Local inflammation occurs before systemic inflammation in patients with COPD.
OBJECTIVE
COPD is associated not only with an abnormal inflammatory response in the lung but also with systemic inflammation, including systemic oxidative stress, activation of circulating inflammatory cells and increased circulating levels of inflammatory cytokines. Understanding the nature and course of systemic inflammation in COPD is important given the potential for anti-inflammatory therapy. This study explored whether local and systemic inflammation occur concurrently in patients with COPD.


METHODS
Forty-four patients with stable COPD, 10 smoking controls and 10 non-smoking controls were enrolled in this observational study. Induced sputum and peripheral blood samples were obtained simultaneously for measurement of inflammatory cell numbers and the concentrations of IL-6 and CRP.


RESULTS
The total number of cells in the sputum total cell number, percentage of neutrophils and the concentration of IL-6 were significantly higher in smoking controls and patients with COPD than in non-smoking controls (P < 0.05 and P < 0.01, respectively). As the disease stage progressed, airway inflammatory cells and IL-6 levels increased. CRP levels in sputum were significantly higher in stage II, III and IV COPD patients than in smoking and non-smoking controls (P < 0.01). However, the peripheral WCC and percentage of neutrophils were similar in patients with COPD, smoking and non-smoking controls. Circulatory concentrations of IL-6 and CRP in stages III and IV COPD patients were significantly higher than in smoking and non-smoking controls (P < 0.05 and P < 0.01, respectively). Additionally, there were positive correlations between sputum and blood IL-6 and CRP levels (r = 0.566, P < 0.01 and r = 0.443, P < 0.01, respectively).


CONCLUSIONS
The increase in the inflammatory cell population and IL-6 and CRP levels in the airway may occur earlier than in the peripheral blood, and reflect the degree of airflow limitation better than do peripheral blood measurements. Systemic inflammation may be present in patients with severe or very severe COPD.
He
Zhihui
Z
Department of Respiratory Medicine, The Second Xiangya Hospital, Central-South University, Changsha, Hunan, China.
Chen
Yan
Y
Chen
Ping
P
Wu
Guobao
G
Cai
Shan
S
D000328:Adult; D000368:Aged; D002097:C-Reactive Protein / Q000378:metabolism; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D007249:Inflammation / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D015850:Interleukin-6 / Q000378:metabolism; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology; D029424:Pulmonary Disease, Chronic Obstructive / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D012720:Severity of Illness Index; D013183:Sputum / Q000166:cytology / Q000378:metabolism
D015850:Interleukin-6; D002097:C-Reactive Protein