Anti-neurone antibodies are not characteristic of amyotrophic lateral sclerosis

Autoantibodies, a suggested cause of motor neurone degeneration in amyotrophic lateral sclerosis (ALS), were sought immunohistochemically after applying diluted sera to sections of normal human spinal cord. Serum from a case of paraneoplastic motor neurone disease provided a positive control, giving strong staining of motor neurones for IgG but not IgM. The sera of 11 of 21 ALS patients contained IgG that could bind to motor neurones, but similar antibodies occurred also in 5 of 8 subjects with other nervous system disorders and in 3 of 9 neurologically normal controls. Bound IgM was more weakly stained than IgG, and was seen as often with control as with ALS sera. These findings do not support the notion that humoral autoantibodies mediate neuronal destruction in ALS.