The IL‐31/CysLT2R axis is associated with itching in patients with allergic rhinitis

Abstract Background Itching is a troublesome symptom that disturbs patients with allergic rhinitis (AR). The molecular mechanisms underlying itching in AR need to be further illuminated. The aim of this study was to investigate the role of epithelial cell‐derived interleukin‐31 (IL‐31) in nasal itching in AR. Methods A total of 33 patients and 20 healthy control subjects were enrolled in this prospective study. The disease severity of patients with AR was assessed by the total visual analog scale score. The levels of IL‐31, cysteinyl leukotriene receptor 1 (CysLT1R), and CysLT2R in the nasal brush specimens from the enrolled subjects were measured by quantitative real‐time polymerase chain reaction (RT–PCR) and immunohistochemical staining. The expression of CysLT2R in a human nasal epithelial cell line (HNEpC) was assessed by immunofluorescence staining. Results Compared with the control subjects, the protein and mRNA levels of IL‐31 and CysLT2R were significantly increased in patients with AR. Higher levels of IL‐31 and CysLT2R in nasal epithelial cells were associated with itching but not nasal congestion, rhinorrhea, or sneezing in AR. A significant relationship was found between IL‐31 and CysLT2R in nasal epithelial cells, with a correlation coefficient of 0.93. Furthermore, RT–PCR and immunofluorescence staining revealed that IL‐31 directly induced CysLT2R expression in HNEpCs. Nasal steroid treatment inhibited IL‐31 and CysLT2R expression in 13 patients with AR in vivo. Conclusions Nasal epithelial cell‐derived IL‐31 might be associated with itching symptoms via CysLT2R in AR.