Department of Immunology and Allergy, Medical University of Łódź, Łódź, Poland. Allergy and Clinical Immunology Research Group, Department of Microbiology, Immunology and Transplantation, KU Leuven, Leuven, Belgium. Department of Cardiovascular and Thoracic Sciences, Fondazione Policlinico Universitario A. Gemelli - IRCCS, Università Cattolica del Sacro Cuore, Rome, Italy. National Heart and Lung Institute (NHLI), Imperial College London, London, UK. Department of Medical Sciences and Public Health "M. Aresu", University of Cagliari, Cagliari, Italy. Basic and Clinical Immunology, Department of Pathology, Faculty of Medicine, University of Porto, Porto, Portugal. Serviço de Imunoalergologia, Centro Hospitalar de São João E.P.E, Porto, Portugal. Department of Respiratory Medicine & Allergology, Institute for Clinical Science, Skane University Hospital, Lund University, Lund, Sweden. Department of Respiratory Medicine, First Faculty of Medicine, Charles University and Thomayer Hospital, Prague, Czech Republic. Epidemiology Research Unit- Instituto de Saúde Pública, University of Porto, Porto, Portugal. Allergy & Immunology Centre, Tbilisi, Georgia. Teaching University Geomedi LLC, Tbilisi, Georgia. Allergy Unit, Hospital CUF Descobertas, Lisbon, Portugal.