Valder R. Arruda, MD, PhD (IMAGE) Children's Hospital of Philadelphia Caption Researchers at Children's Hospital of Philadelphia (CHOP) have identified a key target that may be responsible for treatment failure in about 30% of patients with hemophilia A. The target, known as B cell activating factor (BAFF), appears to promote antibodies against and inhibitors of the missing blood clotting factor that is given to these patients to control their bleeding episodes. Credit CHOP Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.