Guest Editors K.F. Chung K.F. Chung is Prof. of Respiratory Medicine and Head of the Experimental Studies Unit at the National Heart and Lung Institute, Imperial College London (London, UK), and is an Honorary Consultant Physician at the Royal Brompton Hospital (London). K.F. Chung trained in internal and respiratory medicine in Oxford and London, and undertook postdoctoral training as an MRC visiting scientist at the University of California (San Francisco, CA, USA). He was awarded MD and DSc degrees in 1983 and 2001, respectively, from the University of London. K.F. Chung is a Senior Investigator of the UK National Institute for Health Research and co-leader of the IMI-funded EU/EFPIA UBIOPRED project on Systems Biology of Severe Asthma. He has received research grants from the Medical Research Council, the Wellcome Trust, US Health Effects Institute, EU Innovative Medicines Initiative, National Environmental Research Council (UK), Asthma UK and the National Institutes of Health. He currently serves on the editorial boards of several respiratory and pharmacological journals and has authored and co-authored more than 750 scientific articles, reviews and book chapters. E.H. Bel E.H. Bel is Prof. of Medicine and Head of Respiratory Medicine at the Academic Medical Centre (Amsterdam, the Netherlands). She qualified in medicine from the University of Amsterdam and received her PhD degree (cum laude) at Leiden University Medical Centre (the Netherlands). She trained in pulmonary medicine, serving as consultant and senior consultant at Leiden University Medical Centre. Her current research focuses on the more severe types of asthma that are difficult to treat, with a particular emphasis on the phenotyping, pathophysiological mechanisms, monitoring and therapeutic approach of this complex condition. Her research questions emanate directly from daily pulmonary practice and in her attempts to find answers she uses pulmonary physiological, histological and molecular research techniques. She has published extensively in high-profile journals and has been involved in the organisation of international courses and seminars. She is an active member of several respiratory societies including the ATS and the European Respiratory Society where she served as an Assembly Head and member of the Executive Committee until 2008. She is also on the editorial board of the American Journal of Respiratory and Critical Care Medicine, and reviews papers for many other respiratory journals. S.E. Wenzel S.E. Wenzel began her translational research career in the area of asthma in the 1980s, while a pulmonary fellow at the Medical College of Virginia (Richmond, VA, USA). She moved to the National Jewish Health (Denver, CO, USA) in 1987. She was one of the first investigators to perform invasive (bronchoscopic) studies of asthma and has continued performing pathophysiologic studies of asthma and severe asthma. She organised an American Thoracic Society (ATS) workshop which developed a definition for severe asthma that is now widely accepted. S.E. Wenzel is currently Prof. of Medicine and Director of the University of Pittsburgh Asthma Institute @UPMC/UPSOM. She has published over 100 peer reviewed papers and has been active in the ATS, serving as deputy Editor for the American Journal of Respiratory and Critical Care Medicine. She served as a member of the NHLBI Internal Board of Scientific Counsellors (2003–2007) and is currently on the Lung Cellular and Molecular Immunology study section. In 2006, she was given the National Jewish Faculty Award for Scientific Achievement. She received the Elisabeth Rich MD Award for serving as a role model of females in medicine/science and received the ATS 2010 Recognition Award for Scientific Accomplishments. Eur Respir Mon 2011. 51, v. Printed in UK – all rights reserved. Copyright ERS 2011. European Respiratory Monograph ISSN: 1025-448x. DOI: 10.1183/1025448x.10001211 v