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

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. 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. 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. The expression of these proteins was downregulated in AD lesional skin, and IL-4 and IL-13 were shown to suppress their expression. 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.