Periostin concentration in exhaled breath condensate in children with mild asthma

OBJECTIVE: Periostin is considered to be a marker of eosinophilic inflammation in patients with asthma. However, there are no literature data on exhaled breath condensate (EBC) periostin level in pediatric patients with asthma. The aim of this study was to analyze EBC periostin concentration in children with mild asthma and to evaluate the potential usefulness of EBC periostin level as a biomarker for the disease. METHODS: EBC and serum periostin concentrations were measured by enzyme-linked immunosorbent assay in 23 children with asthma and 23 healthy controls. RESULTS: EBC periostin concentration was 250- to 780-fold lower than that found in serum. No significant differences between serum nor EBC periostin concentration in asthmatics and the control group were showed. The comparison between children with Th2 and non-Th2 type of asthma did not show significant differences in periostin concentration, both in serum and EBC. Serum periostin concentration inversely correlated with BMI and age not only in asthma patients but also in controls. CONCLUSIONS: In children with mild asthma, periostin may be measured not only in serum but also in EBC. The low periostin level in patients with mild asthma and lack of difference between asthmatic subjects and controls indicate that EBC periostin may not be useful as an asthma biomarker in this group.