Interleukin 1 and tumor necrosis factor-alpha additively increase the levels of granulocyte-macrophage and granulocyte colony-stimulating factor (CSF) mRNA in human fibroblasts.

Recombinant interleukin (IL) 1 beta and tumor necrosis factor/cachectin (TNF-alpha) induce, usually within 2 h, a dose-dependent increase in the levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) and G-CSF mRNA in cultured human fibroblasts. Maximal induction is reached at about 4-8 h and usually last for at least 48 h. IL 1 beta and TNF have additive effects on the levels of GM- and G-CSF mRNA, and on the secretion of G-CSF activity into the culture medium. IL 1 alpha has the same additive effect that IL 1 beta has with TNF, but no additive effect with IL 1 beta. In contrast, the high basic level of M-CSF (CSF-1) mRNA shows little or lower variations in response to IL 1, TNF-alpha or both IL 1 and TNF-alpha also induce, with similar kinetics, an increase in IL 1 beta but not mRNA level. In contrast to what is observed with macrophages and endothelial cells, E. coli lipopolysaccharide does not modify the fibroblast CSF mRNA level up to 48 h of culture.