Waldenström's macroglobulinemia and neuropathy. Deposition of M-component on myelin sheaths.

Chronic idiopathic polyneuropathy of a primary demyelinating type developed in a man who had had recurrent herpes simplex 2 for 10 years. A serum IgM kappa M-component was demonstrated on the myelin of individual sural nerve fibers by direct immunofluorescence microscopy. Marrow lymphocytosis and serum M-component increased with time. Attempts to confirm antibody activity of the M-component were negative. The evidence suggests that the attachment of M-component to nerve is a physical-chemical one. Interaction of M-component and nerve appears to have led to the neuropathy as an early manifestation of Waldenström's macroglobulinemia.