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.