Idiopathic Factor VIII Inhibitor Autoantibody in a Man Presented After Accident

Acquired hemophilia A is a rare but severe autoimmune bleeding disorder caused by autoantibodies against factor VIII activity and is a potentially life-threatening hemorrhagic disorder. The incidence of acquired hemophilia A has been estimated as 1.48 cases per million per year. The overall rate of death from all causes of acquired hemophilia reaches up to 22%. In this article, the authors describe the case of a 55-year-old man who presented with unusual bleeding after an accident and the fluctuation of his hemostatic parameters during 13 months of follow-up. Initially he had 43 Bethesda unit (BU) inhibitor to factor VIII and <1% of factor VIII activity. The patient was given prednisone and azathioprine therapy (30 and 100 mg/day, respectively) for 4 months, but his hemostatic parameters did not improved during this phase. Then, 2 g cyclophosphamide was injected every 2 days, but no remarkable improvement was observed. Nine months later his inhibitor titers were high. The inhibitor and factor VIII concentrations were assessed I I times during these 13 months, and the mean level of factor VIII inhibitor was 44 BU (with a minimum of 2 BU and a maximum of 103 BU); the minimum and maximum factor VIII concentrations were <1% and 20%, respectively. The patient experienced hemarthroses, severe epistaxis, hematoma, and gastrointestinal bleeding episodes during this phase. His factor VIII concentration spontaneously and gradually improved and increased to 51.5% 8 months after stopping the treatment with undetectable factor VIII inhibitor.