Objective: To clarify the association of clinical and prognostic features with dermatomyositis (DM)-specific autoantibodies (Abs) in adult Japanese patients with DM. Design: Retrospective study. Setting: Kanazawa University Graduate School of Medical Science Department of Dermatology and collaborating medical centers. Patients: A total of 376 consecutive adult Japanese patients with DM who visited our hospital or collaborating medical centers between 2003 and 2008. Main Outcome Measures: Clinical and laboratory characteristics of adult Japanese patients with DM and DMspecific Abs that include Abs against Mi-2, 155/140, and CADM-140. Results: In patients with DM, anti-Mi-2, anti-155/140, and anti-CADM-140 were detected in 9 (2%), 25 (7%), and 43 (11%), respectively. These DM-specific Abs were mutually exclusive and were detected in none of 34 patients with polymyositis, 326 with systemic sclerosis, and 97 with systemic lupus erythematosus. Anti-Mi-2 was associated with classical DM without interstitial lung disease or malignancy, whereas anti-155/140 was associated with malignancy. Patients with anti-CADM-140 frequently had clinically amyopathic DM and rapidly progressive interstitial lung disease. Cumulative survival rates were more favorable in patients with anti-Mi-2 compared with those with anti-155/140 or anti-CADM-140 (P < .01 for both comparisons). Nearly all deaths occurred within 1 year after diagnosis in patients with anti-CADM-140. Conclusion: Dermatomyositis-specific Abs define clinically distinct subsets and are useful for predicting clinical outcomes in patients with DM.
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