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Systemic sclerosis (SSc) is a complex autoimmune connective tissue disease with distinct pathological hallmarks (ie, inflammation, vasculopathy, fibrosis) that may predominate at different stages in the disease course with varying severity. Initial efforts to classify patients with SSc identified a subset of patients with very early SSc. These patients possessed signs of SSc (eg, Raynaud phenomenon, SSc specific autoantibodies and/or nailfold capillary abnormalities) without fulfilling complete SSc classification criteria. Recognizing the inherent value in early diagnosis and intervention in SSc, researchers have endeavored to identify risk factors for progression from very early SSc to definite SSc. The present review summarizes the clinical phenotype of patients with very early and early SSc. Through a scoping review of recent literature, this review also describes risk factors for progression to definite SSc with a focus on the specific clinical features that arise early in the SSc disease course (eg, diffuse cutaneous sclerosis, interstitial lung disease, esophageal dysfunction, renal crisis, cardiac involvement). In addition to clinical risk factors, this review provides evidence for how biological data (ie, serological, genomic, proteomic profiles, skin bioengineering methods) can be integrated into risk assessment models in the future. Furthering our understanding of biological features of very early SSc will undoubtedly provide novel insights into SSc pathogenesis and may illuminate new therapeutic targets to prevent progression of SSc.

Objective To investigate peripheral blood cell (PBCs) global gene expression profile of SSc at its preclinical stage (PreSSc) and to characterize the molecular changes associated with progression to a definite disease over time. Material and methods Clinical data and PBCs of 33 participants with PreSSc and 16 healthy controls (HCs) were collected at baseline and follow-up (mean 4.2 years). Global gene expression profiling was conducted by RNA sequencing and a modular analysis was performed. Results Comparison of baseline PreSSc to HCs revealed 2889 differentially expressed genes. Interferon signalling was the only activated pathway among top over-represented pathways. Moreover, 10 modules were significantly decreased in PreSSc samples (related to lymphoid lineage, cytotoxic/NK cell, and erythropoiesis) in comparison to HCs. At follow-up, 14 subjects (42.4%) presented signs of progression (evolving PreSSc) and 19 remained in stable preclinical stage (stable PreSSc). Progression was not associated with baseline clinical features or baseline PBC transcript modules. At follow-up stable PreSSc normalized their down-regulated cytotoxic/NK cell and protein synthesis modules while evolving PreSSc kept a down-regulation of cytotoxic/NK cell and protein synthesis modules. Transcript level changes of follow-up vs baseline in stable PreSSc vs evolving PreSSc showed 549 differentially expressed transcripts (336 up and 213 down) with upregulation of the EIF2 Signalling pathway. Conclusions Participants with PreSSc had a distinct gene expression profile indicating that molecular differences at a transcriptomic level are already present in the preclinical stages of SSc. Furthermore, a reduced NK signature in PBCs was related to SSc progression over time.

Highlights • Systemic lupus erythematosus (SLE) associates with infection susceptibility. • COVID-19 is a pandemic infectious disease with high morbidity and mortality. • The impact of COVID-19 in SLE is poorly characterised. • A web-based survey amongst patients with SLE suggest a moderate increase in morbidity due to COVID-19. • Hydroxychloroquine does not seem able to prevent COVID-19 in patients with SLE., Background Systemic lupus erythematosus (SLE) is a chronic disease characterised by autoimmunity and increased susceptibility to infections. COVID-19 is a systemic viral disease currently spreading as a pandemic. Little is known about the impact of COVID-19 in patients with SLE. Objective to acquire information on the impact of COVID-19 in SLE. Methods A 26-item anonymous questionnaire investigating demographics, SLE clinical features, COVID-19 diagnoses and changes in treatments and daily habits was administered to patients with SLE from three referral centres through www.surveymonkey.com over 10 days. Data from the survey were compared to those from published estimates about the general population. Results Four-hundred-seventeen patients responded to the survey. More than 60% of subjects complained of symptoms that are also associated to COVID-19. Fourteen COVID-19 diagnoses (five confirmed by polymerase chain reaction) were reported, in contrast to a 0.73% prevalence of confirmed cases in Lombardy. One hospitalisation was reported. Fever, anosmia, dry cough, a self-reported history of neuropsychiatric SLE and a recent contact with confirmed COVID-19 cases were more strongly associated with COVID-19, as were symptoms and lower compliance to behavioural preventive measures in patients’ contacts. No protective effect was seen in subjects on hydroxychloroquine. Conclusion COVID-19 morbidity might only moderately be increased in most patients with SLE, although limited information can be inferred on more severe cases. Hydroxychloroquine apparently seems not to confer protection to infection per se, although other beneficial roles cannot be excluded. Containment policies and behavioural preventive measures could have a major role in limiting the impact of COVID-19 in patients with SLE.

Objectives: The analysis of annotated transcripts from genome-wide expression studies may help to understand the pathogenesis of complex diseases, such as systemic sclerosis (SSc). We performed a whole blood (WB) transcriptome analysis on RNA collected in the context of the European PRECISESADS project, aiming at characterising the pathways that differentiate SSc from controls and that are reproducible in geographically diverse populations. Methods: Samples from 162 patients and 252 controls were collected in RNA stabilisers. Cases and controls were divided into a discovery (n=79+163; Southern Europe) and validation cohort (n=83+89; Central-Western Europe). RNA sequencing was performed by an Illumina assay. Functional annotations of Reactome pathways were performed with the Functional Analysis of Individual Microarray Expression (FAIME) algorithm. In parallel, immunophenotyping of 28 circulating cell populations was performed. We tested the presence of differentially expressed genes/pathways and the correlation between absolute cell counts and RNA transcripts/FAIME scores in regression models. Results significant in both populations were considered as replicated. Results: Overall, 15 224 genes and 1277 functional pathways were available; of these, 99 and 225 were significant in both sets. Among replicated pathways, we found a deregulation in type-I interferon, Toll-like receptor cascade, tumour suppressor p53 protein function, platelet degranulation and activation. RNA transcripts or FAIME scores were jointly correlated with cell subtypes with strong geographical differences; neutrophils were the major determinant of gene expression in SSc-WB samples. Conclusions: We discovered a set of differentially expressed genes/pathways validated in two independent sets of patients with SSc, highlighting a number of deregulated processes that have relevance for the pathogenesis of autoimmunity and SSc., This work was supported by eU/eFPia/innovative Medicines initiative Joint Undertaking PrecisesaDs Grant no. 115 565.

Background: Several studies described the cross-sectional characteristics of systemic sclerosis patients and coexisting primary biliary cholangitis, but longitudinal prognostic data are lacking. Aims: To describe the systemic sclerosis–primary biliary cholangitis phenotype, including baseline characteristics and outcomes. Methods: We performed a multicentre the European Scleroderma Trials and Research Group study of systemic sclerosis patients with primary biliary cholangitis or with primary biliary cholangitis–specific antibodies, matched with systemic sclerosis controls free from hepatobiliary involvement matched for disease duration and cutaneous subset. Data were recorded at baseline and at the last available visit. Results: A total of 261 patients were enrolled (115 primary biliary cholangitis–systemic sclerosis, 161 systemic sclerosis). At baseline, systemic sclerosis–primary biliary cholangitis patients had a higher prevalence of anti-centromere antibodies ( p = 0.0023) and a lower prevalence of complete absence of digital ulcers. The milder vascular involvement was confirmed at follow-up when crucial differences emerged in the percentage of patients experiencing digital ulcers; a significantly higher number of patients who never experienced digital ulcers were observed among primary biliary cholangitis–systemic sclerosis patients ( p = 0.0015). Moreover, a greater incidence of pulmonary arterial hypertension ( p Conclusion: Our data show that systemic sclerosis–primary biliary cholangitis exhibit a mild systemic sclerosis and primary biliary cholangitis phenotype with outcomes being in general favourable.

The autonomic nervous system (ANS) and the immune system are deeply interrelated. The ANS regulates both innate and adaptive immunity through the sympathetic and parasympathetic branches, and an imbalance in this system can determine an altered inflammatory response as typically observed in chronic conditions such as systemic autoimmune diseases. Rheumatoid arthritis, systemic lupus erythematosus, and systemic sclerosis all show a dysfunction of the ANS that is mutually related to the increase in inflammation and cardiovascular risk. Moreover, an interaction between ANS and the gut microbiota has direct effects on inflammation homeostasis. Recently vagal stimulation techniques have emerged as an unprecedented possibility to reduce ANS dysfunction, especially in chronic diseases characterized by pain and a decreased quality of life as well as in chronic inflammation.

Recently, case series studies on patients with SARS-CoV-2 infection reported an association between remdesivir (RDV) administration and incidental bradycardia. However, the phenomenon has not yet been described in detail. We conducted a retrospective case-control study to evaluate the occurrence of RDV-related bradycardia in patients hospitalized for SARS-CoV2 pneumoniae. We retrospectively evaluated 71 patients, hospitalized in six internal medicine wards of the Milan area, affected by mild-to-moderate COVID-19 who received RDV (RDV group) and 54 controls, matched for sex, age and disease severity on admission (CTR group). The mean heart rate value recorded during the first two days of hospitalization was considered as baseline heart rate (HRb). Heart rate values relative to the 5-days treatment and the 5-days post-treatment were extracted for RDV group, while heart rate values relative to 10 days of hospitalization were considered for the CTR group. ΔHR values were calculated as maximum HR drop versus HRb. Possible associations between ΔHR and clinical-demographic factors were assessed through regression analysis. The RDV group experienced a significantly higher incidence of bradycardia compared to the CTR group (56% vs 33%, OR 2.6, 95% CI 1.2-5.4, p value = 0.011). Moreover, the RDV group showed higher ΔHR values than the CTR group. The HR progressively decreased with daily administration of RDV, reaching the maximun drop on day six (-8.6±1.9 bpm). In RDV group, patients who experienced bradycardia had higher drop in HR, higher alanine aminotransferase (ALT) values at the baseline (bALT) and during the RDV administration period. ΔHR was positively associated with HRb (β = 0.772, p 0.001) and bALT (β = 0.245, p = 0.005). In conclusion, our results confirmed a significant association between RDV administration and development of bradycardia. This effect was proportional to baseline HR and was associated with higher levels of baseline ALT, suggesting a possible interaction between RDV liver metabolism and a vagally-mediated effect on HR due to increased availability of RDV metabolites.

Sjögren's syndrome (SS) is a systemic autoimmune disease that frequently occurs concomitantly with other systemic connective tissue disorders, including rare and complex diseases such as systemic lupus erythematosus (SLE) and systemic sclerosis (SSc). The presence of SS influences the clinical expression of the other autoimmune diseases, thus offering the unique opportunity to explore the similarities in genetic signatures, as well as common environmental and biologic factors modulating the expression of disease phenotypes. In this review, we will specifically discuss the possibility of defining "SS/SLE" and "SS/SSc" as distinct subsets within the context of connective tissue diseases with different clinical expression and outcomes, thus deserving an individualised assessment and personalised medical interventions.

Objective. To conduct a systematic review of the possible effects of passive heating protocols on cardiovascular autonomic control in healthy individuals. Approach. The studies were obtained from MEDLINE (PubMed), LILACS (BVS), EUROPE PMC (PMC), and SCOPUS databases, simultaneously. Studies were considered eligible if they employed passive heating protocols and investigated cardiovascular autonomic control by spontaneous methods, such as heart rate variability (HRV), systolic blood pressure variability (SBPV), and baroreflex sensitivity (BRS), in healthy adults. The revised Cochrane risk-of-bias tool (RoB-2) was used to assess the risk of bias in each study. Main results. Twenty-seven studies were included in the qualitative synthesis. Whole-body heating protocols caused a reduction in cardiac vagal modulation in 14 studies, and two studies reported both increased sympathetic modulation and vagal withdrawal. Contrariwise, local-heating protocols and sauna bathing seem to increase cardiac vagal modulation. A reduction of BRS was reported in most of the studies that used whole-body heating protocols. However, heating effects on BRS remain controversial due to methodological differences among baroreflex analysis and heating protocols. Significance. Whole-body heat stress may increase sympathetic and reduce vagal modulation to the heart in healthy adults. On the other hand, local-heating therapy and sauna bathing seem to increase cardiac vagal modulation, opposing sympathetic modulation. Nonetheless, further studies should investigate acute and chronic effects of thermal therapy on cardiovascular autonomic control.

Objectives The DETECT algorithm has been developed to identify SSc patients at risk for pulmonary arterial hypertension (PAH) yielding high sensitivity but low specificity, and positive predictive value. We tested whether cardiopulmonary exercise testing (CPET) could improve the performance of the DETECT screening strategy. Methods Consecutive SSc patients over a 30-month period were screened with the DETECT algorithm and positive subjects were referred for CPET before the execution of right-heart catheterization. The predictive performance of CPET on top of DETECT was evaluated and internally validated via bootstrap replicates. Results Out of 314 patients, 96 satisfied the DETECT application criteria and 54 were positive. PAH was ascertained in 17 (31.5%) and pre-capillary pulmonary hypertension in 23 (42.6%) patients. Within CPET variables, the slope of the minute ventilation to carbon dioxide production relationship (VE/VCO2 slope) had the best performance to predict PAH at right-heart catheterization [median (interquartile range) of specificity 0.778 (0.714–0.846), positive predictive value 0.636 (0.556–0.750)]; exploratory analysis on pre-capillary yielded a specificity of 0.714 (0.636–0.8) and positive predictive value of 0.714 (0.636–0.8). Conclusion In association with the DETECT algorithm, CPET may be considered as a useful tool in the workup of SSc-related pulmonary hypertension. The sequential determination of the VE/VCO2 slope in DETECT-positive subjects may reduce the number of unnecessary invasive procedures without any loss in the capability to capture PAH. This strategy had also a remarkable performance in highlighting the presence of pre-capillary pulmonary hypertension.

Objective To analyse the prevalence, the clinical characteristics, the overall survival and the event-free survival (EFS) of SSc patients who express anti-U11/U12 RNP (RNPC-3) antibodies. Methods A total of 447 SSc patients from Barcelona (n = 286) and Milan (n = 161) were selected. All samples were tested using a particle-based multi-analyte technology. We compared anti-RNPC-3 positive and negative patients. Epidemiological, clinical features and survival were analysed. End-stage lung disease (ESLD) was defined if the patient developed forced vital capacity Results Nineteen of 447 (4.3%) patients had anti-RNPC-3 antibodies and interstitial lung disease (ILD) was more frequent (11, 57.9% vs 144, 33.6%, P =0.030) in individuals with anti-RNPC-3 antibodies. More patients reached ESLD in the positive group (7, 36.8% vs 74, 17.3%, P = 0.006), and a higher use of non-glucocorticoid immunosuppressive drugs was observed (11, 57.9% vs 130, 30.4%, P = 0.012). Anti-RNPC-3 positive patients had lower EFS, both in the total cohort (log-rank P =0.001), as well as in patients with ILD (log-rank P = 0.002). In multivariate Cox regression analysis, diffuse cutaneous subtype, age at onset, the presence of ILD or pulmonary arterial hypertension and the expression of anti-RNPC-3 positivity or anti-topo I were independently associated with worse EFS. Conclusion The presence of anti-RNPC-3 was associated with higher frequency of ILD and either ESLD or death. These data suggest anti-RNPC-3 is an independent poor prognosis antibody in SSc, especially if ILD is also present.

Tackling active disease to prevent damage accrual constitutes a major goal in the management of patients with systemic lupus erythematosus (SLE). Patients with early onset disease or in the early phase of the disease course are at increased risk of developing severe manifestations and subsequent damage accrual, while less is known about the course of the disease in the long term. To address this issue, we performed a multicentre retrospective observational study focused on patients living with SLE for at least 20 years and determined their disease status at 15 and 20 years after onset and at their last clinical evaluation. Disease activity was measured through the British Isles Lupus Assessment Group (BILAG) tool and late flares were defined as worsening in one or more BILAG domains after 20 years of disease. Remission was classified according to attainment of lupus low-disease-activity state (LLDAS) criteria or the Definitions Of Remission In SLE (DORIS) parameters. Damage was quantitated through the Systemic Lupus Erythematosus International Collaborating Clinics/American College of Rheumatology damage index (SLICC/ACR-DI). LLAS/DORIS remission prevalence steadily increased over time. In total, 84 patients had a late flare and 88 had late damage accrual. Lack of LLDAS/DORIS remission status at the 20 year timepoint (p = 0.0026 and p = 0.0337, respectively), prednisone dose ≥ 7.5 mg (p = 9.17 × 10−5) or active serology (either dsDNA binding, low complement or both; p = 0.001) were all associated with increased late flare risk. Late flares, in turn, heralded the development of late damage (p = 2.7 × 10−5). These data suggest that patients with longstanding SLE are frequently in remission but still at risk of disease flares and eventual damage accrual, suggesting the need for tailored monitoring and therapeutic approaches aiming at effective immunomodulation besides immunosuppression, at least by means of steroids.

Chronic pain and dysautonomic symptoms deteriorate Systemic sclerosis (SSc) patients’ health-related quality of life with serious repercussions on social life and even on sleep. Heart Rate Variability (HRV) analysis can identify cardiovascular autonomic control impairment in subclinical condition. The aim of the present observational cross-sectional study was to assess the relationship between dysautonomic symptoms, quality of life status and cardiovascular autonomic profile. ECG and respiration were recorded at rest in 20 SSc patients. HRV analysis was performed using two different approaches: Linear spectral analysis and non-linear symbolic analysis. Pain was evaluated using the Numeric Rating Scale (NRS) and 3 questionnaires were administered for the evaluation of sleep quality (PSQI), mood tone (PHQ-9) and disability (HAQ). We found that sleep impairment was related to sympathetic predominance at rest measured as low-frequency/high-frequency ratio (LF/HF) (r = 0.48 and p = 0.033), poorer sleep quality was related to higher pain values (r = 0.48 and p = 0.034) and depressive symptoms (r = 0.82 and p &lt, 0.01), higher pain scores were related to higher cardiovascular vagal modulation and higher disability indexes (r = 0.47 and p = 0.038 &amp, r = 0.55 and p = 0.012, respectively). In conclusion dysautonomia and chronic pain showed a severe impact on sleep quality and disability with a consequent worsening of depressive symptom in our cohort of SSc patients.

Objective Systemic sclerosis (SSc; scleroderma) is a chronic disease that affects the skin and various internal organs. Dermal fibrosis is a major component of this disease. The mechanisms that promote dermal fibrosis remain elusive. Elevations in tissue adenosine levels and the subsequent engagement of the profibrotic A2B adenosine receptor (ADORA2B) have been shown to regulate fibrosis in multiple organs including the lung, kidney, and penis; however, the role of ADORA2B in dermal fibrosis has not been investigated. We undertook this study to test our hypothesis that elevated expression of ADORA2B in the skin drives the development of dermal fibrosis. Methods We assessed the involvement of ADORA2B in the regulation of dermal fibrosis using a well-established mouse model of dermal fibrosis. Using an orally active ADORA2B antagonist, we demonstrated how inhibition of ADORA2B results in reduced dermal fibrosis in 2 distinct experimental models. Finally, using human dermal fibroblasts, we characterized the expression of adenosine receptors. Results We demonstrated that levels of ADORA2B were significantly elevated in dermal fibrosis and that the therapeutic blockade of this receptor in vivo using an ADORA2B antagonist could reduce the production of profibrotic mediators in the skin and attenuate dermal fibrosis. Antagonism of ADORA2B resulted in reduced numbers of arginase-expressing macrophages and myofibroblasts and in reduced levels of the extracellular matrix proteins fibronectin, collagen, and hyaluronan. Conclusion These findings identify ADORA2B as a potential profibrotic regulator in dermal fibrosis and suggest that ADORA2B antagonism may be a useful approach for the treatment of SSc.

This work was supported by EU/EFPIA/Innovative Medicines Initiative Joint Undertaking PRECISESADS grant No. 115565.

Little is known about the impact of coronavirus disease 2019 (COVID-19) pandemic to the care of patients with systemic lupus erythematosus (SLE) in the long-term. By crossing population data with the results of a web-based survey focused on the timeframes January–April and May–December 2020, we found that among 334/518 responders, 28 had COVID-19 in 2020. Seventeen cases occurred in May–December, in parallel with trends in the general population and loosening of containment policy strength. Age > 40 years (p = 0.026), prednisone escalation (p = 0.008) and infected relatives (p

Objective To provide a large-scale assessment of serum protein dysregulation in diffuse cutaneous systemic sclerosis (dcSSc) and to investigate serum protein correlates of SSc fibrotic features. Methods We investigated serum protein profiles of 66 participants with dcSSc at baseline who were enrolled in the Scleroderma: Cyclophosphamide or Transplant Trial and 66 age- and sex-matched healthy control subjects. A panel of 230 proteins, including several cytokines and chemokines, was investigated. Whole blood gene expression profiling in concomitantly collected samples was performed. Results Among the participants with dcSSc, the mean disease duration was 2.3 years. All had interstitial lung disease (ILD), and none were being treated with immunosuppressive agents at baseline. Ninety proteins were differentially expressed in participants with dcSSc compared to healthy control subjects. Similar to previous global skin transcript results, hepatic fibrosis, granulocyte and agranulocyte adhesion, and diapedesis were the top overrepresented pathways. Eighteen proteins correlated with the modified Rodnan skin thickness score (MRSS). Soluble epidermal growth factor receptor was significantly down-regulated in dcSSc and showed the strongest negative correlation with the MRSS, being predictive of the score's course over time, whereas α1 -antichymotrypsin was significantly up-regulated in dcSSc and showed the strongest positive correlation with the MRSS. Furthermore, higher levels of cancer antigen 15-3 correlated with more severe ILD, based on findings of reduced forced vital capacity and higher scores of disease activity on high-resolution computed tomography. Only 14 genes showed significant differential expression in the same direction in serum protein and whole blood RNA gene expression analyses. Conclusion Diffuse cutaneous SSc has a distinct serum protein profile with prominent dysregulation of proteins related to fibrosis and immune cell adhesion/diapedesis. The differential expression for most serum proteins in SSc is likely to originate outside the peripheral blood cells.

ObjectiveIn the randomised scleroderma: Cyclophosphamide Or Transplantation (SCOT trial) (NCT00114530), myeloablation, followed by haematopoietic stem cell transplantation (HSCT), led to improved clinical outcomes compared with monthly cyclophosphamide (CYC) treatment in systemic sclerosis (SSc). Herein, the study aimed to determine global molecular changes at the whole blood transcript and serum protein levels ensuing from HSCT in comparison to intravenous monthly CYC in 62 participants enrolled in the SCOT study.MethodsGlobal transcript studies were performed at pretreatment baseline, 8 months and 26 months postrandomisation using Illumina HT-12 arrays. Levels of 102 proteins were measured in the concomitantly collected serum samples.ResultsAt the baseline visit, interferon (IFN) and neutrophil transcript modules were upregulated and the cytotoxic/NK module was downregulated in SSc compared with unaffected controls. A paired comparison of the 26 months to the baseline samples revealed a significant decrease of the IFN and neutrophil modules and an increase in the cytotoxic/NK module in the HSCT arm while there was no significant change in the CYC control arm. Also, a composite score of correlating serum proteins with IFN and neutrophil transcript modules, as well as a multilevel analysis showed significant changes in SSc molecular signatures after HSCT while similar changes were not observed in the CYC arm. Lastly, a decline in the IFN and neutrophil modules was associated with an improvement in pulmonary forced vital capacity and an increase in the cytotoxic/NK module correlated with improvement in skin score.ConclusionHSCT contrary to conventional treatment leads to a significant ‘correction’ in disease-related molecular signatures.

Objective: Systemic sclerosis (SSc) and rheumatoid arthritis (RA) are autoimmune diseases that have similar clinical and immunologic characteristics. To date, several shared SSc–RA genetic loci have been identified independently. The aim of the current study was to systematically search for new common SSc–RA loci through an interdisease meta–genome-wide association (meta-GWAS) strategy. Methods: The study was designed as a meta-analysis combining GWAS data sets of patients with SSc and patients with RA, using a strategy that allowed identification of loci with both same-direction and opposite-direction allelic effects. The top single-nucleotide polymorphisms were followed up in independent SSc and RA case–control cohorts. This allowed an increase in the sample size to a total of 8,830 patients with SSc, 16,870 patients with RA, and 43,393 healthy controls. Results: This cross-disease meta-analysis of the GWAS data sets identified several loci with nominal association signals (P < 5 × 10−6) that also showed evidence of association in the disease-specific GWAS scans. These loci included several genomic regions not previously reported as shared loci, as well as several risk factors that were previously found to be associated with both diseases. Follow-up analyses of the putatively new SSc–RA loci identified IRF4 as a shared risk factor for these 2 diseases (Pcombined = 3.29 × 10−12). Analysis of the biologic relevance of the known SSc–RA shared loci identified the type I interferon and interleukin-12 signaling pathways as the main common etiologic factors. Conclusion: This study identified a novel shared locus, IRF4, for the risk of SSc and RA, and highlighted the usefulness of a cross-disease GWAS meta-analysis strategy in the identification of common risk loci.

Aminaphtone, a drug used in the treatment of chronic venous insufficiency (CVI), showed a remarkable role in the modulation of several vasoactive factors, like endothelin-1 and adhesion molecules. We analysed in vitro the effects of Aminaphtone on whole-genome gene expression and production of different inflammatory proteins. ECV-304 endothelial cells were stimulated with IL-1β 100U/ml in the presence or absence of Aminaphtone 6μg/ml. Gene expression profiles were compared at 1, 3, and 6h after stimulation by microarray. Supernatants of ECV-304 cultures were analysed at 3, 6, 12, and 24h by multiplex ELISA for production of several cytokine and chemokines. Microarrays showed a significant down-regulation at all times of a wide range of inflammatory genes. Aminaphtone appeared also able to modulate the regulation of immune response process (down-regulating cytokine biosynthesis, transcripts involved in lymphocyte differentiation and cell proliferation, and cytokine-cytokine receptor interaction) and to regulate genes engaged in homeostasis, secretion, body fluid levels, response to hypoxia, cell division, and cell-to-cell communication and signalling. Results were confirmed and extended analysing the secretome, which showed significant reduction of the release of 14 cytokines and chemokines. These effects are predicted to be mediated by interaction with different transcription factors.Aminaphtone was able to modulate the expression of inflammatory molecules relevant to the pathogenesis of several conditions in which the endothelial dysfunction is the main player and early event, like scleroderma, lung fibrosis, or atherosclerosis.

Background:the prognosis of Systemic lupus Erythematosus (SLE) patients has significantly improved over time, raising the need for more data about disease activity and damage accrual in the long term.Objectives:to investigate the risk of long term disease activity and to identify viable prognostic markers for disease flares in SLE patients with long standing diseaseMethods:data on SLE patients regularly followed at ASST PINI-CTO, Fondazione Ca’ Granda Policlinico and Ospedale San Raffaele, Milan (Milan Systemic Lupus Erythematosus Consortium, SMiLE, cohort) with disease duration ≥ 20 years, were retrospectively analyzed. Organ involvement as per the British Isles Lupus Assessment Group (BILAG) definitions was recorded along with achievement of clinical and complete remission (CR and CCR: clinical SLEDAI =0, PGA Results:data from 168 patients (table 1) were available for analysis. Remission (CR+CCR) and LLDAS were achieved in 22% and 61% at T15 and 25% and 71% at T20. LLDAS was not associated with a history of involvement in any BILAG domain, but it was inversely associated with treatment with mycophenolate at any time (50 vs 23% treated vs not treated; p=0.02). SDI>0 was found in 49% patients at T15 and in 71% at T20. LLDAS at T15 was associated with lower flare rates in the following five years (HR= 0.395, 95%, CI=0.239-0.653; Figure, left panel; pTable 1.Demographic, laboratory and clinical characteristics of patients with SLECharacteristics(n=168)Demographic characteristicsFemale, n (%)150 (89.3)Age at diagnosis years, median (IQR)24 (18-32)Clinical and serological features during 15 years follow up, n (%)Musculoskeletal140 (83)Mucocutaneous135 (80)Constitutional114 (68)Haematological103 (61)Nephritis81 (48)Cardiopulmonary49 (29)NPSLE31 (18)Positive anti-dsDNA136 (81)Hypocomplementemia136 (81)Positive antiphospholipid73 (44)CR / CCR at T1513 (8) / 23 (14)CR / CCR at T2017 (10) / 25 (15)Conclusion:LLDAS is common in SLE patients with long disease duration although up to 37% of patients with 15-year disease duration may experience a flare during the following 5 years. The flare risk increases with failure to attain LLDAS at T15 and with active serology. Late flares associate with damage accrual.References:[1]Aringer M, Ann Rheum Dis. 2019; Franklin K, Ann Rheum Dis 2019Table 2.therapy during the 20 year follow upTherapy (ever)%Prednisone83Hydroxychloroquine91Mycophenolate mofetil33Azathioprine50Methotrexate23Cyclophosphamide36Fig 1:risk of flare according to disease activityDisclosure of Interests:Maria Gerosa: None declared, Giuseppe Alvise Ramirez: None declared, Chiara Bellocchi: None declared, Lorenza Maria Argolini: None declared, Luca Moroni: None declared, Martina Cornalba: None declared, Nicola Farina: None declared, Lorenzo Dagna Grant/research support from: Abbvie, BMS, Celgene, Janssen, MSD, Mundipharma Pharmaceuticals, Novartis, Pfizer, Roche, SG, SOBI, Consultant of: Abbvie, Amgen, Biogen, BMS, Celltrion, Novartis, Pfizer, Roche, SG, and SOBI, Roberto Caporali Consultant of: AbbVie; Gilead Sciences, Inc.; Lilly; Merck Sharp & Dohme; Celgene; Bristol-Myers Squibb; Pfizer; UCB, Speakers bureau: Abbvie; Bristol-Myers Squibb; Celgene; Lilly; Gilead Sciences, Inc; MSD; Pfizer; Roche; UCB, Enrica Bozzolo: None declared, Lorenzo Beretta Grant/research support from: Pfizer

Background:Genome-wide gene expression profiles and pathways analysis may help to discover deregulated processes underlying the pathogenesis of complex diseases or their phenotypic expression. Little or nothing is currently known about pathways associated with disease severity and damage in SSc.Objectives:To perform a whole blood transcriptome analysis and to characterize the individualized functional pathways associated with disease severity scores in SSc patients via a discovery and replication strategy.Methods:Whole blood samples were collected in RNA stabilizers from a discovery and a replication cohort of 67 and 34 patients, respectively. RNAseq data were generated by Illumina sequencing in two independent experiments pathways analysis was conducted according to the Functional Analysis of Individual Microarray Expression (FAIME) protocol (1). FAIME scores from Reactome pathways were correlated with the Scleroderma Clinical Trial Consortium Damage Index (SCTC-DI) total scores or with each of its two components (mortality and morbidity) as calculated from regression coefficient previously published (2). A non-parametric partial correlation analysis correcting the results for the use of steroids, immunosuppressants and disease duration was performed. Results independently associated with damage in both cohorts at the 0.1 level after 1000-fold permutation-testing were considered as significant and replicated.Results:A total of 1116 pathways were analyzed. None of them was associated in both cohorts with the total SCTC-DI; similarly, no association was found with the SCTC mortality component. On the contrary, 26 pathways showed an independent and replicated association with the SCTC morbidity component, including platelet degranulation, the transcriptional activity of SMAD2/SMAD3, Toll Like Receptor 2 (TLR2) cascade and related intracellular signaling events involving MyD88, IRAK and NF-kB, and the deregulation of selected transcription factors (TFAP2, E2F6).Conclusion:Selected molecular events involving the innate immune system, signaling and platelet metabolism are associated with the morbidity component of the SCTC-DI in SSc patients, reflecting an irreversible loss of function in several organs and apparatus. The sensitivity of these associations to individual change in accrual damage is to be determined.References:[1]PMID: 22291585; (2) PMID: 30928903Acknowledgments:This work was partially supported by EU/EFPIA/Innovative Medicines Initiative Joint Undertaking PRECISESADS grant No. 115565Disclosure of Interests:Chiara Bellocchi: None declared, Marzia Rossato: None declared, Guillermo Barturen: None declared, Giulia Segatto: None declared, Barbara Vigone: None declared, Zuzanna Makowska Employee of: Bayer AG, Anne buttgereit Employee of: Bayer AG, Martin Kerick: None declared, Marta Alarcon-Riquelme: None declared, Javier Martin Ibanez: None declared, Lorenzo Beretta Grant/research support from: Pfizer

Background:The staging of interstitial lung disease (ILD) is important to monitor disease progression and for prognostication. A disease severity scale of Systemic Sclerosis (SSc)-related lung disease has long been proposed (i.e. Medsger’s severity scale). This scale was mostly developed by discussion and consensus and stage thresholds were not computed by a data-driven approach. Hidden Markov models (HMM) are methods to estimate population quantities for chronic diseases with a staged interpretation which are diagnosed by markers measured at irregular intervals.Objectives:To build a SSc-ILD specific disease severity scale with prognostic relevance via HMM modeling.Methods:A total of 358 SSc patients at risk for or with ILD were enrolled in a discovery (207 cases, Milan1) and in a validation (151 cases, Milan2, Pavia and Rome) cohort. Patients were included if satisfied the following criteria: 1) Diagnosis of SSc according to the EULAR/ACR 2013 criteria, 2) absence of anticentromere antibodies, 3) dcSSc subset or 4) other subsets with either 4a) ILD-related antibodies (Scl70, PmScl, Ku) or 4b) evidence of ILD on HRCT, 5) disease duration < 5 years at the time of the first pulmonary function test (PFT). Serial PFTs were retrieved and the time up to the last available visit -if the patient alive-, or to death due to pulmonary complications, was recorded. HMM were used to estimate the threshold of a 3-stage model (SL3SI, Scleroderma Lung 3-Stage Index) based on PFT functional values (normal/mild, moderate, severe involvement) in the discovery cohort. Survival estimates of the SL3SI model were compared to Medsger’s severity classes estimates and their predictive capability evaluated via the explained residual variation (R2) of prediction errors (the higher the better). One-hundred random replicates were generated to simulate the prediction effort in patients with different disease duration and lung severity.Results:Patients characteristics are summarized in the Table. Fifteen-years survival estimates for Mesdger’s classes in the discovery set were: normal=0.88, mild=0.86, moderate=0.84 and severe=0.71. The SL3SI was defined by the following thresholds: normal/mild, FVC and DLco >=75%; moderate FVC or DLco 74-55%; severe, FVC or DLco 2values at 15 yrs for the SL3SI compared to Medsger’s classes, providing evidence for a better predictive capability of the former (discovery: 0.31 vs 0.25; validation: 0.28 vs 0.19).Conclusion:The SL3SI, a simplified 3-stage functional model of SSc-ILD, yields better survival estimates and long-term prognostic information than Medsger’s classes. Its reproducibility and ease of use make it a useful tool for the functional and prognostic evaluation of SSc patients at risk for or with ILD.Table:VariablesDiscovery (n=207)Replication (n=151)DcSSc62 (30%)98 (64%)Age at first PFR48.6±1249.1±14.4Disease duration at first PFR1.7±1.61.3±2.4FVC90.5±18.191.1±20.2DLco70.7±19.861.3±20.1ILD on HRCT179 (86%)125 (80%)Scl70157 (76%)153 (78%)SSA63 (30%)32 (21%)n of visits38571473Follow-up time, yrs11±5.610.6±5.7Deaths27 (13%)23 (15%)Disclosure of Interests:Alessandro Santaniello: None declared, Chiara Bellocchi: None declared, Luca Bettolini: None declared, Marcello Cassavia: None declared, Gaia Montanelli: None declared, Adriana Severino: None declared, Monica Caronni: None declared, Corrado Campochiaro Speakers bureau: Novartis, Pfizer, Roche, GSK, SOBI, Enrico De Lorenzis: None declared, Gerlando Natalello: None declared, Paolo Delvino: None declared, Claudio Tirelli: None declared, Lorenzo Cavagna: None declared, Giacomo De Luca Speakers bureau: SOBI, Novartis, Celgene, Pfizer, MSD, Silvia Laura Bosello: None declared, Lorenzo Beretta Grant/research support from: Pfizer

Objective To compare autonomic heart rate variability (HRV) parameters at rest and during active stand in a population of SSc patients, taking into account SSc subsets age-matched to healthy control subjects. Methods Sixty-nine consecutive SSc patients were enrolled in study; these included 12 subjects with early SSc, 39 with limited cutaneous (lcSSc) and 18 with diffuse cutaneous SSc (dcSSc) along with 36 age- and sex-matched healthy controls (HC). ECG and respiration were recorded in supine position and in orthostatism (ORT). HRV analysis was performed on samples of 300 beats. Spectral analysis identified two oscillatory components, low frequency (LFnu, sympathetic) and high frequency (HFnu, vagal). Symbolic analysis identified three patterns, 0 V%, (sympathetic) and 2UV% and 2LV%, (vagal). The %∆ORT was calculated from the differences between HRV in ORT and SUP, normalized (%) by the HRV values at rest. Results SSc as a whole had higher markers of sympathetic (LF, 0 V%) and lower markers of vagal modulation (HR, 2UV%, 2LV%) compared to HCs. In addition, %∆LFnu, %∆HFnu, %∆0 V, %∆2UV and %∆2LV were lower in SSc than HC. dcSSc and lcSSc were dissimilar to HC as far as rest indexes were concerned (↑LF/HF, ↑LFnu, ↓HFnu, ↑0 V% and ↓2UV%) while no differences could be detected between HC and EaSSc. Conclusion SSc showed a reduced vagal and increased sympathetic modulation at rest and a blunted autonomic response to ORT in comparison to HC. These alterations were mostly detectable in the advanced and fibrotic forms of SSc (dcSSc and lcSSc), while EaSSc were similar to HC.

Accumulating evidence suggests that gut microbiota affect the development and function of the immune system and may play a role in the pathogenesis of autoimmune diseases. The purpose of this review is to summarize recent studies reporting gastrointestinal microbiota aberrations associated with the systemic sclerosis disease state. The studies described herein have identified common changes in gut microbial composition. Specifically, patients with SSc have decreased abundance of beneficial commensal genera (e.g., Faecalibacterium, Clostridium, and Bacteroides) and increased abundance of pathobiont genera (e.g., Fusobacterium, Prevotella, Erwinia). In addition, some studies have linked specific genera with the severity of gastrointestinal symptoms in systemic sclerosis. More research is needed to further characterize the gastrointestinal microbiota in systemic sclerosis and understand how microbiota perturbations can affect inflammation, fibrosis, and clinical outcomes. Interventional studies aimed at addressing/correcting these perturbations, either through dietary modification, pro/pre-biotic supplementation, or fecal transplantation, may lead to improved outcomes for patients with systemic sclerosis.

Background In the randomised Scleroderma: Cyclophosphamide or Transplantation (SCOT) trial, myeloablation followed by autologous hematopoietic stem cell transplantation (HSCT) led to improved clinical outcomes compared to monthly cyclophosphamide (CYC) treatment in systemic sclerosis (SSc). 1 Moreover, there is emerging evidence on the role of the Th2 cytokine, interleukin 6 (IL-6) in SSc pathogenesis, and clinical trials targeting the IL-6 pathway have been completed. 2 Objectives To investigate the association of IL-6 with baseline clinical features and to examine its longitudinal changes in the treatment arms of the SCOT trials. Methods The SCOT trial enrolled 75 subjects with diffuse SSc, 65 (HSCT=31, CYC=34) subjects with a mean disease duration of 2.2 years were analysed; 65 age and gender matched controls were also investigated. All available serum samples at the baseline (n=65), 8- (n=55) and 26- (n=45) month visits were included. IL-6 was determined using ultra-sensitive Simoa assay. For purposes of comparison, prominent, pro-inflammatory Th1 cytokines, Interleukin 1β (IL-1β), interleukin 12 (IL-12), and interferon gamma (IFN-γ) were determined by Rule Based Medicine multiplex assays. The serum IFN-γ levels were in undetectable range in the majority of patient and control samples. Therefore, the comparative analysis focused on IL-1β and IL-12. Results Serum IL-6 was higher in SSc patients than controls (fold change=1.62, p A comparison of regression lines revealed a significant decrease in serum IL-6 levels in the HSCT arm relative to CYC (p=0.0004). By 26 months, the HSCT arm no longer showed upregulation of serum IL-6 relative to controls while the CYC arm remained upregulated. In contrast, time trends for IL-1β and IL-12 did not differ significantly between arms (p-values=0.161 and 0.456, respectively). (figure 1). Conclusions The Serum IL-6 levels decreased significantly 26 months after HSCT, while the two Th1, proinflammatory cytokines did not show similar changes. This finding supports the notion that this treatment modality normalises specific serum protein imbalances implicated in SSc pathogenesis. References [1] Sullivan KM, Goldmuntz EA, Keyes-Elstein L, McSweeney PA, Pinckney A, Welch B, et al. Myeloablative Autologous Stem-Cell Transplantation for Severe Scleroderma. N Engl J Med2018. [2] Khanna D, Denton CP, Jahreis A, van Laar JM, Frech TM, Anderson ME, et al. Safety and efficacy of subcutaneous tocilizumab in adults with systemic sclerosis (faSScinate): a phase 2, randomised, controlled trial. Lancet2016. Disclosure of Interest None declared

Intestinal microbiota has been associated with systemic autoimmune diseases, yet the functional consequences of these associations are elusive. We characterized the fecal microbiota (16S rRNA gene amplification and sequencing) and the plasma metabolome (high-performance liquid chromatography coupled to mass spectrometry) in 59 patients with systemic sclerosis (SSc) and 28 healthy controls (HCs). Microbial and metabolic data were cross-correlated to find meaningful associations after extensive data mining analysis and internal validation. Our data show that a reduced model of nine bacteria is capable of differentiating HCs from SSc patients. SSc gut microbiota is characterized by a reduction in protective butyrate-producing bacteria and by an increase in proinflammatory noxious genera, especially Desulfovibrio. From the metabolic point of view, a multivariate model with 17 metabolite intermediates well distinguished cases from controls. The most interesting peaks we found were identified as glycerophospholipid metabolites and benzene derivatives. The microbial and metabolic data showed significant interactions between Desulfovibrio and alpha-N-phenylacetyl-l-glutamine and 2,4-dinitrobenzenesulfonic acid. Our data suggest that in SSc, intestinal microbiota is characterized by proinflammatory alterations subtly entwined with the metabolic state. Desulfovibrio is a relevant actor in gut dysbiosis that may promote intestinal damage and influence amino acid metabolism.

Systemic sclerosis (SSc), an autoimmune disorder, is characterized by vasculopathy, inflammation, progressive perivascular and interstitial fibrosis. Its pathogenesis is largely unknown, however strong evidences suggest that genetic predisposition may contribute to SSc development. Several gene polymorphisms involved in regulatory T cell function have been identified in many autoimmune diseases, including SSc. Moreover, dysregulation of co-stimulatory and/or co-inhibitory signals, including ICOS signalling, can lead to autoimmunity. The aim of the present study was to investigate the association of the FOXP3 rs2294020, ICOS rs6726035 and ICOSL rs378299 SNPs with both the susceptibility and the progression to SSc in an Italian case-series of patients. SNP genotyping results were successfully obtained from a total of 350 subjects including 166 individuals with SSc and 184 healthy controls. Although analysis tests did not show any significant associations between the SNPs under study and susceptibility to SSc, the occurrence of FOXP3 rs2294020 in female patients was associated with decreased time to progression from early to definite SSc (allelic model: HR = 1.43; CI = 1.03-1.99; p = 0.03; dominant model: HR = 1.54; CI = 1.04-2.28; p = 0.03). The inclusion of presence of ACA autoantibodies in the model did not significantly change the estimates. No conclusions can be drawn for the susceptibility to the disease or the time to progression in men due to the low statistical power. This study provides evidence of the association of rs2294020 with SSc evolution in female patients, modulating the time of progression from the diagnosis of early SSc to the diagnosis of definite SSc, while no effect on SSc susceptibility per se was found. rs2294020 may be considered a disease-modifying gene-variant rather than a disease-susceptibility SNP in SSc.

Background Pneumoproteins are attractive biomarker candidates in systemic sclerosis (SSc) related interstitial lung disease (ILD) because they are easily obtainable and lung-specific. KL-6 and CCL-18 (PARC) have been previously reported as promising predictive biomarkers of lung parenchymal damage in multiple disorders including SSc-ILD. Objectives Our goal was to determine the predictive significance of these two pneumoproteins for forced vital capacity % (FVC) decline within the first year of follow-up in patients with early SSc-ILD, in order to inform individualized care in routine clinical practice and facilitate enrichment strategies in clinical trials. Methods GENISOS (Genetics versus ENvironment In Scleroderma Outcome Study) cohort patients who had ILD verified by imaging and available pulmonary function tests at enrollment plus 12–18 months thereafter, were included in this study. All patients had disease duration ≤5 years at enrollment. FVC, expressed as percentage of predicted value was used as surrogate for severity of ILD. Annualized percent change in FVC at one year follow up was calculated. Baseline demographic, clinical variables and two pneumo-proteins, KL-6 and CCL-18 were investigated. KL-6 and CCL-18 were measured in the plasma by commercially available, validated ELISA kits. Linear regression with baseline clinical and demographic variables as independent variables was performed in univariable and multivariable models. Only variables that reached p Results A total of 82 patients with early SSc-ILD were included, 18 were male and 45 had diffuse cutaneous involvement. Mean disease duration was 2.3 years. Rate of FVC% predicted change over time ranged from -0.23 to 0.38, indicating a highly variable course. Baseline KL-6 levels were higher in patients than healthy controls (p p =0.04). Upon categorizing KL-6 using a previously determined optimal cut-off of 1273 u/mL (1), its predictive significance remained in the univariate (p=0.01) and multivariable analyses adjusted for Scl-70, disease type and gender (b=-0.03, p =0.04). Twenty nine (34.5%) patients had KL6 levels equal or above 1273 u/mL. Although CCL-18 was higher in patients than controls ( Conclusions KL-6 but not CCl-18 is predictive of early SSc-ILD progression. In this study, we also validated the previously proposed cut-off of 1273 for KL-6 in an independent cohort. KL-6 is a promising pneumoprotein that can inform individualized clinical care and contribute to enrichment strategies in clinical trials of SSc-ILD. References Kuwana M, Shirai Y, Takeuchi T. Elevated Serum Krebs von den Lungen-6 in Early Disease Predicts Subsequent Deterioration of Pulmonary Function in Patients with Systemic Sclerosis and Interstitial Lung Disease. J Rheumatol 2016. Acknowledgements This study was funded by the National Institute of Health NIH/NIAMS K23 AR061436 (Assassi); NIH/NIAMS P50-AR05414 and the Department of Defense Congressionally Directed Medical Research Programs (W81XWH-07–01–0111- Mayes). Disclosure of Interest None declared

Dysbiosis has been described in systemic autoimmune diseases (SADs), including systemic lupus erythematosus (SLE), Sj&ouml, gren&rsquo, s syndrome (SjS), and primary anti-phosholipid syndrome (PAPS), however the biological implications of these associations are often elusive. Stool and plasma samples from 114 subjects, including in SLE (n = 27), SjS (n = 23), PAPs (n = 11) and undifferentiated connective tissue (UCTD, n = 26) patients, and geographically-matched healthy controls (HCs, n = 27), were collected for microbiome (16s rRNA gene sequencing) and metabolome (high-performance liquid chromatography coupled to mass spectrometry) analysis to identify shared characteristics across diseases. Out of 130 identified microbial genera, a subset of 29 bacteria was able to differentiate study groups (area under receiver operating characteristics (AUROC) = 0.730 &plusmn, 0.025). A fair classification was obtained with a subset of 41 metabolic peaks out of 254 (AUROC = 0.748 &plusmn, 0.021). In both models, HCs were well separated from SADs, while UCTD largely overlapped with the other diseases. In all of the SADs pro-tolerogenic bacteria were reduced, while pathobiont genera were increased. Metabolic alterations included two clusters comprised of: (a) members of the acylcarnitine family, positively correlating with a Prevotella-enriched cluster and negatively correlating with a butyrate-producing bacteria-enriched cluster, and (b) phospholipids, negatively correlating with butyrate-producing bacteria. These findings demonstrate a strong interaction between intestinal microbiota and metabolic function in patients with SADs.

Autoimmune diseases often share common susceptibility genes. Most genetic variants associated with susceptibility to systemic lupus erythematosus are also associated with other autoimmune diseases. The X-linked variant rs2294020 is positioned in exon 7 of the CCDC22 gene. The encoded protein functions in the regulation of NF-kB, a master regulator in immune response. The aim of this study is to investigate whether the rs2294020 polymorphism may be a general susceptibility factor for autoimmunity. We evaluated case-control association between the occurrence of rs2294020 and different autoimmune diseases, including new data for systemic lupus erythematosus and previous genome-wide association studies (GWAS) (though most did not analyse the X chromosome) of psoriasis, celiac disease, Crohn’s disease, ulcerative colitis, multiple sclerosis, vitiligo, type-1 diabetes, rheumatoid arthritis, and ankylosing spondylitis. Cases from patients affected by amyotrophic lateral sclerosis and type-2 diabetes were also included in the study. We detected nominal significant associations of rs2294020 with systemic lupus erythematosus (additive model test: p=0.01), vitiligo (p =0.016), psoriasis (p =0.038), and in only one of two studies of multiple sclerosis (p =0.03). Our results suggest that rs2294020 is associated with the risk of several autoimmune diseases in European populations, specifically with diseases that present themselves, among else, in the skin.

OBJECTIVE. Systemic sclerosis (SSc; scleroderma) is a chronic disease that affects the skin and various internal organs. Dermal fibrosis is a major component of this disease. The mechanisms that promote dermal fibrosis remain elusive. Elevations in tissue adenosine levels and the subsequent engagement of the profibrotic A(2B) adenosine receptor (ADORA2B) have been shown to regulate fibrosis in multiple organs including the lung, kidney, and penis; however, the role of ADORA2B in dermal fibrosis has not been investigated. We undertook this study to test our hypothesis that elevated expression of ADORA2B in the skin drives the development of dermal fibrosis. METHODS. We assessed the involvement of ADORA2B in the regulation of dermal fibrosis using a well-established mouse model of dermal fibrosis. Using an orally active ADORA2B antagonist, we demonstrated how inhibition of ADORA2B results in reduced dermal fibrosis in 2 distinct experimental models. Finally, using human dermal fibroblasts, we characterized the expression of adenosine receptors. RESULTS. We demonstrated that levels of ADORA2B were significantly elevated in dermal fibrosis and that the therapeutic blockade of this receptor in vivo using an ADORA2B antagonist could reduce the production of profibrotic mediators in the skin and attenuate dermal fibrosis. Antagonism of ADORA2B resulted in reduced numbers of arginase-expressing macrophages and myofibroblasts and in reduced levels of the extracellular matrix proteins fibronectin, collagen, and hyaluronan. CONCLUSION. These findings identify ADORA2B as a potential profibrotic regulator in dermal fibrosis and suggest that ADORA2B antagonism may be a useful approach for the treatment of SSc.