Clinical features of Anti-synthetase syndrome associated interstitial lung disease: a retrospective cohort in China
Authors: Zhan Xi , Wei YAN , Ying WANG , Qing LI , Xuhua SHI , Yanli GAO , Qiao YE 
Published: April 2020

Abstract
Background Antisynthetase 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, interstitial lung disease (ILD). ASSD is highly heterogenous due to the different organs 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 behavior of the ASSD) associated ILD. Methods Retrospectively collected the data of 108 cases of ASSD associated ILD in Beijing Chaoyang Hospital since 2017.12 to 2019.3. Data including age, gender, physical examination, laboratory test, pulmonary function and High Resolution Computer Tomography (HRCT), treatment, were obtained from the Electronic Medical Record (EMR) system. Patients were divided into 5 groups according to the distinct Aminoacyl tRNA synthetases (ARS) antibodies, and all patients had a multiple discussion team (MDT) to make a radiological and pathological diagnosis of the ILD pattern. Each patient had at least 1 follow up for no less than 6 months. Patients with missing data of MDT evaluation or follow up were excluded. Results: 108 consecutive patients were recruited in this retrospective cohort. 30 cases received bronchoscopy for a transbronchial lung biopsy. 3 had bronchoscopy for a transbronchial cryobiopsy. 33 were with JO-1 positive and 30 were with PL-7 positive. 23 with EJ positive, 13 with PL12 positive and 9 with OJ positive. JO-1 group had a significant higher rate of mechanic’s hand (57.6%) than other 4 groups, the skin involvement (Gottron Papules and/or Heliotrope Rash) was found in 38 (35%) and no difference was found among the 5 groups. Polymyositis/Dermatomyositis (PM/DM) was diagnosed in 25 (23.1%) patients and no difference was observed among the 5 groups. The anti-PL7 positive group had a higher frequency of UIP pattern (13.3%) than other 4 groups but the difference was not significant due to the small sample size, and EJ group had the most frequent OP pattern(78.2%), which was significantly higher than PL-7 group (P<0.001) and PL-12 group (P=0.025). The median follow-up time were 10.7 months. All received prednisone treatment, with or without immunosuppressants ,and at the 6-month-follow up, the JO-1 group and EJ group had the significantly higher improvement of forced vital capacity that the other 3 groups (P<0.05), and PL-7 group had the lowest FVC improvement (P<0.05). The anti-Jo1-positive group and anti-EJ-positive group had significantly higher anti-RO52-positive occurrence than other 3 groups (P<0.05).Conclusion Anti PL-7 antibody had the same frequency as anti-JO1 in ASSD-ILD, in which the ILD pattern was different with distinct anti-ARS antibodies. All ASSD-ILD responded to therapy of steroids, with or without immunosuppressants. PL-7 group had a highest occurrence of UIP pattern, and significantly lower respondence to therapy.