The National Heart, Lung, and Blood Institute (NHLBI) has funded 3 centers to support a new U54 initiative titled The Centers for the Investigation of the Factor VIII Immune Response in Patients with Hemophilia A. These centers will utilize cross-disciplinary science and novel technologies to define the basic mechanisms involved in the development of anti-FVIII neutralizing antibodies, also known as FVIII inhibitors, in patients with congenital hemophilia A. In addition, each center will establish a skills development core in order to support the development of interdisciplinary research skills and expertise in the next generation of physicians/scientists in the field of hemostasis, including the entire spectrum of blood sciences. The Emory University Center will also serve as the administrative core.