Takahashi K, et al. - In this investigation, researchers ascertained if eosinophilic airway inflammation and airway remodeling in asthma reflect serum periostin levels. In 235 well-controlled asthmatic patients on inhaled corticosteroids (ICS) treatment, they studied the association of serum periostin levels with clinical features, biomarkers for eosinophilic airway inflammation, fraction of exhaled nitric oxide (FeNO) levels, blood eosinophil counts, and pulmonary functions. Serum periostin levels in well-controlled asthmatic patients on ICS treatment were positively correlated with blood eosinophil counts (%) and age, and were negatively correlated with body weight and FEV1/FVC (%). Similarly, blood eosinophil counts and serum periostin levels were related to increased FeNO levels (≥ 40 ppb) in the asthmatics. Serum periostin levels in the asthmatics were better related to fixed airflow limitation than FeNO levels, blood eosinophil counts, or total IgE levels. Overall, the investigators concluded that serum periostin levels serve as a biomarker in well-controlled asthmatics on ICS treatment for both eosinophilic airway inflammation and fixed airflow limitation.