The immunohistochemical effects of a single challenge with an intermediate dose of ultraviolet B on normal human skin.

Ultraviolet B (UVB) irradiation has extensively been advocated for use in the investigation of cutaneous inflammation in vivo. Mostly doses above the threshold of skin damage have been used. Therefore it is not clear whether the changes observed are specific effects of UVB or to a certain extent represent wound healing. In this study the dose-dependent effects of UVB on normal human skin were assessed using histology and immunohistochemistry. The dose of 1 MED was chosen as a dose unducing tissue changes with adequate morphology: no toxicity but evident immunohistochemical changes. The sequential effects of this 1 MED of UVB were studied for up to 14 days after irradiation, using immunohistochemistry with a panel of monoclonal antibodies. Substantial effects were observed, mainly on proliferation and differentiation; the markers for inflammation did not reveal major changes. This model might be a promising approach to evaluate the effect of drugs on epidermal proliferation and differentiation in vivo.