1. "Sapienza" University; Department of Public Health and Infectious Diseases; Rome Italy
2. Institute of Translational Pharmacology (IFT), CNR; Rome Italy
3. National Heart and Lung Institute, Imperial College London and Royal Brompton Hospital; Section of Allergy and Clinical Immunology; London UK
4. Children's Hospital "Bambino Gesù"; Department of Medical and Surgical Pediatric Cardiology - UOC Arrhythmology; Rome Italy
5. University of Genoa; Allergy and Respiratory Diseases Clinic, Department of Internal Medicine (DIMI); Genoa Italy
6. McMaster University; Departments of Clinical Epidemiology and Biostatistics and of Medicine; 1280 Main Street West Hamilton Ontario Canada L8N 4K1