Expression of keratin 1, keratin 10, desmoglein 1 and desmocollin 1 in the epidermis: possible downregulation by interleukin-4 and interleukin-13 in atopic dermatitis

Background: In the pathogenesis of atopic dermatitis (AD), skin barrier dysfunction and T-helper (Th) type 2 immune reactions play important roles. Alterations in the stratum spinosum of AD have not been studied in much detail. Objectives: In this study, we investigated the changes of structural proteins and adhesion molecules residing in the stratum spinosum of AD lesional skin, and whether Th2 cytokines including interleukin (IL)-4 and IL-13 alter the expression of these proteins. Materials & Methods: Skin samples were collected from patients with AD and from healthy controls. Normal human epidermal keratinocytes were cultured and differentiated in the presence or absence of either IL-4 or IL-13 in vitro. The expression of keratin 1, keratin 10, desmoglein 1 and desmocollin 1 was examined by immunofluorescence and western blotting. Results: The expression of these proteins was downregulated in AD lesional skin, and IL-4 and IL-13 were shown to suppress their expression. Conclusion: These results suggest that the stratum spinosum is impaired in AD lesional skin, possibly by Th2 cytokines, which may be involved in the pathogenesis of AD.