喀疾中サイトカイン測定による慢性閉塞性肺疾患患者の気道炎症に関する研究

Abstract

To assess the characteristics of airway inflammation in patients with chronic obstructive pulmonary disease (COPD), I measured the sputum concentration of interleukin-8 (IL-8), tumor necrosis factor α (TNFα), interleukin-5 (IL-5), and RANTES, which are cytokines involved in the migration and activation of neutrophils and eosinophils. I also measured myeloperoxidase (MPO) as a parameter of neutrophil activity and eosinophil cationic protein (ECP) as a parameter of eosinophil activity. Spontaneous sputum samples were obtained from 33 patients with stable COPD and 30 patients with asthma. Induced sputum samples were obtained from 12 healthy controls. The sputum concentrations of IL-8 and TNFα were significantly higher in the patients with COPD than in the patients with asthma (p<0.0001, p<0.001, respectively) or in the controls (p<0.0001, p<0.001, respectively). Concentrations of IL-5, RANTES, MPO and ECP were significantly higher in the patients with COPD than in the controls (p<0.01, p< 0.05, p<0.0001, p<0.0001, respectively) but did not differ significantly betweenn the patients with COPD and those with asthma. In the patients with COPD, the sputum concentration of IL-8 was significantly correlated with the concentration of TNFα (r= 0.45, p<0.01), of MPO (r=0.55, p<0.001) and of ECP (r=0.53, p<0.01). The sputum concentration of IL-8 was negatively correlated with FEV1/FVC(r=-0.78, p<0.0001) in these patients. In conclusion, these results suggest the activation of both neutrophils and eosinophils in the airway of patients with COPD. It appears that IL-8 is mainly involved with this activation. The sputum concentration of IL-8 appears to be closely associated with the degree of airflow obstruction in patients with COPD and may serve as a marker in evaluating the severity of airway inflammation, which is a risk factor for COPD.