Multiple sclerosis: a survey of alternative hypotheses concerning aetiology, pathogenesis and predisposing factors.

There is abundant evidence that both environmental and genetic factors play a role in the aetiology and pathogenesis of multiple sclerosis. Currently, a virus infection and an abnormality of T-cell function are favoured candidates for the environmental and genetic factors, respectively. However, as long as convincing evidence for a specific viral infection and for a pathogenetic role for T-cells in multiple sclerosis is lacking, it may be worthwhile to consider alternative hypotheses that have been proposed in recent years. These have been classified in this review under the headings Toxins, Dietary and Metabolic Abnormalities, Embolism, Infection, and Immunological Mechanisms.