Newly identified autoantibodies: relationship to idiopathic inflammatory myopathy subsets and pathogenesis.

PURPOSE OF REVIEW: There is increasing evidence that patients with polymyositis and dermatomyositis have specific clinico-serological profiles. Myositis-specific autoantibodies target intracellular proteins involved in key processes such as translocation and nuclear transcription, and are closely linked to patterns of disease expression. This review highlights the recent work on novel myositis-specific autoantibodies, their autoantigen targets, the relationship to clinical subsets and potential role in pathogenesis.

RECENT FINDINGS: During the annual review period novel autoantibodies have been described in adult-onset dermatomyositis (anti-SAE autoantibodies) and juvenile dermatomyositis (anti-p155/140 autoantibodies) (anti-MJ or anti-p140 autoantibodies). These findings are important because the function of the autoantigen targets may point to shared pathogenic pathways. Studies highlighting the potential role of autoantigen-driven responses and autoantibody production in disease initiation and propagation are discussed, as well as further evidence on the relationship between autoantigens and corresponding target tissues.

SUMMARY: Considerable progress has been made emphasizing the striking association between genotype, serotype and clinical phenotype in the myositis disease spectrum. Further characterization of the identity and function of autoantigen systems in target tissues will greatly facilitate investigation of models of autoimmunity in this disease.