ANTI-GD(1A) GANGLIOSIDE ANTIBODIES IN PERIPHERAL MOTOR SYNDROMES

High titers of anti-GD(1a) antibodies have been found in patients with Guillain-Barre syndrome or motor neuropathy. To determine the possibl e diagnostic relevance of these antibodies, we measured serum anti-GD( 1a) IgG and IgM antibodies by enzyme-linked immunosorbent assay in 195 patients with different motor syndromes and in 335 control subjects. Moderately high antibody titers (1/ 1,280-1/5,120) were occasionally f ound in patients with chronic inflammatory demyelinating polyneuropath y (5%), multifocal motor neuropathy (18%), lower motor neuron disease (3.8%), or amyotrophic lateral sclerosis (1.8%) and in immunological c ontrol subjects (1.2%), while titers of 1/20,480 or higher were only f ound in 2 patients with Guillain-Barre syndrome (IgG in both) and 2 wi th motor neuropathy and IgM lambda monoclonal gammopathy improving wit h immunotherapy. In both motor neuropathy patients and the Guillain-Ba rre syndrome patient who were retested during recovery, anti-GD(1a) ti ters decreased concomitantly with clinical improvement. High anti-GD(1 a) antibody titers may be found in several motor syndromes but only ma rkedly increased anti-GD(1a) titers are strictly associated with poten tially treatable dysimmune neuropathies.