Understanding the Immune System

Individuals with hemophilia are deficient in one of the clotting factor proteins that are vital in the formation of a clot. Classic hemophilia or hemophilia A is a deficiency of factor VIII, while Christmas Disease or Hemophilia B is a deficiency of factor IX. The deficiency of one of these proteins comes about because of a mutation on the X chromosome. Patients with both types of hemophilia are at risk for prolonged bleeding. In order to prevent complications that result from prolonged bleeding, replacement of the deficient protein is the recommended treatment. Some patients with hemophilia develop antibodies as a complication of their disease. These antibodies to factor VIII or IX are called “inhibitors.” Inhibitors arguably represent the most significant risk factor for morbidity and mortality associated with hemophilia, and patients with inhibitors present complex patient management challenges.