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 (TReg) function in 22 relapsing−remitting MS patients and 16 healthy controls. TReg function was significantly enhanced after 3 and 6 months of IFNβ-1a therapy. Furthermore, there was a trend towards increasing proportions of total CD4+CD25+ and CD4+CD25+GITR+ TReg after 6 months of IFNβ-1a therapy when compared with baseline. In conclusion, IFNβ-1a therapy enhances TReg function, and this may be relevant in the inflammatory environment of MS lesions.