Occurrence of IgE-bearing epidermal Langerhans cells in atopic eczema: a study of the time course of the lesions and with regard to the IgE serum level.

Uninvolved and lesional skin of untreated and treated patients with atopic eczema has been investigated immunohistochemically to determine the conditions in which IgE-bearing CD1a+ Langerhans cells/indeterminate cells (LC/IC) occur in this disease. IgE-bearing epidermal dendritic cells were present in patients with elevated IgE serum level (greater than 300 UI/ml) and the staining pattern was stronger in lesional skin. On double immunostaining, a subpopulation of CD1a+ LC/IC was found not to bear IgE molecules as determined by the ratio IgE+/CD1a+ cells on serial sections as well. The ratio IgE+/CD1a+ cells decreased in patients who underwent a local therapy with glucocorticosteroids. These results suggest that the expression of IgE receptors and/or binding of IgE molecules on epidermal LC/IC in atopic eczema may be controlled by a complex network of mediators from the epidermis or the inflammatory infiltrate, or both, and that this phenomenon could be down regulated by glucocorticosteroids.