2 Allergy and Asthma Medical Clinic, Tirana, Albania.
3 Allergy Department 2nd Pediatric Clinic, University of Athens, Athens, Greece.
4 Department of Allergy and Clinical Immunology, 424 General Military Training Hospital, Thessaloniki, Greece.
5 University Hospital Center "Mother Teresa", Tirana, Albania.
6 Internal Medicine Department, Elbasan Regional Hospital, Elbasan, Albania.
7 Medical University-Sofia, Faculty of Public Health, Sofia, Bulgaria.
8 Acibadem City Clinic Tokuda Hospital, Sofia, Bulgaria.
9 Immunotherapy Outpatient Clinic, Allergy Unit, 2nd Department Dermatology and Venereology, National and Kapodistrian University of Athens, University General Hospital 'Attikon', Athens, Greece.
10 Special Hospital for Pulmonary Diseases, Zagreb, Croatia.
11 Clinical Department for Lung Diseases Jordanovec, University Hospital Center, Zagreb, Croatia.
12 University Medicine and Pharmacy Iuliu Hatieganu, IRGH, Allergy, Cluj-Napoca, Romania.
13 Expertise Centre for Immunology & WAO Centre of Excellence, Cluj-Napoca, Romania.
14 Clinic of Allergology and Immunology, University Clinical Center of Serbia, Belgrade, Serbia.
15 Faculty of Medicine, University of Belgrade, Belgrade, Serbia.
16 Department of Allergy and Immunology, Ankara University School of Medicine, Ankara, Turkey.
17 University Clinic of Respiratory and Allergic Diseases, Golnik, Slovenia.
18 University Hospital "Sv Ivan Rilski", Sofia, Bulgaria.
19 Lydia Becker Institute of Immunology and Inflammation, University of Manchester, Manchester, UK.
20 Section of Allergy and Clinical Immunology, Imperial College London-NHLI, London, UK.