FRI0251 COMBINATION OF COMPUTED TOMOGRAPHY SCAN AND SERUM MYOSITIS SPECIFIC/ASSOCIATED AUTOANTIBODIES HELPS EARLY IDENTIFY AND TREAT PATIENTS WITH IPAF AND CTD-ILD
Authors: S. Lyu, H. C. Chen, T. S. H. Lee, Y. Li, C. J. Cho, F. C. Liu, C. Y. Cheng, S. J. Chu, S. Y. Kuo, D. M. Chang, C. C. Lu
Journal: Annals of the Rheumatic Diseases (2020)

Background: Interstitial lung diseases (ILD) could originate from idiopathic cause or secondary to connective tissue diseases (CTD). The most common causes of CTD associated ILD (CTD-ILD) include mixed connective tissue disease, systemic sclerosis (SSc), inflammatory myositis such as polymyositis (PM) and dermatomyositis (DM). Our preliminary data had demonstrated that ILD is not uncommon in patients with rheumatoid arthritis (RA) and Sjogren’s syndrome (SS) in Asia. Myositis-specific autoantibodies (MSAs) and myositis associate autoantibodies (MAAs) have been used for the early diagnosis of PM/DM and could be noticed in patients with idiopathic ILD. Our previous data also had identified that MSA/MAA were detected quite often in patients with CTD-ILD in addition to inflammatory myositis. Nonetheless, a specific group of ILD patients like interstitial pneumonia with autoimmune features (IPAF) are still challenging for pomologists, rheumatologist and radiologists, either in accurate diagnosis or treatment. Objectives: We aimed to identify the prevalence of serum MSA/MAAs and clinical diagnosis on imaging in patients with IPAF and CTD-ILD and define the correlation between MSA/MAA and clinical imaging features. Methods: Patients who had been suspected with autoimmune rheumatic diseases in the presence of interstitial lung diseases were included in this prospective study at a single medical center in Taiwan between February 2018 and November 2019. All enrolled patients had experienced clinical symptoms of ILD and been identified abnormalities on the chest plain films. All patients were inspected by both pulmonologists and rheumatologist. Computed tomography scans of chest had been reviewed by at least two pulmonary radiologists. Serological immunotherapy strips were performed to detect MSA/MAAs. Correlation analysis was performed among the different collected variables. Results: 870 patients were reviewed by both pulmonologists and rheumatologists and received blood sampling including autoantibody profiling and MSA/MAA tests. The clinical diagnosis of CTD-ILD or IPAF were confirmed in 603 patients, who received 1078 chest CT scan due to clinically suspected CTD-ILD or IPAF. 33 patients received lung biopsies since other CTD-ILD or IPAF patients hesitate to receive invasive procedures. 78 patients had been admitted to intensive care units and received mechanical ventilation and were not suitable for lung biopsies. 22 of 33 patients received more than twice lung biopsies due to challenging diagnosis. 6 patients with CTD-ILD or IPAF had received extracorporeal membrane oxygenation (ECMO) due to ILD with secondary pulmonary infection and acute respiratory distress syndrome. The most commom detected MSA/MAA were anti-Ro-52 (27%), followed by anti-Ku (3.9%), and anti-Mi-2 (3.6%). SS is the most common rheumatic disease in patients with CTD-ILD. MSA/MAAs were identified in patients with IPAF (36.4 %) in the absence of specific rheumatic diseases. Anti-nuclear antibody (27.4%), rheumatoid factor immunoglobulin M (21.6%) and anti-Ro (13.7%) were the most common autoantibodies identified in patients with IPAF. Anti-Ro-52 was positively corelated with nonspecific interstitial pneumonia in patients with CTD-ILD or IPAF, Phi= 0.371 and 0.326, both p &lt; 0.001, respectively. Conclusion: Early diagnosis of CTD-ILD and IPAF is still challenging for both pulmonologists, rheumatologists and radiologists. Identifying how serum MSA/MAAs contribute clinical manifestations on chest CT imaging is warranted and help clinical physicians and patients recognize the necessity of lung biopsy to reduce comorbidity. References: [1]Jee AS, et al. J Clin Med 2017 [2]Wilfong EM, et al. Arthritis Rheumatol 2018 [3]Sambataro G, et al. Eur Respir Rev 2018 Disclosure of Interests: None declared