IL-33/ST2 axis controls Th2/IL-31 and Th17 immune response in allergic airway diseases.

IL-33 targeting ST2 receptor (T1/ST2), expressed on Th2 cell surface, regulates the production of cytokines like IL-17A and IL-31. We studied the role of IL-33/ST2 axis in IL-31 and IL-17A production in patients with allergic rhinitis (AR) and with concomitant allergic asthma and rhinitis (AAR). 20 healthy control subjects (HC), 14 AR and 17 AAR subjects were recruited and blood samples collected. IL-33, soluble ST2 (sST2), IL-17A and IL-31 plasma concentrations were measured by ELISA method. T1/ST2, IL-31 and IL-17A cellular expression were studied in peripheral blood mononuclear cells (PBMC) from HC, AR and AAR (n=6 for each group) by flow-cytometry. In vitro, we also evaluated the effect of beclomethasone dipropionate (BDP) on T1/ST2, IL-31 and IL-17A expression in CD3(+)T-cells from PBMC of AAR (n=6). Plasma levels of IL-33, IL-31 and IL-17A were significantly higher and sST2 was lower in patients with AR and AAR than in HC. IL-31 and IL-17A intracellular levels significantly increased, whereas T1/ST2 expression was significantly lower, in CD3(+)T-cells from AR and AAR compared to HC. Positive correlations were observed between plasmatic components of IL-33/ST2 axis and IL-31 in both AR and AAR and IL-17A in AAR. In vitro IL-31 and IL-17A intracellular levels decreased after BDP treatment, whereas T1/ST2 expression increased in cultured CD3(+)T-cells obtained from AAR. IL-33/ST2 axis is involved in Th2/IL-31 and Th17 immune response during the progression of allergic airway disease. In vitro BDP is able to control Th2/IL-31 and Th17 immune response in PBMC from allergic patients.