[Non-specific immunosuppression and multiple sclerosis]

Several series of arguments favor at least partial efficacy of immunosuppression in multiple sclerosis. Immunosuppression can often treat experimental autoimmune encephalitis, and imperfect model of multiple sclerosis. Certain agents have been shown to affect the pathophysiological processes seen indirectly on magnetic resonance imaging (mitoxantrone and Campath, for example). Therapeutic trials have their methodological weaknesses but do allow certain conclusions. The progressive forms of multiple sclerosis are the most widely studied. Massive but short-term immunosuppression does not appear to affect the course of progression but prolonged immunosuppression would appear to slow down the process, at least in responders. The effect on disease progression is modest and preference should go to well-tolerated treatments. Immunosuppression appears to effectively decrease the number of acute episodes and reduce the number of new lesions detectable by magnetic resonance imaging. The effect of immunosuppression is limited however by the fact that the clinical course of progressive forms depends less on the development of new lesions than on an aggravation of the demyelinization process and possible axon loss within constituted lesions. This is a further argument favoring early immunosuppressive treatment at a stage when it can be most effective.