Cytokine regulation of hemostatic property and IL-6 production of human endothelial cells

The effects of four inflammatory cytokines, IL-1, TNF, IFN-, and IL-6, were assessed on the following functions of human vascular endothelial cells (EC) in culture: expression of procoagulant activity (PCA), endothelial cell-associated thrombomodulin (TM), and IL-6 production. Both IL-1 and TNF induced PCA, reduced TM, and induced IL-6 production in a dose-dependent manner. IFN- had a weak but significant reducing effect on TM and an inducing effect on IL-6 production, while it had no effect on PCA expression. IFN-, however, when added in combination with either IL-1 or TNF, modulated the effects of these cytokines; INF- inhibited the PCA expression and enhanced the reduction of TM and the production of IL-6, which were induced by either IL-1 or TNF. In contrast, IL-6 had no significant effect on the EC functions studied. These results suggest that both IL-1 and TNF are the major cytokines affecting the EC functions that determine the association between the coagulation and the inflammatory response, and that IFN- affects this phenomenon predominantly through the modification of the effects of these cytokines.