POSTN and asthma: The quercetin influences on the production of both substances including periostin, a 90-kDa extracellular matrix protein that is attracting attention as a novel biomarker of airway inflammatory diseases such as AR and asthma, and periostin-induced eosinophil chemoattractants from HNEpC have been examined by Irie et al. Treatment of HNEpC with quercetin at a concentration of 4.0 μM suppressed the ability of cells to produce CC-chemokine ligand 5 (CCL5) and eotaxin.