IFN-β1a and IFN-β1b have different patterns of influence on cytokines

Multiple sclerosis is characterized by elevated levels of proinflammatory cytokines produced by Th1 cells and decreased levels of anti-inflammatory cytokines produced by Th2 cells. IFN-β treatment shifts the immune response from the Th1 to Th2 pattern, thus enhancing the production of anti-inflammatory Th2 cytokines such as IL-4, IL-10, and decreasing the production of proinflammatory Th1 cytokines such as IFN-γ. To determine which IFN-β has the stronger immunomodulatory effect we compared the levels of IL-4, IL-10, and IFN-γ of 12 relapsing-remiting MS patients treated with IFN-β1b (Betaferon®) with those of 10 patients treated with IFN-β1a (Avonex®). There were no statistically significant differences in duration of disease, number of relapses before and during treatment, and in EDSS after 2 years of treatment. After 1 year of treatment the concentration of IFN-γ was significantly lower in the Betaferon® group, and concentrations of IL-4 and IL-10 were significantly higher in the Avonex® group. It appears that IFN-β1b has a downregulatory effect on both Th1 and Th2 cytokines, while IFN-β1a causes a shift of the cytokine profile toward the Th2 phenotype. These two IFN have different influences on the pattern of cytokines in MS: IFN-β1a enhances the production of anti-inflammatory cytokines IL-4 and IL-10 and IFN-β1b decreases the production of the proinflammatory cytokine IFN-γ.