EBC periostin concentration in children with mild-to moderate asthma

Periostin is a matrix protein, expressed in fibroblasts and epithelial cells, involved in various biological processes such as cell proliferation, cell invasion and angiogenesis. It is associated with eosinophil migration and tissue infiltration. Serum periostin is considered to be a marker of Th2 inflammation in asthma patients. However, there are no literature data on exhaled breath condensate (EBC) periostin level in children with asthma. The aim of the study was to analyze EBC periostin concentration in children with asthma, as well as to evaluate the potential usefulness of EBC periostin level as a biomarker for the disease. Methods: The non-concentrated EBC and serum periostin concentration was measured by ELISA method in 23 children with mild-to-moderate asthma and 23 healthy controls. Results: EBC periostin concentration was 250- to 780-fold lower than that found in serum. No significant differences between EBC (0.04 vs. 0.1ng/mL) periostin in asthmatics and controls were demonstrated. Similarly, there was no difference between serum periostin in these two groups (31.3 vs. 25.2ng/mL, respectively). The comparison between children with Th2 and non-Th2 type of asthma, as well as atopic and non-atopic 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-to moderate asthma, periostin may be measured not only in serum but also in EBC. A low and not different from control subjects EBC periostin concentration in patients with mild-to-moderate asthma suggest that it cannot be used in this group as an asthma biomarker.