IL-25 and IL-25 Receptor Expression on Eosinophils from Subjects with Allergic Asthma

• Published in: International archives of allergy and immunology Vol. 163; no. 1; pp. 5 - 10
• Main Authors: Tang, Wei, Smith, Steven G., Beaudin, Sue, Dua, Benny, Howie, Karen, Gauvreau, Gail, O'Byrne, Paul M.
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland S. Karger AG 01.01.2014
• Subjects: Adult; Allergies; Asthma; Asthma - genetics; Asthma - immunology; Asthma - metabolism; Asthma - pathology; Case-Control Studies; Eosinophils - immunology; Eosinophils - metabolism; Eosinophils - pathology; Female; Gene Expression; Humans; Hypersensitivity, Immediate - genetics; Hypersensitivity, Immediate - immunology; Hypersensitivity, Immediate - metabolism; Hypersensitivity, Immediate - pathology; Interleukin-17 - blood; Interleukin-17 - genetics; Interleukin-17 - immunology; Leukocyte Count; Male; Middle Aged; Neurons; Neutrophil Activation; Original Paper; Protein Subunits - genetics; Protein Subunits - immunology; Protein Subunits - metabolism; Receptors, Interleukin-17 - genetics; Receptors, Interleukin-17 - immunology; Receptors, Interleukin-17 - metabolism; Interleukin 17 family; Allergic inflammation; Asthma; Eosinophils
• ISSN: 1018-2438; 1423-0097; 1423-0097
• DOI: 10.1159/000355331

Background: Allergic asthma is an inflammatory airway disease in which Th2 cytokines play an important role. Epithelial-derived interleukin (IL)-25 has been suggested to be important in the maintenance of Th2-type responses. The effects of IL-25 are mediated by the IL-25 receptor, composed of two subunits, IL-17RA and IL-17RB. Eosinophils are effector cells in allergic asthma. The role of IL-25 in eosinophil function is unknown. This study examined the expression of IL-25 and its receptor on eosinophils in allergic asthmatics compared to atopic nonasthmatics and normal controls. Methods: The expression of IL-25, IL-17RA and IL-17RB on eosinophils, and levels of plasma IL-25 were measured in 14 normal control subjects, 15 atopic nonasthmatics and 14 mild allergic asthmatics. Results: The expression of IL-17RB on eosinophils was significantly higher in allergic asthmatics (43.08%, range 33.96-59.98%) than in atopic nonasthmatics (11.98%, range 6.33-27.11%, p = 0.002) and normal controls (17.70%, range 10.97-38.9%, p = 0.01). IL-17RA expression was also significantly higher in the allergic asthmatic group. No differences were observed in the intracellular expression of IL-25. The concentration of IL-25 in plasma was significantly increased in the allergic asthmatics (145 ng/ml, range 64-290 ng/ml) when compared to the normal controls (21 ng/ml, range 0-116 ng/ml, p = 0.012), but not compared to atopic nonasthmatics. There was a significant negative correlation between FEV 1 % predicted and the IL-25 level in the plasma (r = -0.443, p = 0.003). Conclusions: The increased IL-25 levels in plasma and the expression of IL-17RA and IL-17RB on eosinophils in allergic asthma patients suggests that IL-25 may activate eosinophils during allergic inflammation.