Comparison of commercial tests for detecting multiple anti-ganglioside autoantibodies in patients with well-characterized immune-mediated peripheral neuropathies.

BACKGROUND

To assess the performance of commercial anti-ganglioside antibody assays, we determined anti-ganglioside antibody IgG and IgM isotype profiles of patients with acute and chronic well-characterized immune-mediated peripheral neuropathies by one immunodot assays (Zentec/Ingen: Dotzen Ganglio Profile Ab, Euroimmun/BioAdvance: Euroline ganglioprofile), two line-immuno assay (GA Generic Assays/Labodia: Anti-Gangli osid Dot, Euroimmun/BioAdvance: Euroline ganglioprofile), and one enzyme-linked immunosorbent assay (ELISA) (Bühlmann: GanglioCombi). Specific antibody profiles were compared with those obtained by our validated standard in-house immunodot assay (IDA).

METHODS

We selected 33 sera with high levels of IgG and IgM anti-ganglioside antibodies from 15 patients with Guillain-Barre syndrome (GBS) subtypes and variants, 12 patients with CANOMAD syndrome (chronic ataxic neuropathy with ophthalmoplegia, M-paraprotein, cold agglutinins, disialosyl antibodies), 5 patients with chronic motor peripheral neuropathies, and 1 patient with sensory neuropathy and a control group composed of 10 patients with non-autoimmune neuropathy.

RESULTS

The 3 commercial IDAs employing hydrophobic membranes and the ELISA demonstrated different carbohydrate epitopes on 6 to 12 glycolipid antigens used for anti-ganglioside antibody detection. Comparison with the validated in-house IDA showed large variations in sensitivity between tests and a more diverse reactivity to gangliosides than expected. The test with the largest panel of glycolipids detecting 11 anti-ganglioside antibody reactivities (GM1, GM2, GM3, GM4, GD1a, GD1b, GD2, GD3, GT1a, GT1b, GQ1b, and sulfatide) revealed the best concordance with our in-house assay. However, even with this test, differences were observed in the immunoreactivity against some gangliosides and weakly stained bands were not easy to interpret.

CONCLUSIONS

Our data suggest an urgent need for standardization of commercial anti-ganglioside assays and the introduction of international anti-ganglioside antibody reference standards.