Study data published in the Journal of Dermatology outline the unique clinical features of dermatomyositis positive for anti-aminoacyl tRNA synthetase (ARS) antibodies, also known as antisynthetase syndrome (ASS). ASS was associated with increased incidence of interstitial lung disease, psoriasiform tissue reaction in the hand lesions, and fasciitis-dominant myopathy, among other characteristics.

The present study enrolled 59 patients with dermatomyositis in Okayama, Japan. Using enzyme-linked immunosorbent assay (ELISA), serum samples from 48 enrollees were screened for five anti-ARS antibodies: Jo-1, PL-7, PL-12, EJ, and KS. Serum levels of TIF1-c, MDA5, and Mi-2 were also assessed. Patients positive for any anti-ARS antibodies were considered to have ASS; patients positive for one of the other myositis-specific antibodies were classified as non-ASS. Clinical examinations were performed to assess characteristics of the cutaneous, muscular, and pulmonary manifestations of ASS. Medical interviews were carried out with each patient to capture family history.

Among the 59 patients, 20 (33.9%) were positive for one anti-ARS antibody and classified as having ASS. In addition, 21 patients were positive for myositis-specific antibodies (non-ASS group); 15 patients had no ELISA-detected antibodies (antibody-negative group); and 3 patients did not have a full ELISA profile (unknown group). A greater percentage of patients in the ASS group (31%) indicated having a family history of collagen disease compared with the non-ASS group (0%; P =.018). Mechanic’s hands were frequently observed in the ASS group, and 9 of 11 (82%) finger lesion samples displayed a psoriasiform tissue reaction. Compared with the non-ASS group, patients with ASS more frequently had fever (odds ratio [OR], 8.87; 95% CI, 1.36-103.87; P =.0095), arthralgia/arthritis (OR, 4.15; 95% CI, 0.91-21.53; P =.05), and elevated serum C-reactive protein levels (OR, 12.29; 95% CI, 2.35-91.16; P =.00054). The incidence of interstitial lung disease was significantly higher in the ASS group than in the non-ASS group (OR, 23.80; 95% CI, 2.70-1172.96; P =.00043). In patients in the non-ASS group, a greater prevalence of interstitial lung disease was observed in patients positive for the anti-MDA5 antibody. Compared with the non-ASS group, patients with ASS had higher serum levels of muscle enzymes, including CK (P =.0026), ALD (P =.0000095) and Mb (P =.0094). Fasciitis-dominant myopathy was present in 4 of 12 (33%) patients with ASS, compared with just 1 of 11 (9%) patients without ASS.

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These data highlight several distinct characteristics associated with ASS, including psoriasiform tissue reaction in the hand lesions and fasciitis-dominant myopathy. Additionally, the relatives of patients with ASS appeared to be at higher risk for collagen disease. The generalizability of these findings is limited by the small sample size, and further research in a larger cohort is necessary to expand the knowledge of ASS characteristics. “The present study confirmed that patients with anti-ARS antibody form a distinct clinical subtype of dermatomyositis characterized by the presence of [interstitial lung disease] and systemic symptoms such as fever and arthralgia,” the authors wrote.

Disclosure: The ELISA assay kits used in this study were provided by Medical & Biological Laboratories (Nagoya, Japan). Please see the original reference for a full list of authors’ disclosures.

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Reference

Fukamatsu H, Hirai Y, Miyake T, et al. Clinical manifestations of skin, lung and muscle diseases in dermatomyositis positive for anti-aminoacyl tRNA synthetase antibodies. J Dermatol. 2019;46(10):886-897.