Heterogeneity of Polyneuropathy Associated with Anti-MAG Antibodies

Polyneuropathy associated with igm monoclonal gammopathy and anti-myelin associated glycoprotein (mag) antibodies is an immune-mediated demyelinating neuropathy. the pathophysiology of this condition is likely to involve anti-mag antibody deposition on myelin sheaths of the peripheral nerves and it is supposed to be distinct from chronic inflammatory demyelinating neuropathy (cidp),another immune-mediated demyelinating peripheral neuropathy. in this series,we have retrospectively reviewed clinical and laboratory findings from 60 patients with polyneuropathy,igm gammopathy,and anti-mag antibodies. we found that the clinical picture in these patients is highly variable suggesting a direct link between the monoclonal gammopathy and the neuropathy. conversely,one-third of patients had a cidp-like phenotype on electrodiagnostic testing and this was correlated with a low titer of anti-mag antibodies and the absence of widening of myelin lamellae. our data suggest that polyneuropathy associated with anti-mag antibodies is less homogeneous than previously said and that the pathophysiology of the condition is likely to be heterogeneous as well with the self-antigen being mag in most of the patients but possibly being another component of myelin in the others. copyright © 2015 laurent magy et al.