Interleukin-8 production from cultured human dermal fibroblasts by stimulation with supernatant of cultured human epidermal cells.

There is much evidence to support the theory that keratinocytes and dermal fibroblasts actively participate in inflammatory reactions by the production of proinflammatory mediators or cytokines. We investigated the neutrophil chemotactic activity in conditioned media of cultured epidermal cells and dermal fibroblasts, and found that an epidermal cell-derived factor induced fibroblasts to produce a neutrophil chemotactic factor. This neutrophil chemotactic factor was identified as interleukin-8 (IL-8) by the elution position on HPLC and by a neutralization test that uses monoclonal anti-IL-8 antibody (14E4). The epidermal cell-derived factor was fractionated together with thymocyte-proliferating activity on Sephadex G-75 gel chromatography followed by HPLC. It was blocked specifically by anti-interleukin-1 (IL-1) alpha antibody, which indicates that this factor was IL-1 alpha. Since a variety of inflammatory dermatoses is characterized by the infiltration of neutrophils into the skin, induction of IL-8 production in fibroblasts by epidermal cells may play an important role in inflammatory skin diseases.