1. Department of Pediatric Oncology, Hematology and Transplantology University of Medical Sciences Poznan Poland
2. Department of Pediatric Hematology, Oncology and Stem Cell Transplantation Medical University Lublin Poland
3. Department of Pediatric Stem Cell Transplantation, Hematology and Oncology Medical University Wroclaw Poland
4. Department of Pediatric Hematology and Oncology Collegium Medicum Nicolaus Copernicus University Bydgoszcz Poland
5. Department of Microbiology Collegium Medicum Nicolaus Copernicus University Torun Bydgoszcz Poland
6. Stem Cell Transplant Center Department of Clinical Immunology and Transplantology Jagiellonian University Collegium Medicum University Children's Hospital Krakow Poland