An Essential Factor — In a recent issue of the journal Blood, Drs. Sanjeev Gupta and Antonia Follenzi successfully challenge the long-held view that bone marrow transplantation is of little value in the treatment of hemophilia A, the more common form of this rare bleeding disorder. Their research found that, following transplantation therapy, an essential clotting factor (FVIII) appeared in the blood of hemophiliac mice, protecting these mice from bleeding challenges. The authors also traced the source of FVIII to circulating and liver-resident macrophages, a kind of white blood cell, as well as to stem cells within the bone marrow. The study thus illuminates potential new treatment avenues for hemophilia A. The College of Medicine has filed a patent application related to this research that is available for licensing to partners interested in further testing and developing this treatment. Dr. Gupta is professor of medicine and of pathology, and holds the Eleazar & Feige Reicher Chair in Translational Medicine; Dr. Follenzi is visiting assistant professor of pathology.