Atopic dermatitis--immunological abnormality and its background.

The production of IgE is mainly regulated by cognate and/or non-cognate interaction between B cells and T cells. Two types of helper T cells are recognized in the murine system, Th1 and Th2, by the type of cytokine they produce. Several lines of evidence disclosed that unbalanced generation of Th2/Th1-like cells occurs in atopic disorders, such as atopic dermatitis, in which a high level of serum IgE is found in the majority of patients. Analysis of skin-derived immunocompetent cells, such as Langerhans cells and T cells, has provided us with a new understanding of the pathophysiology of atopic dermatitis. The recent progress in immunological aspects of atopic dermatitis is reviewed.