[Autoimmune neuropathy]

Chronic progressive polyneuropathy is frequently cryptogenic but occurs in association with monoclonal gammopathy. In cases of this type, a relatively mild, mainly axonal sensomotor neuropathy is frequently present and may be difficult to distinguish from carcinomatous neuropathy in malignant conditions without the presence of the M-component. In benign essential gammopathy (MGUS) with an M-component of IgM-kappa class, the neuropathy is frequently demyelinizing and the paraprotein reacts specifically with carbohydrate determinants in myelin-associated glycoprotein (MAG) and other glycoproteins and glycolipids in peripheral nerve tissue. Demonstration is undertaken by immune fluorescence investigation (eg on skin biopsy material) whereas serological diagnosis involves difficulties. There is much evidence to suggest that the autoimmune reaction is of significance for the development of nerve damage and uncontrolled trials have shown beneficial effects of immune suppression including plasmapherisis. The latter treatment should be considered in the Guillain-Barré syndrome, neuropathy and HIV-infection and also in motor neurone disease and IgM-MGUS, in which autoimmunological mechanisms may also be of pathophysiological significance.