Serum antibody against a peripheral nerve myelin ganglioside, LM1, in Guillain-Barré syndrome.

Serum IgG antibody against LM1, the predominant ganglioside in the human peripheral nerve myelin, was found in 7 out of 140 patients with Guillain-Barré syndrome (GBS) in the acute phase, 1 out of 33 patients with chronic inflammatory demyelinating polyneuropathy (CIDP), and 2 out of 47 patients with Miller Fisher syndrome (MFS). Anti-LM1 IgM antibody was detected only in 2 patients, each with GBS and MFS. The clinical and electrophysiological features of the seven GBS patients with anti-LM1 IgG antibody in the serum were investigated. Six patients recovered to grade 1 within one month of the onset of neuropathy. Electrophysiological studies revealed demyelination in five patients, of which one had axonal damage in addition, whereas sufficient evidence of demyelination or axonal degeneration was not observed in the remaining two. Five had a respiratory tract infection before the onset of neuropathy, and also had serum anti-GQ1b IgG antibody. IgG antibody against LM1 might be involved in the pathogenetic mechanisms of GBS, as a possible demyelinating factor. Presence of both anti-GQ1b and anti-LM1 antibodies may be associated with some infectious agent(s) affecting the respiratory tract.