Impaired Balance of Th17/Treg in Patients with Nasal Polyposis

Nasal polyposis (NP) is a chronic inflammatory disease of the nasal cavity and sinuses that is regulated by T lymphocyte subsets. Imbalance of Th17/Treg has been considered critical in the development of inflammation and atopic reactions. To assess whether the balance of Th17/Treg is disrupted in patients with NP, we evaluated the distribution of Th17 and Treg cells among peripheral blood mononuclear cells (PBMCs) in atopic patients with NP, non-atopic patients with NP and controls. We then determined mRNA levels of RORc and Foxp3 and protein levels of IL-17, TGF-beta and IL-10 in polyp tissue among the three groups. Finally, we investigated the correlation between Th17-, Treg- and Th1-, Th2-related cytokines (INF-gamma, IL-4, IL-5). The results demonstrated that both atopic and non-atopic patients with NP revealed significantly increased Th17 proportion and decreased Treg proportion in PBMCs, as well as significantly increased RORc and IL-17 levels and decreased Foxp3 and TGF-beta levels in polyp tissue. Furthermore, these differences were significant between atopic and non-atopic groups. The frequency of Treg in PBMCs was found to be negatively correlated with Th1 and Th2 cytokines in polyps. These results indicated that an impaired balance of Th17/Treg existed in patients with NP and was more severe in atopic patients, suggesting that the imbalance of Treg/Th17 may play an important role in the development of NP and that atopy may aggravate NP by promoting the imbalance of Th17/Treg.