**Background of Anti-CARS Antibodies**
Anti-CARS (anti-cysteinyl-tRNA synthetase) antibodies are a subset of autoantibodies targeting the enzyme cysteinyl-tRNA synthetase (CARS), part of the aminoacyl-tRNA synthetase (ARS) family. These enzymes are essential for protein synthesis, attaching specific amino acids to their corresponding tRNAs. Anti-CARS antibodies are primarily associated with autoimmune disorders, notably the anti-synthetase syndrome (ASS), which includes clinical manifestations like myositis, interstitial lung disease (ILD), arthritis, and skin rashes.
First identified in the 1980s, anti-CARS antibodies (alongside other anti-ARS antibodies like anti-Jo-1) serve as diagnostic biomarkers. Their presence aids in distinguishing ASS from other autoimmune conditions. CARS autoantibodies are detected via immunoprecipitation or enzyme-linked immunosorbent assay (ELISA) and correlate with specific disease phenotypes, such as severe ILD.
Research suggests molecular mimicry or environmental triggers (e.g., viral infections) may initiate autoimmunity against CARS. Despite their diagnostic utility, the exact pathogenic role of these antibodies remains unclear, though immune complex formation and interferon signaling are implicated. Current studies focus on improving detection methods and understanding their role in disease progression, guiding targeted therapies for ASS.