Conduction abnormalities induced by sera of patients with multifocal motor neuropathy and anti-GM1 antibodies.
Increased titers of anti-GM1 antibodies have been associated with motor neuron disease and motor neuropathy with or without conduction block. To investigate the pathogenetic role of anti-GM1 antibodies we injected into rat tibial nerves sera from patients with multifocal motor neuropathy and conduction block (MMN) or progressive spinal muscular atrophy (PMA), both presenting anti-GM1 antibodies. Sera of patients with MMN produced reduction of amplitude and dispersion of compound muscle action potential from proximal stimulation. Morphometry revealed demyelination in 6.2% of fibers. Sera of patients with PMA did not produce clear-cut electrophysiological or morphological changes. Differential effects of sera from patients presenting high-titer anti-GM1 antibodies, but with distinct clinical syndromes, might depend on differences in anti-GM1 antibody affinity, valency, or ability to fix complement. Alternatively, circulating factors other than, or in addition to, anti-GM1 antibodies present in sera of patients with MMN, but not of PMA patients, might be responsible for conduction abnormalities and reproduce them after passive transfer.
Uncini
A
A
Department of Neurology, University of Chieti, Italy.
Santoro
M
M
Corbo
M
M
Lugaresi
A
A
Latov
N
N
D000818:Animals; D000906:Antibodies / Q000494:pharmacology*; D003711:Demyelinating Diseases / Q000209:etiology*; D005677:G(M1) Ganglioside / Q000276:immunology / Q000494:pharmacology*; D006801:Humans; D008297:Male; D016472:Motor Neuron Disease / Q000276:immunology / Q000473:pathology / Q000503:physiopathology*; D009134:Muscular Atrophy, Spinal / Q000276:immunology / Q000473:pathology / Q000503:physiopathology*; D009431:Neural Conduction / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013979:Tibial Nerve / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology
D000906:Antibodies; D005677:G(M1) Ganglioside