Connective tissue growth factor (CTGF/CCN2) is a proinflammatory and an oligodendrocyte-differentiating blocking agent. It is found in MS lesions, which raises the possibility of involvement in MS pathogenesis. We found that its CSF and serum levels were higher in RR-MS patients than in controls and for serum compared to PP and SP-MS. Immune cells of both RR-MS and controls secreted CTGF/CCN2, which was enhanced by CD3/CD28 stimulation or by LPS. Anti-CTGF treatment of mice with experimental autoimmune encephalitis ameliorated its clinical severity. CTGF/CCN2 may play a role in the immune pathogenesis of MS and in remyelination failure in early stages of MS.