This study intends to explore the levels of MSRV expression by analyzing the levels of MSRV transcripts in blood, as well as the levels of the MSRV-Env protein in serum in the normal population. This study is important for establishing a baseline to analyze results obtained in MS patients (another dedicated study is performed in parallel in MS patients). The study will be conducted over one year in a cohort of healthy subjects. The MSRV RNA level, MSRV-Env protein levels, reverse transcriptase activity, inflammatory markers assessed by cytokines levels will be analysed to define control levels in the normal population and their variation during one year. The data obtained in this study in healthy controls will be compared to those obtained in a parallel similar study, GN-E-002, conducted in different types of MS patients.

Inclusion Criteria:

• Signature of an informed consent;
• Male or female between 18 and 60 years of age.

Exclusion Criteria:

• Positive serology for hepatitis B or C or HIV;
• Acute infection at inclusion;
• Severe psychiatric disorder, neurological, inflammatory, or autoimmune disease;
• Pregnancy or breastfeeding;
• Heavy smokers i.e. more than 10 cigarettes per day;
• History of alcohol or drug abuse in the last 3 years;
• Participation in a clinical trial (within the last 3 months).

Blood donors coming for regular blood draw in the center of transfusion.