IgM M-protein in a patient with sensory-dominant neuropathy binds preferentially to polysialogangliosides.

A 77-year-old man presented sensory-dominant neuropathy associated with IgM M-protein reacting with various gangliosides. The M-protein bound to gangliosides with polysialosyl residue, such as GD1b, GD3, GT1b, GT3, GQ1b, and GQ1c. In addition, GD1a, GM3 and LM1, having a terminal monosialosyl epitope, were also recognized. Previously, Ilyas et al. described a similar case in which sensory symptoms were associated with IgM M-protein reacting with gangliosides containing a disialosyl group, such as GD3, GD1b, and GT1b, but not GM3 and GD1a. It is suggested that the reactivity of IgM M-protein with polysialogangliosides may be associated with the pathogenesis of sensory-dominant neuropathy.