor has been extended as a type I inhibitor with classical epitope mapping and solely directed against exogenous factor VIII. Due to the occurrence of an anamnestic response associated with a high titre inhibitor, we had recourse to Eptacog alfa during a critical bleeding situation.