1. French Reference Center for Langerhans Cell HistiocytosisTrousseau Hospital Paris France
2. Department of Pediatric Hematology and Oncology Centre Hospitalo‐Universitaire de Bordeaux Bordeaux France
3. Department of Pediatric Hematology and Oncology Centre Hospitalo‐Universitaire de Toulouse Toulouse France
4. Department of Paediatric Hôpital Arnaud de VilleneuveCentre Hospitalo‐Universitaire de Montpellier Montpellier France
5. Department of Pediatric Immunology, Hematology and Rheumatology Necker HospitalAssistance Publique–Hôpitaux de Paris Paris France
6. Institut Imagine Paris UniversitySorbonne‐Paris‐Cité Paris France
7. Department of Pediatric Hematology and Oncology Centre Hospitalo‐Universitaire de Lille Lille France
8. Department of Paediatric Oncology Institut d'Hémato‐Oncologie Pediatrique Lyon France
9. Pediatric, Adolescent and Young Adult Oncology Department Institut Curie Medical Center Paris France
10. Department of Pediatric Hematology and Oncology Faculté de médecine, Trousseau Hospital Sorbonne UniversitéAssistance Publique–Hôpitaux de Paris Paris France
11. Department of Pediatric Hematology and Oncology Centre Hospitalo‐Universitaire de Nancy Vandœuvre‐lès‐Nancy France
12. Department of Pediatric Hematology and Oncology Centre Hospitalo‐Universitaire de Strasbourg Strasbourg France
13. Department of Pediatric Hematology and Oncology Centre Hospitalo‐Universitaire de Cean Cean France
14. Department of Pediatric Hematology and Oncology Centre Hospitalo‐Universitaire de Rouen Rouen France
15. Department of Pediatric Hematology and Oncology Centre Hospitalo‐Universitaire de Grenoble Grenoble France
16. Department of Pediatric Hematology and Oncology Centre Hospitalo‐Universitaire d'Amiens Amiens France
17. Department of Pediatric Hematology and Oncology Centre Hospitalo‐Universitaire de Tours Tours France
18. Department of Pediatric Hematology and Oncology Centre Hospitalo‐Universitaire de Poitiers Poitiers France
19. Department of Pediatric Hematology and Oncology Centre Hospitalo‐Universitaire de Rennes Rennes France
20. Department of Pediatric Hematology and Oncology Centre Hospitalo‐Universitaire Saint Denis de la Réunion St Denis France
21. Department of Pediatric Hematology and Oncology Centre Hospitalo‐Universitaire de Nantes Nantes France
22. Pneumology Department Saint‐Louis HospitalAssistance Publique–Hôpitaux de Paris Paris France
23. Université de ParisINSERM U976 Paris France
24. EA4340UVSQUniversité Paris‐Saclay Boulogne‐Billancourt France