Abstract: The invention relates to methods and reagents for diagnosing and assessing the prognosis of multiple sclerosis. The present invention is based, in part, upon the discovery that anti-glycan antibodies are useful in evaluating the risk of whether clinically isolated syndrome (CIS) patients suggestive of Multiple sclerosis (MS) will have a clinical relapse within, e.g., 24 months. The invention is also based upon the discovery that anti-glycan antibodies are useful for evaluating the risk of CIS patients suggestive of MS to have a rapid disease progression and accumulate disabilities, e.g., permanent disability, within a certain time frame, e.g., 5 years.