Increased IL-22 level in allergic rhinitis significantly correlates with clinical severity

IL-22 regulates various processes and has been linked to diverse effects. However, the importance of IL-22 in the pathogenesis of allergic rhinitis (AR) remains poorly understood. This study sought to evaluate the levels of IL-22 and IL-17A in AR patients and their association with clinical severity ofN AR. Thirty-six AR patients and 22 normal controls were enrolled in this study. The frequencies of IL-22(+), IL-17A(+), and IL-9(+) T helper (Th) cells in peripheral blood of AR patients and normal controls were examined by flow cytometry. Serum levels of IL-22 and IL-17A in AR patients and normal controls were determined by ELISA. The clinical relevance of the percentages of IL-22(+) and IL-17A(+) Th cells as well as serum IL-22 and IL-17A levels were evaluated. The frequencies of IL-22(+) and IL-17A(+) Th cells, but not IL-9(+) Th cells, were significantly increased compared with those in normal controls (p < 0.05). Frequencies of IL-22(+) and IL-17A(+) Th cells in peripheral blood of AR patients significantly correlated with visual analog scale scores of nasal symptoms (nasal congestion and rhinorrhea; p < 0.05). Moreover, the serum levels of IL-22 and IL-17A were significantly increased compared with those in normal controls (p < 0.05) and significantly correlated with the levels of Dermatophagoides pteronyssinus and Dermatophagoides farinae specific IgE in AR patients. Our findings suggested that IL-22 as well as IL-17A may play an important role in the regulation of Th2-skewed inflammation in AR patients.