the available data lead to the following hypothesis : multiple sclerosis is a disease which requires the following factors for the production of demyelinating lesions of the central nervous system : a genetically determined susceptibility , an environmental , probably viral , probably immune-mediated initiatory event producing a symptomless systemic illness , a subsequent alteration of the blood-brain barrier resulting from diverse mechanisms including trauma or a second , immune-mediated event , a myelinoclastic plaque-forming mechanism which is operative only in the central nervous system .
C0012634
disease
C0442893
systemic