Histidyl-tRNA synthetase (HisRS, Jo-1) is an aminoacyl-tRNA synthetase that charges transfer RNAs (tRNAs) with a cognate histidine residue to produce histidyl-tRNA. Histidyl-tRNA is essential for the incorporation of histidine into proteins. Systemic autoimmune diseases lead to aminoacyl-tRNA synthetase autoantibodies that are directed against self structures. HisRS is an antigen in systemic autoimmune diseases such as rheumatic arthritis or polymyositis with associated interstitial lung disease, thrombocytopenia and Raynaud