Exploratory Open Label Study to Investigate the Effect of Teriflunomide on Immune Cell Subsets in the Blood of Patients With Relapsing Forms of Multiple Sclerosis

Primary Objective:To measure the effect of Teriflunomide on lymphocytes subsets in patients with relapsing forms of multiple sclerosis as compared with baseline values and those of a reference population of untreated healthy subjects.Secondary Objectives:To assess if Teriflunomide treatment results in biased T cell clonal diversity. To assess the effect of Teriflunomide on the function of peripheral blood mononuclear cells (proliferation and cytokine production in situ).To assess the circulating cytokines profile in the serum of Relapsing Multiple Sclerosis (RMS) patients during a 24-week treatment versus baseline and healthy controls.To assess the reversibility of all parameter changes in patients who discontinue treatment after accelerated elimination procedure with cholestyramine or activated charcoal.