title: [Interleukin-17 expression and clinical significance in the lung tissue of patients with stable chronic obstructive pulmonary disease].
abstract: OBJECTIVE
  To observe the interleukin-17 (IL-17) expression in lung tussiue of patients with stable chronic obstructive pulmonary disease (COPD) and investigate the clinical significance.
  
  
  METHODS
  A total of 50 patients receiving lung resections in General Hospital, Tianjin Medical University for lung cancer from October 2010 to October 2011 were included and divided into non-smoking COPD group (NS group), smoking non-COPD group (S group), smoking COPD group (COPD group) according to smoking status and 2013 COPD diagnosis standard. The expression of IL-17 was detected by immumohistochemical staining. The volume of IL-17 in the airway and lung parenchyma was calculated by immumohistochemical staining scores which was product of dyeing cells positive rate and intensity. Pearson correlation analysis was used to analyze the relationships between expression of IL-17 in the airway and lung parenchyma and forced expiratory volume in 1 second/predicted value (FEV1%pred), carbon monoxide diffusion amount accounting for the percentage of the expected value (DLCO%pred), COPD assessment test (CAT) score, body mass index (BMI).
  
  
  RESULTS
  The expressions of IL-17 in airway and lung parenchyma in S group (5.6±3.1, 6.4±2.5) were higher than those in NS group (1.6±1.4, 1.4±1.2) (both P<0.05), while expressions in COPD group (7.3±2.5, 7.8±2.1) were further higher than S group (both P<0.05). In the S group and COPD group, the expressions of IL-17 in the airway and lung parenchyma were positively correlated with smoking (r=0.453, P=0.007 and r=0.573, P<0.001); In the COPD group, the expressions of IL-17 in the airway and lung parenchyma were negatively correlated with FEV1%pred (r=-0.729, P=0.001 and r=-0.489, P=0.039), negatively related with DLCO%pred (r=-0.493, P=0.038 and r=-0.520, P=0.027), positively correlated with COPD CAT score (r=0.730, P=0.001 and r=0.644, P=0.004) and negatively related with BMI (r=-0.653, P=0.003 and r=-0.485, P=0.041).
  
  
  CONCLUSIONS
  Smoking increases inflammation of lung tissue, increases IL-17 expression in airway and lung parenchyma; the expression of IL-17 is closely related to the severity of disease, the quality of life and prognosis in COPD patients.
authors.affiliation: Department of Respiratory Medicine, General Hospital, Tianjin Medical University, Tianjin 300052, China (Chen Xin is working in the Department of Respiratory of Tianjin Fourth Center Hospital).
authors.forename: X
authors.initials: X
authors.lastname: Chen
authors.forename: J
authors.initials: J
authors.lastname: Cao
authors.forename: B Y
authors.initials: BY
authors.lastname: Chen
mesh_terms: D005541:Forced Expiratory Volume; D006801:Humans; D007249:Inflammation; D020381:Interleukin-17; D008168:Lung; D029424:Pulmonary Disease, Chronic Obstructive; D011788:Quality of Life; D012907:Smoking
chemical_list: D020381:Interleukin-17