AB1309 CLINICAL CHARACTERISTICS OF NEW-ONSET IDIOPATHIC INFLAMMATORY MYOPATHIES FOLLOWING SARS-CoV-2 INFECTION OR VACCINATION – ANALYSIS OF A CASE SERIES

Background Recent data showed that SARS-CoV-2 infection and vaccination could act as a trigger for different autoimmune diseases, including idiopathic inflammatory myopathies (IIM). Objectives The aim of this study was to describe the clinical characteristics patients diagnosed with IIM following in tertiary rheumatology center. Methods We conducted retrospective analysis on newly IIM, from 1 January 2020 31 December 2022, using information hospital database. were selected according ICD-10 codes indicating (M33.0, M33.1, M33.2, M33.9). cases onset specific symptoms within 6 months after or further analysis. Clinical, biological immunological parameters assessed descriptive statistics. Results A total 58 identified, 10 (17.2 %) (n = 6) 4). All (F:M=1:1, median age 46 years) received mRNA vaccine had several days month vaccination. Among 60.5 years), myopathy variable, minimum 14 maximum infection. Myalgia, muscle weakness elevated levels creatinine kinase reported 9 patients. average CK level 2534.6 (3760.8) U/L, ranging 43 11827 U/L. Skin lesions present all 4 Mechanic’s hands arthralgia noted 5 each. Dyspnea interstitial lung disease (ILD) 8 cases, severe pulmonary involvement 2 cases. Myocarditis patients, case each group. Myositis-specific antibodies (MSAs) myositis-associated (MAAs) Anti-threonyl-tRNA synthetase (anti-PL7) (3 infection), anti- histidyl-tRNA (anti-Jo-1) (in associated anti-PL7 antibodies), anti-isoleucyl-tRNA (anti-OJ antibodies) patient. ILD antibody positive Conclusion Anti-PL7 are frequent Further studies needed investigate relationship between occurrence IIM. References [1]Galeotti C, Bayry J. Autoimmune diseases COVID-19. Nat Rev Rheumatol. Aug;16(8):413–4. [2]Chen Y, Xu Z, Wang P, Li XM, Shuai ZW, Ye DQ, et al. New-onset phenomena post-COVID-19 Immunology. 2022 Apr;165(4):386–401. Acknowledgements I have no acknowledgements declare. Disclosure Interests None Declared.