[Long-term maintenance therapy of multifocal motor neuropathy by weekly administration of human immunoglobulin].

High-dose intravenous immunoglobulin therapy for multifocal motor neuropathy (MMN) exhibits a beneficial, but temporary effect in most cases. We experienced a patient with MMN having a high titer of anti-GM1 ganglioside antibody. He was weekly administered human immunoglobulin, and his muscle strength was successfully improved and maintained at the improved level after high-dose human immunoglobulin infusion. The pattern of improvement and maintenance by weekly administration of human immunoglobulin was variable among the muscles; e.g. only a minimal improvement was observed in the most severely involved brachioradial muscles. Successive measurements with a hand-held dynamometer revealed in detail the changes in the strength of each muscle during treatment. Anti-GM1 ganglioside antibody titers did not significantly change during the treatment, but a slight improvement in motor conduction amplitudes and velocities was observed in mildly affected nerves. Our findings suggest that weekly administration of human immunoglobulin is a safe and effective therapy for MMN and that the anti-GM1 ganglioside antibody titer may not be a good indicator for this therapy.