The Antisynthetase Syndrome"

Antisynthetase syndrome (ASSD) is a rare connective tissue disease (CTD) referring to myositis spectrum disorders (MSDs). The anti-aminoacyl-tRNA synthetase antibodies (anti-ARS) are the serological biomarkers of the disease, and they seem to play a pathogenic role. The most common anti-ARS are the anti-Jo1 antibodies, reported in up to 70% of cases, whereas other specificities are less commonly detected. The concomitant positivity for anti-Ro52 antibodies is not rare. From the clinical point of view, the disease is characterized by the occurrence of the classic triad arthritis, myositis, and interstitial lung disease (ILD), and by the occurrence of manifestations such as the Raynaud’s phenomenon (RP), fever, and mechanic’s hand/hiker’s feet (MH/HF). For practical purposes, these latter are defined as accompanying findings. The temporally heterogeneous presentation of the different findings is typical of ASSD and represents a burden for the correct classification of these patients. With respect to the other MSDs, the association of ASSD with cancer risk is reduced. ILD is the main prognostic factor of ASSD in terms of survival, whereas joint, muscle, and skin involvement impair generally the prognosis quoad functionem of affected patients, although data regarding this aspect are scanty. Immunosuppression is the mainstay of the therapy, and it is based on agents such as calcineurin inhibitors (cyclosporine, tacrolimus), mycophenolate mofetil, azathioprine, cyclophosphamide, and rituximab, generally associated with corticosteroids, although other approaches are possible, including antifibrotic agents for ILD.