Inclusion Criteria:  RR-MS patients only:  This investigator-initiated study/trial (IIT) will be carried out secondary to the discussion of treatment with Ofatumumab and thus our study will not influence or impact the determination of the suitability for candidates to commence therapy with Ofatumumab. This decision will be made by the patient's physician as part of the patient's standard care, and will occur independently of this study. Patients to be enrolled in this longitudinal study will only be asked if they would like to take part in this IIT if their clinician independently chooses Ofatumumab as a treatment option:  Patients must qualify to receive treatment with Ofatumumab (Kesimpta), according to the Multiple Sclerosis Comprehensive Care Center at USC Keck School of Medicine or LAC+USC Medical Center and meet the inclusion criteria defined in, and aligned with, the US Kesimpta (Ofatumumab) Prescribing Information. Patients must have clinically definite Multiple Sclerosis as defined by the revised McDonald criteria of the relapsing-remitting form with an Expanded Disability Status Scale (EDSS) score of 0 to 5.5. Patients must be treatment naive to Ofatumumab (Kesimpta) Patients must have the ability to understand and sign this study-specific IRB-approved informed consent form. Patients must be willing to donate ~80ml of blood each for M00 and M06 that will be used for testing the specific aims described in this proposal. Patients must have a lymphocyte count within the normal range at baseline (3.8-10.8 x1,000/ml)  Healthy Control Subjects only:  Patients must not have clinically definite Multiple Sclerosis as defined by the revised McDonald criteria, any other autoimmune disease, demyelinating co-morbidity, neurological disease or immune system altering disease (e.g. HIV). Patients must have the ability to understand and sign this study-specific IRB-approved informed consent form. Patients must be willing to donate ~80ml of blood at one time only that will be used for testing the specific aims described in this proposal. Patients must have a lymphocyte count within the normal range at baseline (3.8-10.8 x1,000/ml).  Exclusion Criteria:  RR-MS patients only:  Treatment with any of the following within 90 days of commencing treatment with Ofatumumab: teriflunomide (Aubagio®), IV immunoglobulin or plasmapheresis. Previous treatment with natalizumab (Tysabri®) within 30 days of commencing treatment with Ofatumumab. Documented relapse within 30 days prior to baseline. Systemic corticosteroid therapy within 4 weeks prior to baseline. Prior treatment with Mitoxantrone, Cyclophosphamide, Cyclosporine, Azathioprine or Methotrexate or any other immunosuppressant, or total body irradiation or bone marrow transplantation. Prior treatment with a B-cell targeted therapies (e.g., rituximab, ocrelizumab, atacicept, belimumab, or ofatumumab). Prior treatment with alemtuzumab (Lemtrada®). Current supplemental treatment with high dose biotin. Women who are pregnant, lactating, breast feeding or of childbearing age who do not consent to approved contraceptive use during the study. Prior or current treatment with a drug that is experimental Meet any of the exclusion criteria defined in, and aligned with, the US Kesimpta/Ofatumumab Prescribing Information.  Healthy Control Subjects:  Treatment with any FDA-approved drug or experimental drug for any condition. Systemic corticosteroid therapy within 4 weeks prior to blood collection. Women who are pregnant, lactating, or could be pregnant.