Clinical features of anti-synthetase syndrome associated interstitial lung disease: a retrospective cohort in China

Abstract

Background: Anti-synthetase syndrome (ASSD) is a chronic autoimmune condition characterized by antibodies directed against an aminoacycl transfer RNA synthetase (ARS) along with a group of clinical features including the classical clinical triad: inflammatory myopathy, arthritis, and interstitial lung disease (ILD). ASSD is highly heterogenous due to different organ involvement, and ILD is the main cause of mortality and function loss, which presents as different patterns when diagnosed. We designed this retrospective cohort to describe the clinical features and disease behaviour of ASSD associated ILD. Methods: Data of ASSD associated ILD were retrospectively collected in Beijing Chaoyang Hospital from 2017.12 to 2019.3. Data were obtained from the Electronic Medical Record (EMR) system. Patients were divided into 5 groups according to distinct aminoacyl tRNA synthetase (ARS) antibodies. Results: 108 consecutive patients were recruited. 33 were JO-1 positive,30 were PL-7 positive,23 were EJ positive, 13 were PL12 positive and 9 were OJ positive. The JO-1 group had a significant higher rate of mechanic's hand (57.6%) than other 4 groups. Polymyositis/ dermatomyositis (PM/DM) was diagnosed in 25 (23.1%) patients and no difference was observed among the 5 groups. The PL7 group had a higher frequency of UIP pattern (13.3%) than the other 4 groups but the difference was not significant, and the EJ group had the most frequent OP pattern(78.2%), which was significantly higher than PL7 (P<0.001) and PL12 groups (P=0.025). The median follow-up time was 10.7 months. All received prednisone treatment, with or without immunosuppressants. At 6-month-follow up, 96.3% (104/108) had a positive response to therapy, the JO1 and EJ groups had a significantly higher improvement of forced vital capacity (FVC) than the other 3 groups (P<0.05), and PL-7 group had the lowest FVC improvement (P<0.05). The JO1 and EJ groups had significantly higher anti-RO52-positive occurrence than the other 3 groups (P<0.05). Conclusion: Anti PL-7 antibody had the same frequency as anti-JO1 in ASSD-ILD, while the ILD pattern was different with distinct anti-ARS antibodies. Most ASSD-ILD had a positive response to steroids, with or without immunosuppressants. The PL-7 group had the highest occurrence of UIP pattern, and a significantly lower response to therapy.