Fig. 1

Periostin is involved in the pathogenic process of eosinophils and Th2-type asthma. Briefly, allergens induce the secretion of IL-4 and IL-13 from certain immune cells, thereby stimulating eosinophils cells to produce periostin. Periostin, in turn through an autocrine pathway (indicated by the green colored receptors), acts on eosinophils to stimulate the adhesion of purified human blood eosinophils, while also enhancing their recruitment to an asthmatic airway. IL-5, IL-3, or GM-CSF can also stimulate the adhesion of purified human blood eosinophils, thereby leading to a vicious cycle. Macrophage produce periostin, and this can enhance the secretion of matrix metalloproteinases (MMPs). Furthermore, in the presence of histamine, expression of periostin by other cells is enhanced