Mechanistic Studies of Teriflunomide in RRMS

Inclusion Criteria: 1. Patients with clinically-defined relapsing-remitting MS (RRMS) who " are newly starting on teriflunomide (AubagioTM) at the time of enrollment " have no evidence of relapse or corticosteroid treatment use within 2 months prior to enrollment OR Healthy controls who do not have a significant medical condition such as cancer, chronic infection, or autoimmune disease, have not taken steroids in the past 2 months, and who are not on an immune suppressant medication. 2. Ability to give informed consent 3. Willing to have blood drawn as scheduled in the protocol 4. Willing and able to complete all procedures and evaluations related to the study Exclusion Criteria: 1. Medical or psychiatric conditions that may affect the patient's ability to give informed consent 2. Has received an experimental drug within 30 days of enrollment 3. Concomitant other disease modifying medications (such as Rebif, Betaseron, Avonex, Copaxone, Gilenya, Tecfidera, Alemtuzumab, methotrexate, azathioprine, mitoxantrone, cyclophosphamide, cyclosporine, natalizumab, rituxan, ocrelizumab, etc.) without the minimal washout period stated below: " rebif, betaseron, avonex, copaxone within 1 month " zinbryta, plegridy, gilenya, tecfidera within 2 months " natalizumab within 3 months " immunosuppressive/chemotherapeutic medications (e.g. azathioprine, methotrexate) within 6 months " cyclophosphamide within 1 year " rituximab, ofatumumab, ocrelizumab, cladribine within 1 year " alemtuzumab at any time " any mitoxantrone during previous 2 years prior to randomization or evidence of cardiotoxicity following mitoxantrone or a cumulative life-time dose of more than 60 mg/m2 " lymphoid irradiation, bone marrow transplantation or other immunosuppressive treatments with effects potentially lasting over 6 months, at any time 4. Has any contraindication to high-dose immunotherapy, including pregnancy, trying to become pregnant, or breast feeding during the study.