Detection of anti-MAG antibodies in polyneuropathy associated with IgM monoclonal gammopathy.

Abstract

BACKGROUND:

Detection of serum antibodies to myelin-associated glycoprotein (MAG) by Western blot (WB) is a valuable assay to diagnose a distinct type of demyelinating polyneuropathy with immunoglobulin M (IgM) monoclonal gammopathy. In this study, the diagnostic accuracy of a new and more practical ELISA to detect these antibodies was validated.

METHODS:

Routine WBs from 2 independent laboratories and ELISA were used to detect anti-MAG IgM in serum from 207 patients with neuropathy and controls. The sensitivity and specificity of these assays were compared and related to the patient clinical and electrophysiologic characteristics.

RESULTS:

In ELISA, anti-MAG antibodies were found in serum from 49 (72%) of 68 patients with demyelinating polyneuropathy and IgM monoclonal gammopathy. However, in this subgroup of patients, only 30 (44%) and 37 (54%) were positive in the 2 WBs. All of the patients positive in the 2 WBs were also positive in ELISA. A high correlation was found for IgM activity in ELISA to MAG and sulfate-3-glucuronyl paragloboside (SGPG) (Spearman rho = 0.72, p < 0.0001), supporting the notion that the shared sulfated glucuronic acid moiety of MAG and SGPG is preserved. Most patients positive in anti-MAG ELISA had a slowly progressive sensory-motor demyelinating polyneuropathy, even if the WB was negative. In control groups, however, 4 WB-negative patients with a nondemyelinating monoclonal gammopathy-related polyneuropathy were positive in anti-MAG ELISA. The remaining samples were negative in ELISA.

CONCLUSION:

ELISA is more sensitive than Western blot to diagnose anti-myelin-associated glycoprotein related polyneuropathy, although a positive serology may be found in other forms of polyneuropathy as well.

• Authors: M L Kuijf, M Eurelings, A P Tio-Gillen, P A van Doorn, L H van den Berg, H Hooijkaas, J Stork, N C Notermans, B C Jacobs
• Journal: Neurology (Neurology) Vol. 73 Issue 9 Pg. 688-95 (Sep 01 2009) ISSN: 1526-632X [Electronic] United States
• PMID: 19720975 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Autoantibodies
• Biomarkers
• Globosides
• Immunoglobulin M
• Myelin-Associated Glycoprotein
• sulfate-3-glucuronyl paragloboside

Topics

• Autoantibodies (analysis, blood)
• Biomarkers (analysis, blood)
• Disease Progression
• Enzyme-Linked Immunosorbent Assay (methods)
• Globosides (analysis, blood)
• Humans
• Immunoglobulin M (immunology)
• Monoclonal Gammopathy of Undetermined Significance (complications, immunology, physiopathology)
• Myelin Sheath (immunology, pathology)
• Myelin-Associated Glycoprotein (immunology)
• Nerve Fibers, Myelinated (immunology, pathology)
• Peripheral Nerves (immunology, pathology, physiopathology)
• Polyneuropathies (blood, immunology, physiopathology)
• Polyradiculoneuropathy (blood, immunology, physiopathology)