In a study on 67 chronic neuropathies, we have shown that anti-GM1 ant
ibodies are particularly frequent in multifocal motor neuropathies (MM
N) with conduction blocks (17/24 cases). The detection of these antibo
dies by ELAS necessitates a confirmation by immunodetection on thin-la
yer chromatography, so as to distinguish the anti-GM1 antibodies prese
nt in MMN from natura antibodies which are polyreactive and of low aff
inity. There is no direct correlation between the anti-GM1 antibody li
ter, the immunosuppressive treatment and the clinical evolution. Never
theless, the detection of high titer of anti-GM1 antibodies is an addi
tional argument in favor of treatment by IVIg.