1. Pediatric Unit; Department of Medical and Surgical Sciences; University of Bologna; Bologna Italy
2. Pediatric Unit; Department for Mother and Child; Ramazzini Hospital; Carpi Italy
3. Pediatric Allergology Unit; Sandro Pertini Hospital; Rome Italy
4. L'Altrastatistica srl; Consultancy and Training, Biostatistics Office; Rome Italy
5. Allergology Service; San Carlo Clinic; Paderno Dugnano Milan Italy
6. Pediatric Unit; Mazzoni Hospital; Ascoli Piceno Italy
7. Pediatric Department; Second University; Naples Italy
8. Pediatric Department; La Sapienza University; Rome Italy
9. Pediatric Unit; Fatebenefratelli Hospital; Benevento Italy
10. Clinica Pediatrica Unit; Unit of Allergy and Immunology in Evolutive Age; Department of Clinical and Experimental Medicine; University of Parma; Parma Italy
11. Pediatric Clinic 1; Department of Pathophysiology and Transplantation; University of Milan; Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico; Milan Italy
12. Pediatric Clinic 2; Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico; Milan Italy
13. Pediatric Unit; G.B. Rossi Hospital; Verona Italy
14. Pediatric Department; Policlinico of Tor Vergata; Tor Vergata University; Rome Italy
15. Pediatric Unit; San Giuseppe Hospital; Empoli Italy
16. Pediatric Unit; Grassi Hospital; Rome Italy
17. Pediatric Unit; Santa Barbara Hospital; Iglesias Italy
18. Pulmonary Disease and Allergy Unit; G. Gaslini Hospital; Genoa Italy
19. Pediatric Unit; Crotone Italy
20. CNR Institute of Biomedicine and Clinical Immunology; Palermo Italy
21. Research Centre; San Pietro Hospital - Fatebenefratelli; Rome Italy
22. Pediatric Unit; S. Camillo Forlanini Hospital; Rome Italy
23. Department of Laboratory Medicine; University of Padua; Padua Italy
24. Department of Pediatric Pneumology and Immunology; Charité Medical University; Berlin Germany