Clinically isolated syndrome (CIS) is the first manifestation of multiple sclerosis (MS), a chronic inflammatory autoimmune disease of the central nervous system (CNS) affecting over 2.5 million people worldwide.  After CIS, the delay in manifestation of a new relapse, which corresponds to the clinically definite MS (CDMS) according to McDonald’s criteria 2005 , varies from several months to more than 10 years and should be associated with the brain and spinal cord pathology at the time of a relapse . In about a third of the cases, CIS patients will not experience a new relapse activity over long-term follow-up .