Polyneuropathy in Waldenström's macroglobulinaemia. Passive transfer from man to mouse.

To support the hypothesis of an immunopathogenesis of polyneuropathy in Waldenström's macroglobulinaemia (MW), serum IgM fractions of MW patients were applied intraperitoneally to mice for 17 days. Sections of liver, kidney, M. glutaeus maximus, central nervous system (CNS) and both Nn. ischiadici were examined for IgM, IgG, C3 and as control IgD with PAP-immunostaining. IgM deposits were found in every organ except the CNS. In peripheral nerves larger amounts were visualized in perineurium and endoneural space, whereas myelin lamellae and periaxon did not stain. Therefore, perhaps our investigation reveals a greater permeability of the blood-nerve barrier (BNB) compared with the blood-brain barrier (BBB). The involvement of the monoclonal IgM of MW, which has been shown to react in vitro with peripheral nerve constituents, appears possible in the pathogenesis of polyneuropathy.