Comparison of serum biomarkers between patients with asthma and with chronic obstructive pulmonary disease

Objective: Asthma and chronic obstructive pulmonary disease (COPD) have distinct pathophysiological mechanisms but sometimes share similar clinical manifestations. Distinguishing between these diseases is important. This study compared the profiles of serum biomarkers between patients with asthma and those with COPD. Methods: Serum levels of the chitinase like protein YKL-40, periostin, interleukin (IL)-18, and chemokine (C-C motif) ligand 18 (CCL18) were measured in asthma patients (n=20), COPD patients (n=16), and normal controls (n=20). Results: Serum levels of YKL-40 were higher in COPD patients [median (range), 55 (17-565) versus 208 (74-922) ng/mL, p < 0.0001], but no differences were observed between asthma and COPD patients after adjusting for age and forced expiratory volume in 1 s (FEV1). No differences in serum levels of periostin, IL-18, or CCL18 were observed between the patient groups. Total IgE and airway hypersensitivity were negatively correlated (r = -0.485, p = 0.007). CCL18 levels were related to patients' age in asthmatic patients (r=-0.562, p = 0.010). Serum levels of CCL18 and IL-18 were positively correlated in patients with COPD (r=0.696, p=0.003). Conclusions: No differences in the serum profiles of periostin, IL-18, or CCL18 were observed between patients with asthma and those with COPD. Serum levels of YKL-40 were not different between asthma and COPD patients after adjusting for age and FEV1. There were negative correlation between CCL18 and age in patients with asthma and positive correlation between IL-18 and CCL18 in patients with COPD.