Epithelial derived cytokines IL-25, IL-33 and TSLP in obstructive lung diseases

An epithelium-derived cytokines represent a master switch at the interface between environmental allergens and pulmonary immunologic response. IL-33, IL-25, and TSLP are released by airway epithelial cells and may affect innate lymphoid cells (ILC2). These cells are a rich source of Th2 cytokines, that are involved in airway eosinophilia, mucus production and airway hyperreactivit. The aim of the study was to define the TSLP, IL-25 and IL-33 expression and its correlation with clinical features of obstructive lung diseases. Methods: the study enrolled 38 patients: 12 of IgE-mediated asthma, 16 with COPD and 10 controls who underwent lung function test and sputum induction. In induced sputum (IS) mRNA and protein expression levels of TSLP, IL-25 and IL-33 were evaluated (using real-time PCR and ELISA method, respectively). Results: both asthma and COPD patients had elevated concentration of TSLP, IL-25 and IL-33 in IS vs. control. Significantly higher eosinophil percentage in IS was found in asthmatics compared to controls, while COPD group were characterized by increased percentage of IS neutrophils vs controls. There were no significant differences between IS levels of TSLP, IL-25 and IL-33 and their mRNA expression in asthma vs COPD patients. In all groups IS concentration of TSLP and IL-25 correlated positively with the percentage of neutrophils in IS and with the value of FEV1% and FEV1%VC. Conclusions: TSLP, IL-25 and IL-33 expression is elevated in obstructive lung diseases. Th2 mediated immunological response could be observed not only in asthma but also in COPD. The result of this study warrant further evaluation of the role of these cytokines in particular phenotypes of asthma and COPD.