Rating sputum cell quality in clinical trials for asthma and COPD treatment

Frauke Pedersen,1,2 Ulrich M Zissler,3 Henrik Watz,2 Klaus F Rabe,1 Jens M Hohlfeld,4,5 Olaf Holz41LungenClinic Grosshansdorf, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Grosshansdorf, Germany; 2Pulmonary Research Institute at LungenClinic Grosshansdorf, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Grosshansdorf, Germany; 3Center of Allergy & Environment (ZAUM), Technical University of Munich and Helmholtz Center Munich, German Research Center for Environmental Health, Germany, Member of the German Center for Lung Research (DZL), Munich, Germany; 4Fraunhofer ITEM, Clinical Airway Research – Biomedical Research in End-stage and Obstructive Lung Disease Hannover (BREATH), German Center for Lung Research (DZL), Hannover, Germany; 5Department of Respiratory Medicine, Hannover Medical School (MHH), Biomedical Research in End-stage and Obstructive Lung Disease Hannover (BREATH), Hannover, GermanyBackgroundInduced sputum is a method to assess airway inflammation in clinical trials for asthma and COPD.1–3 Sputum is a heterogeneous, viscous material containing inflammatory cell plugs, cellular debris, mucus, and saliva with squamous cells.The quality of sputum cell preparations for differential cell count analysis depends on multiple factors and can be highly variable.4,5 Percentage of squamous cell contamination (SQ%) is often used to assess the quality of sputum cell preparations.6Here, we evaluated a comprehensive quality score,7 which also includes an assessment of the inflammatory cell morphology and amount of cellular debris.