RESEPTOR 5-HT7

Treatment tested

• Blood sample

Other measures (5)

Inclusion Criteria: * Men and women * Aged between 18 and 50 years old, * With multiple sclerosis already diagnosed and fulfilling the modified Mc Donald criteria * Stable (no relapse in the last 6 months and MRI less than a year old, with no new lesions) and with at least 1 year of treatment with Natalizumab, Ocrelizumab, Teriflunomide or Fumarate * Subject medically fit to give a maximum of 50 ml of extra whole blood * Patient having given their consent to participate in the study Exclusion Criteria: * HIV serology known or discovered during the present episode * Demented patient * Patient treated with corticosteroids in the last month * Non-affiliated person or non-beneficiary of a social security scheme * Uncooperative patient * Patient under legal protection, guardianship or curatorship * Pregnant or breastfeeding women

Multiple Sclerosis is a chronic autoimmune disease associated with inflammatory response harmful for the Central Nervous System. Immunological imbalance is involved with Th1 and Th17 cells in correlation with a disturbance of regulators mechanisms as Treg cells. Despite years of research, the mechanisms involved remain unclear. Serotonin (5-HT) seems to be play an essential role in developing CNS inflammatory diseases and in particular in MS. Indeed, several studies have shown the anti-inflammatory potential of this neurotransmitter and also its vulnerability in inflammatory context. Moreover, a recent study has shown that 5-HT can reduced CD4 T cells proliferation and pro-inflammatory cytokines released in vitro. Interestingly, treatment, treatment with SSRIs (selective serotonin reuptake inhibitor) in an animal model of MS, on Experimental Autoimmune Encephalomyelitis, was shown to improve the clinical score and promote remission of the disease. Among serotonin receptors, the 5-HT7 receptor, can be considered as an interesting target to treat neurological disorders associated with inflammatory context. Present in humans and mice, this receptor is expressed on the surface of a large number of cells, such as T-lymphocytes, macrophages, dendritic cells as well as on cells of CNS such as neurons, astrocytes and microglia. Given the importance of the positive cells for 5-HT7 receptor, in the inflammatory context observed in multiple sclerosis, the investigators propose to study the receptor expression in blood samples from multiple sclerosis patient.