The role of regulatory T cells in allergic rhinitis and their correlation with IL-10, IL-17 and neopterin levels in serum and nasal lavage fluid

Purpose Allergic rhinitis (AR), is an IgE-mediated inflammation of the nose. Regulatory T cells (Tregs) and inflammatory cytokines have been shown to play a critical role in allergic airway inflammation. The aim of the study was to compare the levels of blood T lymphocyte subsets and IL-10, IL-17 and neopterin concentrations in serum and nasal lavage of patients with AR compared to healthy subjects. Methods The study included 38 subjects with moderate-severe AR and 36 sex- and age-matched controls. Peripheral blood CD3+, CD3+CD4+ and CD4+CD25+Foxp3 percentages were evaluated using flow cytometry. Levels of IL-10, IL-17 and neopterin were measured both in serum and nasal lavage fluid with ELISA and HPLC, respectively. Results No difference was found in the percentages of T lymphocyte subsets between the two groups (p > 0.05). Serum IL-10 levels were similar (p > 0.05), whereas nasal IL-10 was lower in AR subjects compared to control group (2.22 +/- 0.91 and 3.12 +/- 1.45 pg/ml, respectively) (p < 0.05). Mean serum and nasal IL-17 were higher in AR (107.7 +/- 79.61 and 527.36 +/- 738.7 pg/ml) than the control group (76.29 +/- 28.94 and 328.9 +/- 430.8 pg/ml) (p < 0.05 and p > 0.05). There were no significant differences in serum and nasal neopterin levels (p > 0.05). Conclusions Although there were no differences in the distribution of lymphocyte subsets between the AR and control groups, the finding of higher levels of serum and nasal IL-17 and lower levels of nasal IL-10 support the cytokine imbalance in the pathogenesis of AR.