HARS also known as HisRS, HARS1 is a cytoplasmic enzyme which belongs to the class II family of aminoacyl-tRNA synthetases. HARS plays a crucial role in protein synthesis by charging transfer RNAs (tRNAs) with histidine, which is essential for the incorporation of this amino acid into proteins. Proper functioning of HARS ensures proteins are synthesized correctly, which is particularly important in maintaining cellular functions and overall organismal health. Dysregulation of HARS can lead to the production of autoantibodies in systemic autoimmune diseases, where the immune system mistakenly targets its own proteins. HARS is recognized as an antigen in conditions such as rheumatic arthritis and polymyositis, which can be associated with interstitial lung disease, thrombocytopenia, and Raynaud′s phenomenon, a condition characterized by vasospastic attacks that constrict blood vessels.