Most experts in the field consider Multiple Sclerosis as the main auto immune disease of the central nervous system. In spite of many works, the data in the literature concerning the antigens targeted by the CD8+ T-Cell response are still contradictory and insufficient.

30 patients distributed in 3 groups of 10 patients with specific inclusion criteria will participate in this trial:

• 10 MS patients in early disease onset,
• 10 MS patients under Natalizumab treatment
• and control group of 10 patients with other neurological diseases.

The aim of this clinical trial is to detect the CD8+ myelin specific T-Cells in the blood of Multiple Sclerosis patients.

Inclusion Criteria:

Group 1: HLA-A2 patients whose Multiple Sclerosis has just been diagnosed

• 18 year old and older patients,
• HLA-A2 Patients with Multiple Sclerosis or clinically isolated syndrome at high risk of being affected by Multiple Sclerosis (criteria of spatial scattering according to the 2010 or 2005 McDonald's criteria)
• Patients without treatment or treated with immunomodulating therapy
• Patients affiliated to health insurance coverage
• Information and comprehensive agreement signed by the patient and the investigator

Group 2: HLA-A2 patients hospitalized in the neurology department who are not affected with a neuroimmunological disorder

• 18 year old and older patients,
• HLA-A2 patients hospitalized in the neurology department
• Patient not affected by Multiple Sclerosis or a related inflammatory disorder
• Affiliated or profitable subject of a national insurance scheme
• Patients affiliated to health insurance coverage
• Information and comprehensive agreement signed by the patient and the investigator

Group 3: HLA-A2 Multiple Sclerosis patients treated by Natalizumab therapy

• 18 year old and older patients,
• HLA-A2 patients with relapsing remitting (RR) MS fulfilling McDonald 2005 or 2010 Multiple Sclerosis diagnostic criteria
• Patients treated by Natalizumab therapy for at least 3 months
• Patients affiliated to health insurance coverage
• Information and comprehensive agreement signed by the patient and the investigator

Exclusion Criteria:

Group 1 and 3:

• Patients undergoing immunosuppressive therapy at present or in the past except Natalizumab
• Pregnant women

Group 2:

• Patients undergoing immunosuppressive therapy at present or in the past
• Patients affected by Multiple Sclerosis or a related disorder
• Pregnant women