Effect of IFN-beta therapy on the frequency and function of CD4(+)CD25(+) regulatory T cells and Foxp3 gene expression in relapsing-remitting multiple sclerosis (RRMS): a preliminary study.

Interferon-beta (IFN-beta) is an immunomodulatory drug of choice to control relapsing-remitting multiple sclerosis (RR-MS), although its function is still unclear. A reduced suppressive function of CD4(+)CD25(+) regulatory T cells (T(reg)) has been shown in RR-MS patients. In this study, to understand the effect of IFN-ss on CD4(+)CD25(+) regulatory T cells, we analyzed the frequency and function of these cells and Foxp3 gene expression before and after treatment. We evaluated the frequency and function of CD4(+)CD25(+)Foxp3(+) regulatory T cells by flow cytometry and co-culture inhibition test respectively and gene expression of Foxp3 by real-time PCR in a longitudinal follow-up study in 18 relapsing-remitting MS patients. Our data revealed that IFN-beta significantly improved frequency and suppressive function of T(reg) cells (P<0.05) without any significant effect on gene expression of Foxp3 after 6 months. The results of the present study indicate that IFN-beta therapy in some of patients with RR-MS may restore function of regulatory T cells and control the unchecked immune cascade activity. Larger longitudinal studies on more MS patients are required to confirm our findings.