Anti-G M1 ganglioside antibodies with differing fine specificities in patients with multifocal motor neuropathy

Abstract

Antibodies to gangliosides were detected in sera from three of 19 patients with chronic inflammatory polyneuropathy (CIP) by a thin-layer chromatogram overlay technique. All three of the patients fell into a clinical subset of the group that had multifocal motor neuropathy, and in all three patients the antibodies reacted with G M1 ganglioside. However, the fine specificities of the antibodies differed as demonstrated by cross-reactivity with different gangliosides in each of the three patients. The antibodies in patient 1 reacted with G M1, G D1b, and asialo-G M1 suggesting that the terminal Gal(β1–3)GalNAc moiety that is common to these three glycolipids is an important part of the epitope(s). This was confirmed by showing reactivity of the antibodies with Gal(β1–3)GalNAc conjugated to bovine serum albumin. Patient 2 had antibodies that did not react with G D1b, but cross-reacted with G M2 ganglioside suggesting that the epitope(s) involved the inner portion of the oligosaccharide moiety that is shared between G M1 and G M2. Patient 3 had antibodies that reacted with G M1 and asialo-G M1, but they did not cross-react with either G D1b or G M2. These results provide further evidence for a relationship between motor nerve syndromes and anti-G M1 antibodies and also suggest that G M1 could be a principal target antigen since other reactive gangliosides differed among the patients. However, the possible pathogenic effects of anti-G M1 antibodies on motor nerves remain to be established.