Possible Role of Cytokines in Cellular Proliferation of the Skin Transplanted Onto Nude Mice

Background and Design: In recent studies on the behavior of aged skin transplanted onto nude mice, the epidermis of aged and young skin showed an increase in proliferation and thickness following engraftment, and became almost identical. The aim of this study was to ascertain a possible role for the release of local cytokines in this phenomenon. Grafted human skin was injected intradermally with anti—interleukin-6 (IL) and anti—IL-lα, and comparisons of epidermal thymidine incorporation and thickness were made. Grafts injected with irrelevant antibodies served as control. Results: Interleukin-6 and IL-1α expression were studied in grafts by immunoperoxidase staining. Only IL-6 expression was found in the 1-month grafts. Intradermal injections of anti—IL-1α and anti—IL-6 showed an inhibitory effect on cellular proliferation in the epidermis. A significant difference in the response of epidermal proliferation and, consequently, in thickness was found in samples injected with anti—IL-1α and anti—IL-6 compared with those injected with irrelevant antibodies. Conclusions: These data may indicate that local cytokines released by the keratinocytes are involved in the cellular proliferative activity in skin engrafted onto the mice. (Arch Dermatol. 1995;131:38-42)