Abstract
Background: Mast cells are increasingly recognized as important contributors to smoking-induced inflammation. IL-17A is a cytokine produced by inflammatory cells which promotes neutrophilic inflammation. We evaluated whether IL-17A is expressed by mast cells in the airways of smokers.
Methods: Immunohistochemical staining was performed in large (LA) and small (SA) airways from 12 (ex-) smokers undergoing lung cancer resection. In airways free of tumour a double staining protocol was used for the simultaneous visualization of mucosal (MCT, positive for the protease tryptase) and connective tissue (MCTC, positive for the proteases chymase and tryptase) mast cells as well as for IL-17A and MCT resp. MCTC. Image analysis was performed using spectral microscopy. Values are expressed as cells/BM length for inner and outer layers.
Results: See Table 1.
Conclusion: A marked proportion of mast cells in LA and SA of smokers express IL-17A. High expression of IL-17A was observed in both MCT and MCTC, and mast cells situated in the outer layer. These findings suggest that mast cells contribute to inflammation in LA and SA via IL-17A expression.
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