[Fatal opportunistic infection following disappearance of antibodies by immunosuppressive therapy in a patient with acquired factor VIII inhibitor].

An 83-year-old man without history of the hemorrhagic diathesis was admitted to our hospital with a 4-months history of purpura and subcutaneous hematoma. He had an extraordinarily prolonged activated partial thromboplastin time, and his factor VIII (F VIII) activity level was 0.2%. A study revealed the existence of an IgG type anti-F VIII inhibitor at a titer of 1004 Bethesda units/ml. He received recombinant factor VIIa and immunosuppressive therapy with cyclophosphamide, prednisolone and cyclosporin, but despite this the titer of F VIII inhibitor remained high. Although the inhibitor disappeared after methylprednisolone mini-pulse therapy, the patient died of opportunistic infections with cytomegalovirus and pneumocystis carinii. The majority of patients with acquired F VIII inhibitor belong to the elderly population, and the standard therapeutic strategy to eliminate the acquired F VIII inhibitor has not been established. Those patients with high titers of F VIII inhibitor require particularly long term immunosuppressive therapy. Therefore, it is important to bear in mind treatment-related opportunistic infections in a case with a high titer of acquired F VIII inhibitor.