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Anti-Zo antibodies in Japanese myositis patients detected by a newly developed ELISA
Y. Muro1, T. Hashimoto2, S. Izumi3, M. Ogawa-Momohara4, T. Takeichi5, H. Yamashita6, H. Yasuoka7, M. Akiyama8
- Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan. ymuro@med.nagoya-u.ac.jp
- Division of Rheumatology, Department of Internal Medicine, Fujita Health University School of Medicine, Toyoake, Japan.
- Department of Respiratory Medicine, National Centre for Global Health and Medicine, Shinjuku, Tokyo, Japan.
- Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
- Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
- Division of Rheumatic Diseases, National Centre for Global Health and Medicine, Shinjuku, Tokyo, Japan.
- Division of Rheumatology, Department of Internal Medicine, Fujita Health University School of Medicine, Toyoake, Japan.
- Department of Dermatology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
CER13719
2022 Vol.40, N°2
PI 0219, PF 0223
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PMID: 33124571 [PubMed]
Received: 22/06/2020
Accepted : 07/09/2020
In Press: 09/10/2020
Published: 25/02/2022
Abstract
OBJECTIVES:
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.
CONCLUSIONS:
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.
