[Diagnosis and treatment of autoimmune acquired coagulation factor deficiency]

Autoimmune coagulation factor deficiency (AiCFD) is an acquired bleeding disorder caused by immunoglobulins (autoantibodies) that target a single coagulation factor. Most of these autoantibodies are polyclones and primarily neutralizing antibodies (inhibitors) that inhibit the function of coagulation factors; however, non-neutralizing autoantibodies that enhance clearance are also present. AiCFD has been reported in nearly all coagulation factors and von Willebrand factor, and its representative disease is acquired hemophilia A, which is caused by autoantibodies against coagulation factor VIII. The treatment for AiCFD consists of hemostatic therapy according to the bleeding symptoms and immunosuppressive therapy to eradicate autoantibodies. Hemostatic treatment varies depending on the deficient coagulation factor, and coagulation factor replacement therapy, platelet or fresh frozen plasma transfusions, and bypassing agents are provided. Although AiCFD is a rare disease, raising awareness of this disease is necessary because general physicians may also encounter it.