Fig. 2.
Epithelial/mesenchymal interaction via periostin in the pathogenesis of skin allergic diseases (modified from [16, 29]). a IL-4/IL-13 produced by TH2 cells activated by exposure to allergens induces periostin production in fibroblasts. Periostin acts on keratinocytes activating NF-κB followed by production of pro-inflammatory cytokines including TSLP, which acts on dendritic cells (DCs), accelerating type 2 inflammation. Thus, IL-4/IL-13, periostin, and TSLP generate a vicious cycle in the pathogenesis of skin allergic diseases. b IL-1α and periostin produced by keratinocytes and fibroblasts, respectively, cooperate to act on fibroblasts activating NF-κB. Activated fibroblasts produce IL-6 accelerating proliferation of keratinocytes