Interferon beta-1a therapy enhances CD4+ regulatory T-cell function: an ex vivo and in vitro longitudinal study in relapsing-remitting multiple sclerosis.

Interferon beta-1a (IFNâ-1a) has demonstrated efficacy in multiple sclerosis (MS), although its mechanism of action remains only partly understood. We evaluated the ex vivo and in vitro effects of IFNâ-1a (Rebif) on regulatory T-cell (T(Reg)) function in 22 relapsing-remitting MS patients and 16 healthy controls. T(Reg) function was significantly enhanced after 3 and 6 months of IFNbeta-1a therapy. Furthermore, there was a trend towards increasing proportions of total CD4(+)CD25(+) and CD4(+)CD25(+)GITR(+) T(Reg) after 6 months of IFNbeta-1a therapy when compared with baseline. In conclusion, IFNbeta-1a therapy enhances T(Reg) function, and this may be relevant in the inflammatory environment of MS lesions.