Factor VIII alloantibodies in hemophilia

Purpose of review The development of an inhibitory response to factor VIII (FVIII) remains a puzzling challenge both for clinicians and scientists, not to mention the difficulties of maintaining hemostasis in patients producing inhibitors. Recent findings Three main research lines have been explored in recent months. The mechanisms by which an anti-FVIII antibody response is elicited in patients has been examined at both the B- and T-cell levels, with particular emphasis on the generation of specific B- and T-cell clones. The hemophilia A mouse model has served to confirm the main characteristics of the anti-FVIII immune response in terms of T-cell dependency and memorization of the response. Novel strategies for the prevention and downregulation of inhibitors have emerged, with special interest in antigen-specific approaches. Summary Although the ultimate goal, preventing or suppressing inhibitor formation in patients, is not yet achieved, the research activity developed over the past months brings us forward in that direction.