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Sensory nerve conduction deficit in experimental monoclonal gammopathy of undetermined significance (MGUS) neuropathy. Muscle Nerve 2001 Jun;24(6):809-16

Date

05/22/2001

Pubmed ID

11360265

DOI

10.1002/mus.1073

Scopus ID

2-s2.0-0035008590 (requires institutional sign-in at Scopus site)   9 Citations

Abstract

An emerging body of evidence from in vitro studies and in vivo animal models supports a pathogenic role of antibodies in the development of peripheral neuropathy associated with monoclonal gammopathy of undetermined significance (MGUS). Although the assessment of motor and sensory nerve fiber function is of clinical importance, it is seldom applied experimentally. We describe the application of an electrophysiologic method for the evaluation of motor and sensory nerve fiber function using an experimental model of MGUS neuropathy. Supramaximal stimulation of the tibial nerve elicited an early motor response (M-wave, 1.7 +/- 0.1 ms, n = 10) and a late sensory (H-reflex, 7.8 +/- 0.1 ms, n = 10) response that was recorded from the hind foot of anesthetized rats. Intraneural injection of serum antibodies from a MGUS patient with sensorimotor polyneuropathy, but not from an age-matched control subject, produced a marked attenuation of the H-reflex (P < 0.01, n = 10) without affecting the M-wave. Light and electron microscopy of affected nerve showed myelinoaxonal degeneration with sparing of the smaller unmyelinated nerve fibers. The combined electrophysiologic and morphologic findings presented in this study are consistent with a selective sensory conduction deficit in MGUS neuropathy. Selective injury of afferent nerve fibers by this patient's serum antibodies may result from reactivity to neural antigens uniquely expressed by sensory neurons.

Author List

Lawlor MW, Richards MP, Fisher MA, Stubbs EB Jr

Author

Michael W. Lawlor MD, PhD Adjunct Professor in the Pathology department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Aged
Animals
Disease Models, Animal
Evoked Potentials
H-Reflex
Humans
Immunoglobulin M
Immunoglobulin kappa-Chains
Male
Nervous System Diseases
Neural Conduction
Neurons, Afferent
Paraproteinemias
Rats
Rats, Inbred Lew
Sciatic Nerve