1. Division of Respiratory Medicine and Respiratory Research Unit, University of Nottingham, Nottingham, United Kingdom
2. National Heart and Lung Institute, Imperial College London and MRC & Asthma UK Centre in Allergic Mechanisms of Asthma, London, United Kingdom
3. Respiratory Medicine, Guy’s and St Thomas’ NHS Trust, London, United Kingdom; and
4. Department of Histopathology, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom