Anti-OJ Antibodies

SARDs are a heterogeneous group of disorders characterized by dysregulation of the immune system, that starts to turn against the body’s own tissues. Major SARDs include systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis and Sjögren’s syndrome. These diseases can affect multiple organs and share common symptoms such as fatigue, fever, joint pain and skin rash. Diagnosis relies on a combination of clinical assessment and specific autoantibody tests. Early diagnosis is crucial to initiate appropriate therapy and slow down disease progression.

Anti-OJ autoantibodies against isoleucyl-tRNA synthetase are part of the aminoacyl-tRNA synthetase family and are one of the eight anti-synthetase autoantibodies (ASA) associated with myositis. These autoantibodies are linked to anti-synthetase syndrome, a condition characterised by interstitial lung disease (ILD), Raynaud’s phenomenon, “mechanic’s hands,” non-erosive arthritis, fever, and occasionally skin rash. The presence of ASA has generally been associated with a better ILD treatment response compared to ILD in myositis patients without ASA. Therefore, their serological detection is highly relevant for identifying different clinical phenotypes, stratifying prognosis and guiding therapeutic management.