Autoimmunity related to IgM monoclonal gammopathy of undetermined significance. Peripheral neuropathy and connective tissue sensibilization caused by IgM M-proteins.
In eight of 10 consecutive cases of IgM monoclonal gammopathy of undetermined significance (MGUS), the M-protein had specificity towards various tissues as estimated by direct and indirect immunofluorescence studies of skin and/or sural nerve biopsies. Five of the cases had neuropathy. In three of them, including two siblings with a demyelinating peripheral neuropathy, the IgM was bound to the myelin-associated glycoprotein (MAG) of peripheral nerves. One had axonal neuropathy with IgM activity against the peri- and endoneurium, while another case with post-infectious neuritis had IgM activity against structures in the endoneurium but no IgM autoimmunity in the direct fluorescence test. The latter improved clinically in parallel with a decrease in the M-protein indicating a pathogenetic role of the autoantibody. In three other cases, the IgM was bound to connective tissue structures, two of them also had plasma antibodies against the peri- and endoneurium in the indirect fluorescence test. Finally, two cases showed no reaction of the M-protein against any tissue structures. Since an autoimmune pathogenesis is suspected, the HLA types of seven patients are reported.
Jønsson
V
V
Department of Internal Medicine and Haematology, Gentofte Hospital, Hellerup, Copenhagen, Denmark.
Schrøder
H D
HD
Staehelin Jensen
T
T
Nolsøe
C
C
Stigsby
B
B
Trojaborg
W
W
Svejgaard
A
A
Hippe
E
E
D000368:Aged; D000911:Antibodies, Monoclonal / Q000032:analysis*; D001259:Ataxia / Q000276:immunology*; D001323:Autoantibodies / Q000032:analysis*; D001798:Blood Proteins / Q000276:immunology* / Q000378:metabolism; D005260:Female; D006801:Humans; D006942:Hypergammaglobulinemia / Q000276:immunology*; D007075:Immunoglobulin M / Q000276:immunology*; D007136:Immunoglobulins; D008297:Male; D008875:Middle Aged; D009420:Nervous System / Q000276:immunology; D012867:Skin / Q000276:immunology
D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D001798:Blood Proteins; D007075:Immunoglobulin M; D007136:Immunoglobulins; C009823:M-proteins (Myeloma)