ERS | monograph Guest Editors Claus Bachert Claus Bachert MD, PhD is chief of the clinic and Professor at the University Hospital of Ghent, Belgium, and also holds a position as Professor at the Karolinska Institute, Stockholm, Sweden. He qualified from the University of Heidelberg, Germany, and trained in ENT diseases and allergology in Mannheim and Düsseldorf, Germany. His research interests include the pathophysiology and management of diseases of the nose and sinuses, such as allergic and nonallergic rhinitis, chronic rhinosinusitis, and nasal polyposis. Specifically, he has worked on endotyping rhinosinusitis, innovative treatments such as biologicals for recalcitrant disease and the role of Staphylococcus aureus in the inflammation of nasal polyp disease. He chairs the Upper Airways Research Laboratory at Ghent University and has published over 460 peer-reviewed articles in international journals. He has received several national and international prizes, and two doctor honoris causa (Capital University, Beijing, China and Democritus University, Thrace, Greece). Claus Bachert forms part of the international guidelines groups ARIA (Allergic Rhinitis and its Impact on Asthma) and EPOS (European Position Paper on Sinusitis and Nasal Polyposis), has served on the Boards of the European Academy of Allergy and Clinical Immunology and World Allergy Organization, and was President (2007–2010) and Vice-President (2011–2016) of the German Allergy Society (DGAKI). He currently serves as an Associate Editor for the Journal of Allergy and Clinical Immunology. Arnaud Bourdin Arnaud Bourdin MD, PhD is head of pulmonology and a Consultant and Professor of Respiratory Medicine at Hôpital Arnaud de Villeneuve, Montpellier, France. He gained his MD and PhD in 2001 and 2006, respectively, from the University of Montpellier, and was subsequently a fellow at Monash University, Melbourne, Australia, working alongside Professor Tom Kotsimbos. Copyright ©ERS 2017. Print ISBN: 978-1-84984-085-9. Online ISBN: 978-1-84984-086-6. Print ISSN: 2312-508X. Online ISSN: 2312-5098. https://doi.org/10.1183/2312508X.10008017 ix