Patient description: The patient is a 20 year old Caucasian female presents to the clinic with one-sided vision lost and facial weakness, dysarthria and numbness lasting for 1 day. She visited her PCP and underwent brain MRI which revealed a single plaque in the brainstem. After few months, she experienced lower extremities weakness led to balance problem. The second MRI revealed another lesion in the left cerebral hemisphere. The diagnosis of Relapsing Remitting Multiple Sclerosis (RRMS) is confirmed after the second MRI. Her past surgical history is significant for a C-section 2 years ago and she has a one child. She is divorced and is not currently in any sexual relationship. She smokes 10 cigarettes per day and drinks alcohol occasionally. She is working as an editor in a publisher company and she is happy that she can keep working from home most of the time. She is under the treatment of RRMS from 7 months ago.

Clinical trial eligibility criteria: eligible ages (years): 18.0-60.0,  Multiple Sclerosis, Relapsing-Remitting Healthy subjects H-1. Written informed consent must be obtained before any assessment is performed H-2. Male and female subjects aged 18 years H-3. No history of multiple sclerosis or clinically isolated syndrome H-4. No history of other autoimmune diseases, which has been treated systemically with corticosteroids, immunomodulators or immunosuppressive drugs at any time point. RRMS patients MS-1. Written informed consent must be obtained before any assessment is performed MS-2. Male and female subjects aged 18 years MS-3. Patients with RRMS, defined by 2010 revised McDonald criteria  RRMS patients MS-1. Known hypersensitivity to dimethyl fumarate or any ingredients of Tecfidera® (microcrystalline cellulose; croscarmellose-sodium; talcum; high dispersion, hydrophobic silicon dioxide; magnesiumstearate (Ph. Eur.); triethylcitrate; methacrylic acid-methacrylate copolymer (1:1) (Ph. Eur.); methacrylic acid-ethylacrylate copolymer (1:1)-dispersion 30% (Ph. Eur.), simeticon, sodiumdodecylsulfate, polysorbate 80, gelantine, titanium oxide (E171), brilliant blue (E133), hydrated Iron(III)-oxide hydroxide (E172), shellac, potassium hydroxide MS-2. A MS-relapse within 30 days prior to screening MS-3. Known history of active tuberculosis or active tuberculosis determined by a positive QuantiFERON® TB Gold test (i.e. a negative test result has to be provided at screening unless a negative test result exists from the last 3 months prior to screening) MS-4. Moderate to severe impairment of liver function or persisting elevations > 2 x ULN (confirmed by retest) of serum glutamic pyruvic transaminase/ alanine aminotransferase (SGPT/ALT) or serum glutamic oxaloacetic transaminase/aspartate aminotransferase (SGOT/AST), except patients with confirmed Gilbert´s syndrome (Meulengracht´s disease) MS-5. Moderate to severe impairment of renal function, as shown by serum creatinine > 133 μmol/L (or > 1.5 mg/dL) MS-6. Patients with significantly impaired bone marrow function or significant anemia, leukopenia, neutropenia or thrombocytopenia MS-7. Women of childbearing potential not utilizing highly effective contraception. Both populations MS/H-1. Mental condition rendering the subject unable to understand the nature, scope, and possible consequences of the study MS/H-2. Subjects unlikely to comply with protocol as determined by investigator, e.g., uncooperative attitude, inability to return for follow-up visits (e.g. major physical disability), and known unlikelihood of completing the study