[Environment, genetics and immunology in multiple sclerosis].

The cause of multiple sclerosis remains unknown. Epidemiological studies indicate that it is a multi-factorial disease. The environmental factors are still unknown. No virus has been yet demonstrated to play a role in multiple sclerosis. The role of HLA in the genetic susceptibility has been known since the seventies; the detailed analysis is underway. Immunological factors playing a role in the course of multiple sclerosis are better known and may serve as basis to new therapeutical approaches.