1. Department of Immunology; Erasmus MC, University Medical Centre Rotterdam; Rotterdam the Netherlands
2. Department of Paediatric Haematology and Oncology; Zabrze Poland
3. Medical University of Silesia (SUM); Katowice Poland
4. Dutch Childhood Oncology Group; The Hague the Netherlands
5. Department of Paediatric Haematology and Oncology; 2nd Faculty of Medicine; Charles University (DPH/O) and University Hospital Motol; Prague Czech Republic
6. Cancer Research Centre (IBMCC-CSIC); Department of Medicine and Cytometry Service; University of Salamanca (USAL) and Institute of Biomedical Research of Salamanca (IBSAL); Salamanca Spain
7. Department of Paediatrics; Leiden University Medical Centre; Leiden the Netherlands
8. Department of Immunohaematology and Blood Transfusion; Leiden University Medical Centre; Leiden the Netherlands