The puzzling natural history of multiple sclerosis: a

Multiple sclerosis (MS) is a human inflammatory demyelinating disease of the central nervous system with a relatively low incidence and prevalence, but, although it can be considered a rare disease, it is of great interest to the scientists involved in various research fields. For a long time numerous studies have been devoted to the polymorphic aspects of this disease with the continuous publication of high level scientific papers and the frequent organization of meetings and symposia. However, despite the employment of large resources and the involvement of several leading Institutions around the world, and although MS was clinically recognized already in the 19th century by the French neurologist Charcot, there are still numerous points to be clarified regarding the etiology, the pathogenic mechanism and the treatment of this disease. Perhaps also owing to its vagueness, the most commonly accepted concept is that MS is a disease caused by destruction of the myelin sheet through an autoimmune process that originates in subjects with genetic predisposition as a consequence of the intervention of largely unknown exogenous factors. Although many aspects of MS both in the central nervous system and in the peripheral system are clearly due to inflammatory phenomena, MS is not an acute disease, but due to its characteristics, MS has a natural course resembling that of chronic degenerative diseases, and thus it can be subdivided into five phases: susceptibility, induction, the preclinical phase, the degenerative phase, and rehabilitation. In this supplement of Journal of Neurovirology are published the views that some of the most important scientist in this field gave during the ‘International Symposium on Multiple Sclerosis Research and Care’, organized in Milan from May 6th to 9th, 1999, from the Don C Gnocchi Foundation, IRCCS. The topics and the speakers were essentially selected taking into account the model of natural history of chronic degenerative disorders and that can also be proposed for MS.