1 Department of Immunology, Instituto de Investigación Sanitaria Hospital Universitario de La Princesa (IIS-Princesa), Universidad Autónoma de Madrid (UAM), Madrid, Spain.
2 Faculty of Medicine and Biomedicine, Alfonso X El Sabio University (UAX), Madrid, Spain.
3 Division of Emergency Medicine, Cincinnati Children's Hospital Medical Center, the Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA.
5 Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.
6 Department of Allergy and Immunology, Health Research Institute-Fundación Jiménez Díaz University Hospital, UAM, Madrid, Spain.
7 Department of Women and Children's Health (Pediatric Allergy), School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, London, UK.
8 Peter Gorer Department of Immunobiology, School of Immunology and Microbial Sciences, King's College London, London, UK.
9 Children's Allergy Service, Evelina London Children's Hospital, Guy's and St Thomas' Hospital, London, UK.
10 Department of Medicine, McMaster Immunology Research Centre (MIRC), Schroeder Allergy and Immunology Research Institute (SAIRI), McMaster University, Hamilton, Ontario, Canada.
11 Faculty of Experimental Sciences, Universidad Francisco de Vitoria (UFV), Madrid, Spain.
12 Department of Health Sciences, University of Florence, Florence, Italy.
13 Allergy Unit, Meyer Children's Hospital IRCCS, Florence, Italy.