Intravenous immunoglobulin treatment in lower motor neuron disease associated with highly raised anti-GM1 antibodies.

The effect of intravenous immunoglobulin (IVIg) treatment was studied in five patients with lower motor neuron disease associated with highly raised anti-GM1 antibodies but without evidence of conduction block on neurophysiological examination. The patients received IVIg treatment (0.4 g/kg for five consecutive days) in an open study. Only one patient responded to IVIg treatment, which was confirmed in a double blind, placebo controlled study (two placebo treatments and two IVIg treatments in a randomised order). However, after six months of maintenance IVIg treatment (0.4 g/kg weekly) muscle weakness gradually deteriorated below pretreatment levels despite continued treatment. It is concluded that the presence of raised anti-GM1 antibodies does not identify a subgroup of patients with lower motor neuron disease who respond to IVIg treatment and although some patients with lower motor neuron disease may initially respond, IVIg treatment does not seem to be sufficient as long term treatment.