Antiganglioside antibodies in motor-neuron diseases and peripheral neuropathies: study by ELISA technique and immunodetection on thin-layer chromatography.

We report here our studies on IgM reactivity towards peripheral nervous system gangliosides, in motor-neuron diseases (MND) without IgM gammopathies, and in peripheral neuropathies with IgM gammopathies. We showed by enzyme linked immunosorbent assay technique, that anti-GM1 IgM antibodies were often present at a low level in normal controls in contrast to anti-GD1b antibodies, which were never detected in control sera. We evidenced that several steps of the ELISA technique were critical such as the nonaddition of detergent in buffer solutions used for dilutions and for washing and the choice of the ELISA plates. We studied 50 cases of motor-neuron diseases, among which 40 typical cases of Amyotrophic Lateral Sclerosis, only a few had high anti-GM1 antibodies levels, which were always confirmed by immunodetection on thin-layer chromatography. These antibodies were generally directed against the oligosaccharide epitope present also in asialoGM1. No correlation has been as yet established in relation to the clinical state of the patients. In a few cases of polyneuropathies associated with IgM gammopathies, antiganglioside antibodies have been reported. We have found anti-GD1b antibodies to be present in a sensory-motor axonal neuropathy; axonal involvement was evidenced by electrophysiological study.