Reactivity of sera and isolated monoclonal IgM from patients with Waldenström's macroglobulinaemia with peripheral nerve myelin.

Sera of 23 patients with Waldenström's macroglobulinaemia and six monoclonal IgM paraproteins, which had been isolated from these sera, were examined for reactivity against peripheral nerve tissue. Of these 23 patients, 12 had clinical signs of peripheral polyneuropathy (PN). Using an indirect immunofluorescence method, all sera and monoclonal IgM preparations reacted with peripheral nerve structures, displaying a distinct granular fluorescence pattern with anti-IgM sera.