Cytokine regulation during epidermal differentiation and barrier formation.

The role of structural components and cell adhesion molecules in the epidermis has not been fully studied in terms of the pathophysiology of atopic dermatitis (AD). In this issue, Omori-Miyake et al. (2014) report that IL-4 and IL-13, which are Th2 cytokines, downregulate the expression of keratins and desmosomal cadherins in a STAT6-dependent manner, leading to keratinocyte fragility in the face of mechanical stress. Th2 cytokine–induced instability of the epidermis may be considered to be one of the pathogenic mechanisms that have roles in AD.