Glucocorticoid treatment restores the impaired suppressive function of regulatory T cells in patients with relapsing-remitting multiple sclerosis.

Patients relapsing from multiple sclerosis (MS) are treated with high-dose, short-term intravenous injection of glucocorticoid (GC), although its mechanism of action remains only partly understood. We evaluated the ex vivo and in vitro effects of GC on regulatory T cell (T(reg)) function in 14 relapsing-remitting MS (RR-MS) patients in acute phase and 20 healthy controls (HC). T(reg) function was enhanced significantly after 5 days of GC treatment. Furthermore, there was a trend towards increasing proportions of CD4(+)CD25(+)forkhead box P3(+) T cells and interleukin-10 secretion with GC treatment when compared with HC. In conclusion, GC treatment restores the impaired T(reg) function in patients with RR-MS in its acute phase.