The present invention relates to the diagnosis, the prevention and the treatment of demyelinating disorders of the central nervous system (CNS), in particular disorders exhibiting altered levels of antibodies directed against α1-3-galactose, such as multiple sclerosis (MS) and clinically isolated syndrome (CIS). The diagnosis of MS and CIS still suffers from a lack of reliable biomarkers and there is cure for these diseases, except medication acting on the immune component of the overt disease, with the usual side effects of the immunosuppression or anti inflammation intended to relieve the associated symptoms. The inventors showed that there is a significant decrease in the levels of antibodies directed against α1-3-galactose in individuals having a MS or a CIS. In addition, the present invention relates to the prevention and/or the treatment of a demyelinating disorder of the CNS in an individual, comprising a step of administering a compound suitable for generating an immune reaction directed against α1-3-galactose in the said individual. Large cohorts of human individuals having MS or CIS have been studied and compared to matched cohorts on the basis of age and gender.
