Anti-aminoacyl tRNA synthetase antibodies showing the discrepancy between enzyme-linked immunosorbent assay and RNA-immunoprecipitation

• Published in: Immunological medicine Vol. 47; no. 3; pp. 166 - 175
• Main Authors: Sasai, Tsuneo, Ishikawa, Yuki, Nakashima, Ran, Isayama, Takuya, Tanizawa, Kiminobu, Handa, Tomohiro, Shirakashi, Mirei, Hiwa, Ryosuke, Tsuji, Hideaki, Kitagori, Koji, Akizuki, Shuji, Yoshifuji, Hajime, Mimori, Tsuneyo, Morinobu, Akio
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis Group 01.09.2024
• Subjects: Adult; Aged; Amino Acyl-tRNA Synthetases - immunology; Anti-aminoacyl tRNA synthetase antibody; anti-synthetase syndrome; Autoantibodies - blood; dermatomyositis; Enzyme-Linked Immunosorbent Assay; Female; Humans; Immunoprecipitation - methods; interstitial lung disease; Lung Diseases, Interstitial - diagnosis; Lung Diseases, Interstitial - immunology; Male; Middle Aged; Myositis - diagnosis; Myositis - immunology; RNA; dermatomyositis; anti-synthetase syndrome; interstitial lung disease; Anti-aminoacyl tRNA synthetase antibody
• ISSN: 2578-5826; 2578-5826
• DOI: 10.1080/25785826.2024.2328918

Anti-aminoacyl-tRNA synthetase (ARS) antibodies are myositis-specific antibodies associated with anti-synthetase syndrome (ASSD). Some patients are positive for anti-ARS antibodies on enzyme-linked immunosorbent assay (ELISA) but negative on RNA-immunoprecipitation (RNA-IP) (the gold standard method). Whether these patients should be considered truly positive for anti-ARS antibodies remains unclear. Therefore, we investigated the clinical characteristics of these patients and verified the authenticity of their anti-ARS positivity. Patients who were positive for anti-ARS antibodies on ELISA were divided into the non-discrepant (positive on RNA-IP,  = 52) and discrepant (negative on RNA-IP,  = 8) groups. Patient clinical characteristics were compared between the groups. For each positive individual, the authenticity of anti-ARS antibody positivity on ELISA was cross-examined using protein-IP and western blotting. All patients in the discrepant group had lung involvement, including five (63%) with interstitial lung disease. The overall survival time was significantly lower in the discrepant group than in the non-discrepant group (  < 0.05). Validation tests confirmed the presence of anti-ARS antibodies in the sera of the discrepant group but indicated different reactivity from typical anti-ARS antibodies. In conclusion, some anti-ARS antibodies are detected by ELISA but not RNA-IP. Such anti-ARS antibody discrepancies need further elucidation to attain validation of the diagnostic process in ASSD.