Contents Preface v Guest Editors vi Introduction ix List of abbreviations xii 1. Definition and impact 1 William W. Busse 2. Understanding the experience of people living with severe asthma 16 Vanessa M. McDonald, Erika Kennington and Michael E. Hyland 3. The contribution of comorbidities, psychosocial factors and adherence 30 to the presentation of severe asthma Mark Hew and Liam G. Heaney 4. Clinical phenotypes: adults 48 Tae-Bum Kim, Elisabeth H. Bel and Wendy Moore 5. Clinical phenotypes: children 64 W. Gerald Teague and Graham Roberts 6. Mechanisms underlying fixed airflow obstruction and exacerbations 82 Nizar N. Jarjour and Satoshi Konno 7. Clinical biomarkers and noninvasive assessment 93 Sarah Svenningsen, Stephen J. Fowler and Parameswaran Nair 8. Imaging 113 Salman Siddiqui, Mario Castro and Christopher E. Brightling 9. Pathophysiology 132 Ian M. Adcock and Sharon Mumby 10. The lessons from U-BIOPRED 152 Scott S. Wagers and Ian M. Adcock 11. SARP: dissecting subphenotypes and endotypes 167 Deborah A. Meyers, Sally E. Wenzel and Eugene R. Bleecker ERS monograph Severe Asthma Number 84 June 2019