Multiple sclerosis is a condition in which the CNS of a person present a special kind of distributed lesions (sclerosis) whose pathophysiology is complex and still under investigation. It is considered a pathological entity by some authors and a clinical entity by some others. At least five characteristics are present in CNS tissues of MS patients: Inflammation beyond classical white matter lesions, Intrathecal Ig production with oligoclonal bands, An environment fostering immune cell persistence, Follicle-like aggregates in the meninges and a disruption of the blood-brain barrier also outside of active lesions...