IL-17 is increased in asthmatic airways and induces human bronchial fibroblasts to produce cytokines

Abstract

Background: IL-17 is a cytokine that has been reported to be produced by T lymphocytes. In vitro, IL-17 activates fibroblasts and macrophages for the secretion of GM-CSF, TNF-α, IL-1β, and IL-6. A number of these cytokines are involved in the airway remodeling that is observed within the lungs of asthmatic individuals. Objective: In this study, we investigated the expression of IL-17 in sputum and bronchoalveolar lavage specimens obtained from asthmatic subjects and from nonasthmatic control subjects. Methods: IL-17 was detected through use of immunocytochemistry, in situ hybridization, and Western blot. Bronchial fibroblasts were stimulated with IL-17, and cytokine production and chemokine production were detected through use of ELISA and RT-PCR. Results: Using immunocytochemistry, we demonstrated that the numbers of cells positive for IL-17 are significantly increased in sputum and bronchoalveolar lavage fluids of subjects with asthma in comparison with control subjects (P