A limited number of studies on microRNA expression variation in immune cells have been reported in relapsing-remitting multiple sclerosis (RRMS). These studies have been performed mostly on a small scale and on whole blood mononuclear cells (PBMC).

In a number of cases, RRMS progresses to a severe secondary neurodegenerative form. In this context, it is important to look for biomarkers that could indicate the pathogenic activity of certain immune cell subpopulations.

SEP-MIR is a prospective, single-center, descriptive study.

Participants will be recruited among adult patients with RRMS coming for a follow-up consultation in the Neurology Department, Nervous System Diseases Pole, at the hôpital Pitié - Salpêtrière (Paris).

As this is a descriptive study, the recruitment of 20 participants (10 patients with relapsing-remitting MS and 10 patients with relapsing-remitting MS) should meet the objectives of this study.

A 50 ml blood sample will be obtained from each participant and several clinical data regarding their pathology will be collected.

Inclusion Criteria:

• Caucasian population
• Female and male individuals with an f/m ratio of 2-4/1
• Individuals with RRMS according to the 2010 McDonald criteria for less than 15 years, with EDSS 1-6, in remission or relapse
• Participant's condition compatible with a maximum of 50 ml of blood collection
• Persons affiliated with a social security plan.

Exclusion Criteria:

• MS treatment with steroidal anti-inflammatory drugs, immunomodulators or immunosuppressants within 2 months prior to blood collection
• Persons with acute and chronic infectious disease, autoimmune/inflammatory disease or cancer other than MS
• Pregnant or lactating women
• Be under guardianship,
• Be deprived of liberty by judicial or administrative decision, or be under legal protection.