1. Department of Paediatric Onco-hematology, Hospital L'Archet II, Nice, France;
2. Research Unit EA 3279 and Department of Public Health, Hôpital Nord, Marseille, France;
3. Department of Paediatric Hematology, Children's Hospital of La Timone, Marseille, France;
4. Department of Paediatric Onco-hematology, Hospital Arnaud de Villeneuve, Montpellier, France; and
5. Department of Paediatric Onco-Hematology, Children's Hospital of Brabois, Vandoeuvre Les Nancy, France