It affects young adults in the most active period of life, leading to major perturbations in their daily and professional activities. Therefore, the full economic and emotional costs of the disease are substantial. An overwhelming deal of information on MS pathogenesis has appeared during the last decade. It is currently believed that autoreactive CD4 cells play a paramount role at the initial steps of CNS inflammation, although other cells such as glia and macrophages are implicated as well. Complement and autoantibodies against different myelin antigens may also play a role, taking into account that heterogeneity in MS pathogenesis is currently accepted.

Magnetic resonance imaging (MRI) has provided new and important data on MS pathogenesis being the most accurate method to assess disease activity. Likewise, MR spectroscopy (MRS) has showed that demyelination, the hallmark of the disease, is not able to completely explain the permanent deficits of patients. Axonal damage seems to be the major cause of patients' impairment and this finding has been confirmed pathologically. It has been also shown that axonal loss may contribute to the brain atrophy that MS patients may show in MRI studies.

The evidence that MS has an autoimmune pathogenesis has led to the successful use of interferon beta in its treatment, positively affecting the natural history of the disease. Such medication diminishes the relapse rate, disease progression and brain atrophy. Likewise, immunosupressors and stem cell transplantation may be useful in selected cases.

We are living a historical age in the research of MS. The investigation of last recent years has provided new insights in the mechanisms of the disease as well as treatments that, although not curative, greatly improve the quality of live of our patients. Some of the invited speakers are responsible for those advances. We all gratefully acknowledge their effort.