Elevated Levels of Interleukin-33 in the Nasal Secretions of Patients with Allergic Rhinitis

Abstract

Background: Interleukin (IL)-33, which is a member of the IL-1 family of cytokines, is now recognized as an important contributor to Th2-type immune responses. We examined whether the levels of IL-33 in sera and nasal secretions are upregulated in allergic rhinitis (AR) patients, and we tested for correlations between the IL-33 level and the parameters of atopy and the nasal symptom score. Methods: The study included 24 Japanese cedar pollinosis patients (12 male and 12 female patients with a mean age of 47.7 years) with a history of moderate-to-severe AR, 14 house-dust-mite-sensitized patients with AR (9 male and 5 female patients with a mean age of 42 years) and 8 normal controls. We used Japan Rhinoconjunctivitis Quality-of-Life Questionnaire sheets to evaluate the nasal symptoms. We collected sera and nasal secretions to examine the level of IL-33 protein by ELISA. Results: IL-33 protein was not detected in the serum of any of the subjects. However, the IL-33 level in nasal secretions was significantly elevated in patients with Japanese cedar pollinosis at peak season and in patients with perennial AR compared to Japanese cedar pollinosis patients at preseason and the normal controls. Furthermore, IL-33 in nasal secretions correlated significantly with the total nasal symptom score. Conclusions: Our results suggest that IL-33 in nasal secretions may be related to exacerbation of AR, including that of Japanese cedar pollinosis cases.