Abstract: Objective To study the expression of interleukinIL-31(IL-31), and interleukin-33(IL-33)and its receptor ST2, in the nasal mucosa of patients with refractory rhinosinusitis(RRS), and to investigate their role in the pathogenesis of RRS. Methods In this study, a refractory group, an initial treatment group, and a control group were established. The hematoxylin and eosin staining method was used to observe the morphology and detect the number of eosinophils(EOS)present in the mucosal tissues. The relative levels of IL-31, IL-33, and ST2 in the tissues were detected by immunohistological examination.Quantitative fluorescence real-time polymerase chain reaction was used to detect the mRNA levels of IL-31, IL-33, and ST2, and total serum immunoglobulin E(IgE)expression in the peripheral blood. Results (1)The number of EOS in the refractory group and initial treatment group were higher than that in the control group. Further, the number of EOS in the refractory group were higher than that in the initial group. (2) On immunohistological examination, the expression levels of IL-31 and IL-33 proteins in the refractory group and the initial treatment group were higher than those in the control group. Additionally, the expression levels of both IL-31 and IL-33were higher in the refractory group than in the initial treatment group. The expression of ST2 in the refractory group and the initial treatment group was higher than that in the control group, but there was no significant difference in the expression of ST2 between the refractory group and the initial treatment group. (3) At the level of mRNA expression, the levels of IL-31 and IL-33 in the refractory group and the initial treatment group were higher than those in the control group. Furthermore, the levels of IL-31 and IL-33 mRNA in the refractory group were higher than those in the initial treatment group. The ST2 mRNA levels in the refractory group and the initial treatment group were higher than that in the control group, but there was no significant difference between the refractory group and the initial treatmentgroup. (4) There was no significant difference between the three groups in the total IgE levels in the peripheral blood. Conclusion IL-31, and IL-33 along with its receptor ST2, may play an important role in the pathogenesis of chronic rhinosinusitis, especially in patients with RRS. Eosinophilic infiltration may also play an important role in the development of RRS.

Key words: Sinusitis, refractory, Receptor ST2, Eosinophils, Interleukin 33, Interleukin 31