A Comparison of Line Blots, Enzyme-linked Immunosorbent, and RNA-immunoprecipitation Assays of Antisynthetase Antibodies in Serum Samples from 44 Patients

• Shinoda Koichiro

  First Department of Internal Medicine, University of Toyama, Japan

• Okumura Maiko

  First Department of Internal Medicine, University of Toyama, Japan

• Yamaguchi Satoshi

  First Department of Internal Medicine, University of Toyama, Japan

• Matsui Atsushi

  First Department of Internal Medicine, University of Toyama, Japan

• Tsuda Reina

  First Department of Internal Medicine, University of Toyama, Japan

• Hounoki Hiroyuki

  First Department of Internal Medicine, University of Toyama, Japan

• Suzuki Shigeaki

  Department of Neurology, Keio University School of Medicine, Japan

• Tobe Kazuyuki

  First Department of Internal Medicine, University of Toyama, Japan

Abstract

Objective To determine the differences between anti-aminoacyl tRNA synthetase (ARS) antibodies among line blots, enzyme-linked immunosorbent assay (ELISA) anti-ARS tests, and RNA-immunoprecipitation (IP) assays. Methods Sera from patients with confirmed or suspected antisynthetase syndrome (ASS) that were positive for either the anti-ARS test or the line-blot assay were used to perform an RNA-IP assay and ELISA to detect individual anti-ARS antibodies. Results Among the 44 patients, 10 were positive only in line-blot assays, 6 were positive only in the anti-ARS test, and 28 were positive in both assays. We compared the accuracy of these assays against the gold standard RNA-IP assay. The κ coefficient was 0.23 in the line-blot assay, but this increased to 0.75 when the cut-off was increased from 1+ to 2+. The κ coefficient was 0.73 in the anti-ARS test. The κ coefficient was 0.85 for positivity in both assays. Patients with ASS that was positive in an RNA-IP assay more frequently had mechanic's hand (62.1% vs. 20%: p=0.031), myositis (51.7 vs. 10%: p=0.028) and more ASS symptoms than those who were positive only in line-blot assays (3.48 vs. 2.2: p=0.019). Conclusions Clinicians need to understand the features of each assay and determine diagnoses by also considering clinical presentations. Diagnoses should not be judged based only on the results of line-blot assays due to the risk of a misdiagnosis from false positives.

Journal

• Internal Medicine

  Internal Medicine 61 (3), 313-322, 2022-02-01

  The Japanese Society of Internal Medicine

Keywords

• antisynthetase syndrome
• RNA-immunoprecipitation assay
• line-blot assay
• anti-synthetase enzyme-linked immunosorbent assay (anti-ARS test)

Details

• CRID: 1390853879727898240
• NII Article ID: 130008150353
• DOI: 10.2169/internalmedicine.7824-21
• ISSN: 13497235
• ISSN: 09182918
• Web Site: https://www.jstage.jst.go.jp/article/internalmedicine/61/3/61_7824-21/_pdf
• Web Site: https://search.jamas.or.jp/link/ui/2023054945
• Text Lang: en
• Data Source:
  • JaLC
  • Crossref
  • CiNii Articles
  • KAKEN
• Abstract License Flag: Disallowed