Autoantibodies and their significance in myositis.

Myositis autoantibodies continue to be the subject of substantial interest, with several significant recent developments. Recent studies have emphasized that anti-Jo-1 or other antisynthetases can be associated with interstitial lung disease, even in the absence of myositis. Anti-Jo-1 autoantibody levels were shown to correlate with disease activity over time. Immunization of mice with anti-Jo-1 led to muscle and lung inflammation, reminiscent of human disease. The complexity of the antibody picture in myositis continues to increase. Several new autoantibodies have been described or better characterized. Among these were a new antisynthetase reactive with phenylalanyl-transfer RNA synthetase (anti-Zo); an autoantibody that immunoprecipitates 155- and 140-kD proteins and was common in children but seemed to be associated with malignancy in adults; and an autoantibody to a small ubiquitin-like modifier--activating enzyme associated with dermatomyositis and interstitial lung disease. These findings have significant clinical implications and suggest promising areas of further research.