PLoS ONE (Jan 2014)

The multicenter study of a new assay for simultaneous detection of multiple anti-aminoacyl-tRNA synthetases in myositis and interstitial pneumonia.

  • Ran Nakashima,
  • Yoshitaka Imura,
  • Yuji Hosono,
  • Minae Seto,
  • Akihiro Murakami,
  • Kizuku Watanabe,
  • Tomohiro Handa,
  • Michiaki Mishima,
  • Michito Hirakata,
  • Tsutomu Takeuchi,
  • Keishi Fujio,
  • Kazuhiko Yamamoto,
  • Hitoshi Kohsaka,
  • Yoshinari Takasaki,
  • Noriyuki Enomoto,
  • Takafumi Suda,
  • Kingo Chida,
  • Shu Hisata,
  • Toshihiro Nukiwa,
  • Tsuneyo Mimori

DOI
https://doi.org/10.1371/journal.pone.0085062
Journal volume & issue
Vol. 9, no. 1
p. e85062

Abstract

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OBJECTIVE: Autoantibodies to aminoacyl-tRNA synthetases (ARSs) are useful in the diagnosis of idiopathic inflammatory myopathy (IIM) with interstitial pneumonia (IP). We developed an enzyme-linked immunosorbent assay (ELISA) system using a mixture of recombinant ARS antigens and tested its utility in a multicenter study. METHODS: We prepared six recombinant ARSs: GST-Jo-1, His-PL-12, His-EJ and GST-KS expressed in Escherichia coli, and His-PL-7 and His-OJ expressed in Hi-5 cells. After confirming their antigenic activity, with the exception of His-OJ, we developed our ELISA system in which the five recombinant ARSs (without His-OJ) were mixed. Efficiency was confirmed using the sera from 526 Japanese patients with connective tissue disease (CTD) (IIM n = 250, systemic lupus erythematosus n = 91, systemic sclerosis n = 70, rheumatoid arthritis n = 75, Sjögren's syndrome n = 27 and other diseases n = 13), 168 with idiopathic interstitial pneumonia (IIP) and 30 healthy controls collected from eight institutes. IIPs were classified into two groups; idiopathic pulmonary fibrosis (IPF) (n = 38) and non-IPF (n = 130). RESULTS were compared with those of RNA immunoprecipitation. RESULTS: Sensitivity and specificity of the ELISA were 97.1% and 99.8%, respectively when compared with the RNA immunoprecipitation assay. Anti-ARS antibodies were detected in 30.8% of IIM, 2.5% of non-myositis CTD, and 10.7% of IIP (5.3% of IPF and 12.3% of non-IPF). Anti-ARS-positive non-IPF patients were younger and more frequently treated with glucocorticoids and/or immunosuppressants than anti-ARS-negative patients. CONCLUSION: A newly established ELISA detected anti-ARS antibodies as efficiently as RNA immunoprecipitation. This system will enable easier and wider use in the detection of anti-ARS antibodies in patients with IIM and IIP.