1. LMU Munich; University Children's Hospital; Munich Germany
2. Department of Pediatric Pneumology and Allergy; University Children's Hospital Regensburg (KUNO); Regensburg Germany
3. Department of Pediatric Pneumology, Allergy and Neonatology; Hannover Medical School; Hannover Germany
4. Children's Hospital, and Christine Kühne-Center for Allergy Research and Education; University of Zurich; Zurich Switzerland
5. Swiss Institute of Allergy and Asthma Research (SIAF); University of Zurich; Davos Switzerland
6. Christine Kühne-Center for Allergy research and Education; Hochgebirgsklinik Davos-Wolfgang; Davos Switzerland
7. National Jewish Health; Denver CO USA
8. Institute of Epidemiology and Medical Biometry; Ulm University; Ulm Germany
9. Department of Clinical Chemistry and Molecular Diagnostics; Philipps University of Marburg; Marburg Germany
10. Living Environment and Health Unit; National Institute for Health and Welfare; Kuopio Finland
11. Swiss Tropical and Public Health Institute; Basel Switzerland
12. University of Basel; Basel Switzerland
13. Children's Hospital Schwarzach; Schwarzach Austria
14. Children's Hospital of Eastern Switzerland; St. Gallen Switzerland
15. University Hospital of Besançon; the Research Unit Health and Rural Environment; University of Franche-Comté; Besançon France
16. Department of Public health; University of Helsinki; Helsinki Finland