Unusually high frequency of autoantibodies to PL‐7 associated with milder muscle disease in Japanese patients with polymyositis/dermatomyositis

Abstract

Objective. Autoantibodies to aminoacyl transfer RNA synthetases, such as histidyl (Jo-1), threonyl (PL-7), alanyl (PL-12), glycyl (EJ), and isoleucyl (OJ), are closely associated with a subset of patients with polymyositis/dermatomyositis (PM/DM) complicated by interstitial lung disease (ILD). Anti-Jo-1 is by far the most common, found in 15-25% of patients with PM/ DM, whereas the other types are found in only ϳ3% of these patients. In this study, the clinical associations of these autoantibodies in Japanese patients with PM/DM were investigated.Methods. The diagnoses of PM/DM and amyopathic DM (ADM) were based on the Bohan and Peter criteria and Sontheimer's definition, respectively. Sera from 36 Japanese patients with PM/DM (13 with PM, 20 with DM, 3 with ADM) were screened by immunoprecipitation and by enzyme-linked immunosorbent assay (for Jo-1). Clinical and laboratory data were collected.Results. The frequencies of autoantibodies to Jo-1 (22%) and to EJ, OJ, and PL-12 (3-6%) were similar to those found in previous studies, including studies of Japanese subjects. However, anti-PL-7 was found in 17% of patients, in contrast to a frequency of 1-4% in previous studies (P < 0.02-0.0002). The 6 anti-PL-7-positive patients were not related, and no skewing in year or month of disease development, place of residence or work, or occupation was found. All patients had ILD, consistent with the clinical features of antisynthetase-positive patients. The patients with anti-PL-7 had lower serum muscle enzyme levels and milder muscle weakness (P < 0.05) compared with anti-Jo-1-positive patients.Conclusion. Anti-PL-7 was found at an unusually high frequency in this group of Japanese patients with myositis. Although anti-PL-7, similar to anti-Jo-1, is associated with PM/DM with ILD, muscle involvement in the patients with anti-PL-7 appeared to be milder than that in the anti-Jo-1 subset.

Antisynthetase syndrome positive for anti-threonyl-tRNA synthetase (anti-PL7) antibodies

“…Although these results should be interpreted carefully since our study is retrospective, the high prevalence of ILD and low prevalence of other symptoms is in agreement with observations from previous anti-PL7 series [2][3][4].…”

“…Several antisynthetase antibodies [1] have been described, with anti-Jo1 being the most common. Little is known about the clinical manifestations of ASS associated with anti-threonyl-tRNA synthetase antibodies (anti-PL7) [2][3][4], most probably because anti-PL7 antibodies are particularly rare (5% of myositis [5]) and have not been routinely researched in the past.…”

“…the type of diet, could also play some role. The Mediterranean diet, rich in olive oil and fish, is protective against the MetS [2][3][4], but no study has examined the association of MetS and OSA in Mediterranean countries. We hypothesised that prevalence of the MetS might be lower in OSA patients living in the Mediterranean area compared with the prevalence values found in non-Mediterranean countries.…”

Pulmonary hypertension in antisynthetase syndrome: prevalence, aetiology and survival

“…Aside from myositis and ILD, other unspecific symptoms are quite commonly reported in ASS and include arthritis, mechanic's hands and Raynaud's phenomenon. Associated symptoms of Sjögren's syndrome or systemic sclerosis (SSc) have also been reported in different proportions [1][2][3][4].…”

Antisynthetase syndrome

“…Patients with anti-PL7 autoantibodies may also show different clinical features when compared to Jo-1 positives. Anti-PL-7 autoantibodies have been associated with milder muscle weakness (46) and almost all patients reported have had ILD (46;47). Seven patients with anti-OJ autoantibodies were described by Sato et al (48) of whom all had ILD, and four presented muscle weakness and polyarthritis.…”