1. Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN;
2. Penn-CHOP Blood Center for Patient Care and Discovery and Hematology-Oncology Division, Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA;
3. Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA; and
4. Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA