1Pediatric Oncology-Hematology, Santa Maria della Misericordia Hospital, Perugia, Italy
2Pediatric Hematology, Santa Creu Hospital, Sant Pau, Barcelona, Spain
3Pediatric Hematology, La Paz Hospital, Madrid, Spain
4Pediatric Hematology-Oncology, Azienda Ospedaliera Universitaria Integrata, Verona, Italy