Biological Activity and Safety of Low Dose IL2 in Relapsing Remitting Multiple Sclerosis

Inclusion Criteria: * Age 18-65 years old ; * Male and Female; * Presenting relapsing remitting multiple sclerosis as determined by revised McDonald criteria (2010) ; * On MRI : 1) Presenting 1-2 lesions enhanced by gadolinium (Gd+) (T1) without clinical expression of the disease clinique upon inclusion or 6 months prior to inclusion or 2) presenting one new lesion T2 * Expanded Disability Status Scale (EDSS) score comprised between 0 and 6; * No flare (with or without any corticosteroid therapy) for the past 2 months * Under β-Interferon treatment for ≥ 6 months ; or any other first-line treatment of the Relapsing-Remitting Multiple Sclerosis (RRMS): Dimethyl fumarate or teriflunomide treatment for ≥ 6 months or glatiramer acetate for ≥ 9 months * For women of childbearing age, contraception for more than 2 weeks upon confirmation of inclusion criteria and negative Beta HCG on inclusion visit (D-30 to D-7); * Patient informed consent should be signed by the patient and investigator before performing any clinical examination required for the study. * Affiliation to the French Social Security Regimen Exclusion Criteria: * Number of lesions enhanced by gadolinium (Gd+) on MRI in T1 \> 2 upon inclusion; * Known intolerance to IL2 (see SPC): * Hypersensibility to active substance or one of the excipients ; * Signs of evolving infection requiring treatment * Other clinically significant chronic disorders (beside RR-MS) * History of organ allograft * Administration of a non-authorized treatment; bolus of corticosteroids in the last 2 months, or treatment with cyclophosphamide, mitoxantrone, or rituximab in the last 6 months; * Heart failure (≥ grade III NYHA), renal insufficiency, or hepatic insufficiency (transaminase\>5N), or lung failure * White blood cell count \<3000 /mm3, lymphocytes\< 1000 /mm3, platelets \<150 000 /mm3 * Poor venous access not allowing repeated blood tests * Vaccination with live attenuated virus in the months preceding the inclusion or planned during the study * Surgery with general anaesthesia during the last 2 months or surgery planned during the study * Participation in other biomedical research in the last one month or planned during the study * Concomitant psychiatric disease or any other chronic illness or drug-abuse that could interfere with the ability to comply with the protocol or to give informed consent * Cancer or history of cancer cured for less than five years (except in situ carcinoma of the cervix or basocellular carcinoma) * Pregnant or lactating women; * Men and women of childbearing potential without effective contraception for the duration of treatment * Patients under a measure of legal protection