Peripheral neuropathy in monoclonal gammopathy of undetermined significance: prevalence and immunopathogenetic studies.
In an unselected series of patients with monoclonal gammopathy of undetermined significance (MGUS) we found neuropathy in 2 of 34 patients with IgG (6%), 2 of 14 with IgA (14%), and 8 of 26 with IgM MGUS (31%). The neuropathy was subclinical in 6 patients (1 IgG, 1 IgA, and 4 IgM). Patients with IgG or IgA MGUS had a prominent motor impairment with electrophysiologic and morphologic findings suggestive of predominant axonal degeneration. No deposit of the M-protein in sural nerve and no reactivity of the M-protein with nerve was detected in these patients. Patients with IgM MGUS had a prominent sensory impairment with evidence of predominant demyelination. In 6 of these patients the M-protein reacted with the myelin-associated glycoprotein (MAG). The higher prevalence of neuropathy in patients with IgM MGUS may be related to the frequent reactivity of IgM M-proteins with MAG.
Nobile-Orazio
E
E
Institute of Clinical Neurology, Dino Ferrari Centre, University of Milan, Ospedale Maggiore Policlinico, Italy.
Barbieri
S
S
Baldini
L
L
Marmiroli
P
P
Carpo
M
M
Premoselli
S
S
Manfredini
E
E
Scarlato
G
G
D000328:Adult; D000368:Aged; D001327:Autoimmune Diseases / Q000175:diagnosis / Q000276:immunology*; D001798:Blood Proteins / Q000276:immunology*; D003711:Demyelinating Diseases / Q000175:diagnosis / Q000276:immunology; D004576:Electromyography; D000939:Epitopes / Q000276:immunology; D005260:Female; D006801:Humans; D007136:Immunoglobulins / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009185:Myelin Proteins / Q000276:immunology*; D018992:Myelin-Associated Glycoprotein; D009460:Neurologic Examination; D010265:Paraproteinemias / Q000175:diagnosis / Q000276:immunology*; D010523:Peripheral Nervous System Diseases / Q000175:diagnosis / Q000276:immunology*; D009435:Synaptic Transmission / Q000502:physiology
D001798:Blood Proteins; D000939:Epitopes; D007136:Immunoglobulins; C009823:M-proteins (Myeloma); D009185:Myelin Proteins; D018992:Myelin-Associated Glycoprotein