Antibodies to Myelin Associated Glycoproteins (MAG) may be found in demyelinating polyneuropathies associated with autoimmune mechanisms. The autoantibodies appear to be pathogenic and their levels correlate with disease activity. Anti-MAG antibodies are also found in some chronic sensory neuropathies and in Guillain Barre syndrome. The IgM anti-MAG can be polyclonal but in most (85%) cases is monoclonal, particularly IgMk paraproteins directed against the MAG of central and peripheral nerves. Reports suggest that 50% of IgM paraproteins may bind to MAG. Other IgMk paraproteins bind to sulphatides of perpiheral nerve axons associated with sensory or motor syndromes.
Seen in chronic sensorimotor neuropathies and occasionally Guillain-Barre syndrome. Should be assayed in all cases of neuropathy associated with an IgM paraprotein.
Present in >90% pateints with Immune mediated sensory motor polyneuropathy.
Serum Separator Tube (SST)
Referred test: only available to neurology staff.
Southern General Hospital Department of Neurology