BackgroundAs autoimmune phenomena following anti-nSARS-CoV2 vaccine was reported in the healthy population, there is increasing concern in patients with inflammatory joint diseases regarding possible side effects and disease flare-ups.ObjectivesWe set out to evaluate the possible risk of disease exacerbation and the predisposing risk factors for the flare up.MethodsThis is a single center prospective cohort study, enrolling patients attending Arthritis Clinic at San Bortolo Hospital, during a follow-up of 12 months. All patients, after obtaining informed consent, answered a 24-item questionnaire including information about nSARS-CoV2 infection, vaccination, disease activity, ongoing treatment, vaccine side effects, disease flare up and need to change therapy.ResultsA total of 109 patients, 60 (55.1%) females and 49 (44.9%) males with a mean age of 60.1 years ±12.6 SD were enrolled. Forty-three (39.5%) were affected by rheumatoid arthritis, 43 (39.5%) from psoriatic arthritis and 23 from anchylosing spondylitis. There were 19 (17.43%) nSARS-CoV2 infection, of them 3 (15.8%) need hospitalization. Ninety-five (87.2%) receive at least one shot of nSARS-CoV2 vaccine, of these 78 (82.1%) got three shots of vaccine. Vaccine-related side effects were reported in 36 (37.9%), of these 15 (41.7%) have fever, 14 (38.8%) arthralgia and 29 (80.5%) fatigue. No patients required medical attention. Twenty (21.05%) of patients who receive at least one vaccine shot experienced a flare up. Nine (45%) need to change therapy. The risk of flare up was significantly associated with low disease activity/active disease in the last 12 months, p=0.009; OD 4.0; 95% CI: 1.5-11.3.ConclusionOverall, the nSARS-CoV2 vaccine is well tolerated in patients with inflammatory arthritis. The risk of disease flare is associated with active disease within the past 12 months. According to our results, the patients affected by inflammatory arthritis in sustained remission have no reason to hesitate to get the nSARS-CoV2 vaccination.Disclosure of InterestsNone declared

BackgroundIdiopathic Inflammatory myopathies (IIM) encompass a group of heterogeneous systemic autoimmune diseases for which biomarkers are needed. Extracellular vesicles (EVs) are cell-derived nanoparticles regulating several biological functions[1]and likely involved in the pathogenesis of autoimmune diseases[2], yet their role in IIM was not investigated thoroughly.Objectives1) to develop an effective and reproducible laboratory method to isolate EVs from venous blood; 2) to trace any prominent EVs cellular origin; 3) to perform a quantitative and comparative evaluation of EVs between IIM patients and healthy donors (HD) and across distinct IIM subsets.MethodsWe enrolled adult (≥18 years) consecutive IIM patients (EULAR 2017 criteria) and sex- and age-matched HD. Clinical evaluation of IIM patients was performed by an expert rheumatologist. A venous blood sample (5 mL) was collected from each participant and processed through size exclusion chromatography (SEC) and subsequent ultra-filtration (UF). Particles morphology was observed via transmission electron microscopy (TEM). Nanoparticle tracking analysis (NTA) was performed to evaluate the concentration of EV. The characterization of EV surface markers was conducted through imaging flow cytometry (IFC). Comparisons were carried out using Student’s t-test or one-way ANOVA with multiple comparisons.ResultsSixty-five consecutive IIM patients (dermatomyositis (DM) n=19; polymyositis (PM) n=8; inclusion body myositis (IBM) n=2; anti-synthetase syndrome (ASyS) n=17; cancer-associated myositis (CAM) n=16; unspecified n=3) and 65 HDs were included.Isolated EVs concentration values reached 1010EV/mL. IFC showed surface expression of EVs tetraspanins CD63, CD81, CD9, and integrin CD11c and highlighted a predominance of CD19+ EVs vs. CD3+ EVs in both IIM and HDs (p<0.0001 for both). TEM images showed intact small particles with the typical EVs-“cup-shape” morphology. NTA showed a significantly higher mean concentration of circulating EVs in IIM vs. HD (mean [EVs/mL] ± SD 1.71x1010± 1.29x1010vs. 1.31x1010± 7.17x109, p=0.031).Across IIM subsets, the highest EVs levels were found in CAM vs. HD (2.35x1010± 2.20x1010vs. 1.31x1010± 7.17x109, p=0.0026) and vs. no-CAM patients (2.35x1010± 2.20x1010vs. 1.51x1010± 7.51x109, p=0.0206). Patients in clinical remission (n=26, 40%) displayed higher EVs levels than active patients (2.13x1010± 1.60x1010vs. 1.46x1010± 1.02x1010, p=0.0452) (Figure 1).Concerning treatment, patients on glucocorticoids (GC) alone (n=20, 30.7%) displayed higher EVs levels than patients receiving GC plus immunosuppressants (IS) (2.23x1010± 1.99x1010vs. 1.49x1010± 7.25x109, p=0.0341). EVs concentration was significantly decreased in patients receiving rituximab (RTX) vs. other IS (9.63x109± 3.26x109vs. 1.96x1010± 1.46x1010, p<0.001).ConclusionThe combination of SEC and UF is a reliable approach to obtain intact EVs with preserved morphology and good purity from blood, as confirmed by diverse characterization techniques. The prevalence of CD19+ circulating EVs might indicate B cells as their main origin. Different EVs concentrations discriminate IIM from HD and may provide distinction among specific IIM subsets and treatment response.References[1]Buzas, E.I. The roles of extracellular vesicles in the immune system.Nat Rev Immunol(2022).https://doi.org/10.1038/s41577-022-00763-8[2]Wu WC, ert al. Role of Extracellular Vesicles in Autoimmune Pathogenesis. Front Immunol. 2020;11:579043. doi: 10.3389/fimmu.2020.579043Figure 1.Representation of EVs shape (TEM), surface markers (IFC) and quantitative analysis (NTA) across IIM susbetsAcknowledgements:NIL.Disclosure of InterestsNone Declared.

BackgroundCytokines (CKs) are known to play a role in the pathogenesis of lupus nephritis (LN), yet their role as biomarkers is still debated.ObjectivesTo describe the CKs picture in patients with active LN and to assess possible clinical correlates in LN course.MethodsA prospective cohort study including patients with active biopsy-proven LN was performed. Serum CKs were assessed at the time of diagnosis and at 3 subsequent time points (3, 6 and 12 months) during follow-up.Clinical and serological data were collected for further analysis.BLyS (B Lymphocyte stimulator) and interleukin (IL)-37 were measured by ELISA assays (Quantikine BAFF, R&D, USA, detection limit DL 0.02 ng/mL; IL37 ELISA kit, Adipogen, Swizerland, DL 0.001 ng/mL), IL-2, IL-10, IL-17A and IL-18 (pg/mL) by Luminex multiplex assay (Millipore, USA, DL 0.6 pg/mL for all), according to the manufacturers’ instructions. Measurements for IL-37 and BLyS were matched with sera of sex- and age- matched healthy subjects (HC).Mann-Whitney test was used for comparisons between two independent groups, Wilcoxon log-rank test for paired comparisons at different time points, Spearman’s correlation coefficient for associations between CK and between CK and clinical features.ResultsTwenty-seven patients with active LN (mean±SD age 41.75±14.74, 78.8% women) were included for initial CK analysis at the time of LN activity.At baseline (T0), BLyS levels were significantly increased in LN compared with HC (median [range], 1.107 [0.326-4.00] vs. 0.563 [0.265-1.409]; p<0.0001); IL-37 was significantly reduced in LN compared with HC (median [range] 0.016 [0.001-0.251] vs. 0.056 [0.001-1.147]; p = 0.0185).At T0, median (range) levels of IL-2, IL-10, IL-17A and IL-18 were: IL-2 0.640 (0-37.82), IL-10 2.60 (0-106.86), IL-17A 2.10 (0-138.20), IL-18 243.10 (28.20-950.30).The longitudinal association study between CK levels of the entire cohort revealed a trend of inverse correlation between IL-37 and BLyS (r=-0.281, p=0.06) and a direct correlation between BLyS and IL-18 (r=0.330, p=0.04) and between IL-2 and IL-17A (r=0.470, p<0.001) (Figure 1).A subset of 17 patients (70.6% F, mean age at renal flare 34.3±18.6y, mean duration of disease at the time of renal flare 4.99±8.94y, caucasian ethnicity n=14, 82.3%), was followed-up prospectively: 7 (41.18%) had biopsy-proven (III-IV class) proliferative glomerulonephritis. Proteinuria at T0 was 2.19±1.35 g/24h. All patients were treated with pulsed glucocorticoids (GCS, 750-2500 mg) followed by oral GCS (0.3-0.5mg/kg/day prednisone equivalent) and immunosuppression1.Higher titres of IL-18 were present in the sera of patients with proliferative forms of LN (p=0.053) and with a higher SLEDAI-2K score at T0 (p=0.0759).A significant correlation was found between IL-2, and to a lesser extent of IL-17, with anti-dsDNA antibodies (IL2: r=0.6098, p=0.0094; IL17: r=0.4591, p=0.0638). High levels of IL-17 correlated with lower C3 at T0 (r=-0.5085, p=0.0372).No significant longitudinal changes in CKs levels nor correlation with clinical features were observed.ConclusionPatients with proliferative LN and higher SLEDAI-2K scores displayed higher levels of IL-18, thus supporting IL-18 likely role in the pathogenesis of LN.We documented a correlation between IL2 and higher titres of anti-dsDNA antibodies and an inverse correlation between IL-17 and C3 at baseline, suggesting a contribution of CKs to LN onset.Our study was limited by the small sample size, limiting retrieval of significant data on CK levels and clinical-laboratoristic changes at different time points, demanding further studies.References[1]Fanouriakis A, et al 2019 Ann Rheum Dis 2019;78:736-745[2]Mende, et al. Front Immunol vol. 9 1250. 7 Jun. 2018, doi:10.3389/fimmu.2018.01250Figure 1Acknowledgements:NIL.Disclosure of InterestsNone Declared.

Purpose of review Idiopathic inflammatory myopathies (IIMs) are a group of rare autoimmune disorders characterized by muscle weakness and inflammation. MicroRNAs (miRNAs) are the main class of small noncoding RNAs regulating a wide range of physiological and pathological processes and play a role in mediating autoimmunity and inflammation. In this review, we summarize the latest knowledge on the role of miRNAs in systemic autoimmune diseases with particular focus on IIMs. Recent findings Study on miRNA expression in IIMs is helping in understanding the pathogenetic basis of the disease at a tissue and systemic level. Several miRNAs, even with a muscle-specific expression (myomiRs), have been shown to be involved in immune and nonimmune mechanisms of myofiber damage. MiRNAs modulate and orchestrate the local inflammatory infiltrate and could be used as potential biomarkers as they correlate with disease activity and response to therapy. Summary IIMs comprise different clinical phenotypes and still little is known about the molecular signature of each subset. Further research about miRNA profiling will provide additional insights in the disease characterization with an expected impact on the therapeutic strategies.