Clinical Utility of an Enzyme-Linked Immunosorbent Assay for Detecting Anti-Melanoma Differentiation-Associated Gene 5 Autoantibodies

PLoS One. 2016 Apr 26;11(4):e0154285. doi: 10.1371/journal.pone.0154285. eCollection 2016.

Abstract

Objective: Autoantibodies to melanoma differentiation-associated gene 5 (MDA5) are specifically expressed in patients with dermatomyositis (DM) and are associated with a subset of DM patients with rapidly progressive interstitial lung disease (RP-ILD). Here, we examined the clinical utility of a newly developed enzyme-linked immunosorbent assay (ELISA) system for detecting these antibodies.

Methods: Here we developed an improved ELISA for detecting anti-MDA5 antibodies. We then performed a multicenter clinical study involving 8 medical centers and enrolled 242 adult patients with polymyositis (PM)/DM, 190 with non-PM/DM connective tissue disease (CTD), 154 with idiopathic interstitial pneumonia (IIP), and 123 healthy controls. Anti-MDA5 antibodies in the patients' serum samples were quantified using our newly developed ELISA, and the results were compared to those obtained using the gold-standard immunoprecipitation (IP) assay. In addition, correlations between the ELISA-quantified anti-MDA5 antibodies and clinical characteristics were evaluated.

Results: In patients with PM/DM, the anti-MDA5 antibody measurements obtained from the ELISA and IP assay were highly concordant; the ELISA exhibited an analytical sensitivity of 98.2%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 99.5% (compared to the IP assay). Anti-MDA5 antibodies were detected in 22.7% of the DM patients, but not in any of the patients with PM, non-PM/DM CTD, or IIP. Clinically amyopathic DM, RP-ILD, arthritis, and fever were more prevalent in DM patients who were anti-MDA5 antibody-positive than in those who were antibody-negative (P ≤ 0.0002 for all comparisons). In addition, anti-MDA5 antibody-positive patients with RP-ILD exhibited higher antibody levels than those without RP-ILD (P = 0.006).

Conclusion: Our newly developed ELISA can detect anti-MDA5 antibodies as efficiently as the gold standard IP assay and has the potential to facilitate the routine clinical measurement of anti-MDA5 antibodies in patients who suspected to have DM.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Autoantibodies / blood*
  • Case-Control Studies
  • Connective Tissue Diseases / blood
  • Connective Tissue Diseases / diagnosis*
  • Connective Tissue Diseases / immunology
  • Dermatomyositis / blood
  • Dermatomyositis / diagnosis*
  • Dermatomyositis / immunology
  • Diagnosis, Differential
  • Enzyme-Linked Immunosorbent Assay / standards*
  • Female
  • Gene Expression
  • Humans
  • Idiopathic Interstitial Pneumonias / blood
  • Idiopathic Interstitial Pneumonias / diagnosis*
  • Idiopathic Interstitial Pneumonias / immunology
  • Immunoprecipitation
  • Interferon-Induced Helicase, IFIH1 / antagonists & inhibitors
  • Interferon-Induced Helicase, IFIH1 / genetics
  • Interferon-Induced Helicase, IFIH1 / immunology*
  • Male
  • Middle Aged
  • Polymyositis / blood
  • Polymyositis / diagnosis*
  • Polymyositis / immunology
  • Sensitivity and Specificity

Substances

  • Autoantibodies
  • IFIH1 protein, human
  • Interferon-Induced Helicase, IFIH1

Grants and funding

This work was supported by a research grant on intractable diseases from the Japanese Ministry of Health, Labor, and Welfare. The funder had no role in the study design, data collection and analysis, decision to publish, or manuscript preparation.