Immunomodulatory effects of IFN beta-1b on the mRNA-expression of TGF beta-1 and TNF alpha in vitro

The mechanisms by which IFN beta-1b acts in the treatment of multiple scler osis (MS) patients are not, completely known. We investigated the influence of IFN beta-1b on the mRNA-expression of the immunosuppressive cytokine TG F beta-1 and the proinflammatory mediator TNF alpha in an in vitro model by the method of non-radioactive in situ hybridization. Peripheral blood lymp hocytes (PBL) were isolated from eight patients with relapsing remitting fo rm of MS during remission and from six healthy controls. They were stimulat ed with IFN beta -1b in different concentrations for 24 h. In both groups a statistically significant dose-dependent increase of TGF beta-1-mRNA and d ecrease of TNF alpha-mRNA was demonstrable in the cultured stimulated blood lymphocytes compared to unstimulated cells. Stimulations with lipopolysacc haride (LPS) led to an increase of both cytokine-mRNAs in the lymphocytes. These data suggest specific and dose-dependent effects of IFN beta-1b and h int at immunomodulatory properties of this drug to regulate the cytokine dy sbalance in MS. This might be one mechanism by which IFN beta-1b mediates i ts beneficial effects on the course of the disease. (C) 1999 Elsevier Scien ce B.V. All rights reserved.