Intranervous immunoglobulin deposits: an underestimated mechanism of neuropathy.
There are several pathogenic mechanisms of peripheral nerve involvement in patients with monoclonal dysglobulinemia. Intranervous proliferation of malignant cells, immunoglobulin, or amyloid deposits in the endoneurial space can only be determined by examination of nerve biopsy specimens. We present clinical, electrophysiological, and histological data from seven patients whose polyneuropathy was induced by immunoglobulin deposits in the endoneurial space. As these lesions cannot be demonstrated on clinical and electrophysiological grounds, the indication for nerve biopsy derives from careful analysis of each patient presenting with a polyneuropathy and a monoclonal dysglobulinemia. To visualize and clearly characterize these deposits, electron microscopic examination is indispensable. Immunocytochemical methods using both light and electron microscopy for ultrastructural analysis are of great value. Demonstration of endoneurial immunoglobulin deposits may have major therapeutic consequences. Indeed, identification of these deposits prompted the use of aggressive treatment, which was quite effective in five of our seven patients.
Department of Neurology and Centre National de Référence Neuropathies Périphériques Rares, University Hospital, 2 Avenue Martin Luthert King, Limoges Cedex, France. jean-michel.vallat@unilim.fr
Jean-Michel
JM
Vallat
Laurent
L
Magy
Laurence
L
Richard
Martine
M
Piaser
Philippe
P
Sindou
Judith
J
Calvo
Karima
K
Ghorab
Didier
D
Cros
D000328:Adult; D000368:Aged; D001706:Biopsy; D002452:Cell Count; D003450:Cryoglobulins / Q000378:metabolism; D004568:Electrodiagnosis; D004594:Electrophysiology; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007136:Immunoglobulins / Q000378:metabolism*; D008297:Male; D016253:Microscopy, Immunoelectron; D008875:Middle Aged; D009046:Motor Neurons / Q000378:metabolism / Q000473:pathology; D009413:Nerve Fibers, Myelinated / Q000473:pathology; D009417:Nerve Tissue / Q000378:metabolism* / Q000473:pathology*; D009431:Neural Conduction / Q000502:physiology; D009475:Neurons, Afferent / Q000378:metabolism / Q000473:pathology; D010265:Paraproteinemias / Q000378:metabolism / Q000473:pathology; D011115:Polyneuropathies / Q000378:metabolism* / Q000473:pathology*
D003450:Cryoglobulins; D007136:Immunoglobulins