Antisynthetase syndrome (ASSD) is a rare clinical condition that is characterized by the occurrence of a classic clinical triad, encompassing myositis, arthritis, and interstitial lung disease (ILD), along with specific autoantibodies that are addressed to different aminoacyl tRNA synthetases (ARS). Until now, it has been unknown whether the presence of a different ARS might affect the clinical presentation, evolution, and outcome of ASSD. In this study, we retrospectively recorded the time of onset, characteristics, clustering of triad findings, and survival of 828 ASSD patients (593 anti-Jo1, 95 anti-PL7, 84 anti-PL12, 38 anti-EJ, and 18 anti-OJ), referring to AENEAS (American and European NEtwork of Antisynthetase Syndrome) collaborative group’s cohort. Comparisons were performed first between all ARS cases and then, in the case of significance, while using anti-Jo1 positive patients as the reference group. The characteristics of triad findings were similar and the onset mainly began with a single triad finding in all groups despite some differences in overall prevalence. The “ex-novo” occurrence of triad findings was only reduced in the anti-PL12-positive cohort, however, it occurred in a clinically relevant percentage of patients (30%). Moreover, survival was not influenced by the underlying anti-aminoacyl tRNA synthetase antibodies’ positivity, which confirmed that antisynthetase syndrome is a heterogeneous condition and that antibody specificity only partially influences the clinical presentation and evolution of this condition.

We report a case of a 45-year-old man with an 8-month history of rheumatoid arthritis, who was treated with hydroxychloroquine 400 mg per day and 15 mg intramuscular methotrexate per week without reaching a good control of the disease. The patient was successfully treated with 3 mg/kg infliximab for 20 weeks. Before the last infusion, drug-induced lupus (DIL) was diagnosed based on the clinical features of fever > 37.5°C, recurrence of active synovitis, myalgia, erythematosus rash, pericardial and pleural effusion, and of some laboratory findings (antinuclear antibodies 1:160 and anti double-strand DNA positive by DNA recombinant plasmid assay dsDNA). After infliximab discontinuation and the beginning of therapy with methylprednisolone, lupus symptoms resolved within 6 weeks. A new rheumatoid arthritis flare, occurring after 8 weeks, was controlled by methotrexate plus leflunomide. We also review the development of antinuclear and antidouble-strand DNA antibodies and drug-induced lupus in patients treated with anti-TNFα agents (infliximab, etanercept, and adalimumab).