The role of type I interferons and other cytokines in dermatomyositis

A Review of Myositis-Associated Interstitial Lung Disease

There is a well-established relationship between different subsets of idiopathic inflammatory myopathies (IIMs, myositis) and interstitial lung disease (ILD), with lung complications sometimes presenting prior to myopathic manifestations. The subtypes of myositis include those that are strongly associated with ILD, such as polymyositis (PM) and dermatomyositis (DM). Research has shown that in certain patients, these can then be further divided into subtypes using myositis-specific antibodies (MSAs), which are specific for myositis, and myositis-associated antibodies (MAAs), which can be found in myositis in overlap syndromes with other connective tissue diseases (CTDs). Notably, certain MSAs and MAAs are associated with ILD in patients with myositis. The clinical presentations of ILD in patients with myositis can vary widely and can be insidious in onset and difficult to diagnose. As ILD can progress rapidly in some cases, it is essential that clinicians are able to identify and diagnose ILD in patients with myositis. For this reason, the aim of this review is to highlight the clinical features, diagnostic criteria, important histopathologic, laboratory, and radiographic features, and treatment modalities for those patients with myositis-associated ILD.

Effect of type I interferon on engineered pediatric skeletal muscle: a promising model for juvenile dermatomyositis

OBJECTIVE

To investigate pathogenic mechanisms underlying JDM, we defined the effect of type I IFN, IFN-α and IFN-β, on pediatric skeletal muscle function and expression of myositis-related proteins using an in vitro engineered human skeletal muscle model (myobundle).

METHODS

Primary myoblasts were isolated from three healthy pediatric donors and used to create myobundles that mimic functioning skeletal muscle in structural architecture and physiologic function. Myobundles were exposed to 0, 5, 10 or 20 ng/ml IFN-α or IFN-β for 7 days and then functionally tested under electrical stimulation and analyzed immunohistochemically for structural and myositis-related proteins. Additionally, IFN-β-exposed myobundles were treated with Janus kinase inhibitors (JAKis) tofacitinib and baricitinib. These myobundles were also analyzed for contractile force and immunohistochemistry.

RESULTS

IFN-β, but not IFN-α, was associated with decreased contractile tetanus force and slowed twitch kinetics. These effects were reversed by tofacitinib and baricitinib. Type I IFN paradoxically reduced myobundle fatigue, which did not reverse after JAKi. Additionally, type I IFN correlated with MHC I upregulation, which normalized after JAKi treatment, but expression of myositis-specific autoantigens Mi-2, melanocyte differentiation-associated protein 5 and the endoplasmic reticulum stress marker GRP78 were variable and donor specific after type I IFN exposure.

CONCLUSION

IFN-α and IFN-β have distinct effects on pediatric skeletal muscle and these effects can partially be reversed by JAKi treatment. This is the first study illustrating effective use of a three-dimensional human skeletal muscle model to investigate JDM pathogenesis and test novel therapeutics.

Analysis of characteristics related to interstitial lung disease or pulmonary hypertension in patients with dermatomyositis

INTRODUCTION

Dermatomyositis (DM) is often associated with interstitial lung disease (ILD) or pulmonary hypertension (PH). The aim of this study was to investigate the clinical characteristics of DM patients with ILD or PH.

METHODS

This study retrospectively analysed the clinical characteristics of 372 patients with DM, including cytokines, lymphocyte subsets, immunoglobulin and complement. The DM patients were divided into different groups according to whether complicated with ILD, PH or anti-melanoma differentiation-associated gene 5 antibodies (MDA5). A qualitative and quantitative data analysis was performed.

RESULTS

IgG, IgA and IgM in the DM-associated ILD (ILD-DM) were higher than that of the DM non-complicating ILD (Non-ILD-DM) (p = 0.022, 0.002 and 0.029, respectively). Meanwhile, IL-6 (p = 0.008) and IL-10 (p = 0.001) were increased in the DM-associated PH (PH-DM) than in the DM non-complicating PH (Non-PH-DM), while IL-17 (p = 0.004), double positive (DP) cell ratio and B lymphocyte ratio were reduced in the PH-DM. Moreover, the incidence of ILD and levels of C4 were higher in the DM with MDA5 (MDA5+ DM) than that of the DM without MDA5.

CONCLUSION

ILD-DM has higher IgG, IgA and IgM than that of Non-ILD-DM. PH-DM has higher IL-6, IL-10 and lower IL-17, DP cell ratio and B lymphocyte ratio than that of Non-PH-DM.

Patients with dermatomyositis shared partially similar transcriptome signature with COVID-19 infection

Dermatomyositis (DM) is an autoimmune disease that primarily affects the skin and skeletal muscle. Virus infection and type I interferon-related signaling pathways play an important role in the pathogenesis of dermatomyositis. In this study, we found that the skin of patients with DM and the skin of patients with COVID-19 have similar transcriptional profiles, and identified key genes involved in dermatomyositis based on bioinformatics analysis. These hub-genes might be served as potential biomarkers for the early diagnosis and therapy of DM, including MX1, ISG15, IFIT3, IFIT1, RSAD2, IFIT2, IFI6, XAF1, IRF9, MX2.

Recombinant Porcine Interferon-α Decreases Pseudorabies Virus Infection

Interferon (IFN) is a cell-secreted cytokine possessing biological activities including antiviral functioning, immune regulation, and others. Interferon-alpha (IFN-α) mainly derives from plasmacytoid dendritic cells, which activate natural killer cells and regulate immune responses. IFN-α responds to the primary antiviral mechanism in the innate immune system, which can effectively cure acute infectious diseases. Pseudorabies (PR) is an acute infectious disease caused by pseudorabies virus (PRV). The clinical symptoms of PRV are as follows: reproductive dysfunction among pregnant sows and high mortality rates among piglets. These pose a severe threat to the swine industry. Related studies show that IFN-α has broad applications in preventing and treating viral diseases. Therefore, a PRV mouse model using artificial infection was established in this study to explore the pathogenic effect of IFN-α on PRV. We designed a sequence with IFN-α4 (M28623, Genbank) and cloned it on the lentiviral vector. CHO-K1 cells were infected and identified using WB and RT-PCR; a CHO-K1 cell line with a stable expression of the recombinant protein PoIFN-α was successfully constructed. H&E staining and virus titer detection were used to investigate the recombinant protein PoIFN-α's effect on PR in BALB/c mice. The results show that the PoIFN-α has a preventive and therapeutic impact on PR. In conclusion, the recombinant protein can alleviate symptoms and reduce the replication of PRV in vivo.

Impaired muscle strength is associated with ultrastructure damage in myositis

The muscle fiber ultrastructure in Idiopathic Inflammatory Myopathies (IIM) has been scarcely explored, especially in Inclusion Body Myositis. The aim of this study was to implement the Scanning Electron Microscopy (SEM) in a small cohort of IIM patients, together with the characterization of immunological profile for a better understanding of the pathophysiology. For immunological profile characterization, we identified the presence of autoantibodies (Ro-52, OJ, EJ, PL7, PL12, SRP, Jo-1, PMScl75, PMScl100, Ku, SAE1, NXP2, MDA5, TIF1γ, Mi-2α, Mi-2β) and quantified cytokines (IL-1β, IFN-α2, IFN-γ, TNF-α, IL-6, IL-10, IL-12p70, IL-17A, IL-18, IL-23, IL-33) and chemokines (CCL2, CXCL8). The histological analysis was made by hematoxylin-eosin staining while the muscle fiber ultrastructure was characterized by SEM. We observed changes in the morphology and structure of the muscle fiber according to muscle strength and muscle enzymes. We were able to find and describe muscle fiber ultrastructure with marked irregularities, porosities, disruption in the linearity and integrity of the fascicle, more evident in patients with increased serum levels of muscle enzymes and diminished muscle strength. Despite the scarce reports about the use of SEM as a tool in all clinical phenotypes of IIM, our work provides an excellent opportunity to discuss and reframe the clinical usefulness of SEM in the diagnostic approach of IIM.

Activation of cGAS‐STING pathway – A possible cause of myofiber atrophy/necrosis in dermatomyositis and immune‐mediated necrotizing myopathy

Objective

The objective was to investigate the expression of the cGAS‐STING pathway‐associated protein in idiopathic inflammatory myopathy (IIM) and to investigate whether it is related to myofiber atrophy/necrosis in patients with dermatomyositis and immune‐mediated necrotizing myopathy.

Material and Methods

Muscle specimens obtained by open biopsy from 26 IIM patients (14 with dermatomyositis (DM), 8 with immune‐mediated necrotizing myopathy (IMNM), and 4 with other types of IIM), 4 dystrophinopathy, and 9 control patients were assessed for expression of cGAS‐STING pathway members via Western blot, quantitative real‐time PCR analysis (qRT‐PCR), and immunochemistry. Meanwhile, analysis its location distribution througn immunochemistry.

Results

Compared to the control group, the expression of cGAS, STING, and related molecules was obviously increased in muscle samples of IIM patients. Upregulated cGAS and STING were mainly located in the vascular structure, inflammatory infiltrates, and atrophic and necrotic fibers. While comparing to the Dys patients, the mRNA level of cGAS, STING, and TNF‐a was upregulated, meanwhile, the protein of the TBK1, P‐TBK1, and P‐IRF3 associated with interferon upregulation was overexpressed through Western blot in IMNM and DM. Considering that cGAS and STING are located in necrotic and Mx1‐positive atrophic fibers, it is really possible that the cGAS‐STING pathway may lead to fibers atrophy/necrosis by producing IFNs.

Conclusion

The cGAS‐STING pathway was activated in the muscle samples of IIM patients and its activation may be the reason of myofiber atrophy and necrosis in DM and IMNM patients.

Involvement of Type-I Interferon Signaling in Muscle Stem Cell Proliferation During Dermatomyositis

Background and objective:

The idiopathic inflammatory myopathy Dermatomyositis (DM) is an acquired disease that combines muscle, lung and skin impairments. DM patients show a wide range of severity of proximal skeletal muscle weakness, associated with inflammatory infiltrates, vasculitis, and capillary dropout, perifascicular myofiber atrophy. Moreover, DM muscles show signs of muscle regeneration. Since muscle stem cells (MuSCs) are responsible for myofiber repair, we asked wether the proliferative properties of muscle stem cells (MuSCs) are altered in DM muscle. We investigated the role of type-I interferon (IFN-I) in this process since DM is associated with sustained inflammation with high IFN-I levels.

Methods:

MuSCs isolated from normal, adult and juvenile DM muscles were grown in culture and were analyzed in vitro for their proliferating properties, their myogenic capacities and their senescence. Gain and loss of function experiments were performed to assess the role of IFN-I signaling in the prolfierative capacities of MuSCs.

Results:

MuSCs derived from 8 DM adult patients (DM-MuSCs) (5 severe form and 3 mild form, established from histological evaluation), from 3 juvenile DM patients and from normal muscle were used to analyze their myogenesis in vitro. DM-MuSCs exhibited strongly reduced proliferating capacities as compared with healthy MuSCs (-31 to -43% for severe and mild DM, respectively), leading to poor myotube formation (-36 to -71%). DM-MuSCs were enriched in senescent, beta-galactosidase positive cells, explaining partly the proliferation defect. Gain and loss of function experiments were performed to assess the role of IFN-I on the proliferative capacity of MuSCs. High concentrations of IFN-I decreased the proliferation of healthy MuSCs. Similarly, conditioned-medium from DM-MuSCs decreased the proliferation of healthy MuSC (-15 to -22%), suggesting the delivery of an autocrine effector. Then, pharmacological blockade of the IFN signaling (using ruxolitinib or anti-IFN-receptor antibodies) in DM-MuSCs rescued their proliferation up to the control values.

Discussion:

These results show that autocrine IFN-I signaling prevents MuSC expansion, leading to muscle repair deficit. This process may explain the persistent muscle weakness observed in severe DM patients.

A novel model of dermatomyositis induced by membrane antigen and calciphylaxis in rats

Dermatomyositis (DM) is a severe autoimmune disease of the connective tissue characterized by inflammatory and degenerative changes in the skin and muscle. However, the lack of experimental models of DM represents a challenge for the development of effective drugs. The aim of the present study was to establish a pharmacodynamic rat model of DM that would recapitulate the clinical manifestation seen in patients. The DM model was established using membrane antigen-induced autoimmune injury, followed by toxin-induced subcutaneous calciphylaxis. The rats were divided into five groups and were subcutaneously injected with membrane antigen. Of these, four antigen-immunized groups then received dihydrotestosterone (DHT), iron-dextrin (Fe-Dex), polymyxin (PMX) either individually or in combination to induce cutaneous calciphylaxis. The clinical manifestation score, ratio of infiltrated lymphocytes, ratio of arteriole calcified nodules in skeletal muscles, serum antibody levels [anti-histidyl tRNA synthetase (Jo-1) and anti-melanoma differentiation-associated protein 5 (MDA5)] and serum cytokine levels [tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ)] were then detected. The results demonstrated that all five autoimmune groups displayed local cutaneous swelling and weakness, increased serum antibody and cytokine levels, and T lymphocyte infiltration in perimysial and perivascular sites. Moreover, pathological changes indicative of calciphylaxis were observed in the PMX and DHT + Fe-Dex + PMX. Among all groups, the rats in the PMX and DHT + Fe-Dex + PMX displayed characteristics most closely resembling those of DM pathogenesis in patients. In conclusion, membrane antigen immunization combined with toxin-induced calciphylaxis can be used as a DM model in rats. This model may be used for the development of effective drugs for DM treatment.

Plasma exosomal RNAs has potential as both clinical biomarkers and therapeutic targets of dermatomyositis

OBJECTIVES

Dermatomyositis (DM) is characterized by skeletal muscle weakness and cutaneous manifestations. Plasma exosomes (EXOs) contain proteins, RNAs, DNA, and lipid cargoes and are transferred among cells. Deeply investigated plasma EXO RNAs potentially improve our understanding of DM pathogenesis. We aimed to identify new potential biomarkers and therapeutic targets of DM.

METHODS

The RNAs (mRNA, miRNA and lncRNA) profiles of plasma EXOs were evaluated by sequencing on the Illumina HiSeq 3000 platform. Differentially expressed (DE) RNAs and bioinformatic analyses were performed. Human skeletal muscle myoblasts (HSkMCs) were stimulated with plasma EXOs, rapamycin or IFN-β. Real-time PCR and western blot were used to detect related genes and proteins.

RESULTS

A total of 689 DE mRNAs, 53 DE miRNAs and 452 DE lncRNAs were identified in DM plasma EXOs. Bioinformatic analysis inferred that plasma EXOs were secreted mainly by CD8+ T cells, regulatory T cells and natural killer cells. The DE miRNAs participated in the autophagy, TGF-β and Wnt signalling pathways. Three DE miRNAs (hsa-miR-125a-3p, hsa-miR-1246 and hsa-miR-3614-5p) were correlated with serological indices, organs involvement and myositis-specific autoantibodies. The DE lncRNAs participated in autophagy, interferon-β production and mTOR signalling. DM plasma EXOs can induce autophagy in HSkMCs by regulating 3 miRNAs (hsa-miR-125a-3p, hsa-miR-1246 and hsa-miR-3614-5p) and 3 lncRNAs (ENST00000584157.1, ENST00000523380.1, and ENST00000560054.1), which formed an autophagy network, playing the muscle damage roles.

CONCLUSIONS

Our study provides an overview of distinct RNAs profiles in DM plasma EXOs, and verified some miRNAs as potential biomarkers and therapeutic targets. The findings provide important clues for more in-depth explorations of plasma EXOs in DM.

Identification of Vital Hub Genes and Potential Molecular Pathways of Dermatomyositis by Bioinformatics Analysis

Dermatomyositis is an autoimmune disease characterized by severe symmetrical muscle dysfunction and pain. This study was aimed at discovering vital hub genes and potential molecular pathways of DM through bioinformatics analysis, which contributes to identifying potential diagnostic or therapeutic biomarkers and targets. In this study, a total of 915 DEGs in DM samples including 167 upregulated genes and 748 downregulated genes were screened out by the limma package based on the GSE142807 dataset from the Gene Expression Omnibus (GEO) database. Furthermore, the results of Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis indicated that these downregulated genes were highly associated with the immune-related biological processes and pathways. Therefore, 41 genes closely related to DM were extracted for further study based on the subcluster analysis through the Molecular Complex Detection (MCODE) software plugin in Cytoscape. Ultimately, 10 hub genes (including ISG15, DDX58, IFIT3, CXCL10, and STAT1) were identified as the potential candidate biomarkers and targets. Besides, we found that the identified hub genes directly or indirectly communicated with each other via molecular signaling pathways on the protein and transcription level. In general, under the guidance of bioinformatics analysis, 10 vital hub genes and molecular mechanisms in DM were identified and the expression of proinflammatory factors and interferon family proteins and genes showed high association with DM, which might help provide a theoretical foundation for the development of point-to-point targeted therapy in the future treatment of DM.

Siglec-1 expression on monocytes is associated with the interferon signature in juvenile dermatomyositis and can predict treatment response

Objective

JDM is a rare chronic immune-mediated inflammatory disease with a predominant role for type I IFN responses. We aimed to determine the potential of Siglec-1 expression on monocytes as a novel IFN-inducible biomarker for disease activity monitoring and prediction of treatment response in patients with JDM.

Methods

Siglec-1 was measured by flow cytometry on circulating monocytes of 21 newly diagnosed JDM patients before start of treatment and, for 10 of these, also during follow-up. The expression levels of five type I IFN-stimulated genes, MX1, IFI44, IFI44L, LY6E and IFIT3, were measured by RT-qPCR to determine the IFN signature and calculate an IFN score. IFN-inducible plasma proteins CXCL10 and galectin-9 were measured by multiplex immunoassay.

Results

Siglec-1 and IFN score were increased in JDM patients compared with controls and correlated with clinical disease activity. Stratification of patients by Siglec-1 expression at diagnosis identified those with high Siglec-1 expression as having a higher risk of requiring treatment intensification within the first 3 months after diagnosis (55% vs 0% of patients, P = 0.01). Siglec-1 expression strongly correlated with plasma levels of previously validated biomarkers CXCL10 (r_s = 0.81, P < 0.0001) and galectin-9 (r_s = 0.83, P < 0.0001), and was superior to the IFN score in predicting treatment response (area under the curve 0.87 vs 0.53, P = 0.01).

Conclusion

Siglec-1 on monocytes is a novel IFN-inducible biomarker in JDM that correlates with clinical disease activity and identifies patients at risk for a suboptimal treatment response. Further studies are required to validate these findings and their clinical potential.

Interferon-related gene expression in response to TNF inhibitor treatment in ankylosing spondylitis patients: a pilot study

OBJECTIVE

Ankylosing spondylitis (AS) is a chronic inflammatory arthritis primarily affecting the spine and sacroiliac joints. TNF inhibitor (TNFi) drugs are recommended for patients not responding to NSAIDs; however, there is a significant need for biomarkers of response. IFN-regulated genes (IRGs) and other cytokines/chemokines are linked to autoimmune diseases and have been associated with treatment response. Our objective was to explore whether IRGs and cytokines/chemokines can be associated with response to TNFiagents in AS.

METHODS

Peripheral blood mononuclear cells were obtained from 26 AS patients who were to receive a TNFi (I, n = 15) or placebo (P, n = 11) at week 0 and week 22. Response (R)/non-response (NR) was defined as reduction in ASDAS ≥ 1.2 points or reduction in sacroiliac/vertebral MRI lesions. The expression of 96 genes was quantified using TaqMan assays. Finally, ELISA was used to measure IL-6 in serum samples from another 38 AS patients.

RESULTS

Analysis of gene expression in 26 baseline samples segregated patients into four groups defined by a signature of 15 genes (mainly IRGs). ASDAS response was associated with one group independently of treatment received. We then analysed response to the TNFi (n = 15) and identified a 12-gene signature associated with MRI response. A third IRG signature was also associated with a reduction in IRGs expression post-TNFi samples (n = 10 pairs). Finally, decreased circulating IL-6 was associated with BASDAI-R.

CONCLUSION

This pilot study suggests an association between IRG expression and response to TNFi in AS. These findings require validation in a larger cohort in order to construct predictive algorithms for patient stratification.

Time-Dependent Analysis of Risk of New-Onset Heart Failure Among Patients With Polymyositis and Dermatomyositis

OBJECTIVE

To determine the risk and time trends of heart failure (HF) leading to hospitalization in individuals newly diagnosed as having polymyositis/dermatomyositis (PM/DM) relative to non-PM/DM controls at the general population level.

METHODS

A retrospective cohort study was conducted using data from a nationwide insurance database in Taiwan. Patients with incident PM/DM and without a history of HF were selected between 2000 and 2013. Unmatched and propensity score-matched cohorts were established separately. A multivariable Cox proportional hazards regression model was used to estimate the adjusted hazard ratio (HR) for the risk of HF in the unmatched cohort. In the propensity score-matched cohort, general population controls were selected and matched at a 1:1 ratio to the patients with PM/DM based on propensity scores, which accounted for the confounding factors of age, sex, index date (year) of first diagnosis, comorbidities, and medication usage. The cumulative incidence of HF was estimated using the Kaplan-Meier method. A stratified Cox proportional hazards model was used to calculate the HR for the risk of HF events at different follow-up time points among patients with PM/DM compared with non-PM/DM controls in the propensity score-matched cohort.

RESULTS

In the unmatched cohort, the study assessed 2,025 patients with PM/DM and 196,109 general population controls. Results of multivariable Cox regression analysis, adjusted for age, sex, comorbidities, and medication usage, revealed a greater risk of HF leading to hospitalization in the PM/DM group than in the control group (adjusted HR 3.29, 95% confidence interval [95% CI] 2.60-4.18). After matching based on propensity score, a total of 1,997 pairs of PM/DM patients and general population controls were identified. In this propensity score-matched cohort, the cumulative incidence of HF in patients with PM/DM at 3 years, 5 years, and 10 years was 3.3%, 4.4%, and 7.4%, respectively. The absolute difference in HF risk in the PM/DM group compared with the control group was 1.8% at 3 years, 2.1% at 5 years, and 3.0% at 10 years. Compared with general population controls, patients with PM/DM exhibited an augmented risk of HF (HR 2.06, 95% CI 1.36-3.12). Analyses stratified according to follow-up time point revealed that the increased risk of HF persisted for up to 10 years after the PM/DM diagnosis.

CONCLUSION

These results indicate that the risk of HF leading to hospitalization was increased in patients with PM/DM throughout the study period, supporting the need for greater vigilance in the monitoring of patients with PM/DM for the development of this potentially lethal complication.

JAK-inhibitors for dermatomyositis: A concise literature review

Refractory dermatomyositis (DM) is defined as cases that do not show improvement after initial treatment with two different immunosuppressives combined with corticosteroids with or without intravenous immunoglobulins. In recent years, few studies have reported a positive response to the use of Janus kinase inhibitors (JAK-inhibitors) for the treatment of refractory DM. A systematic literature review was performed for articles studying the use of JAK-inhibitors for the treatment of refractory DM. We identified 38 females and 15 males treated with JAK-inhibitors without serious side effects. Tofacitinib was the most frequently used JAK-inhibitor followed by ruxolitinib. Significant improvement in CDASI score, muscle strength, body weight, and skin lesions were reported in most of the studies. The duration of follow-up ranged from 1 to 15 months without relapse. Therefore, the use of JAK-inhibitors looks promising in the treatment of refractory DM and further high volume research may be required to validate the current concept. As only case reports and series were identified without direct comparison for review, there is a potential risk of bias. Despite these limitations, we believe that the result of this analysis allows a better understanding of treatment options for refractory DM and will help generate a hypothesis that can be further tested.

S95021, a novel selective and pan-neutralizing anti interferon alpha (IFN-α) monoclonal antibody as a candidate treatment for selected autoimmune rheumatic diseases

Increased interferon-α (IFN-α) production is a critical component in the pathophysiology of systemic lupus erythematosus (SLE) and other rheumatic autoimmune diseases. Herein, we report the characterization of S95021, a fully human IgG1 anti-IFN-α monoclonal antibody (mAb) as a novel therapeutic candidate for targeted patient populations. S95021 was expressed in CHOZN GS-/- cells, purified by chromatography and characterized by using electrophoresis, size exclusion chromatography and liquid chromatography-mass spectrometry. High purity S95021 was obtained as a monomeric entity comprising different charge variants mainly due to N-glycosylation. Surface plasmon resonance kinetics experiments showed strong association rates with all IFN-α subtypes and estimated KDs below picomolar values. Pan-IFN-α-binding properties were confirmed by immunoprecipitation assays and neutralization capacity with reporter HEK-Blue IFN-α/β cells. S95021 was IFN-α-selective and exhibited superior potency and broader neutralization profile when compared with the benchmark anti-IFN-α mAbs rontalizumab and sifalimumab. STAT-1 phosphorylation and the type I IFN gene signature induced in human peripheral blood mononuclear cells by recombinant IFN-α subtypes or plasmas from selected autoimmune patients were efficiently reduced by S95021 in a dose-dependent manner. Together, our results show that S95021 is a new potent, selective and pan IFN-α-neutralizing mAb. It is currently further evaluated as a valid therapeutic candidate in selected autoimmune diseases in which the IFN-α pro-inflammatory pathway is dysregulated.

Novel associations between cytokines and pulmonary involvement in juvenile dermatomyositis - a cross-sectional study of long-term disease

OBJECTIVES

To examine associations between cytokines and pulmonary involvement in patients with medium- to long-term JDM.

METHODS

In a cross-sectional study, 58 patients examined median (range) 16.8 (6.6-27.0) years after symptom onset were stratified in inactive (JDM-inactive) and active (JDM-active) disease (updated PRINTO criteria); 56 age/sex matched controls were included. Twenty-nine cytokines (in serum) were analysed (Luminex technology/ELISA). Pulmonary function test included forced vital capacity, total lung capacity (TLC) and diffusing capacity for carbon monoxide reported as % of predicted and low forced vital capacity/TLC/diffusing capacity for carbon monoxide. In patients, the presence of clinical pulmonary damage was assessed and high resolution computed tomography scans were scored for interstitial lung disease, chest wall calcinosis and airways disease.

RESULTS

Median age of patients was 21 (7-55) years, 59% were female and 36% inactive. In JDM-active and all patients, higher MCP-1, IP-10 and eotaxin correlated with high-resolution computed tomography findings (rs 0.34-0.61; P < 0.05). MCP-1 and eotaxin correlated with pulmonary damage in JDM-active and all patients (rs 0.41-0.49; P < 0.01). Higher TGF-β1 and PDGF (growth factors) were associated with lower lung volumes (forced vital capacity/TLC measures) in all patients; PDGF in JDM-active and TGF-β1 in JDM-inactive patients. IP-10 correlated with TLC% in JDM-active patients. No associations between cytokines and pulmonary function test were found in controls.

CONCLUSIONS

In JDM, we found a novel association (not previously described in myositis) between eotaxin and pulmonary involvement; we have previously shown an association between eotaxin and cardiac dysfunction. The associations between IP-10/growth factors/MCP-1 and pulmonary involvement are novel in JDM and were mostly seen in JDM-active patients.

Juvenile dermatomyositis resembling late-stage Degos disease with gastrointestinal perforations successfully treated with combination of cyclophosphamide and rituximab: case-based review

Dermatomyositis (DM) is a multi-system disease that results in chronic inflammation principally of the skin and striated muscle. Small blood vessel injury in the GI tract has been described in dermatomyositis, manifesting as bleeding, ulceration, pneumatosis intestinalis, and ultimately perforation. Recent histopathological studies have shown deposits in the capillaries of the skin, gastrointestinal tract, and brain of patients with dermatomyositis similar to that found in patients with Degos disease, suggesting these disease processes are closely related or represent varying degrees of severity on the same pathologic spectrum. We report a case of juvenile dermatomyositis (JDM) resembling late-stage Degos disease with gastrointestinal perforations successfully treated with combination rituximab and cyclophosphamide therapy. We systematically reviewed the literature detailing the medical and surgical treatments for gastrointestinal perforation in dermatomyositis, Degos-like dermatomyositis, and Degos disease. In addition to our case, as of October 2019, we identified 36 cases describing gastrointestinal perforation in patients with underlying dermatomyositis, 5 cases of Degos-like dermatomyositis and 17 cases of idiopathic Degos disease. Corticosteroid therapy was used widely for dermatomyositis and Degos-like dermatomyositis, while antiplatelet and anticoagulant medications were chiefly used for patients with idiopathic Degos disease. However, there were no cases that detailed the successful treatment of dermatomyositis or Degos disease with gastrointestinal perforation with rituximab alone or combined with cyclophosphamide. We report that rituximab, in combination with cyclophosphamide, can be used as a novel adjunctive therapy to successfully treat dermatomyositis with Degos-like gastrointestinal perforation.

Malignancy and myositis, from molecular mimicry to tumor infiltrating lymphocytes

Cancer-associated dermatomyositis provides a unique opportunity to explore the relationship between autoimmunity and cancer. In this review, we describe the related epidemiological issues, considering the various currently accepted myositis phenotypes, their link with cancer, and the possible mechanisms leading to this relationship. We discuss current evidence regarding the role of molecular mimicry, somatic DNA tumor mutations, and the PD-1/PD-L1 pathway in the association between cancer and myositis. We also review tumor-infiltrating lymphocytes as a relevant factor to be evaluated in cancer-associated myositis, their interaction with tumor neoantigens, and the tumor mutational burden, all of which have implications for the treatment of these patients with immunotherapy. Finally, we discuss clinical scenarios related to the relationship between cancer and myositis, delineating a comprehensive theory linking autoimmunity and cancer.

Gene expression analysis delineates the potential roles of multiple interferons in systemic lupus erythematosus

A role for interferon (IFN) in systemic lupus erythematosus (SLE) pathogenesis is inferred from the prominent IFN gene signature (IGS), but the major IFN species and its relationship to disease activity are unknown. A bioinformatic approach employing individual IFN species gene signatures to interrogate SLE microarray datasets demonstrates a putative role for numerous IFN species, with prominent expression of IFNB1 and IFNW signatures. In contrast with other SLE-affected organs, the IGS is less prominent in lupus nephritis. SLE patients with active and inactive disease have readily detectable IGS and the IGS changes synchronously with a monocyte signature but not disease activity, and is significantly related to monocyte transcripts. Monocyte over-expression of three times as many IGS transcripts as T and B cells and IGS retention in monocytes, but not T and B cells from inactive SLE patients contribute to the lack of correlation between the IGS and SLE disease activity.

Distinct interferon signatures stratify inflammatory and dysimmune myopathies

Objective

The role of interferons (IFN) in the pathophysiology of primary inflammatory and dysimmune myopathies (IDM) is increasingly investigated, notably because specific neutralisation approaches may constitute promising therapeutic tracks. In present work we analysed the muscular expression of specific IFNα/β and IFNγ-stimulated genes in patients with various types of IDM.

Methods

39 patients with IDM with inclusion body myositis (IBM, n=9), dermatomyositis (DM, n=10), necrotising autoimmune myopathies (NAM, n=10) and antisynthetase myositis (ASM, n=10), and 10 controls were included. Quantification of expression levels of IFNγ, ISG15, an IFNα/β-inducible gene and of six IFNγ-inducible genes (GBP2, HLA-DOB, HLA-DPB, CIITA, HLA-DRB and HLA-DMB) was performed on muscle biopsy samples.

Results

DM usually associated with strong type I IFNα/β signature, IBM and ASM with prominent type II IFNγ signature and NAM with neither type I nor type II IFN signature. Immunofluorescence study in ASM and IBM showed myofibre expression of major histocompatibility class 2 (MHC-2) and CIITA, confirming the induction of the IFNγ pathway. Furthermore, MHC-2-positive myofibres were observed in close proximity to CD8+ T cells which produce high levels of IFNγ.

Conclusion

Distinct IFN signatures allow a more distinct segregation of IDMs and myofibre MHC-2 expression is a reliable biomarker of type II IFN signature.

Comparison of RT-qPCR and Nanostring in the measurement of blood interferon response for the diagnosis of type I interferonopathies

Type I interferonopathies are characterized by an increase of circulating type I interferon (IFN) concentration. Type I interferonopathies refer to rare Mendelian genetic disorders such as Aicardi-Goutières Syndrome (AGS) as well as more frequent and polygenic auto-immune diseases like systemic lupus erythematosus (SLE). Yet, detection of type I IFN in these patients remains challenging as its amount is usually very low in patients' sera. Thus, the detection of interferon-stimulating genes has been proposed as an alternative for the detection of this cytokine but sensitivy, specificity and predictive values of the assay have not been reported so far. In this study, we propose two different methods based on Nanostring or RT-qPCR to measure in the clinical routine the IFN response, defined as a set of transcripts that are systemically induced by IFNs. The IFN signature is composed of 6 IFN stimulated genes (ISGs) and has a strong predictive value for the diagnosis of type I interferonopathies. The use of this simple test might represent a gold standard for the evaluation of various autoimmune diseases. Moreover, this test could also be used to monitor patients treated with drugs targeting type I IFN pathway. When comparing both methods - Nanostring and qPCR - in terms of analytical performance, they provided similar results but Nanostring was quicker, easier to multiplex, and almost fully-automated, which represent a more reliable assay for the daily clinical practice.

Differential Clinical Associations of Anti-Nuclear Matrix Protein 2 Autoantibodies in Patients With Idiopathic Inflammatory Myopathies

OBJECTIVE

To investigate the associations between anti-nuclear matrix protein 2 (anti-NXP-2) autoantibody levels and disease activity as well as calcinosis severity in patients with idiopathic inflammatory myopathies (IIMs).

METHODS

Serum levels of anti-NXP-2 autoantibodies were determined in 709 patients with IIMs and also serially measured in the patients' sera with an in-house enzyme-linked immunosorbent assay using MORC3 recombinant protein. Patients with anti-NXP-2 autoantibodies were divided into 2 subgroups: those with and those without calcinosis. Associations of anti-NXP-2 autoantibody levels with organ-specific disease activity (using 10-cm visual analog scale [VAS] scores), serum creatine kinase (CK) levels, and calcinosis severity were investigated in cross-sectional and longitudinal analyses.

RESULTS

A cross-sectional analysis of 56 IIM patients with anti-NXP-2 autoantibodies (38 without calcinosis and 18 with calcinosis) showed that in patients without calcinosis, the levels of anti-NXP-2 autoantibodies were positively correlated with the physician's global assessment of disease activity and muscle VAS scores and serum CK levels, whereas no such association was found in patients with calcinosis. Results of the longitudinal study revealed strong correlations of anti-NXP-2 antibody levels with the physician's global assessment and constitutional, cutaneous, gastrointestinal, and muscle VAS scores and serum CK levels in patients without calcinosis, but in patients with calcinosis, only a moderate correlation was observed between anti-NXP-2 antibody levels and the physician's global VAS and constitutional VAS scores. Of note, in patients without calcinosis, anti-NXP-2 autoantibodies were found to disappear during periods of clinical remission, but reappeared with disease relapse. No association between anti-NXP-2 antibody levels and the severity of calcinosis was observed.

CONCLUSION

These findings indicate that anti-NXP-2 autoantibodies serve as a useful marker for disease activity in patients with IIMs, especially in the absence of calcinosis. The differential associations observed between anti-NXP-2 autoantibody levels and disease activity suggest that there may be a phenotypic difference between patients with and those without calcinosis.

Increased Levels of Soluble Programmed Death Ligand 1 Associate with Malignancy in Patients with Dermatomyositis

Objective.

To investigate the levels of soluble programmed death ligand 1 (sPD-L1) and evaluate its association with malignancy in patients with dermatomyositis (DM).

Methods.

Levels of sPD-L1 were measured in serum from 88 DM patients without malignancies (sDM), 40 with cancer-related DM (CRDM), and 30 healthy controls (HC) using ELISA. The CRDM subjects were divided into new-onset cancers (nCRDM) and stable cancers (sCRDM). Receiver-operating characteristic (ROC) curve analysis was performed to determine the cutoff sPD-L1 value that distinguished patients with nCRDM from those who were sDM. Serum antitranscriptional intermediary factor 1-γ (TIF1-γ) antibodies were detected using immunoblot, and the diagnostic values for malignancy were compared with sPD-L1 levels in patients with DM.

Results.

Serum sPD-L1 levels were significantly higher in sDM [median 12.3 ng/ml, interquartile range (IQR) 8.4–16.2] than in HC (median 1.3 ng/ml, IQR 0.4–2.2, p = 0.0001). Extremely high sPD-L1 levels were seen in nCRDM (median 18.5 ng/ml, IQR 13.8–22.4), much higher than those in sCRDM (median 8.5 ng/ml, IQR 6.8–11.8, p = 0.0001). The sPD-L1 levels in 4 patients with nCRDM decreased after curative cancer treatment (p = 0.013). ROC curve analysis revealed that the sPD-L1 value distinguishing nCRDM from sDM was 16.1 ng/ml, with an area under the curve value of 0.72 ± 0.04 (p = 0.0001). The combination of sPD-L1 and anti-TIF1-γ antibodies yielded greater specificity and positive predictive value in diagnosing cancer, reaching values of 95% and 70%, respectively.

Conclusion.

Serum sPD-L1 levels increased significantly in sDM, and markedly high sPD-L1 levels could be a diagnostic indicator for malignancies in patients with DM, especially in those with anti-TIF1-γ antibodies.

Role of the IL-12/IL-35 balance in patients with Sjögren syndrome

BACKGROUND

An interferon signature is involved in the pathogenesis of primary Sjögren syndrome (pSS), but whether the signature is type 1 or type 2 remains controversial. Mouse models and genetic studies suggest the involvement of T_H1 and type 2 interferon pathways. Likewise, polymorphisms of the IL-12A gene (IL12A), which encodes for IL-12p35, have been associated with pSS. The IL-12p35 subunit is shared by 2 heterodimers: IL-12 and IL-35.

OBJECTIVE

We sought to confirm genetic association of the IL12A polymorphism and pSS and elucidate involvement of the IL-12/IL-35 balance in patients with pSS by using functional studies.

METHODS

The genetic study involved 673 patients with pSS from 2 French pSS cohorts and 585 healthy French control subjects. Functional studies were performed on sorted monocytes, irrespective of whether they were stimulated. IL12A mRNA expression and IL-12 and IL-35 protein levels were assessed by using quantitative RT-PCR and ELISA and a multiplex kit for IL-35 and IL-12, respectively.

RESULTS

We confirmed association of the IL12A rs485497 polymorphism and pSS and found an increased serum protein level of IL-12p70 in patients with pSS carrying the risk allele (P = .016). Serum levels of IL-12p70 were greater in patients than control subjects (P = .0001), especially in patients with more active disease (P = .05); conversely, IL-35 levels were decreased in patients (P = .0001), especially in patients with more active disease (P = .05). In blood cellular subsets both IL12p35 and EBV-induced gene protein 3 (EBI3) mRNAs were detected only in B cells, with a trend toward a lower level among patients with pSS.

CONCLUSION

Our findings emphasize involvement of the IL-12/IL-35 balance in the pathogenesis of pSS. Serum IL-35 levels were associated with low disease activity, in contrast with serum IL-12p70 levels, which were associated with more active disease.

Dysregulated innate immune function in the aetiopathogenesis of idiopathic inflammatory myopathies

The idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of systemic muscle conditions that are believed to be autoimmune in nature. They have distinct pathological features, but the aetiopathogenesis of each subtype remains largely unknown. Recently, there has been increased interest in the complex role the innate immune system plays in initiating and perpetuating these conditions, and how this may differ between subtypes. This article summarises the traditional paradigms of IIM pathogenesis and reviews the accumulating evidence for disturbances in innate immune processes in these rare, but debilitating chronic conditions.

Bioinformatics analysis of gene expression profiles of dermatomyositis

Dermatomyositis (DM) is a type of autoimmune inflammatory myopathy, which primarily affects the skin and muscle. The underlying mechanisms of DM remain poorly understood. The present study aimed to explore gene expression profile alterations, investigate the underlying mechanisms, and identify novel targets for DM. The GSE48280 dataset, which includes data from five DM and five normal muscle tissue samples, was obtained from the Gene Expression Omnibus. Firstly, differentially expressed genes (DEGs) were screened by limma package in R. Subsequently, functional and pathway enrichment analyses were performed using ClueGO from Cytoscape. Finally, protein‑protein interaction (PPI) networks were constructed using STRING and Cytoscape, in order to identify hub genes. As a result, 180 upregulated and 21 downregulated genes were identified in the DM samples. The Gene Ontology enrichment analysis revealed that the type I interferon (IFN) signaling pathway was the most significantly enriched term within the DEGs. The Kyoto Encyclopedia of Genes and Genomes pathway analysis identified 27 significant pathways, the majority of which can be divided into the infectious diseases and immune system categories. Following construction of PPI networks, 24 hub genes were selected, all of which were associated with the type I IFN signaling pathway in DM. The findings of the present study indicated that type I IFNs may have a central role in the induction of DM. In addition, other DEGs, including chemokine (C‑C motif) ligand 5, C‑X‑C motif chemokine 10, Toll‑like receptor 3, DEXD/H‑Box helicase 58, interferon induced with helicase C domain 1, interferon‑stimulated gene 15 and MX dynamin‑like GTPase 1, may be potential targets for DM diagnosis and treatment.

Morc3 mutant mice exhibit reduced cortical area and thickness, accompanied by altered haematopoietic stem cells niche and bone cell differentiation

Morc3, a member of a highly conserved nuclear matrix protein super-family plays an important part in chromatin remodeling, DNA repair, epigenetic regulation and cellular senescence. However, its role in bone homeostasis is not known. In the present study, a phenotype-driven ENU mouse mutagenesis screen revealed that Morc3^{mut +/−} mice exhibit reduced cortical area and thickness with increased cortical porosity. Morc3^{mut +/−} mice displayed reduced osteoclast numbers and surface per bone surface as well as osteocyte numbers, concomitant with altered gene expressions such as Rankl/Opg and Sost in ex vivo long bones. In vitro experiments revealed a significant increase in the number of Sca-1⁺/c-kit⁺ haematopoietic stem cells (HSCs), and a significant reduction in senescence associated β-galactosidase activity in bone marrow macrophages (BMMs). In addition, we observed a decrease in osteoclastogenesis and bone resorption accompanied by upregulation of STAT1 expression in osteoclast lineage cells. Strikingly, Morc3 protein localization within the nuclear membrane was shifted to the cytoplasm in Morc3^{mut +/−} osteoclasts. Further, Morc3^{mut +/−} mice displayed increased osteoblast differentiation and altered gene expression. Collectively, our data show that Morc3 is a previously unreported regulator of cortical bone homeostasis and haematopoietic stem cells niche, accompanied by altered bone cell differentiation.

Update on the role of plasmacytoid dendritic cells in inflammatory/autoimmune skin diseases

Plasmacytoid dendritic cells (pDCs) represent a specialized dendritic cell population that exhibit plasma cell morphology, express CD4, CD123, blood-derived dendritic cell antigen-2 (BDCA-2) and Toll-like receptor (TLR)7 and TLR9 within endosomal compartments. When activated, pDCs are capable of producing large quantities of type I IFNs (mainly IFN-α/β), which provide antiviral resistance and link the innate and adaptive immunity. While generally lacking from normal skin, pDCs infiltrate the skin and appear to be involved in the pathogenesis of several inflammatory, infectious (especially viral) and neoplastic entities. In recent years, pDC role in inflammatory/autoimmune skin conditions has been extensively studied. Unlike type I IFN-mediated protective immunity that pDCs provide at the level of the skin by regulated sensing of microbial or self-nucleic acids upon skin damage, excessive sensing may elicit IFN-driven inflammatory/autoimmune diseases. In this review, focus will be on the role of pDCs in cutaneous inflammatory/autoimmune dermatoses.

Increased Risk of Herpes Zoster Following Dermatomyositis and Polymyositis: A Nationwide Population-Based Cohort Study

This study explored the possible association between dermatomyositis or polymyositis (DM or PM) and the subsequent risk of herpes zoster (HZ). We used data from the Taiwan National Health Insurance (NHI) system to address the research topic. The exposure cohort comprised 2023 patients with new diagnoses of DM or PM. Each patient was frequency matched according to age, sex, index year, and comorbidities including diabetes, renal disease, obesity, malignancy, rheumatoid arthritis, immunodeficiency virus infection, autoimmune disease not elsewhere classified, mixed connective tissue disease, or vasculitis with 4 participants from the general population who did not have a history of HZ (control cohort). Cox proportional hazards regression analysis was conducted to estimate the relationship between DM or PM and the risk of subsequent HZ. The incidence of HZ in the exposure and control cohorts was 35.8 and 7.01 per 1000 person-years, respectively. The exposure cohort had a significantly higher overall risk of subsequent HZ than did the control cohort (adjusted hazard ratio [HR] = 3.90, 95% confidence interval [CI] = 3.18-4.77). The risk of HZ in patients with DM or PM in whichever stratification (including sex, age, and comorbidity) was also higher than that of the control cohort. The findings from this population-based retrospective cohort study suggest that DM or PM is associated with an increased risk of subsequent HZ. A synergistic effect was observed between DM or PM and one of the comorbidities.