Takahashi K, et al. - In 235 well-controlled asthmatic patients on inhaled corticosteroids (ICS) treatment, researchers investigated the ability of serum periostin levels to indicate eosinophilic airway inflammation and airway remodeling. The association of serum periostin levels with clinical features, biomarkers for eosinophilic airway inflammation, fraction of exhaled nitric oxide (FeNO) levels and blood eosinophil counts, and pulmonary functions, was assessed. In well-controlled asthmatic patients who were consuming daily dose of 453 µg equivalent to fluticasone propionate, a positive correlation of serum periostin levels with blood eosinophil counts (%) and age, and a negative correlation with body weight and FEV1/FVC (%) were observed. A significant association of fixed airflow limitation with high serum periostin levels (≥97 ng/ml) was also observed in multivariate analysis. Overall, in this patient population, a role of serum periostin levels as a biomarker for both eosinophilic airway inflammation and fixed airflow limitation was established.