Immunohistochemical comparison of actinic reticuloid with allergic contact dermatitis.

Biopsy specimens of chronic lesions and ultraviolet-induced lesions from actinic reticuloid patients were examined by immunoperoxidase techniques and compared with those of allergic contact dermatitis skin, one of the delayed-type hypersensitivity conditions. Each lesion of actinic reticuloid showed a clear predominance of suppressor/cytotoxic T cells to helper/inducer T cells and an increase of Langerhans cells in the epidermis and the dermis. These findings are generally similar to those in the late phase (on day 7 and 11) but not in the early phase (on day 2) of allergic contact dermatitis and suggest that delayed-type hypersensitivity might be involved in some parts of the pathogenesis of actinic reticuloid. CD36+DR+ epidermal cells were also observed in ultraviolet-induced lesions from actinic reticuloid patients, suggesting a possible role in the modulation of the mechanism.