IL17A and chronic obstructive pulmonary disease: Even though it is known that ICS decrease cellular inflammation (including mast cells) in the large airways in patients suffering from COPD [34] and IL-17 expression is reduced by dexamethasone in peripheral blood and bronchoalveolar lavage fluid in asthmatics rats [35], no effect of ICS use on different mast cells subpopulations and their IL-17 expression could be seen in our study population using an univariate analysis.