Treatment of autoimmune neuromuscular diseases with high-dose intravenous immune globulin

The majority of autoimmune neuromuscular diseases fall into three groups: 1) The autoimmune neuropathies, which include the acute inflammatory demyelinating polyneuropathy (Guillain-Barré syndrome), the chronic inflammatory demyelinating polyneuropathy, the paraproteinemic polyneuropathies, and the anti-GM1-associated motor neuropathies with conduction block; 2) the inflammatory myopathies, which include the dermatomyositis and polymyositis complex; and 3) the autoimmune neuromuscular junction defects, which include myasthenia gravis, and the Lambert-Eaton myasthenic syndrome. Laboratory and clinical evidence suggests that circulating antibodies or sensitized lymphocytes are operating in the pathogenesis of these conditions. Current immunotherapies include treatment with plasmapheresis, high-dose steroids, or immunosuppressive drugs. Although all of these therapies are effective in a number of patients and for some period of time, they often result in serious side effects that necessitate their discontinuation. The need for safer and more effective therapies in the treatment of these conditions prompted the use of high-dose i.v. immune globulin (IVIG). A number of small trials and a few reports suggest that IVIG is safe and effective in the treatment of patients with autoimmune neuropathies, inflammatory myopathies, and myasthenia gravis unresponsive to conventional therapies. We will present current experience with IVIG in the above-mentioned autoimmune neuromuscular diseases, and we will stress the need for long-term controlled studies. The possible immunomodulatory action of IVIG in these conditions will also be discussed.