We went on to show that periostin gene expression in airway epithelial cells is a marker of an asthma subphenotype driven by excessive Th2-type inflammation and characterized by high levels of serum IgE, systemic and lung eosinophilia, increased thickness of the reticular basement membrane and responsiveness to corticosteroids 3. This evidence concerns the gene POSTN and Increased total eosinophil count.