Inclusion criteria:
* Age: 15 - 50 years.
* Three months within the acute onset of neurological symptoms suggestive of the first attack of multiple sclerosis.
* Diagnosis of CPMS C3 (Poser criteria).
* Positive brain MRI according to Fazekas criteria.
* Negative pregnancy test and use of effective contraceptive for female patients who are sexually active.
* Signed written informed consent.
Exclusion criteria:
* Blood tests suggestive of other autoimmune diseases.
* Known allergic reactions to MRI contrast media.
* A clear regression of the neurological symptoms after the first attack that suggests a primary-progressive course.
* Corticosteroid treatment in the previous 4 weeks (28 days).
* Previous treatment with immunosuppressive medications such as cyclophosphamide, azathioprine, methotrexate, mitoxantrone or cyclosporine.
* Previous treatment with interferon beta 1a or 1b, copolymer-1, IVIg, plasmapheresis.
