RT Journal Article SR Electronic T1 MicroRNA profiling in bronchial biopsies of asthma patients JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 619 DO 10.1183/13993003.congress-2020.619 VO 56 IS suppl 64 A1 Mirjam P. Roffel A1 Ilse M. Boudewijn A1 Jos Van Nijnatten A1 Corneel J. Vermeulen A1 Antoon J.M. Van Oosterhout A1 Karen Affleck A1 Ken R. Bracke A1 Tania Maes A1 Irene H. Heijink A1 Corry-Anke Brandsma A1 Maarten Van Den Berge YR 2020 UL http://erj.ersjournals.com/content/56/suppl_64/619.abstract AB Alterations in miRNA expression may play a role in the pathogenesis of asthma. Our aim was to identify miRNAs that are differentially expressed in bronchial biopsies of asthma patients compared to healthy controls and to explore their association with clinical parameters.Small RNA sequencing data derived from bronchial biopsies of 79 asthmatics and 82 healthy controls was used to determine differential miRNA expression. To exclude potential effects of smoking status and inhaled corticosteroids (ICS), a sensitivity analysis was performed in a subset comparing asthma patients (n=30) and healthy controls (n=42) excluding smokers and ICS treated patients. The remaining differentially expressed miRNAs were associated with clinical parameters, including FEV1 % predicted, PC20AMP, eosinophil and neutrophil counts in blood, sputum and tissue in asthma patients using linear regression.In total of 78 differentially expressed miRNAs in bronchial biopsies of asthma patients compared to healthy controls, of which 62 remained differentially expressed in the sensitivity analysis. The most significant miRNAs were miR-93-5p, miR-16-5p, miR-125a/b and the let-7 family. Of the 62 asthma-associated miRNAs, 25 miRNAs correlated with one or more clinical asthma parameters. Lower levels of let-7a was associated with higher levels of blood and tissue eosinophils in asthma patients, while lower levels of miR-125a/b were associated with lower FEV1% predicted and higher levels of eosinophils and neutrophils in blood.In conclusion, we identified several miRNAs that are differentially expressed in bronchial biopsies of asthma patients compared to healthy controls and up to one third of them are associated with the clinical expression of asthma.FootnotesCite this article as: European Respiratory Journal 2020; 56: Suppl. 64, 619.This abstract was presented at the 2020 ERS International Congress, in session “Respiratory viruses in the "pre COVID-19" era”.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).