Atopic dermatitis and cytokines: recent patents in immunoregulatory and therapeutic implications of cytokines in atopic dermatitis--part I: cytokines in atopic dermatitis.

Atopic dermatitis is a chronic allergic inflammatory disease of the skin. Its pathophysiology involves an orchestrated sequence of allergic provocation by IgE-mediated and non-IgE-mediated Th2 responses to allergens. Allergen sensitization precedes the immunopathogenesis. Th2 cytokines such as IL-4 and IL-5 play a key role in both the sensitization and effector phases of allergic skin inflammation. Recently, the roles of new cytokines including IL-16, IL-17, IL-21, IL-22, IL-23, IL-27, IL-31, IL-33, IL-35 and thymus stromal lymphopoietin (TSLP), and Th2 polarization in the immunopathogenesis of skin inflammation and physically injured skin have been described, in addition to roles for IL-4, IL- 5, IL-9, IL-13, IFN-γ and TGF-β. Sensitization occurs via the skin for aeroallergen including house dust mites and superantigens and through the gastrointestinal tract for food allergens. Alternatively, food allergens can be sensitized through skin. Atopic dermatitis is described under the structure of sensitization phase and effector phase in this review. Especially, the clinically effective applications of cytokines in AD and relevant patents are updated in this review.