1. Department of Pediatric Hematology and Oncology, Collegium Medicum, Nicolaus Copernicus University Toruń, Bydgoszcz, Poland
2. Department of Pediatric Transplantology, Hematology and Oncology, Medical University, Wrocław, Poland
3. Department of Hematology, Medical University, Gdańsk, Poland
4. Department of Hematology, Poznań University of Medical Sciences, Poznań, Poland
5. Department of Pediatric Surgery, Collegium Medicum, Nicolaus Copernicus University Toruń, Bydgoszcz, Poland
6. Department of Hematology, Collegium Medicum, Jagiellonian University, Kraków, Poland
7. Department of Hematology, Medical University, Warszawa, Poland
8. Department of Hematology, Institute of Hematology and Transfusion Medicine, Warszawa, Poland
9. Department of Pediatric Oncology and Hematology, Medical University, Białystok, Poland
10. Department of Oncology, Children's Memorial Health Institute, Warszawa, Poland
11. Department of Microbiology, Collegium Medicum, Nicolaus Copernicus University Toruń, Bydgoszcz, Poland
12. Department of Pediatric Oncology and Hematology, University Children's Hospital, Jagiellonian University Collegium Medicum, Kraków, Poland
13. Department of Pediatrics, Hematology and Oncology, Medical University, Gdańsk, Poland
14. Department of Pediatric Hemato-Oncology and Gastroenterology, Pomeranian Medical University, Szczecin, Poland
15. Department of Pediatric Hematology and Oncology, Silesian Medical University, Zabrze, Poland