The skin barrier, atopic dermatitis and allergy: a role for Langerhans cells?

The skin barrier (stratum corneum) is a major factor for determining the nature of immune response to antigens presented at the skin surface. Genetic abnormalities in skin barrier function are associated with allergy and atopic dermatitis, and removal of the skin barrier by tape stripping results in dominant Th2 responses to protein antigens. Langerhans cells take up antigen applied to skin from which the skin barrier has been removed; they then migrate to draining lymph nodes and initiate typical Th2 responses. These observations lead us to propose that the high frequency of allergic disease in the industrialized world might be due to lifestyle choices that result in loss of integrity of the skin barrier such as excessive washing and exfoliation of the skin.