Subcutaneous application of Interferon-ß-1b (IFN-ß-1b) is an established therapy for patients with Relapsing/Remitting Multiple Sclerosis (RRMS), but early side effects are still a major concern.

In vitro studies with Myelin Basic Protein (MBP)-specific T-Cell lines revealed a synergistic suppressive effect of IFN-ß-1b and the Phosphodiesterase inhibitor Pentoxifylline (PTX) on proliferation and the production of Tumor Necrosis Factor-alpha (TNF-), LymphoToxin (LT), and Interferon-gamma (IFN-).

In an initial, open labeled prospective trial, the Cytokine messenger RNA (mRNA) expression of Blood MonoNuclear Cells from MS patients, receiving either IFN-ß-1b alone or in combination with oral PTX, was determined by semi-quantitative Reverse Transcriptase Polymerase Chain Reaction (RT-PCR).

Patients treated with IFN-ß1b alone reported more side effects during the first 3 months of treatment and had upregulated TNF- as well as IFN- mRNA expression during the first month, which was not detected in patients receiving both drugs.

A synergistic effect of both drugs was observed on the upregulation of InterLeukin-10 (IL-10) mRNA, which was accompanied by an increase in IL-10 Serum levels.

Both in vitro and in vivo data suggest that co-treatment of IFN-ß-1b with PTX is a promising approach to correct the disturbed Cytokine balance in MS patients.