1. Department of Internal Medicine 5, Haematology and Oncology, University Hospital Erlangen, Erlanger, Germany;
2. Center for Chronic Immunodeficiency, University Medical Center Freiburg, University of Freiburg, Freiburg, Germany;
3. Institute for Transfusion Medicine, University of Ulm, Ulm, Germany;
4. Institute for Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Service, Ulm, Germany;
5. Hospital for Children and Adolescents, University of Leipzig, Leipzig, Germany;
6. Division of Pediatric Haematology and Oncology, Department of Pediatric and Adolescent Medicine, University Medical Center Göttingen, Göttingen, Germany;
7. Department of Pediatrics, University Hospital Erlangen, Erlangen, Germany;
8. Department of Neuroscience, Psychology, Drug Area and Child Health (NEUROFARBA), Section of Child's Health, University of Florence, Florence, Italy;
9. Department of Pediatric and Adolescent Medicine, HELIOS Klinikum Krefeld, Krefeld, Germany;
10. Department of Pediatrics, University Medical Centre Hamburg, Hamburg, Germany;
11. Department of Pediatric Oncology, Klinikum Kassel, Kassel, Germany;
12. Department of Pediatrics, Pediatric Oncology Center, Technische Universität München, Munich, Germany;
13. Department of Pediatric Allergy and Immunology, Royal Manchester Children’s Hospital, University of Manchester, Manchester, United Kingdom;
14. Clinical and Experimental Haematology Unit, Giannina Gaslini Children’s Hospital, Genoa, Italy; and
15. Center for Paediatrics and Adolescent Medicine, University Medical Center, University of Freiburg, Freiburg, Germany