1. Pediatric Respiratory and Cystic Fibrosis Unit, Department of Clinical and Experimental Medicine, San Marco Hospital, University of Catania, 95121 Catania, Italy
2. Pediatric Unit, Department of Human and Pediatric Pathology “Gaetano Barresi”, AOUP G. Martino, University of Messina, Via Consolare Valeria, 1, 98124 Messina, Italy
3. Cystic Fibrosis Regional Reference Center, Department of Pediatric Medicine, Meyer Children’s Hospital IRCCS, 50139 Firenze, Italy