[Multiple sclerosis. Current status of research. I].

Multiple sclerosis (MS) affects nearly 40 000 patients in France. Many factors are mixed up in the development of MS. Epidemiologic studies demonstrate the importance of environmental factors and some possible epidemics of MS in Faroe Islands and Iceland. Recent investigations in Orkney Islands present the hypothesis of two periods of peculiar vulnerability. In Caucasians, genetic investigations show the overpresentation of antigens HLA A3, B7, DR2-DW2. It is possible that remittent MS is related to B7, DW2, DR2 and progressive MS to DR3, B8 DR3, A1 B8 DR3. This distinctions could be also applied to response to immunosuppressive treatment. However, studies of familial MS suggest that only one gene is not able to induce susceptibility to MS. Interpretation of virologic studies is difficult; recent advances in virologic research (isolation, hybridization) will perhaps demonstrate the importance of viral components in MS. Interpretation of presence of myelin basic protein, antimyelin antibodies, anti-oligodendrocytes antibodies, antigangliosides antibodies, antibrain antibodies is also difficult because identification methods are in constant progress and it is not possible to know whether these antibodies are cause or only consequence of pathologic process. Lymphocytic populations studies demonstrate that immunoregulation is probably defective in MS and that T lymphocytes subpopulations fluctuate, according to the state of the illness. Variations of NK activity are discussed. MS lymphocyte production of interferon is probably decreased. Recent advances in neuropathologic studies, central nervous system tissue cultures and in experimental demyelination are summarized. Cultures of precursors of oligodendrocytes and their maturation in vitro, selection and culture of mature oligodendrocytes, their applications to MS oligodendrocytes are emphasized. The recent models of chronic experimental allergic encephalomyelitis (EAE), the prevention of EAE by interferon, basic protein, copolymer I have already place and implication in the comprehension and treatment of MS. Virologic models are also in important progress. Interests of evoked potentials, C.T. Scan and of nuclear magnetic resonance are discussed. Main therapeutic trends are emphasized. The underlying ethic problem of the choice of a therapy is discussed.