1. Department of Medicine and Center for Sickle Cell Disease, Howard University, Washington, DC, USA
2. Department of Public Health Sciences, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
3. Southern Iron Disorders Center, and Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
4. Veterans Affairs Long Beach Healthcare System, Long Beach, and Division of Hematology/Oncology, Department of Medicine, University of California, Irvine, California, USA
5. Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA
6. Department of Epidemiology, University of California, Irvine, California, USA
7. Division of Extramural Research, National Institute of Dental and Craniofacial Research, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, USA
8. Department of Medicine, London Health Sciences Centre, London, Ontario, Canada
9. Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota, USA
10. Division of Cardiovascular Sciences, National Heart, Lung, and Blood Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, USA