Background and objective: While recent studies have shown that patients with COPD and patients with asthma exhibit evidence of airway and systemic inflammation, markers of systemic inflammation have not been compared between the two diseases.
Methods: To evaluate circulating inflammatory markers, blood was sampled from 111 patients with COPD, 75 control subjects and 46 asthmatic patients (some of whom were smokers). Measurements of WCC, serum levels of fibrinogen, high-sensitivity (hs)-CRP, IL-8, IL-6, tumour necrosis factor-alpha (TNF-alpha), transforming growth factor (TGF)-beta1, tissue inhibitors of metalloproteinase (TIMP)-1, neutrophil elastase and alpha1-antitrypsin (alpha1-AT) were performed.
Results: Serum TNF-alpha, IL-6 and TIMP-1 concentrations were significantly higher in patients with stable COPD and patients with asthma than in control patients. Serum alpha1-AT levels were significantly higher in COPD patients than in asthmatic patients and control subjects, and serum TGF-beta1 levels were higher in asthma patients than in COPD patients. Smoking status had no effect on markers in COPD and asthmatic patients.
Conclusions: Although COPD and asthma share common markers of systemic inflammation, serum levels of TGF-beta1 and alpha1-AT may reflect differences between the diseases.