Multiple sclerosis: the present position.

The advances of the past decade particularly in the application of evoked potential techniques and electrophoresis of CSF proteins have improved the accuracy of early diagnosis of multiple sclerosis. The geographical distribution of the disease, the effect of migration on prevalence, and the existence of clusters suggest that an environmental factor is involved in the aetiology; it is probably infective. Family and twin studies provide evidence for a genetic contribution which is probably multifactorial and related to immune regulation. The pathogenesis is at least in part immunologically mediated. A rational approach to therapy is difficult. In the present state of knowledge we are unlikely to be able to modify the course of multiple sclerosis by tackling a putative environmental agent. We are more likely to be able to do so by manipulating the pathogenesis, although an effective means of doing so has yet to be defined.