ABSTRACT
Background: Dermatomyositis (DM) is a rare idiopathic infammatory myopathy that can present with a variable spectrum of cutaneous and systemic manifes-tations1. Correlations between myositis-specifc autoantibodies (MSAs) and disease phenotype have been documented in DM in particular in association with the development of interstitial lung disease (ILD). Ongoing studies focus on the potential role of MSAs in similarities of the pathophysiological mechanisms of COVID-19 associated ILD and that related to DM suggesting an intriguing cross talk between autoimmunity and COVID-192. Objectives: To explore clinical patterns including ILD and MSAs profile in DM patients from a population-based single-center study carried out in a Tertiary Referral Rheumatologic Clinic. SARS-CoV-2 infections and vaccination were also analysed. Methods: We enrolled patients affected by DM classified according to 2017 EULAR/ACR criteria1 with a disease onset at ≥18 years referring to the Rheumatologic Clinic of Tor Vergata University Hospital in Rome (Italy). Clinical data were collected from medical records: gender, age of onset of symptoms and diagnosis, clinical features, auto-antibodies patterns (ANA, MSAs including anti-tRNA synthetase,-Jo1,-PL7,-EJ,-MDA5,-NXP2, SAE, Mi2, and myositis-associated antibodies comprising anti-PM/Scl,-Ro-52,-Ku, U1RNP), pattern of lung abnormalities at thoracic CT scans, and treatments. The prevalence of SARS-CoV-2 infection and vaccination profile were also investigated. Results: Among eligible cases (n=30), patients who completed the study (n=19) included almost entirely women (F=73.7%). The median age at disease onset was 57.4±12.4 yrs while the mean diagnostic delay resulted as 12±10 months. Skin manifestations and myalgia were the prevalent symptoms (79% and 63%, respectively) whereas dyspnea and cough occurred in a third of the cohort at DM onset. Besides the skin involvement, the decrease in pulmonary function was the main clinical manifestation at the frst rheumatological referral (52.6% of cases) followed by joint pain (36.8%) and cardiovascular events (10.6%). ANA titer≥1:160 occurred in 79% of patients. All patients showed MSAs positivity with a similar distribution: a single case of double positivity was registered in a man with anti-MDA5 and-NXP2. The most common CT fndings were ground-glass opacity and parenchymal band in a third of patients (32%). The entire cohort had undergone cycles of steroids from the onset of DM and during the follow-up, according to disease severity. The main used therapies were methotrexate (47%), intravenous immunoglobulin (42%) and mofetil micofenolate (31.6%). None of patients had SARS-CoV-2 infection (until December 2021). The 63% of the cohort received at least one dose of the anti-SARS-CoV-2 mRNA vaccine (BNT162b2), of which 10% had completed with the booster dose. No adverse reactions or post-vaccination DM fare were registered. A third of the cohort had not been vaccinated due to concomitant disease activity or therapies. No cases of post-COVID19 new-onset DM were diagnosed. Conclusion: Our preliminary findings support the relevant impact of lung involvement in DM. The availability of MSAs can help to stratify patients with DM for outcome and risk of potential disease complications. The impact of MSAs on ILD associated or not to COVID-19 deserve further investigations in a larger DM cohort and for a longer post-COVID-19 pandemia follow-up time.