Reliability and clinical utility of Enzyme-linked immunosorbent assay for detection of anti-aminoacyl-tRNA synthetase antibody

Abstract

Anti-aminoacyl-tRNA synthetase (ARS) antibody is one of the myositis-specific autoantibodies to make a diagnosis of polymyositis (PM) and dermatomyositis (DM). Recently a new enzyme-linked immunosorbent assay (ELISA) kit of concurrently detected anti-ARS antibodies (anti-Jo-1, anti-PL-7, anti-PL-12, anti-EJ and anti-KS) have become to measure in the clinical setting. To evaluate the reliability of this ELISA kit, we measured anti-ARS antibodies in 75 PM and DM patients using by this ELISA assay and compared them with the results by RNA immunoprecipitation assay. Between the measurements of anti-PL-7, anti-PL-12, anti-EJ and anti-KS autoantibodies by ELISA assay and RNA-IP assay, the concordance rate of reproducibility is 95.1% and the positive agreement rate is 90.9% and negative agreement rate is 96.0% and kappa statistic is 0.841. Between the measurements of existing anti-Jo-1 antibody ELISA kit and anti-ARS antibody ELISA kit, the concordance rate of reproducibility is 96.9%, the positive agreement rate is 100%, negative agreement rate is 96.1% and kappa statistic is 0.909. The lung involvement in patients with PM and DM patients are positive of anti-ARS antibodies and anti-melanoma differentiation associated gene5 (MDA5) antibody at a rate around 70%. Then most life-threatening ILD with anti-MDA5 positive clinically amyopathic dermatomyositis patients could be highly guessed when anti-ARS antibodies are negative.

Bench to bedside review of myositis autoantibodies

“…Anti-Jo-1 is the only autoantibody routinely tested as widely available in most commercial ENA screening assays. An ELISA screening test has been recently developed to identify ARS, with high sensibility and specificity if compared to IP [ 26 ] and some commercially available IBs can identify some non-Jo-1 anti-synthetase antibodies [ 20 , 25 ].…”

Recent Advances in Research Regarding Autoantibodies in Connective Tissue Diseases and Related Disorders

“…High-resolution computed tomography (HRCT) of ILD with anti-MDA5 tends to show intralobular reticular opacities and the predominance of consolidation or ground-glass attenuation (GGA) in the lower lung fields, as well as random GGA patterns (85). In Japan, an ELISA for anti-MDA5 has been established since 2016 and is recognized as a useful assay for detecting anti-MDA5 for the earlier initiation of intensive immunosuppression therapies (60,86). We recently found that some anti-MDA5 antibody-positive patients had a novel antibody to splicing factor proline/glutamine-rich protein (SFPQ), which is known to play a role in innate immune responses (87).…”