Confocal microscopic localization of anti-myelin-associated glycoprotein autoantibodies in a patient with peripheral neuropathy initially lacking a detectable IgM gammopathy

Acta Neuropathol. 1998 May;95(5):540-6. doi: 10.1007/s004010050835.


We report here on a patient with anti-myelin-associated glycoprotein (MAG) neuropathy in whom examination of a sural nerve biopsy by multichannel confocal microscopy showed a partly overlapping distribution of MAG and IgM deposits in myelinated fibers. Our data demonstrate that MAG in Schmidt-Lanterman incisures and paranodal loops, as well as some additional HNK-1-positive components of the basal lamina, are the major targets of the anti-MAG monoclonal IgM autoantibodies in this neuropathy in vivo. Perforation of the basal lamina can allow the penetration and binding of anti-MAG IgM inside myelinated fibers. Our results support and extend the notion that the production of monoclonal anti-MAG IgM may be antigenically driven by MAG molecules and that this process may occur in the immunologically privileged environment of the nerve prior to the appearance of a genuine gammopathy in serum.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Autoantibodies / metabolism*
  • Humans
  • Immunoglobulin M / metabolism*
  • Immunohistochemistry
  • Male
  • Microscopy, Confocal
  • Middle Aged
  • Myelin-Associated Glycoprotein / immunology
  • Myelin-Associated Glycoprotein / metabolism*
  • Paraproteinemias / metabolism*
  • Paraproteinemias / pathology
  • Peripheral Nervous System Diseases / metabolism*
  • Peripheral Nervous System Diseases / pathology
  • Sural Nerve / pathology


  • Autoantibodies
  • Immunoglobulin M
  • Myelin-Associated Glycoprotein