[Anti-synthetase syndrome treatment]

Anti-synthetase syndrome (ASS) is a systemic autoimmune disease associated with the presence of anti-aminoacyl tRNA synthetase antibodies, primarily anti-Jo1, PL7, and PL12. It may be limited to a single organ and involves the lungs in approximately 75% of cases. Pulmonary involvement and its severity determine both prognosis and treatment. Management relies on high-dose corticosteroid therapy, which is effective in inducing remission. Nevertheless, relapses occur in roughly 50% of cases with monotherapy by corticosteroid. The early addition of an immunosuppressant has demonstrated benefits in terms of survival and relapse reduction. The most commonly used immunosuppressants are azathioprine (AZA), mycophenolate mofetil (MMF), methotrexate (MTX), tacrolimus (TAC), rituximab (RTX), and cyclophosphamide (CYC). Chimeric Antigen Receptor T (CAR-T) cells and bispecific antibodies are promising innovative therapies. Antifibrotic drugs can be used in cases of progressive pulmonary fibrosis. However, there are currently no dedicated treatment guidelines for ASS, as available data are mainly derived from retrospective studies or extrapolated from clinical trials including patients with inflammatory myopathy or connective tissue disease-associated interstitial lung disease. This review aims to synthesize existing data on the efficacy and safety of treatments in ASS and to present an updated treatment algorithm.