Although various autoantibodies have been found for the diagnosis of polymyositis/dermatomyositis (PM/DM), the clinical relevance of these antibodies has yet to be determined.

Patients with PM/DM were enrolled at Okayama University Hospital and antibody profiles were examined using a line immunoassay. Based on serological examination of anti-aminoacyl-tRNA synthetase (ARS) antibodies, including anti-Jo-1, PL-7, PL-12, EJ, OJ, and SS-A/Ro-52 antibodies, hierarchical cluster analysis was done. The proportions of clinical symptoms and relapses were compared between these groups. 


This research included 61 individuals, 28 of whom had PM and 33 of whom had DM. The three clusters identified were as follows: 1) anti-Jo-1 and anti-SS-A/Ro-52 antibodies were double positive (10/10, 100%); (n = 24), anti-SS-A/Ro-52 antibody positive (20/24, 83%), anti-Jo-1 antibody negative (24/24, 100%), and anti-ARS antibodies (excluding anti-Jo-1 antibody) positive (15/24, 63%); and 3 (n = 27), anti-Jo-1 and anti-SS-A/Ro52 antibodies double negative (26/27, 96%). Cluster 3 had a lower proportion of relapsed individuals than clusters 1 and 2 (risk ratio, 0.37; 95% confidence interval, 0.17-0.83; p = 0.026 and risk ratio, 0.42; 95% confidence interval, 0.20-0.89; P = 0.019, respectively). Clusters 1 and 2 had the same proportion of relapsed patients.

According to cluster analysis, anti-SS-A/Ro52 antibodies, or any anti-ARS antibodies, or both, may be important to clinical outcomes.