Dendritic cells and Th17/Treg ratio play critical roles in pathogenic process of chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is a common disorder of respiratory system. This study aimed to evaluate changes of mature dendritic cells (DCs) and regulatory T cells (Treg) in lung tissues and peripheral blood of COPD patients. For lung tissue analysis, patients were divided into no-smoking and no-COPD (CS-COPD-), smoking and no-COPD (CS + COPD-) and COPD group. For peripheral blood analysis, patients were divided into CS-COPD-, CS + COPD-, stable COPD (SCOPD) and acute exacerbation of COPD (AECOPD) group. Hematoxylin and eosin (HE) staining was used to evaluate inflammation of lung tissues. Immunohistochemistry assay was employed to examine CD80, CCR6, IL-17 A, FoxP3 in lung tissues. DCs and Treg cells were isolated from lung tissues and peripheral blood. Levels of CD80, FoxP3+ Treg, CCR6 and IL-17 A were detected by using flow cytometry. Results showed that FEV%, FVC% and FEV1/FVC were significantly reduced and Bosken scores were remarkably increased in COPD patients compared to non-COPD patients (p < 0.05). CD80 and FoxP3 levels were lower, and CCR6 and IL-17A levels were higher obviously in COPD compared to non-COPD patients (p < 0.05). COPD patients illustrated reduced mDCs levels and enhanced imDCs levels. COPD patients exhibited remarkably higher Th17 levels compared to no-smoking patients (p < 0.05). COPD patients illustrated obviously lower Treg levels and significantly higher Th17/Treg ratio compared to non-smoking patients (p < 0.05). Th17% (Th17/Treg) negatively and Treg% was positively correlated with FEV1%, FEVC%, FEV1/FEVC (p < 0.05). In conclusion, dendritic cells and Th17/Treg ratio play critical roles for pathogenic process of chronic obstructive pulmonary disease.