Complement-mediated demyelination in patients with IgM monoclonal gammopathy and polyneuropathy

Salvatore Monaco, Bruno Bonetti, Sergio Ferrari, Giuseppe Moretto, Ettore Nardelli, Francesco Tedesco, Tom Eirik Mollnes, Eduardo Nobile-Orazio, Emanuela Manfredini, Luisa Bonazzi, Nicola Rizzuto

Research output: Contribution to journalArticlepeer-review


We investigated the role of complement in the pathogenesis of the demyelinating polyneuropathy that occurs in some patients with IgM monoclonal gammopathy. Seven patients with chronic sensorimotor polyneuropathy and IgM monoclonal gammopathy were examined. In six patients, the monoclonal protein recognized an epitope shared by myelin-associated glycoprotein and two peripheral-nerve glycolipids, whereas in one patient, IgM bound to an unidentified myelin antigen. Direct and indirect immunofluorescence and immunoperoxidase assays showed colocalization along the myelin sheaths of peripheral-nerve fibers of monoclonal protein with complement components C1q, C3d, and C5. In addition, terminal-complement complex that was not associated with S protein was detected in myelin sheaths. It appeared that alterations in myelin geometry caused by the separation of myelin lamellae corresponded to sites at which terminal-complement complex was deposited. We conclude that demyelination in polyneuropathy associated with IgM monoclonal gammopathy may be mediated by complement.

Original languageEnglish
Pages (from-to)649-652
Number of pages4
JournalNew England Journal of Medicine
Issue number10
Publication statusPublished - Mar 8 1990

ASJC Scopus subject areas

  • Medicine(all)


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