1. Center for Chronic Immunodeficiency, University Medical Center Freiburg and University of Freiburg, Freiburg, Germany;
2. Department of Internal Medicine 5, Haematology and Oncology, University Hospital Erlangen, Erlangen, Germany;
3. Center for Paediatrics and Adolescent Medicine, University Medical Center, University of Freiburg, Freiburg, Germany;
4. Institute for Transfusion Medicine, University of Ulm, Ulm, Germany;
5. Institute of Pathology, Charité – University Medicine Berlin, Campus Benjamin Franklin, Berlin, Germany;
6. Department of Paediatric Immunology, Great North Children's Hospital, Newcastle upon Tyne, United Kingdom;
7. Institute of Cellular Immunology, Newcastle University, Newcastle upon Tyne, United Kingdom;
8. Institute of Immunology, Department of Medicine Microbiology and Hygiene, and
9. Department of Internal Medicine II, University Medical Center Freiburg, Freiburg, Germany;
10. Department of Paediatrics, Jena University Hospital, Jena, Germany;
11. Department of Pediatric Hematology and Oncology, Hannover Medical School, Hanover Hannover, Germany;
12. Division of Pediatric Haematology and Oncology, Department of Pediatric and Adolescent Medicine, University Medical Center Göttingen, Göttingen, Germany;
13. Department of Paediatric Haematology/Oncology, University Medical Center Bremen, Bremen, Germany,
14. Paediatric Haematology-Oncology, Medical University of Graz, Graz, Austria; and
15. Institute for Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Service, Ulm, Germany