POS0870 CLINICAL CHARACTERIZATION OF PORTUGUESE PATIENTS WITH ANTISYNTHETASE SYNDROME
Authors: P. Martins, E. Dourado, A. T. Melo, B. Samões, M. Sousa, R. Freitas, M. H. Fernandes Lourenco, B. M. Fernandes, E. Costa, H. Parente, F. R. Martins, J. E. Fonseca, V. C. Romão, N. Khmelinskii, R. Campanilho-Marques, I. Cordeiro
Journal: Annals of the Rheumatic Diseases (2021)

Background: Antisynthetase syndrome (ASyS) may have different clinical phenotypes and outcomes associated with different anti-aminoacyl RNA-synthetase (anti-ARS) antibodies. Its wide clinical spectrum can include inflammatory myopathy, interstitial lung disease (ILD), arthritis, fever, mechanic’s hands, and Raynaud phenomenon (RP). Objectives: To describe a nationwide, multicentre cohort of Portuguese patients with ASyS. Methods: Retrospective analysis of patients with ASyS from nine Portuguese Rheumatology centers. Data on patients’ signs and symptoms, laboratory results, pulmonary radiological findings (computed tomography) and treatment (immunomodulators) were collected. Results: Among the 70 patients included, 42 patients (60%) were anti-Jo1–positive, 11 (15.7%) were anti-PL12–positive, 10 (14.3%) were anti-PL7–positive, 4 (5.7%) were anti-EJ–positive and 2 (2.9%) were anti-OJ positive. In one patient it was not possible to identify the type of antibody. Antibody overlap was found in 15 patients (21.4%), who were positive for anti-Ro52 antibodies. The general clinical characteristics are shown in Table 1. The diagnostic delay was greater in patients positive for anti-OJ, followed by anti-Jo-1 and anti-PL12. The follow-up was shorter for anti-PL7 and anti-OJ-positive patients. Anti-PL7-positive patients had lower rates of arthritis when compared to anti-Jo1 (p&lt; 0.01). When compared with anti-Jo-1 ARS, myositis was less common in anti-PL12 (p &lt; 0.01). ILD prevalence was similar in the different ARS subgroups. Glucocorticoids (GCs) were the most frequently used class of drugs. A more conservative treatment plan (e.g. GCs plus methotrexate or azathioprine) was the treatment of choice in ASyS with myositis and/or arthritis involvement. Rituximab or mycophenolate mofetil were preferred when lung involvement occurred. Only two deaths were reported, being one associated with lung neoplasia. Conclusion: This is the first study investigating the clinical phenotypes of Portuguese patients with ASyS. These results are generally concordant with data retrieved from international cohorts. References: [1]Mahler M, Miller FW, Fritzler MJ. Idiopathic inflammatory myopathies and the anti-synthetase syndrome: a comprehensive review. Autoimmun Rev 2014;13:367–71. Table 1. Patient characteristics according to the anti-ARS. ILD - interstitial lung disease; IQR- interquartile range; NSIP - Non-specific interstitial pneumonia; UIP - Usual interstitial pneumonia; yrs - years Variables Overall, n=70 Jo-1, n=42 (60% ) PL-12, n=11 (15.7% ) PL-7, n=10 (14.3% ) EJ, n=4 (5.7% ) OJ, n=2 (2.9% ) Mean age at onset, yrs 52 ± 15 46.6 ± 14.4 55.2 ± 14.7 56.5±12.5 56.3±11.2 73.5±2.1 Female, n (%) 49 (70) 29 (69) 9 (81.8) 7 (70) 2 (50) 2 (100) Median age in years at disease onset (IQR) 52 (15-75) 48 (15-70) 59 (20-70) 62 (39-73) 60 (40-65) 73.5 (72-75) Median follow-up time in yrs (IQR) 3 (0-32) 5 (0-32) 3 (0-13) 1 (1-4) 4 (2-21) 1 (0-2) Median diagnostic delay in yrs (IQR) 6 (1-33) 7 (1-33) 7 (2-19) 4 (1-23) 1.5 (1-2) 12.5 (2-21) Myositis, n (%) and Comparison Anti-Jo.1 ARS vs PL-12 and PL-7 36 (51.4) 25 (59.5) 3 (27.3) *p &lt; 0.01 4 (40) p=0.7 3 (75) - 0 - ILD, n (%) and Comparison Anti-Jo.1 ARS vs PL-12 and PL-7 53 (75.7) 33 (78.6) 8 (72.7) p = 0.98 6 (60) p=0.56 4 (100) - 1 (50) - ILD pattern - NSIP, n (%) 30 (56.6) 18 (54.5) 6 (75) 3 (50) 1 (25) 0 ILD pattern - UIP, n (%) 6 (11.3) 3 (9.1) 1 (12.5) 1 (16.7) 1 (25) 0 ILD pattern - other specific pattern, n (%) 6 (11.3) 4 (12.1) 0 2 (33.3) 1 (25) 0 ILD pattern - non-specific pattern, n (%) 11 (15.7) 8 (24.2) 1 (12.5) 0 1 (25) 1 (100) Mechanic’s hands (%), n (%) 23 (32.9) 14 (33.3) 3 (27.3) 2 (20) 0 1 (50) General impairment, n (%) 18 (25.7) 11 (26.2) 3 (27.3) 2 (20) 2 (50) 0 Fever, n (%) 7 (10) 4 (9.5) 2 (20.2) 0 1 (25) 0 Raynaud phenomenon, n (%) 22 (31.4) 11 (26.2) 7 (63.6) 0 2 (50) 0 Arthritis, n (%) and Comparison Anti-Jo.1 ARS vs PL-12 and PL-7 43 (61.4) 29 (69) 5 (45.4) p=0.07 2 (20) *p &lt; 0.01 2 (50) - 1 (50) - Malignancy, n (%) 4 (5.7) 3 (7.1) 1 (9.1) 0 0 0 Deaths, n (%) 2 (2.9) 2 (2.4) 0 0 0 1 (50) Disclosure of Interests: None declared