Serum IL-17 and IL-18 levels in asthma-COPD overlap syndrome patients

Background: Proinflammatory cytokine s play an important role in chronic airways inflammation in COPD. However, the role of cytokines in the development of Asthma-COPD Overlap Syndrome (ACOS) has not been clarified. The aim was to study the blood levels of IL-17, IL-18, TNF-α and to analyze relation between circulating cytokines and FEV 1 in patients with ACOS, COPD and asthma. Methods: cytokine plasma levels (IL-17, IL-18, TNF-α) in 42 COPD patients, 30 ACOS patients, 12 asthmatics and 10 control subjects were assessed by immunoassay analysis. Results: Circulating IL-17, IL-18,TNF-α levels were significantly higher in COPD, ACOS and asthmatic patients compared to healthy controls. The inflammatory biomarkers blood concentrations in COPD and ACOS patients were progressively increased with the severity of COPD. TNF-α serum levels in COPD and ACOS patients were higher than in patients with asthma (p=0,034 and p=0,011). Circulating IL-17 and IL-18 concentrations did not differ in COPD, ACOS and asthmatics. In patients with COPD, plasma IL-17 and TNF-α levels correlated significantly with FEV 1 (rs= -0.53; p=0.001 and rs= -0.31; p=0.04). In ACOS patient, only serum IL-17 correlated with FEV 1 (rs= -0.48; p=0.007). Circulating cytokines levels were not correlated with FEV 1 in asthmatic patients. Conclusion: Patients with ACOS and COPD showed significantly higher IL-17, IL-18 and TNFα serum levels then asthmatics and healthy controls. Our results suggest that IL-17 may be associated with the inflammation severity in both ACOS and COPD.