釜田 康行

Objective： To investigate the association between joint symptoms and related conditions in Japanese patientswith polymyositis（ PM） and dermatomyositis（ DM）.Methods： We retrospectively reviewed all patients with PM/DM who were admitted to our departmentfrom January 2007 to March 2012. Clinical data on these patients were retrieved from the medical records.Results： Seventy-eight patients （20 with PM and 58 with DM） were enrolled. Among them, 37 patients（47%）had arthralgia or arthritis. Joint symptoms were more frequent in DM than PM （53% vs. 30%,P=0.07）. Anti-aminoacyl tRNA antibodies （ASA） were positive in 25 patients （32%）, and anti-cyclic citrullinatedpeptide （CCP）antibody was positive in 7 patients （9%）. Patients with anti-Jo-1 antibody had a highfrequency of polyarthritis（ 82%）, while anti-CCP antibody was positive in 4 out of 11 patients with anti-Jo-1antibody （36%）. Among patients with joint symptoms, anti-Jo-1 antibody was positive in 67% of the patientswith PM, but was positive in only 16% of the patients with DM. Four of the 78 patients （5%） were initiallydiagnosed and treated as having rheumatoid arthritis. Multivariate analysis showed that fever, Raynaud'sphenomenon, and anti-Jo-1 antibody were associated with joint symptoms, whereas overall ASA positivityshowed no significant difference between patients with or without joint symptoms.Conclusion： Forty-seven percent of patients with PM/DM had joint symptoms. Except for anti-Jo-1 antibody,ASA were not associated with joint symptoms in Japanese PM/DM patients.