[Late-onset multiple sclerosis and serum monoclonal gammopathy: an incidental association?].

Four patients older than 45 years with a central nervous system demyelinating disease associated to a monoclonal gammopathy are reported. The neurologic disease met the diagnostic criteria of multiple sclerosis, with the particularity of a late onset. Monoclonal paraproteinemia was also present in the cerebrospinal fluid, associated with an intrathecal immunoglobulin synthesis. The clinical data and the course of the disease were comparable to the previous reports of late onset multiple sclerosis. A causal link between the dysglobulinemia and the neurological disease may not be demonstrated. However, such an association may underline the role of humoral processes in multiple sclerosis.