Myositis and Myocarditis With Anti- Jo-1 Antibodies Following SARS-CoV-2 mRNA Vaccination Or COVID-19 Infection

ABSTRACT

Background: Myocarditis without myositis has been described following mRNA SARS-CoV-2 vaccination. The literature on post-vaccine antibody mediated myositis is limited and to date no case series have been reported with a distinct clinical syndrome and a single myositis specific antibody, related to SARS-CoV-2 mRNA vaccination or COVID-19. Over a 6-month period in 2021, 54 patients were referred to our tertiary referral centre for suspected myositis. Out of 25 patients with a diagnosis of myositis, we identified three patients with a distinct clinical syndrome with myositis and myocarditis with anti-Jo-1 antibodies, following SARS-CoV-2 mRNA vaccination (BNT162-Pfizer-BioNtech;n=2) or following a mild COVID-19 infection (n=1). Results: Three patients (one woman, two men;49, 50 and 58 years old) developed progressive muscle weakness and muscle pain following either vaccination (patient 1 and 2) or mild COVID-19 infection (patient 3). Patients 2 and 3 had a history of anti- CCP positive rheumatoid arthritis (RA), which had been untreated for three years in patient 2. Both post-vaccine cases had severe pitting edema of the legs, patient 2 also had arthritis. None of the patients had mechanic's hands, Raynaud's phenomenon, or interstitial lung disease (ILD). The time interval between the SARS-CoV-2 trigger and the onset of progressive muscle weakness was between 10 and 14 days (patient 1 and 3) and was estimated cybetween three and seven days in patient 2. Laboratory tests showed highly elevated CK levels (17-32 times upper limit of normal (ULN)) and troponine T levels (14-34 times ULN). In patient 2, in addition, troponin I was tested (42 times ULN), which is more specific for myocardial involvement. In patient 1 supraventricular tachycardia, unspecific ST- and Twave abnormalities and elevated NTproBNP were found. In all patients, testing for myositis specific antibodies (MSAs;EUROline myositis 16 Ag. lineblot assay) showed anti-Jo-1 antibodies (semi-quantitatively in the highest possible range). Muscle MRI showed widespread muscle edema in all patients and extensive fascial and subcutaneous edema in the legs in the post-vaccine cases (figure 1). Muscle biopsies showed inflammatory myopathy. Cardiac MRI showed abnormalities in all patients Pericardial effusion and/or late contrast enhancement of the epicardial myocardium (figure 1). All patients showed major improvement in response to immunosuppressive therapy and could discontinue highdosed steroids after three and six months. Discussion: In conclusion, we report three patients with a distinct clinical picture of anti-Jo-1 myositis and myocarditis without ILD, following SARS-CoV-2 mRNA vaccination or COVID-19. Although it is difficult to determine a causal relationship between SARS-CoV-2 and anti-Jo-1 myositis based on these small numbers, we suspect a SARSCoV- 2 trigger of anti-synthetase syndromes given the typical combination of symptoms and previously demonstrated association with antecedent viral infections. In addition, we have collected nationwide data on myositis specific antibodies (MSAs) in 2019 (pre- COVID-19) and 2021 (during COVID-19) from six medical centers in the Netherlands. We are currently analysing these data to examine whether the proportion of positive MSAs in 2021 is higher as compared to 2019. The results will be presented at the ICNMD.