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Background:Sicca complaints are a frequent reason for rheumatology consultation in an outpatient setting. Though Sjögren’s disease (SjD) and to a lesser extent systemic sclerosis (SSc) are the main systemic autoimmune disorders accounting for oral and ocular dryness, autoimmune thyroid disease (ATD) has been also previously associated with sicca features1 and the presence of perivascular infiltrates in minor salivary gland (MSG) biopsies2. However, data regarding the prevalence of ATD in an unselected sicca cohort is scarce.Objectives:To uncover the frequency and clinical associations of ATD in a well-investigated cohort of patients presenting with sicca complaints in an outpatient rheumatology setting.Methods:Demographic, clinical, laboratory, and histopathological data were thoroughly collected from 92 consecutive patients investigated for sicca complaints. Immune profile testing included rheumatoid factor, ANA titer/pattern, antibodies to nuclear extractable (Ro/SSA, La/SSB, U1RNP/Sm complex), and thyroid antigens [thyroglobulin, thyroid peroxidase (TPO)] as well as SSc-specific autoantibodies using a commercially available immunoblot kit [EuroLine Systemic Sclerosis Profile (IgG)]. Testing for chronic viral infections (HIV, HCV), chest X-ray (to exclude sarcoidosis) and MSG biopsy were also performed on all study participants. Additionally, available MSG biopsies from a subgroup of patients were subjected to real-time PCR for interferon (IFN) inducible genes (IFIGs), preferentially those induced by type I IFN. Statistical analysis was performed by GraphPad Prism 10.0 and SPSS 26.0.Results:Fifty-two out of 92 patients (56.5%) in the cohort fulfilled the classification criteria for SS, while 34 out of 92 (37%) for ATD, respectively. While the prevalence of ATD among patients with SS was 34.6% (18/52), in those not fulfilling SS criteria the corresponding value was 40% (16 out of 40). No association between ATD and anti-Ro/SSA status was observed. Interestingly, ATD displayed the highest frequency (52%) in the subgroup of patients not fulfilling SS criteria and lacking serum SSc-autoantibodies. The presence of ATD in the context of SS was associated with lower rates of salivary gland enlargement and anti-La/SSB positivity, while Schirmer’s test was more often abnormal. Moreover, these patients exhibited lower urine PH, as well as lower neutrophil blood count compared to their SS counterparts without evidence of ATD. Of interest, overexpression of IFI44 (p=0.007) and its ligand IFI44L (p=0.003) transcripts was observed in MSG biopsies of sicca patients with TPO serum reactivity, as shown in Figure 1.Conclusion:ATD is frequently detected in sicca patients and is often the sole immunological abnormality in those lacking autoantibodies for SS and SSc. Furthermore, an increased IFN I signature -namely for IFI44 and IFI44L- in MSG tissue derived from anti-TPO+ sicca patients provides a possible immunopathological explanation for ATD sicca symptomatology. Testing for ATD should therefore be included in the diagnostic workup for SS.REFERENCES:[1] Mavragani CP, Niewold TB, Chatzigeorgiou A, Danielides S, Thomas D, Kirou KA, Kamper E, Kaltsas G, and Crow MK (2013): Increased serum type I interferon activity in organ-specific autoimmune disorders: clinical, imaging, and serological associations. Front.Immunol. 4:238. doi: 10.3389/fimmu.2013.00238[2] Marketos N, Koulouri V, Piperi EP, Georgaki ME, Nikitakis NG, Mavragani CP. Scleroderma-specific autoantibodies: Should they be included in the diagnostic workup for Sjögren’s syndrome? Semin Arthritis Rheum. 2022;55(May):152026. doi:10.1016/j.semarthrit.2022.152026Figure 1.IFI44 (a) and IFI44L (b) are overexpressed in MSG tissues of sicca patients with serum positivity for TPO.Acknowledgements:NIL.Disclosure of Interests:None declared.

Objective:To investigate the effect of the tumour necrosis factor (TNF) blocking agent infliximab in patients with treatment-resistant inflammatory myopathies.Methods:A total of 13 patients with refractory polymyositis (PM), dermatomyositis (DM), or inclusion body myositis (IBM) were treated with 4 infliximab infusions (5 mg/kg body weight) over 14 weeks. Outcome measures included myositis disease activity score with improvement defined according to The International Myositis Assessment and Clinical Studies Group (IMACS), and MRI. Repeated muscles biopsies were investigated for cellular infiltrates, major histocompatibility complex (MHC) class I and II, TNF, interleukin (IL)1α, IL6, high mobility group box chromosomal protein 1 (HMGB-1), interferon γ (IFNγ), myxovirus resistance protein A (MxA) and membrane attack complex (MAC) expression. Type I IFN activity was analysed in sera.Results:Nine patients completed the study. Three patients discontinued due to adverse events and one due to a discovered malignancy. Three of the completers improved by ⩾20% in three or more variables of the disease activity core set, four were unchanged and two worsened ⩾30%. No patient improved in muscle strength by manual muscle test. At baseline, two completers had signs of muscle inflammation by MRI, and five at follow-up. T lymphocytes, macrophages, cytokine expression and MAC deposition in muscle biopsies were still evident after treatment. Type I IFN activity was increased after treatment.Conclusions:Infliximab treatment was not effective in refractory inflammatory myopathies. In view of radiological and clinical worsening, and activation of the type I IFN system in several cases, infliximab is not an alternative treatment in patients with treatment-resistant myositis.

Background:Raynaud’s phenomenon (RP) is a vasospastic condition seen in approximately 5% of the general population, classified into primary (idiopathic) and secondary (in the presence of an underlying disorder). The latter may precede the onset of systemic autoimmune rheumatic diseases (SARDs) and particularly systemic sclerosis (SSc) by many years and therefore, it can serve as a warning sign for systemic autoimmunity, coupled with the appropriate laboratory investigations. While the prevalence and prognostic value of classical SSc autoantibodies (Anti-centromere, anti-Scl70, RNA polymerase III) in the setting of SSc are well defined, data on the prevalence and clinical significance of newer SSc autoantibodies among patients presenting with RP is limited.Objectives:The aim of this study is to determine the prevalence, distribution, and clinical associations of a wide spectrum of SSc autoantibodies in patients presenting with RP either alone or along with other clinical features.Methods:The study population included 150 consecutive patients with RP referred to “Molecular Physiology and Clinical Applications Unit, Department of Physiology, National and Kapodistrian University of Athens” for evaluation of the full spectrum of SSc-specific autoantibodies using a commercially available immunoblot kit [EuroLine Systemic Sclerosis Profile (IgG)]. Reactivities against CENPA and B, PM/Scl 75 and 100, Scl-70, Ku, NOR90, RP11, RP155, fibrillarin, PDGFR, Th/To and Ro52 autoantigens) were tested in all study participants. Moreover, clinical, laboratory and imaging features were recorded for all patients following thorough chart review. For patients tested positive for SSc-specific autoantibodies, additional work up including, pulmonary function tests, cardiac ultrasound and chest high resolution computed tomography (HRCT) imaging were performed upon clinical indication. Statistical analysis was performed by Graphpad prism 10.0 and SPSS 26.0.Results:In this cohort, the prevalence of patients with positive SSc autoantibodies and anti-Ro52 was 38.7% (58 out of 150) and 14% (21 out of 150), respectively (Figure 1A). The frequency of ANA≥1/160 was 64.5%. The distribution of reactivities among positive SSc autoantibodies ranking from higher to lower frequencies was the following: 26.7% for anti-CENPA & CENPB, 22.1% for anti-PM/Scl75&100, 15.1% for anti-RP11/155, 10.5% for anti-Scl-70, 9.3% for anti-Th/To, 7.0% for anti-Ku, 5.8% for anti-fibrillarin and 3.5% for anti-NOR90 (Figure 1B). Patients with positive antibodies had a higher percentage of sclerodactyly than those without positive antibodies (8.6% vs 1.1%, p value=0.032), while there were no significant associations with other classical signs of SSc. Two out of twelve patients with antibodies against RP11/155 were diagnosed with breast cancer (16.7%). In SSc autoantibody positive patients, the mean±SD values for FEV1/FVC, FVC, DLCO, TLC and RVSP were 90.9±10.3, 103.5± 15.7, 79.3± 12.9, 97.1±12.2 and 27.5±4.4, respectively. Four out of 18 patients (22.2%) tested had an estimated pulmonary arterial pressure of more than 30mmHg on cardiac ultrasound. Thoracic HRCT performed in 44 patients with positive serum titers of SSc autoantibodies upon clinical indication revealed the presence of abnormal findings in 28 (63.6%) including ground glass abnormalities, fibrotic lesions, bronchiectasis, peribronchial thickening and the presence of emphysema.Conclusion:A wide spectrum of SSc autoantibodies is frequently identified in patients presenting with RP in an outpatient rheumatology setting in association with sclerodactyly. Follow up studies are warranted to clearly define their prognostic role in early diagnosis of SSc or other SARDs and prompt detection of internal organ involvement.REFERENCES: NIL.Acknowledgements:Asimina Karampela and Christos Stylianopoulos contributed equally to this work.Disclosure of Interests:Clio Mavragani SOBI, Lilly, Pfizer, UCB, Abbvie, Boehringer Ingelheim, Lilly, Abbvie, Vasiliki Koulouri: None declared, Asimina Karampela: None declared, Christos Stylianopoulos Lilly, Charalampos Skarlis: None declared, Nikolaos Marketos: None declared.

Background:Idiopathic inflammatory myopathies (IIM) are a group of autoimmune diseases, characterised by muscle inflammation (myositis) and weakness, impacting various organ systems. IIMs are reported with a prevalence of 14/100,000 and an onset of 45-60 years of age for adults. Clinical subtypes include dermatomyositis (DM), antisynthetase syndrome (ASyS), immune-mediated necrotising myopathy (IMNM) and inclusion body myositis (IBM). More recently myositis-specific autoantibodies (MSAs) and myositis-associated autoantibodies (MAAs) have been used in clinical practice as they are closely associated with distinct clinical phenotypes of IIM and can be used as confirmatory diagnostic tools. Interferons (IFNs) have been shown to play a central role in IIMs and particularly in the inflammatory process which characterises IIMs. Interferon stimulated genes (ISGs) induced by type I IFN have an established role in DM and are significantly involved in patients with DM, positive for anti-melanoma differentiation-associated gene 5 (MDA5) autoantibodies. ISGs induced by type II IFN have been shown to be upregulated in IBM and ASyS while it is yet unclear whether IFNs play a substantial role in IMNM. It was shown that in muscle biopsies, ISG15, IFI6, and MX1 were the most upregulated ISGs in DM and PSMB8, GBP1 and GBP2 were the most upregulated ISGs in ASyS and IBM, highlighting the predominant involvement of both type I and II ISGs in different IIM clinical subtypes. However, muscle biopsies are estimated to have a false negative rate of 23%, while they also constitute an invasive procedure which is difficult to be repeated longitudinally in the context of a follow-up. A thorough clinical examination, coupled with the presence of MSAs or MAAs and the occasional verification via magnetic-resonance imaging (MRI) can suffice to reach a diagnosis, digressing from the need to perform muscle biopsies.Objectives:In this context, we aimed to investigate the type I and II IFN profiles in the peripheral blood of patients with IIM features who were seropositive for MSAs or MAAs.Methods:124 peripheral blood samples, stored in the Biobank of Molecular Physiology and Clinical Applications Unit, Department of Physiology from seropositive patients for MSA or MAA autoantibodies detected by a commercial immunoblot kit (EUROIMMUN) were subjected to RNA extraction, cDNA synthesis and qPCR for the quantitation of the following genes: ISG15, IFI6, MX1, PSMB8, GBP1 and GBP2. MSAs included anti-Jo-1, anti-PL-7, anti-PL-12, anti-EJ, anti-OJ, anti-Mi-2, anti-TIF1γ, anti-MDA5, anti-NXP2, anti-SAE1, and anti-SRP and MAAs: anti-PM-Scl, anti-Ku, and anti-Ro-52. Patients provided their written informed consent while samples were collected at baseline and are treatment-naïve.Results:We showed that the expression of ISG15, MX1 and IFI6 is more prevalent than that of GBP1, GBP2 and PSMB8 in patients positive for MSAs or MAAs. Specifically, ISG15 expression was highest in patients with DM related autoantibodies (Mi2, NXP2, TIF1g, MDA5) and to a lesser extent in patients with ASyS (particularly PL7, PL12) (Figure 1A&B). The expression of ISG15 was 3.5 times greater (p=0.001) in patients who presented with muscle weakness than those who did not. Patients who presented with dysphagia had 3.8 times greater ISG15 expression (p=0.001) than those who had no such symptom.Conclusion:In conclusion, ISG15 peripheral blood expression was found to be predominantly upregulated in seropositive patients characterized by the presence of DM related autoantibodies and therefore could serve as a noninvasive biomarker potentially guiding a tailored therapeutic approach.Figure 1.A) Expression (FC) of ISGs among MSA and MAA positive patients. Only monospecific seropositivity is displayed (n=87). B) ISG15 exdpression (FC) among autoantibody groups.REFERENCES:NIL.Acknowledgements:NIL.Disclosure of Interests:None declared.

Background:The mechanisms of vascular degeneration in PSV, although partly described so far, include among others the acceleration of the 3 classical types of arterial damage (inappropriate arterial remodeling, atheromatosis and arteriosclerosis), affecting both the micro- and macro-circulation [1]. This is attributed to the interplay between tissue and systemic inflammation, immunosuppressive therapy, and common cardiovascular disease (CVD) risk factors contributing to the observed increased CVD morbidity and mortality of these patients [2,3]. Based on easy to use, non-invasive vascular indices, the monitoring of subclinical vascular damage not only provides insights on the development of these vascular pathologies in PSV, but might be also used to guide treatment, in similar ways as in individuals with other non-inflammatory as well as systemic autoimmune rheumatic diseases with increased CVD risk including systemic lupus erythematosus and rheumatoid arthritis (RA) [4-6].Objectives:To explore the presence and potential reversibility of subclinical vascular dysfunction and/or damage both in the micro- and macro-circulation in PSV by evaluating four main vascular pathologies (atheromatosis, arterial stiffening, arterial remodeling and pressure wave reflection impairment) in four different vascular beds (carotid, femoral arteries, aorta, and retina) using gold-standard in clinical practice, non-invasive vascular biomarkers.Methods:Seventy-three PSV patients [42 (57.5%) with a type of large (LVV), 4 (5.5%) with medium (MVV) and 27 (37%) with small vessel vasculitis (SVV), matched at 1:1 according to age/sex/all CVD risk factors and associated therapies with non-inflammatory controls-(NIC), RA and polymyalgia rheumatica (PMR) controls were studied. Atheromatosis (carotid/femoral plaques), arterial stiffening (carotid-femoral pulse wave velocity-cfPWV), pressure wave reflections (augmentation index-AIx) and arterial remodeling (carotid-intima media thickness-cIMT and retinal vessel calibers) in two time points (activity-remission) were evaluated.Results:Aortic PWV in PSV was higher by 0.7 m/sec compared to NIC, and by 1.3 m/sec to RA-controls (p=0.003) and was more pronounced in LVV/MVV patients (p=0.08 and p=0.001 respectively). AIx was decreased in all PSV (p=0.03) and predominantly in SVV compared to NIC (p=0.04) and RA-controls (p=0.09 all, p=0.07 active disease). Atherosclerotic plaque formation prevailed in all vascular beds at diagnosis being more enhanced in LVV/MVV (p=0.007, p=0.03, p=0.004), compared to NIC and only both carotid/femoral (p=0.02) to RA-controls. Carotid IMT was higher in LVV/MVV irrespectively to disease state and control group and was the most sensitive to change biomarker between activity-inactivity. Active giant cell arteritis (GCA) was associated with increased PWV/plaques/cIMT compared to matched-NIC, RA and PMR-controls. The retinal microcirculation exhibited vasodilation in at least partly reversible (venules), and irreversible manner [arterioles, NIC (p=0.029) and RA-controls (p=0.008)], associated with the level of the inflammatory response and irrespectively of the underlying disease-specific pathogenetic mechanisms, suggesting that digital retinoscopy might represent an easy direct tool to monitor disease activity in PSV.Conclusion:Accelerated atheromatosis and arteriosclerosis are present at diagnosis in PSV suggesting disease specific more than drug related pathogenetic links. Early identification and management of CVD risk may reduce long-term CVD morbidity and mortality in PSV patients.REFERENCES:[1] Argyropoulou OD et al. Curr Opin Rheumatol. 2018.[2] Savage COS et al. Lancet 1997.[3] Clifford AH et al. Atherosclerosis. 2021.[4] Vlachopoulos C et al. Atherosclerosis. 2015.[5] Drosos GC et al. Ann rheum Dis 2022.[6] Agca R et al. Ann rheum Dis 2016.Acknowledgements:Ourania D Argyropoulou and Petros P. Sfikakis (two of the listed authors) are members of the European Reference Network for Rare Immunodeficiency, Autoinflammatory and Autoimmune Diseases (RITA-ERN). The study was partially funded by the Hellenic Rheumatology Society.Disclosure of Interests:None declared.

BackgroundInflammatory myopathies are heterogeneous with variable clinical course and prognosis [1]. Despite conventional treatment, some patients are refractory [2].ObjectivesTo describe the efficacy and safety of JAK inhibitors (JAKi) in patients with refractory dermatomyositis (DM).MethodsRetrospective analysis of 6 patients with active DM, refractory to previous immunosuppressive treatment including methotrexate, rituximab, mycophenolate mofetil, cyclophosphamide and intravenous immunoglobulin. Demographical, clinical characteristics, outcomes and adverse events after JAKi administration were recorded.Results83.3% of the patients were women, with mean age 62.4±10.9 years. All patients had long-standing disease with mean disease duration 9±8.1 years. Three patients were seropositive: one with positive anti-MDA5 antibodies, one with association of anti-Jo1 and anti-Ro52 antibodies and the latter with positive anti-Ro52 antibodies. The most frequently used JAKi was upadacitinib (50%), followed by tofacitinib (33.3%) and baricitinib (16,6%). Mean daily dose of corticosteroids at baseline was 8. 5mg.Prior to treatment with JAKi, mean muscle strength was 108±35, with mean CPK levels of 997±2244. Four patients had active skin rash. After a mean follow-up period of 7.6 months, all four patients with persistent skin involvement had clinical response (MMT-8=127±30). Muscle strength was improved in 4 patients (66.6%). Of note, the two patients that did not respond to JAKi were seronegative with marked muscular atrophy. One patient discontinued treatment due to severe thrombocytopenia. No other adverse events were recorded.ConclusionIn this case series, JAKi treatment resulted in clinical improvement in seropositive patients with longstanding, refractory DM with acceptable safety profile. Prospective data are necessary to confirm these preliminary findings and define the subset of DM patients most likely to benefit from JAKi treatment.References[1]Lundberg, I.E., Fujimoto, M., Vencovsky, J. et al. Idiopathic inflammatory myopathies. Nat Rev Dis Primers 7, 86 (2021).[2]Oddis CV, Aggarwal R. Treatment in myositis. Nat Rev Rheumatol. 2018 May;14(5):279-289. doi: 10.1038/nrrheum.2018.42. Epub 2018 Mar 29. Erratum in: Nat Rev Rheumatol. 2018 Oct;14(10):619.Acknowledgements:NIL.Disclosure of InterestsNone Declared.

Sjögren's Syndrome (SS) is a chronic systemic autoimmune disease of unknown etiology, carrying the highest lymphoma risk among autoimmune diseases, with significant impact on mortality and morbidity of patients. To describe: i) the clinical phenotype of SS, ii) the histologic type, stage, treatment options regarding lymphomas and iii) the prognosis of patients with SS related lymphoproliferative disorders. Eight hundred and fifteen consecutive SS patients' records from a single center fulfilling the 2016 ACR/EULAR were reviewed retrospectively for the purpose of this study. One hundred twenty-one patients with a diagnosis of non-Hodgkin Lymphoma (NHL) were identified and enrolled in the study population. Cumulative clinical, laboratory and histologic data were recorded and overall survival as well as event free survival curves were constructed using the Kaplan-Meier method. An event was defined as a disease progression, lymphoma relapse, treatment failure, histologic transformation, development of a 2nd lymphoma or death from any cause. From 121 pSS patients with lymphoma the most common histologic type encountered was MALT lymphoma (92/121, 76,0%) followed by DLBCL (11/121, 9.0%) and NMZL (8/119, 6.6%). The remaining 10 patients had various lymphomas of B (follicular, lymphoplasmacytic, chronic lymphocytic leukemia} and T cell origin (peripheral T cell lymphoma not otherwise specified, primary cutaneous T cell lymphoma, angioimmunoblastic t-cell lymphoma). Permanent salivary gland enlargement (66.1%, 80/121), palpable purpura (34,7% 42/121), peripheral nervous involvement (9,9%, 12/121), interstitial lung disease (8,2%, 10/121) presence of serum cryoglobulins (38,7%, 43/111) and C4 hypocomplementemia (69,8% 81/116) present at least 1 year before the development of lymphoma were the main pSS related features. The median age at lymphoma diagnosis was 58 years old (range 29-82) while MALT lymphomas developed earlier compared to DLBCL from pSS diagnosis (8 vs 3 OR= 3.84, 95%CI: 0.29 to 10.46; p=0.0266). The commonest biopsy proven extranodal sites included the labial minor salivary (43,8% patients) and parotid glands (30,5%) while 11% of patients had more than 1 extranodal sites affected. Bone marrow involvement was evident in 24,3% of patients (29/119) while nodal involvement in 35,5% (42/118). The majority of patients (65%) had limited disease (stage I or II). A watch and wait therapeutic policy was chosen in 40 patients while the rest received rituximab with or without chemotherapy. The 10-year survival and event free rates were 79% and 45,5% for MALT lymphomas, 40,9% and 24,2% for DLBCL and 46% and 31% for NMZL respectively (Figure 1). The Mantel-Cox log-rank comparison of the overall survival curves revealed a statistically significant difference (p=0.0016) among lymphoma subtypes. This is the largest single center series of SS- associated lymphoma patients, providing a detailed description of SS and lymphoma related features, combined with a 10-year survival and event free curves for the first time in the literature. None declared. [Display omitted]

Background:In our previous Sjögren’s Disease (SjD) Genome-Wide Association Study (GWAS) in European populations, significant single nucleotide polymorphism (SNP) peaks were identified between PRDM1 and ATG5 [1]. ATG5 is an autophagy-related protein that plays a crucial role in neutrophil extracellular trap (NET) formation, degranulation, and limiting autoantigens in blood. Dysregulated autophagy has been implicated in SjD and systemic lupus erythematosus (SLE) pathology and poor disease outcomes [2, 3]. The transcriptional repressor PRDM1 plays a role in regulating lymphocyte differentiation [4].Objectives:Identify and functionally evaluate SjD and SLE risk variants in the PRDM1-ATG5 risk locus.Methods:By conducting a meta-analysis of SjD and SLE GWAS datasets, we defined a credible SNP set in the PRDM1-ATG5 locus. A GWAS involving 15,691 SjD and SLE cases and 52,521 population controls of European ancestry was performed, and SNP-trait associations were tested using logistic regression models in PLINK. Bioinformatic analyses (RegulomeDB, HaploReg v4.2, promoter capture Hi-C, eQTLs, etc.) further prioritized SNPs. A CRISPR inhibition (CRISPRi) assay was used to assess the effects of these SNPs on ATG5 expression. Luciferase assays in A235 salivary gland epithelial cell line, PLB985 malignant myelomonoblasts, and GM12878 EBV-transformed B cells tested the activation and/or repressive activity of candidate SNPs.Results:Our investigation revealed several candidate functional SNPs within the PRDM1-ATG5 region. Among them, rs533733 (p=1.15E-18), rs34582442 (p=2.79E-08), rs34599047 (p=2.82E-08), rs77846660 (p=8.39E-04), and rs56886418 (p=4.23E-03) emerged as noteworthy, suggesting their involvement in the regulatory landscape of this locus. Expanding our focus, the inclusion of rs1152966 (p=3.39E-15), rs11152964 (p=7.18E-11), rs573775 (p=6.13E-06), and rs12175062 (p=2.67E-03) in the analysis revealed a broader understanding of eQTLs and chromatin accessibility and modification patterns associated with these SNPs. The extensive influence of these SNPs was observed across various cell types, including minor salivary glands and blood cells, emphasizing their relevance in the pathogenesis of SjD and SLE. Functional assays further elucidated the allele-specific effects of selected SNPs. Notably, rs56885418 and rs3804333 demonstrated a significant decrease in enhancer activity, while rs533733 and rs62422881 exhibited an increase in enhancer activity, particularly in the A253 cell line. These findings underscore the dynamic regulatory impact of these SNPs on gene expression, providing valuable insights into the molecular mechanisms at play in the PRDM1-ATG5 locus.Conclusion:Functional characterization of SNPs in the PRDM1-ATG5 locus provides new insights into the regulatory mechanisms governing gene expression in SjD and SLE. Ongoing studies will focus on in vitro validation of predicted functional SNPs in A235 and GM12878 cells.REFERENCES:[1] Khatri B, et al. Nat Commun. 2022 Jul;13(1):4287.[2] Byun YS, et al. Sci Rep. 2017 Dec;7(1):17280.[3] Wible DJ, et al. Cell Discov. 2019; 5:42.[4] Kallies A, Nutt SL. Curr Opin Immunol. 2007 Apr;19(2):156-62.Acknowledgements:National Institutes of Health (NIH): R01AR071410, R01AR073855, R01AR065953, P50AR060804, U01DE028891; National Research Foundation of Korea (NRF-2021R1A6A1A03038899); Sjögren’s Foundation; Presbyterian Health Foundation; Jerome L. Greene Foundation.Disclosure of Interests:Marcin Radziszewski: None declared, Mandi M Wiley: None declared, Bhuwan Khatri: None declared, Astrid Rasmussen: None declared, Kandice L Tessneer: None declared, Kwangwoo Kim: None declared, Edward M. Vital: None declared, Nick Dand: None declared, Chen Gong: None declared, David Morris: None declared, Phil Tombleson: None declared, Elena Pontarini: None declared, Michele Bombardieri: None declared, Maureen Rischmueller: None declared, Marie Wahren-Herlenius: None declared, Marika Kvarnström: None declared, Torsten Witte: None declared, Hendrika Bootsma: None declared, Gwenny M. Verstappen: None declared, Frans G.M. Kroese: None declared, Arjan Vissink: None declared, Sarah Pringle: None declared, Athanasios Tzioufas: None declared, Clio Mavragani: None declared, Alan Baer Received consulting fees from Bristol Myers Squibb (BMS) and iCell Gene Therapeutics., Marta Alarcon-Riquelme: None declared, Javier Martin: None declared, Xavier Mariette: None declared, Gaetane Nocturne: None declared, Jacques-Olivier Pers: None declared, Jacques-Eric Gottenberg: None declared, Wan-Fai Ng I have consulted for Novartis, BMS, Janssen, Sanofi, Abbvie, IQVIA, Argenx, Resolve Therapeutics., Caroline Shiboski: None declared, Kimberly E Taylor: None declared, Lindsey Criswell: None declared, Blake M Warner: None declared, A Darise Farris Grant/research support from Johnson and Johnson Innovative Medicine (formerly Janssen; ended 12/31/2023)., Patrick M Gaffney: None declared, Judith A. James: None declared, R Hal Scofield Received consulting fees from Johnson and Johnson Innovative Medicine (formerly Janssen) and Merk Pharmaceuticals., Joel M Guthridge: None declared, Daniel J Wallace: None declared, Swamy Venuturupali: None declared, Michael T Brennan: None declared, Juliana Imgenberg-Kreuz: None declared, Lars Ronnblom: None declared, Eva Baecklund: None declared, Maija-leena Eloranta: None declared, Lara A Aqrawi: None declared, Øyvind Palm: None declared, Johan G Brun: None declared, Daniel Hammenfors: None declared, Malin V Jonsson: None declared, Silke Appel: None declared, Sara Magnusson Bucher: None declared, Helena Forsblad-d’Elia: None declared, Thomas Mandl Employee of UCB., Per Eriksson: None declared, Sang-Cheol Bae: None declared, Timothy J Vyse: None declared, Betty Tsao: None declared, Gunnel Nordmark: None declared, Christopher J Lessard Grant/research support from Johnson and Johnson Innovative Medicine (formerly Janssen; ended 12/31/2023).

Background:Sjögren’s disease (SjD) is a complex systemic autoimmune disease with substantial morbidity and 21 known genetic associations. The International Sjögren’s Genetics Network (SGENE) is a growing international collaboration focused on understanding how genetic variants influence SjD pathology. As sample sizes increase, we are focusing our efforts on the analyses of clinical subsets, which few studies have done.Objectives:Our genome-wide association study (GWAS) aimed to identify additional risk loci of genome-wide significance (GWS, p<5E-08; suggestive, p<5x10E-5) in European-derived subsets of SjD.Methods:This study was conducted with IRB/EC approvals. All SjD patients met the 2002 AECG criteria for SjD. A total of 5058 cases and 25943 controls were genotyped on GWAS arrays. After QC, 4855 cases and 25408 controls were included in the analyses. Logistic regression was calculated, adjusting for ancestry using the first 4 principal components to identify SjD-associated SNPs. Cases were split into Ro/SSA+ (n=2898) and Ro/SSA- (n=1313), and analyzed vs. each other, controls, and all-SjD.Results:We observed many differences in the genomic architecture of Ro/SSA- compared to Ro/SSA+ and all SjD (Figure 1a,b), most notably, a complete loss of the significance of the association with MHC on chromosome 6 in the Ro/SSA- cases(Figure 1b). The Ro/SSA+ subjects had a much stronger HLA association with OR ≈ 4 (Figure 1a), while the overall SjD showed OR ≈ 3. While none of the associations observed in the Ro/SSA- population reached GWS, 8 regions (near PLXNA2, PCDH7, IRF5-TNPO3, DLD, LOC100134229, JAK3, LOC643529, and TMTC1) show suggestive associations (Figure. 1a). Of these, only two, IRF5-TNPO3 and LOC643529, are also suggestive in the Ro/SSA+ subset. However, while the Ro/SSA+ have both the IRF5 promoter effect and the extended haplotype through TNPO3, the Ro/SSA- lack the IRF5 promoter effect. Interestingly, previous studies have shown that lupus and systemic sclerosis have both haplotypes while primary biliary cholangitis only has the haplotype extending into TNPO3, similar to Ro/SSA- SjD [1]. When comparing Ro/SSA- to the all-SjD dataset, PLXNA2 and LOC100134229 showed no association; PCDH7, DLD, and TMTC1 showed some association but did not reach suggestive levels; and LOC643529, IRF5-TNPO3, and JAK3 surpassed the suggestive threshold, the latter two nearing or surpassing GWS. Two of the novel suggestive associations in Ro/SSA- are particularly intriguing. PLXNA2 is a member of a semaphorin co-receptor family that mediates repulsive effects on axon pathfinding during nervous system development; interestingly, Ro/SSA- SjD has a higher frequency of neurological involvement. JAK3 is a member of the Janus kinase (JAK) family of tyrosine kinases involved in cytokine receptor-mediated intracellular signal transduction; it is predominantly expressed in immune cells. Mutations in this gene are associated with autosomal severe combined immunodeficiency disease. Novel drugs target the JAK-STAT pathways, making this finding markedly relevant.Conclusion:Our findings highlight the relevance of expanding genetic studies to specific subphenotypes of the disease. While we continue to increase our GWAS sample size and explore other subphenotypes, more work is needed to increase the power of these studies to determine if the suggestive regions will surpass the GWS threshold.REFERENCES:[1] Kottyan LC, et al. Hum Mol Genet. 2015 Jan 15;24(2):582-96.Acknowledgements:NIH/NIAMS R01 AR073855, P50 AR060804; NIH/NIDCR U01DE028891; Sjögren’s Foundation; Jerome L. Greene Foundation.Disclosure of Interests:Astrid Rasmussen: None declared, Marcin Radziszewski: None declared, Bhuwan Khatri: None declared, Kandice L Tessneer: None declared, Elena Pontarini: None declared, Michele Bombardieri: None declared, Maureen Rischmueller: None declared, Marie Wahren-Herlenius: None declared, Marika Kvarnström: None declared, Torsten Witte: None declared, Hendrika Bootsma: None declared, Gwenny M. Verstappen: None declared, Frans G.M. Kroese: None declared, Arjan Vissink: None declared, Sarah Pringle: None declared, Athanasios Tzioufas: None declared, Clio Mavragani: None declared, Alan Baer Received consulting fees from Bristol Myers Squibb (BMS) and iCell Gene Therapeutics., Marta Alarcon-Riquelme: None declared, Javier Martin: None declared, Xavier Mariette: None declared, Gaetane Nocturne: None declared, Jacques-Olivier Pers: None declared, Jacques-Eric Gottenberg: None declared, Wan-Fai Ng I have consulted for Novartis, BMS, Janssen, Sanofi, Abbvie, IQVIA, Argenx, Resolve Therapeutics., Caroline Shiboski: None declared, Kimberly E Taylor: None declared, Lindsey Criswell: None declared, Blake M Warner: None declared, A Darise Farris Grant/research support from Johnson and Johnson Innovative Medicine (formerly Janssen; ended 12/31/2023)., Judith A. James: None declared, R Hal Scofield Received consulting fees from Johnson and Johnson Innovative Medicine (formerly Janssen) and Merk Pharmaceuticals., Joel M Guthridge: None declared, Daniel J Wallace: None declared, Swamy Venuturupali: None declared, Michael T Brennan: None declared, Juliana Imgenberg-Kreuz: None declared, Lars Ronnblom: None declared, Eva Baecklund: None declared, Maija-leena Eloranta: None declared, Lara A Aqrawi: None declared, Øyvind Palm: None declared, Johan G Brun: None declared, Daniel Hammenfors: None declared, Malin V Jonsson: None declared, Silke Appel: None declared, Sara Magnusson Bucher: None declared, Helena Forsblad-d’Elia: None declared, Thomas Mandl Employee of UCB., Per Eriksson: None declared, Gunnel Nordmark: None declared, Christopher J Lessard Grant/research support from Johnson and Johnson Innovative Medicine (formerly Janssen; ended 12/31/2023).

Background:Sjögren’s syndrome (SS) is characterized by the presence of lymphocytic infiltration around the ductal epithelium of the salivary and lachrymal glands. The periepithelial inflammatory lesions and the enclosed B cell component are responsible for the glandular and extraglandular manifestations of the disease. Previous studies have shown that the severity of inflammation observed within the salivary glands is correlated with the occurrence of extraglandular manifestations. However, in these studies either the number of patients is small or the SS criteria are not well defined. To explore the association between the degree of inflammation within the salivary glands and the phenotype of the disease, large and well characterized cohorts of SS patients is required.Objectives:To compare the phenotypic features of SS patients with low and high degree of inflammation within the minor salivary glands as reflected by the focus score (FS).Methods:From a total cohort of 1723 consecutive SS patients who fulfill the 2016 EULAR/ACR criteria and are followed up in 4 clinical centers ([Universities of Pisa, Athens, Harokopio and Ioannina, (PAHI)], those who had performed a lip biopsy and the focused score was available, were classified into low grade (FS<3) or high grade (FS≥3). Glandular (dry mouth, dry eyes, parotid gland enlargement) and extra-glandular manifestations (Raynaud’s phenomenon, arthralgias/myalgias, arthritis, palpable purpura, liver involvement, kidney involvement, lung involvement, neurologic involvement, long standing lymphadenopathy and lymphoma) as well as serologic features (ANA, RF, anti-Ro/SSA, anti-La/SSB) were compared between the 2 groups. Statistical analysis for categorical variables was performed by Fisher exact or chi-square tests and for continuous variables with t test or Mann-Whitney accordingly.Results:Eight hundred and eight minor salivary gland biopsies were available and evaluated based on focus score at the initial evaluation of SS patients, of whom 753 had low grade (FS<3) and 153 high grade (≥3) inflammation. The median disease duration after SS diagnosis was not statistically significant different for the 2 groups (median: 4 years, range: 0-36 years). SS patients with high grade inflammation displayed higher prevalence of salivary gland enlargement (SGE) (40% vs 25%, p=0,0002), long standing lymphadenopathy (22% vs 14%, p=0,02), ANA (97% vs 88%, p=0,0001), anti-La/SSB (52% vs 32%, p<0,0001), RF (61,5% vs 48%, p=0,003), peripheral neuropathy (PN) (5,3% vs 1,5, p=0,01) and of lymphoma (26% vs 8%, p<0,0001, OR=4,142, 95%CI=2,65 to 6,47) compared to those with low grade inflammation.Conclusion:SS patients with FS ≥3 at the initial evaluation, display higher prevalence of lymphoma as well as higher B cell hyperactivity and certain clinical manifestations (SGE, PNS, lymphadenopathy) that constitute risk factors for lymphoma development.Disclosure of Interests:Loukas Chatzis: None declared, Vasileios Pezoulas: None declared, Francesco Ferro: None declared, Valentina Donati: None declared, Aliki Venetsanopoulou: None declared, Evangelia Zampeli: None declared, Maria Mavromati: None declared, Paraskevi Voulgari: None declared, Clio Mavragani: None declared, Dimitris Fotiadis: None declared, Fotini Skopouli: None declared, Salvatore De Vita Consultant of: Roche, Human Genome Science, Glaxo Smith Kline and Novartis, Gorgoulis Vassilis: None declared, Chiara Baldini: None declared, Haralampos M. Moutsopoulos: None declared, Andreas Goules: None declared, Athanasios Tzioufas: None declared