Anti-Zo antibodies in Japanese myositis patients detected by a newly developed ELISA

Yoshinao Muro, Takako Hashimoto, Shinyu Izumi, Mariko Ogawa-Momohara, Takuya Takeichi, Hiroyuki Yamashita, Hidekata Yasuoka, Masashi Akiyama

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


Objective The myositis-specific autoantibodies that characterise certain forms of idiopathic inflammatory myopathy (IIM) are useful for diagnosing dermatomyositis (DM) / polymyositis (PM) and predicting its prognosis. The autoantibody to phenylalanyl-tRNA synthetase (anti-Zo) has been identified as a disease marker antibody for anti-synthetase syndrome only in a UK cohort. Here we aim to establish an ELISA for the measurement of anti-Zo and to characterise the clinical features of Japanese patients who have this autoantibody. Methods Anti-Zo was investigated by immunoprecipitation with recombinant phenylalanyl-tRNA synthetase α/β proteins. The results were confirmed by immunoprecipitation-Western blotting with cell extract. Sera from patients with DM/PM (n=224) were screened by an ELISA with the recombinant proteins. Medical records were retrospectively reviewed to obtain detailed information on the clinical phenotypes of the anti-Zo-positive patients. Results Only two male patients were confirmed to have anti-Zo. Both patients had fever, myopathy, interstitial lung disease, and mechanic’s hands, and these clinical features are consistent with those of anti-synthetase syndrome. Another patient’s serum showed a higher level than the cut-off value for anti-phenylalanyl-tRNA synthetase α by our in-house ELISA, but was judged to be negative for anti-Zo by immunoprecipitation-Western blotting. Conclusion This is the first report of anti-Zo-positive IIM patients from Asia. Although Japanese patients with anti-Zo have a clinical phenotype similar to that of Caucasian patients, further large cohort studies are necessary to confirm the frequency of anti-Zo in Japanese IIM patients. Our newly developed ELISA should be validated for sensitivity and specificity in large cohorts.

Original languageEnglish
Pages (from-to)219-223
Number of pages5
JournalClinical and Experimental Rheumatology
Issue number2
Publication statusPublished - 2022

All Science Journal Classification (ASJC) codes

  • Rheumatology
  • Immunology and Allergy
  • Immunology


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