Chest
Volume 138, Issue 5, November 2010, Pages 1140-1147
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Original Research
Asthma
Expression of the T Helper 17-Associated Cytokines IL-17A and IL-17F in Asthma and COPD

https://doi.org/10.1378/chest.09-3058Get rights and content
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open access

Background

Asthma and COPD are characterized by airway dysfunction and inflammation. Neutrophilic airway inflammation is a common feature of COPD and is recognized in asthma, particularly in severe disease. The T helper (Th) 17 cytokines IL-17A and IL-17F have been implicated in the development of neutrophilic airway inflammation, but their expression in asthma and COPD is uncertain.

Methods

We assessed IL-17A and IL-17F expression in the bronchial submucosa from 30 subjects with asthma, 10 ex-smokers with mild to moderate COPD, and 27 nonsmoking and 14 smoking control subjects. Sputum IL-17 concentration was measured in 165 subjects with asthma and 27 with COPD.

Results

The median (interquartile range) IL-17A cells/mm2 submucosa was increased in mild to moderate asthma (2.1 [2.4]) compared with healthy control subjects (0.4 [2.8]) but not in severe asthma (P = .04). In COPD, IL-17A+ cells/mm2 submucosa were increased (0.5 [3.7]) compared with nonsmoking control subjects (0 [0]) but not compared with smoking control subjects (P = .046). IL-17F+ cells/mm2 submucosa were increased in severe asthma (2.7 [3.6]) and mild to moderate asthma (1.6 [1.0]) compared with healthy controls subjects (0.7 [1.4]) (P = .001) but was not increased in subjects with COPD. IL-17A and IL-17F were not associated with increased neutrophilic inflammation, but IL-17F was correlated with the submucosal eosinophil count (rs = 0.5, P = .005). The sputum IL-17 concentration in COPD was increased compared with asthma (2 [0–7] pg/mL vs 0 [0–2] pg/mL, P < .0001) and was correlated with post-bronchodilator FEV1% predicted (r = −0.5, P = .008) and FEV1/FVC (r = −0.4, P = .04).

Conclusions

Our findings support a potential role for the Th17 cytokines IL-17A and IL-17F in asthma and COPD, but do not demonstrate a relationship with neutrophilic inflammation.

Cited by (0)

Funding/Support: This study was funded by Asthma UK, MedImmune Ltd, and a Wellcome Senior Clinical Fellowship (C. B.).

Ms Doe and Dr Bafadhel contributed equally to this article.

This is an Open Access article distributed under the terms of the Creative Commons Attribution-Noncommercial License (http://creativecommons.org/licenses/by-nc/3.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Information for commercial entities is available online (http://www.chestpubs.org/site/misc/reprints.xhtml).