1 Paediatric Respiratory Unit, Department of Paediatrics, Heraklion University Hospital, University of Crete Medical School, Heraklion, Crete, Greece eparaska@uoc.gr.
2 Medical School, Democritus University of Thrace, Alexandroupolis, Greece.
3 Paediatric Respiratory Unit, University Hospital of Patras, Patras, Greece.
4 Department of Pneumonology, Medical School, Democritus University of Thrace, Alexandroupolis, Greece.
5 Department of Paediatrics, Medical School, Democritus University of Thrace, Alexandroupolis, Greece.
6 Department of Paediatrics, National Heart and Lung Institute, London, UK.
7 Department of Paediatric Respiratory Medicine, Royal Brompton Hospital, London, UK.