CCL18 and chronic obstructive pulmonary disease: The serum concentrations of CCL-18 and IL-23 were most related to the GOLD grade (OR = 2.764 for CCL-18 and OR = 4.215 for IL-23) and detection of both showed considerable sensitivity (72.57% for CCL-18 and 76.92% for IL-23) and specificity (92.50% for CCL-18 and 77.5% for IL-23) in identifying COPD.