1. Department of Haematology, University College London Cancer Institute, London, United Kingdom;
2. Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA;
3. Whitehead Institute for Biomedical Research, Cambridge, MA;
4. Department of Immunohematology, Leiden University Medical Center, Leiden, The Netherlands;
5. Department of Biology, Massachusetts Institute of Technology, Cambridge, MA; and
6. Division of Hematology/Oncology, Children’s Hospital, Boston, MA