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Myelin uncompaction and axo‐glial detachment in chronic ataxic neuropathy with monospecific IgM antibody to ganglioside GD1b
Author(s) -
Tagliapietra Matteo,
Zanusso Gianluigi,
Ferrari Sergio,
Orlandi Riccardo,
Bertolasi Laura,
Cavallaro Tiziana,
Monaco Salvatore
Publication year - 2020
Publication title -
journal of the peripheral nervous system
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1
H-Index - 67
eISSN - 1529-8027
pISSN - 1085-9489
DOI - 10.1111/jns.12359
Subject(s) - pathology , myelin , medicine , sural nerve , nerve biopsy , peripheral neuropathy , central nervous system , endocrinology , diabetes mellitus
To describe clinical features, disease course, treatment response, and sural nerve biopsy findings in a patient with chronic sensory ataxic neuropathy, Binet stage A chronic lymphocytic leukemia, and monoclonal IgMλ paraprotein against ganglioside GD1b. During 9 months of hospitalization at two neurologic centers, the patient underwent serial neurologic examinations, neurophysiologic studies, imaging investigations, extensive laboratory work‐up, bone marrow, and sural nerve biopsies. The patient had a severe progressive sensory neuropathy accompanied by motor involvement, dysautonomia, and marked bulbar weakness with preserved ocular movements. Conduction studies were characterized by prolonged F‐wave minimal latencies, prolonged distal latencies, reduction of compound motor action potentials, and absence of sensory nerve action potentials. Sural nerve biopsy showed endoneurial edema, axonal degeneration, and regeneration, in the absence of cellular inflammation, macrophagic activation, and B‐lymphocyte infiltration; no IgM or complement deposition was detected. Myelinated fibers showed redundant/abnormally thickened myelin, myelin vacuolation, and frank intramyelinic edema with condensed axoplasm. Ultrastructural features included axo‐glial detachment, disruption of membrane integrity, and myelin uncompaction. This study shows that monospecific anti‐GD1b IgM paraprotein is associated with non‐inflammatory nerve damage. We suggest that the loss of myelin and axonal integrity reflects antibody‐induced disruption of membrane lipid rafts.