1 University of Groningen, University Medical Center Groningen, Department of Pathology and Medical Biology, Groningen, The Netherlands.
2 University of Groningen, University Medical Center Groningen, GRIAC (Groningen Research Institute for Asthma and COPD), Groningen, The Netherlands.
3 Division of Pediatric Pneumology & Allergology, University Medical Center Schleswig-Holstein, Campus Centrum Lübeck, Member of Airway Research Center North (ARCN) of the German Center of Lung Research (DZL), Lübeck, Germany.