Efficacy of intravenous gammaglobulin therapy in chronic refractory polymyositis and dermatomyositis: an open study with 20 adult patients

Polymyositis and dermatomyositis are connective tissue diseases characterized by inflammation and deterioration of the muscles, inflammation of the skin, and accumulation of tissue fluid. The cause of these conditions is not known, but may be related to immune or viral factors. Polymyositis can be treated with corticosteroids, drugs that suppress the immune system, radiation therapy, or plasmapheresis (a blood preparation procedure). However, these various approaches to treating polymyositis are not consistently effective, and may cause side effects. Polyvalent human intravenous immunoglobulin (IVIG) is an immune protein preparation that has been effective against certain immune disorders. The effectiveness of IVIG was assessed in 14 patients with polymyositis, and in six patients with dermatomyositis. These patients did not respond to other drugs commonly used to treat these conditions. IVIG was the drug of choice for one patient, who tested positive for infection with picornavirus. Treatment with IVIG was combined with prednisone in 15 patients, with methotrexate in six patients, and with plasmapheresis in one patient. The immune protein contained in the IVIG preparation was immunoglobulin G. Doses of one gram per kilogram (g/kg) were given two days a month to 13 patients, and 0.4 g/kg were given five days a month to seven patients. IVIG therapy caused clinical improvement in 15 patients and biochemical improvement in 18 patients. It improved muscle strength and reduced levels of creatine kinase, which are usually increased during muscle injury. IVIG caused only mild side effects in four patients and reduced the steroid dose needed by the patients. These findings suggest that IVIG is effective in treating polymyositis and dermatomyositis, and may be an alternative to treatment with steroids or immunosuppressive agents. (Consumer Summary produced by Reliance Medical Information, Inc.)