1. 1Department of Pediatrics, Section of Hematology/Oncology/Bone Marrow Transplantation, Medical College of Wisconsin, Milwaukee, WI;
2. 2Division of Hematology and Oncology, UC Davis School of Medicine, Sacramento, CA; and
3. 3Laboratory of Sickle Thrombosis and Vascular Biology, Sickle Cell Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD