Acquired hemophilia possibly induced by etanercept in a patient with rheumatoid arthritis.

A 47-year-old woman with rheumatoid arthritis (RA) treated successively with infliximab, abatacept, and etanercept spontaneously developed subcutaneous bruises and a noncompressive hematoma 11 months after starting etanercept therapy (50mg/week). Her prothrombin time was normal but her activated partial thromboplastin time was increased to 2.48 (normal range, 0.85-1.17). She had a circulating anticoagulant (Rosner index, 45; normal,<13) due to an anti-factor VIII antibody in a titer of 45 Bethesda units. Her factor VIII level was less than 1% (normal range, 55-150). The etanercept and leflunomide were stopped and prednisone was given in a daily dosage of 1mg/kg, in combination with rituximab, two 1-g doses at an interval of 2 weeks. After 5 months, persistence of the anti-factor VIII antibody prompted the initiation of azathioprine therapy, 2mg/kg/d. A remission was achieved 9 months after the diagnosis of acquired hemophilia and was sustained at last follow-up after 3 years. This new case of acquired hemophilia in a patient with RA may reflect a simple association or an inducing role of etanercept.