About the Authors

Susan J. M. Hoonhorst

Affiliations University of Groningen, University Medical Center Groningen, Department of Pulmonary Diseases, Groningen, The Netherlands, University of Groningen, University Medical Center Groningen, GRIAC research institute, Groningen, The Netherlands

Nick H. T. ten Hacken

Affiliations University of Groningen, University Medical Center Groningen, Department of Pulmonary Diseases, Groningen, The Netherlands, University of Groningen, University Medical Center Groningen, GRIAC research institute, Groningen, The Netherlands

Judith M. Vonk

Affiliations University of Groningen, University Medical Center Groningen, GRIAC research institute, Groningen, The Netherlands, University of Groningen, University Medical Center Groningen, Department of Epidemiology, Groningen, The Netherlands

Wim Timens

Affiliations University of Groningen, University Medical Center Groningen, GRIAC research institute, Groningen, The Netherlands, University of Groningen, University Medical Center Groningen, Department of Pathology and Medical Biology, Groningen, The Netherlands

Pieter S. Hiemstra

Affiliation Leiden University Medical Center, Department of Pulmonology, Leiden, The Netherlands

Thérèse S. Lapperre

Affiliation Leiden University Medical Center, Department of Pulmonology, Leiden, The Netherlands

Peter J. Sterk

Affiliation University of Amsterdam, Academic Medical Centre Amsterdam, Department of Pulmonary Diseases, Amsterdam, The Netherlands

Dirkje S. Postma

d.s.postma@umcg.nl

Affiliations University of Groningen, University Medical Center Groningen, Department of Pulmonary Diseases, Groningen, The Netherlands, University of Groningen, University Medical Center Groningen, GRIAC research institute, Groningen, The Netherlands

Competing Interests

SH, JV, WT and TL have no conflicts of interest to declare. NtH: The University of Groningen received funding from Boehringer Ingelheim, GSK, AstraZeneca, Nycomed and Chiesi. PH: received research grants from GlaxoSmithKline, Boehringer Ingelheim, and Galapagos. PS: received grants from Innovative Medicines Initiative (IMI) by Europe Union, university grants, and pharmaclinical grants. DP: The University of Groningen received funding, i.e. an unrestricted educational grant for research from AstraZeneca, Chiesi, GSK; travel to ERS and/or ATS from AstraZeneca, Chiesi, GSK, Nycomed. Fees for consultancies were given to the University of Groningen by AstraZeneca, Boehringer Ingelheim, Chiesi, GSK, Nycomed, and TEVA. This does not alter the authors’ adherence to all the PLOS ONE policies on sharing data and materials.

Author Contributions

Wrote the paper: SH. Performed analysis: SH. Provided final approval of the manuscript: SH NtH JV WT PH TL PS DP. Supervised the original study: NtH PH PS DP. Performed bronchoscopies in the study: NtH. Supervised current analyses: NtH. Critically revised the manuscript: NtH JV WT PH TL PS DP. Supervised analysis: JV DP. Supervised the original study including biopsy analyses: WT. Collected clinical data in the original study: TL.