Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 14 3 2015 10 18 273 279 EN Baohong Tao Department of Otorhinolaryngology, Taizhou Municipal Hospital, the Affiliated Hospital of Medical College of Taizhou University, Taizhou, Zhejiang, 318000, China Guiying Ruan Department of Paediatrics, Taizhou Municipal Hospital, the Affiliated Hospital of Medical College of Taizhou University, Taizhou, Zhejiang, 318000, China Dongguo Wang Central Laboratory, Taizhou Municipal Hospital, the Affiliated Hospital of Medical College of Taizhou University, Taizhou, Zhejiang, 318000, China Yong Li Department of Otorhinolaryngology, Taizhou Municipal Hospital, the Affiliated Hospital of Medical College of Taizhou University, Taizhou, Zhejiang, 318000, China Zhuping Wang Department of Paediatrics, Taizhou Municipal Hospital, the Affiliated Hospital of Medical College of Taizhou University, Taizhou, Zhejiang, 318000, China Genquan Yin Department of Respiratory, Guangzhou Children's Hospital, Guangzhou, Guangdong, 510120, China 2015 10 18 2015 10 18 The purpose of the present study is to investigate the prevalence of Th17 and regulatory T (Treg) cells in children with allergic rhinitis (AR) accompanying with bronchial asthma (BA).24 children with AR, 22 children with BA, 18 children with AR accompanying with BA,and 20 healthy controls were recruited. The prevalence of peripheral blood Th17 and Treg cells were determined by flow cytometry. mRNA expression of retinoid-acid receptor-related orphan  receptor  (ROR)-γt  and  forkhead  box  P3  (Foxp3) were  determined  by  realtime polymerase chain reaction. Cytokine expressions in plasma were determined by enzyme linked immunosorbent assay.The frequency of Th17 cells, ROR-γt mRNA expression, and the plasma levels of IL-17 were significantly higher, while Treg cells and Transforming growth factor (TGF)-β1 were significantly lower in children with AR accompanying with BA compared with those in children with AR or BA alone or control subjects. In children with allergic airway disease, total IgE levels were positively correlated to the frequency of Th17 cells (r=0.607, p<0.01), plasma IL-17 levels, and negatively correlated to the frequency of Treg cells (r=-0.429, p<0.01) and TGF-β1 levels (r=-0.224, p<0.01). While Forced expiratory volume in one second (FEV1) (% predicted) was negatively correlated to the frequency of Th17 cells (r=-0.602, p<0.01), plasma IL-17 levels (r=-0.577,  p<0.01), and positively correlated to  the frequency of Treg cells (r=0.504, p<0.01) and TGF-β1 levels (r=0.231, p<0.05).Our  results  demonstrate  that  the  imbalance  of  peripheral Th17/Treg  cells  plays  an important role in the pathogenesis of AR accompanying with BA. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/567 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/567/452