Pathogenesis of immune-mediated neuropathies

A variety of peripheral neuropathies are believed to be immune-mediated. Acute inflammatory demyelinating polyneuropathy or Guillain-Barré syndrome (GBS) is the prototype of these neuropathies. GBS is characterized by acute progressive motor weakness of the extremities and of bulbar and facial musculature. Deep tendon reflexes are reduced or absent, and sensory symptoms are mild. Respiratory failure and autonomic dysfunction may be seen. The cerebrospinal fluid shows increased protein and no or very few cells. The nerve conduction velocity is slowed, and the pathology shows segmental demyelination with mononuclear cell infiltration. Studies from man and experimental animals suggest an immunologic basis for demyelination of the peripheral nerves in GBS, but the mechanism is not well understood. Experimental allergic neuritis, an animal model of GBS, is induced in laboratory animals by immunization with myelin P2 protein, some peptides of P2 protein, and galactocerebroside. The animals develop weakness and show electrophysiologic and pathologic features similar to GBS. P2-reactive T cells and antigalactocerebroside antisera can adoptively transfer experimental allergic neuritis. Various antibodies to peripheral nerve myelin and circulating immune complexes have been found in patients with GBS. The target antigen(s) for these antibodies are not well understood, but neutral glycolipids cross-reactive with Forssman antigen and gangliosides are possible candidates. The mainstay of therapy is the management of the paralyzed patient. Steroids are ineffective. Plasmapheresis, especially early in the course of the disease, can shorten the duration of paralysis and intubation. Results from a multicenter study in the Netherlands demonstrate the efficacy of high-dose immune globulin therapy in GBS.(ABSTRACT TRUNCATED AT 250 WORDS)