Objective: To investigate the influence of interferon (IFN) beta-1b on the serum levels of sTNF-R1, sTNF-R2 and TNF-beta in patients with multiple sclerosis (MS) in correlation with clinical and MRI activity.

Methods: Serum samples were obtained every 3 months from 24 patients treated with 8 x 10(6) U of IFN beta-lb every other day (treatment group) and from 21 patients without any immunomodulatory therapy (control group) over a 15-month observation period. The cytokine levels were measured by ELISA. Cranial MRI was performed every 6 months to determine the burden of disease of every patient.

Results: In the treatment group we found an obvious increase of sTNFR1 and sTNF-R2 (P < 0.001) and relatively stable serum levels of TNFbeta with no statistical significance (P = 0.56). In the control group, sTNF-R1 showed a significant decrease (P < 0.001) during the same observation period of 15 months. During the 15-month observation period, the MRI-responders group had significant larger mean AUC (area under the concentration-time curve) values of sTNF-R1 (P = 0.04) and sTNF-R2 (P = 0.01) when compared to the group of MRInonresponders.

Conclusions: The present data suggest that IFN beta-1b induces the expression and shedding of TNF-R1 and TNF-R2. The magnitude of an increase of sTNF-Rs may be a marker for the effectiveness of treatment with IFN beta-1b.