19 - Immune-mediated neuropathies

Abstract

This chapter discusses the pathophysiological and clinical aspects of immune mediated neuropathies. Establishing animal models of acute and chronic polyneuritis such as experimental autoimmune neuritis (EAN) has fostered the understanding of human disease pathophysiology and has helped to dissect different forms of immune-mediated neuropathies. EAN is an acute inflammatory demyelinating polyradiculoneuropathy that can be induced in rats, mice, rabbits, and monkeys by active immunization with whole peripheral nerve homogenate, myelin, and myelin proteins P0 and P2 or peptides thereof. Guillain–Barré Syndrome (GBS) is another type of acute immune-mediated neuropathy. It is characterized by areflexia and a rapidly ascending flaccid paralysis. The pathogenesis and pathophysiology of GBS are prototypic for immune-mediated neuropathies. It is caused by an inflammatory attack on the myelin sheath (acute inflammatory demyelinating polyneuritis [AIDP]) or axons (acute motor axonal polyneuritis, [AMAN]). Chronic immune-mediated neuropathies include chronic inflammatory demyelinating polyneuropathy (CIDP), multifocal motor neuropathy and variants, paraproteinemic neuropathies and neuropathies with anti-MAG antibodies, and disimmune sensory ganglionopathies. Several systemic autoimmune diseases such as vasculitic neuropathies and cryoglobulinemic neuropathy also affect the peripheral nerve. Vasculitic neuropathies affect subacutely sensorimotor nerves in a multiplex fashion with stepwise progression. The chapter also discusses the immune-mediated exacerbation of nonimmune peripheral nerve disease. Patients with immune-mediated neuropathy superimposed on nonimmune neuropathy have added a fascinating aspect to the understanding of peripheral nerve disease.