Quantitative determination of IL-1 alpha-induced IL-8 mRNA levels in cultured human keratinocytes, dermal fibroblasts, endothelial cells, and monocytes.

The presence of the leukocyte chemotactic cytokine interleukin 8 (IL-8) in psoriatic scales and in epidermal tissue overlying allergic patch test reactions suggests a role for this cytokine in certain inflammatory skin diseases. IL-8 can be produced by several cell types present in the skin. Their relative potentials for IL-8 expression has, however, not yet been studied, due to the lack of convenient methods for quantitative comparison of specific mRNA amounts in different cell types. Using a new method for quantification, we compared specific IL-8 mRNA amounts in cultures of keratinocytes, dermal fibroblasts, endothelial cells, and monocytes, stimulated with interleukin 1 alpha (IL-1 alpha). Endothelial cells produced very high, fibroblasts and monocytes intermediate, and keratinocytes low amounts of IL-8 mRNA. We also studied the time course of IL-8 mRNA levels in the four cell types following IL-1 alpha stimulation, and found a clear difference both in onset and stability of the response. We discuss the different strength of the response at different time points in the cell types analyzed in relation to their possible role in regulation of the normal response to stimulation.