The interferon signature in autoimmune diseases. Curr Opin Rheumatol. 2013;25:248-253. [PMID: 23249830 DOI: 10.1097/bor.0b013e32835c7e32]

Single-cell analysis with childhood and adult systemic lupus erythematosus

Patients with systemic lupus erythematosus (SLE), a heterogeneous and chronic autoimmune disease, exhibit unique changes in the complex composition and transcriptional signatures of peripheral blood mononuclear cells (PBMCs). While the mechanism of pathogenesis for both childhood-onset SLE (cSLE) and adult-onset SLE (aSLE) remains unclear, cSLE patients are considered more unpredictable and dangerous than aSLE patients. In this study, we analysed single-cell RNA sequencing data (scRNA-seq) to profile the PBMC clusters of cSLE/aSLE patients and matched healthy donors and compared the PBMC composition and transcriptional variations between the two groups. Our analysis revealed that the PBMC composition and transcriptional variations in cSLE patients were similar to those in aSLE patients. Comparative single-cell transcriptome analysis between healthy donors and SLE patients revealed IFITM3, ISG15, IFI16 and LY6E as potential therapeutic targets for both aSLE and cSLE patients. Additionally, we observed that the percentage of pre-B cells (CD34-) was increased in cSLE patients, while the percentage of neutrophil cells was upregulated in aSLE patients. Notably, we found decreased expression of TPM2 in cSLE patients, and similarly, TMEM150B, IQSEC2, CHN2, LRP8 and USP46 were significantly downregulated in neutrophil cells from aSLE patients. Overall, our study highlights the differences in complex PBMC composition and transcriptional profiles between cSLE and aSLE patients, providing potential biomarkers that could aid in diagnosing SLE.

The story of clobenpropit and CXCR4: can be an effective drug in cancer and autoimmune diseases?

Clobenpropit is a histamine H3 receptor antagonist and has developed as a potential therapeutic drug due to its ability to inhibit CXCR4, a chemokine receptor involved in autoimmune diseases and cancer pathogenesis. The CXCL12/CXCR4 axis involves several biological phenomena, including cell proliferation, migration, angiogenesis, inflammation, and metastasis. Accordingly, inhibiting CXCR4 can have promising clinical outcomes in patients with malignancy or autoimmune disorders. Based on available knowledge, Clobenpropit can effectively regulate the release of monocyte-derived inflammatory cytokine in autoimmune diseases such as juvenile idiopathic arthritis (JIA), presenting a potential targeted target with possible advantages over current therapeutic approaches. This review summarizes the intricate interplay between Clobenpropit and CXCR4 and the molecular mechanisms underlying their interactions, comprehensively analyzing their impact on immune regulation. Furthermore, we discuss preclinical and clinical investigations highlighting the probable efficacy of Clobenpropit for managing autoimmune diseases and cancer. Through this study, we aim to clarify the immunomodulatory role of Clobenpropit and its advantages and disadvantages as a novel therapeutic opportunity.

Prognostic value of anti-IFI16 autoantibodies in pulmonary arterial hypertension and mortality in patients with systemic sclerosis

OBJECTIVES

To determine the diagnostic value of anti-interferon gamma inducible protein 16 (IFI16) autoantibodies in systemic sclerosis (SSc) patients negative for all tested SSc-specific autoantibodies (SSc-seronegative patients) and to evaluate the clinical significance of these autoantibodies, whether isolated or in the presence of anti-centromere autoantibodies (ACA).

METHODS

Overall, 58 SSc-seronegative and 66 ACA-positive patients were included in the study. All patients were tested for anti-IFI16 autoantibodies by an in-house direct ELISA. Associations between clinical parameters and anti-IFI16 autoantibodies were analysed.

RESULTS

Overall, 17.2% of SSc-seronegative and 39.4% of ACA-positive patients were positive for anti-IFI16 autoantibodies. Anti-IFI16 autoantibodies were found only in patients within the limited cutaneous SSc (lcSSc) subset. A positive association between anti-IFI16 positivity and isolated pulmonary arterial hypertension (PAH) was found (odds ratio [OR]=5.07; p=0.014) even after adjusting for ACA status (OR=4.99; p=0.019). Anti-IFI16-positive patients were found to have poorer overall survival than negative patients (p=0.032). Cumulative survival rates at 10, 20 and 30 years were 96.9%, 92.5% and 68.7% for anti-IFI16-positive patients vs. 98.8%, 97.0% and 90.3% for anti-IFI16-negative-patients, respectively. Anti-IFI16-positive patients also had worse overall survival than anti-IFI16-negative patients after adjusting for ACA status in the multivariate Cox analysis (hazard ratio [HR]=3.21; p=0.043).

CONCLUSION

Anti-IFI16 autoantibodies were associated with isolated PAH and poorer overall survival. Anti-IFI16 autoantibodies could be used as a supplementary marker of lcSSc in SSc-seronegative patients and for identifying ACA-positive patients with worse clinical outcome.

A cluster of type I interferon-regulated genes associates with disease activity and prognosis in patients with IgA nephropathy

The exact pathogenesis of IgA nephropathy (IgAN) is complex and so far, not well defined. Since it has been shown that microbial infections could induce high levels of type I interferon (IFN-I) and there is an evident link between mucosal infection and gross hematuria in IgAN, we hypothesized that IFN-I may play a role in the pathogenic process. In this study, we investigated the type I interferon status in IgAN based on the expression of 17 IFN-regulated genes (IRGs) in whole blood from 59 IgAN patients in a cross-sectional study, of which 34 patients followed longitudinally. Analysis of the IFN-score showed that there was a significant elevated IFN-score in the IgAN patients compared with healthy controls (n = 28, p = 9.80 × 10-3), and we observed an elevated IFN-score in the group with less tubular atrophy/interstitial fibrosis (p = 1.07 × 10-2) and with a lower proportion of mesangial hypercellularity (p = 1.23 × 10-2). In the longitudinal analysis, Cox regression analysis revealed that a higher IFN level was associated with a better renal outcome in IgAN after adjustments for gender and age (hazard ratio, 0.90; 95 % confidence interval, 0.81 to 0.97; p = 4.20 × 10-2). In conclusion, our finding suggested that IFN score may represent a novel type of biomarker in IgAN, which requires further exploration on its mechanism and therapeutic targeting.

Complement C3 and marginal zone B cells promote IgG-mediated enhancement of RBC alloimmunization in mice

Administration of anti-RhD immunoglobulin (Ig) to decrease maternal alloimmunization (antibody-mediated immune suppression [AMIS]) was a landmark clinical development. However, IgG has potent immune-stimulatory effects in other settings (antibody-mediated immune enhancement [AMIE]). The dominant thinking has been that IgG causes AMIS for antigens on RBCs but AMIE for soluble antigens. However, we have recently reported that IgG against RBC antigens can cause either AMIS or AMIE as a function of an IgG subclass. Recent advances in mechanistic understanding have demonstrated that RBC alloimmunization requires the IFN-α/-β receptor (IFNAR) and is inhibited by the complement C3 protein. Here, we demonstrate the opposite for AMIE of an RBC alloantigen (IFNAR is not required and C3 enhances). RBC clearance, C3 deposition, and antigen modulation all preceded AMIE, and both CD4+ T cells and marginal zone B cells were required. We detected no significant increase in antigen-specific germinal center B cells, consistent with other studies of RBC alloimmunization that show extrafollicular-like responses. To the best of our knowledge, these findings provide the first evidence of an RBC alloimmunization pathway which is IFNAR independent and C3 dependent, thus further advancing our understanding of RBCs as an immunogen and AMIE as a phenomenon.

Absence of Type I Interferon Autoantibodies or Significant Interferon Signature Alterations in Adults With Post-COVID-19 Syndrome

Genetic defects in the interferon (IFN) system or neutralizing autoantibodies against type I IFNs contribute to severe COVID-19. Such autoantibodies were proposed to affect post-COVID-19 syndrome (PCS), possibly causing persistent fatigue for >12 weeks after confirmed SARS-CoV-2 infection. In the current study, we investigated 128 patients with PCS, 21 survivors of severe COVID-19, and 38 individuals who were asymptomatic. We checked for autoantibodies against IFN-α, IFN-β, and IFN-ω. Few patients with PCS had autoantibodies against IFNs but with no neutralizing activity, indicating a limited role of type I IFNs in PCS pathogenesis. In a subset consisting of 28 patients with PCS, we evaluated IFN-stimulated gene activity and showed that it did not correlate with fatigue. In conclusion, impairment of the type I IFN system is unlikely responsible for adult PCS.

Genome-wide DNA methylation sequencing reveals epigenetic features and potential biomarkers of Sjögren syndrome

AIM

Sjögren syndrome (SS) is a slowly progressive, inflammatory, autoimmune disease. The aim of this study was to construct the DNA methylation profiles of whole blood of SS patients and healthy controls (HC), and to explore the role of differentially methylated genes in the pathogenesis of the disease.

METHODS

Whole-genome bisulfite sequencing was performed on three SS patients and four HC. The biological function of genes associated with differentially methylated regions (DMRs) was investigated using Gene Ontology functional analysis and Kyoto Encyclopedia of Genes and Genomes pathway analysis, using network-based key driver analysis (KDA) to find KDA genes. In clinical samples of SS patients and controls, the expression levels of KDA genes were validated by quantitative real-time polymerase chain reaction and immunohistochemical analysis. Moreover, the diagnostic value of KDA genes for SS was confirmed using receiver operating characteristic curves.

RESULTS

We identified 322 DMRs, annotated as 162 associated genes. Six genes were selected via the number of networks of KDA genes. Differential expression of genes such as human leukocyte antigen (HLA) class I, ADAR, and OAS2 was observed in patients' peripheral blood mononuclear cells and the minor salivary glands, which can be used as potential diagnostic biomarkers for SS.

CONCLUSION

Clinical sample validation suggested that HLA class I, ADAR, and OAS2 might play a role in the development of SS. Our study shows epigenetic regulatory mechanisms and potential disease markers associated with SS, which in turn will enable us to identify new therapeutic targets.

Expansion of extrafollicular B and T cell subsets in childhood-onset systemic lupus erythematosus

Introduction

Most childhood-onset SLE patients (cSLE) develop lupus nephritis (cLN), but only a small proportion achieve complete response to current therapies. The prognosis of children with LN and end-stage renal disease is particularly dire. Mortality rates within the first five years of renal replacement therapy may reach 22%. Thus, there is urgent need to decipher and target immune mechanisms that drive cLN. Despite the clear role of autoantibody production in SLE, targeted B cell therapies such as rituximab (anti-CD20) and belimumab (anti-BAFF) have shown only modest efficacy in cLN. While many studies have linked dysregulation of germinal center formation to SLE pathogenesis, other work supports a role for extrafollicular B cell activation in generation of pathogenic antibody secreting cells. However, whether extrafollicular B cell subsets and their T cell collaborators play a role in specific organ involvement in cLN and/or track with disease activity remains unknown.

Methods

We analyzed high-dimensional mass cytometry and gene expression data from 24 treatment naïve cSLE patients at the time of diagnosis and longitudinally, applying novel computational tools to identify abnormalities associated with clinical manifestations (cLN) and disease activity (SLEDAI).

Results

cSLE patients have an extrafollicular B cell expansion signature, with increased frequency of i) DN2, ii) Bnd2, iii) plasmablasts, and iv) peripheral T helper cells. Most importantly, we discovered that this extrafollicular signature correlates with disease activity in cLN, supporting extrafollicular T/B interactions as a mechanism underlying pediatric renal pathogenesis.

Discussion

This study integrates established and emerging themes of extrafollicular B cell involvement in SLE by providing evidence for extrafollicular B and peripheral T helper cell expansion, along with elevated type 1 IFN activation, in a homogeneous cohort of treatment-naïve cSLE patients, a point at which they should display the most extreme state of their immune dysregulation.

Variants in the DDX6-CXCR5 autoimmune disease risk locus influence the regulatory network in immune cells and salivary gland

Fine mapping and bioinformatic analysis of the DDX6-CXCR5 genetic risk association in Sjögren's Disease (SjD) and Systemic Lupus Erythematosus (SLE) identified five common SNPs with functional evidence in immune cell types: rs4938573, rs57494551, rs4938572, rs4936443, rs7117261. Functional interrogation of nuclear protein binding affinity, enhancer/promoter regulatory activity, and chromatin-chromatin interactions in immune, salivary gland epithelial, and kidney epithelial cells revealed cell type-specific allelic effects for all five SNPs that expanded regulation beyond effects on DDX6 and CXCR5 expression. Mapping the local chromatin regulatory network revealed several additional genes of interest, including lnc-PHLDB1-1 . Collectively, functional characterization implicated the risk alleles of these SNPs as modulators of promoter and/or enhancer activities that regulate cell type-specific expression of DDX6 , CXCR5 , and lnc-PHLDB1-1 , among others. Further, these findings emphasize the importance of exploring the functional significance of SNPs in the context of complex chromatin architecture in disease-relevant cell types and tissues.

Reticulocytes in donor blood units enhance red blood cell alloimmunization

Although red blood cell (RBC) transfusions save lives, some patients develop clinically-significant alloantibodies against donor blood group antigens, which then have adverse effects in multiple clinical settings. Few effective measures exist to prevent RBC alloimmunization and/or eliminate alloantibodies in sensitized patients. Donor-related factors may influence alloimmunization; thus, there is an unmet clinical need to identify which RBC units are immunogenic. Repeat volunteer blood donors and donors on iron supplements have elevated reticulocyte counts compared to healthy non-donors. Early reticulocytes retain mitochondria and other components, which may act as danger signals in immune responses. Herein, we tested whether reticulocytes in donor RBC units could enhance RBC alloimmunization. Using a murine model, we demonstrate that transfusing donor RBC units with increased reticulocyte frequencies dose-dependently increased RBC alloimmunization rates and alloantibody levels. Transfusing reticulocyte-rich RBC units was associated with increased RBC clearance from the circulation and a robust proinflammatory cytokine response. As compared to previously reported post-transfusion RBC consumption patterns, erythrophagocytosis from reticulocyte-rich units was increasingly performed by splenic B cells. These data suggest that reticulocytes in a donated RBC unit impact the quality of blood transfused, are targeted to a distinct compartment, and may be an underappreciated risk factor for RBC alloimmunization.

Targeting the chemokine receptor CXCR4 with histamine analog to reduce inflammation in juvenile arthritis

Introduction

Among immune cells, activated monocytes play a detrimental role in chronic and viral-induced inflammatory pathologies, particularly in Juvenile Idiopathic Arthritis (JIA), a childhood rheumatoid arthritis (RA) disease. The uncontrolled activation of monocytes and excessive production of inflammatory factors contribute to the damage of bone-cartilage joints. Despite the moderate beneficial effect of current therapies and clinical trials, there is still a need for alternative strategies targeting monocytes to treat RA.

Methods

To explore such an alternative strategy, we investigated the effects of targeting the CXCR4 receptor using the histamine analog clobenpropit (CB). Monocytes were isolated from the blood and synovial fluids of JIA patients to assess CB's impact on their production of key inflammatory cytokines. Additionally, we administered daily intraperitoneal CB treatment to arthritic mice to evaluate its effects on circulating inflammatory cytokine levels, immune cell infiltrates, joints erosion, and bone resorption, as indicators of disease progression.

Results

Our findings demonstrated that CXCR4 targeting with CB significantly inhibited the spontaneous and induced-production of key inflammatory cytokines by monocytes isolated from JIA patients. Furthermore, CB treatment in a mouse model of collagen-induce arthritis resulted in a significant decrease in circulating inflammatory cytokine levels, immune cell infiltrates, joints erosion, and bone resorption, leading to a reduction in disease progression.

Discussion

In conclusion, targeting CXCR4 with the small amino compound CB shows promise as a therapeutic option for chronic and viral-induced inflammatory diseases, including RA. CB effectively regulated inflammatory cytokine production of monocytes, presenting a potential targeted approach with potential advantages over current therapies. These results warrant further research and clinical trials to explore the full therapeutic potential of targeting CXCR4 with CB-like molecules in the management of various inflammatory diseases.

Regulation of human interferon signaling by transposon exonization

Innate immune signaling is essential for clearing pathogens and damaged cells, and must be tightly regulated to avoid excessive inflammation or autoimmunity. Here, we found that the alternative splicing of exons derived from transposable elements is a key mechanism controlling immune signaling in human cells. By analyzing long-read transcriptome datasets, we identified numerous transposon exonization events predicted to generate functional protein variants of immune genes, including the type I interferon receptor IFNAR2. We demonstrated that the transposon-derived isoform of IFNAR2 is more highly expressed than the canonical isoform in almost all tissues, and functions as a decoy receptor that potently inhibits interferon signaling including in cells infected with SARS-CoV-2. Our findings uncover a primate-specific axis controlling interferon signaling and show how a transposon exonization event can be co-opted for immune regulation.

Evidence for increased interferon type I activity in CD8+ T cells in giant cell arteritis patients

Introduction

Giant cell arteritis (GCA) is a vasculitis of the medium- and large-sized arteries. Interferon type I (IFN-I) is increasingly recognized as a key player in autoimmune diseases and might be involved in GCA pathogenesis, however evidence is limited. IFN-I activates Janus kinase/signal transducers and activators of transcription (JAK-STAT) pathways, leading to increased expression of interferon stimulated genes. In this study, IFN-I activity in GCA is explored, focusing on CD8+ T cells.

Methods

Expression of phospho-STAT (pSTAT) 1, 3 and 5 was investigated in IFN-α-stimulated peripheral mononuclear cells (PBMCs) gated separately for CD8+ T cells of patients with GCA (n=18), healthy controls (HC, n=15) and infection controls (n=11) by Phosphoflow method combined with fluorescent cell barcoding technique. Furthermore, IFN-I induced myxovirus-resistance protein A (MxA) and CD8+ T cell expression was investigated by immunohistochemistry in temporal artery biopsies (TAB) of GCA patients (n=20) and mimics (n=20), and in aorta tissue of GCA (n=8) and atherosclerosis patients (n=14).

Results

pSTAT1 expression was increased in IFN-α stimulated CD8+ T cells from GCA patients, whereas no difference was observed in pSTAT3 and pSTAT5 expression. MxA was present in TABs of 13/20 GCA patients compared to 2/20 mimics and in 8/8 GCA+ compared to 13/14 GCA- aorta tissues. MxA location partially co-localized with CD8+T cells.

Conclusions

Our results provide evidence for increased IFN-I activity in CD8+ T cells of GCA patients, both systemically and locally. These findings warrant further investigation regarding IFN-I induced biomarkers and IFN-I related novel therapeutic options in GCA.

2022 EULAR points to consider for the measurement, reporting and application of IFN-I pathway activation assays in clinical research and practice

BACKGROUND

Type I interferons (IFN-Is) play a role in a broad range of rheumatic and musculoskeletal diseases (RMDs), and compelling evidence suggests that their measurement could have clinical value, although testing has not progressed into clinical settings.

OBJECTIVE

To develop evidence-based points to consider (PtC) for the measurement and reporting of IFN-I assays in clinical research and to determine their potential clinical utility.

METHODS

EULAR standardised operating procedures were followed. A task force including rheumatologists, immunologists, translational scientists and a patient partner was formed. Two systematic reviews were conducted to address methodological and clinical questions. PtC were formulated based on the retrieved evidence and expert opinion. Level of evidence and agreement was determined.

RESULTS

Two overarching principles and 11 PtC were defined. The first set (PtC 1-4) concerned terminology, assay characteristics and reporting practices to enable more consistent reporting and facilitate translation and collaborations. The second set (PtC 5-11) addressed clinical applications for diagnosis and outcome assessments, including disease activity, prognosis and prediction of treatment response. The mean level of agreement was generally high, mainly in the first PtC set and for clinical applications in systemic lupus erythematosus. Harmonisation of assay methodology and clinical validation were key points for the research agenda.

CONCLUSIONS

IFN-I assays have a high potential for implementation in the clinical management of RMDs. Uptake of these PtC will facilitate the progress of IFN-I assays into clinical practice and may be also of interest beyond rheumatology.

SARS-CoV-2 Evasion of the Interferon System: Can We Restore Its Effectiveness?

Type I and III Interferons (IFNs) are the first lines of defense in microbial infections. They critically block early animal virus infection, replication, spread, and tropism to promote the adaptive immune response. Type I IFNs induce a systemic response that impacts nearly every cell in the host, while type III IFNs' susceptibility is restricted to anatomic barriers and selected immune cells. Both IFN types are critical cytokines for the antiviral response against epithelium-tropic viruses being effectors of innate immunity and regulators of the development of the adaptive immune response. Indeed, the innate antiviral immune response is essential to limit virus replication at the early stages of infection, thus reducing viral spread and pathogenesis. However, many animal viruses have evolved strategies to evade the antiviral immune response. The Coronaviridae are viruses with the largest genome among the RNA viruses. Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) caused the coronavirus disease 2019 (COVID-19) pandemic. The virus has evolved numerous strategies to contrast the IFN system immunity. We intend to describe the virus-mediated evasion of the IFN responses by going through the main phases: First, the molecular mechanisms involved; second, the role of the genetic background of IFN production during SARS-CoV-2 infection; and third, the potential novel approaches to contrast viral pathogenesis by restoring endogenous type I and III IFNs production and sensitivity at the sites of infection.

Chronic Epstein-Barr virus infection: A potential junction between primary Sjögren's syndrome and lymphoma

Primary Sjögren's syndrome (pSS) is an autoimmune disease that targets exocrine glands, leading to exocrine dysfunction. Due to its propensity to infect epithelial and B cells, Epstein-Barr virus (EBV) is hypothesized to be related with pSS. Through molecular mimicry, the synthesis of specific antigens, and the release of inflammatory cytokines, EBV contributes to the development of pSS. Lymphoma is the most lethal outcome of EBV infection and the development of pSS. As a population-wide virus, EBV has had a significant role in the development of lymphoma in people with pSS. In the review, we will discuss the possible causes of the disease.

DDX23 of black carp negatively regulates MAVS-mediated antiviral signaling in innate immune activation

Mammalian DDX23 is involved in multiple biological processes, such as RNA processing and antiviral responses. However, the function of teleost DDX23 still remains unclear. In this paper, we have cloned the DDX23 homologue of black carp (Mylopharyngodon piceus) (bcDDX23) and elucidated its role in the antiviral innate immunity. The coding region of bcDDX23 comprises 2427 nucleotides and encodes 809 amino acids. The transcription of bcDDX23 was promoted by the stimulation of LPS, poly(I:C), and SVCV; and immunoblotting (IB) assay showed that bcDDX23 migrated aground 94.5 kDa. Immunofluorescence (IF) assay revealed that bcDDX23 was mainly distributed in the nucleus, and the amount of cytosolic bcDDX23 was significantly increased after SVCV infection. The reporter assay showed that bcDDX23 inhibited bcMAVS-mediated transcription of the IFN promoter. And the co-immunoprecipitation (co-IP) assays identified the interaction between bcDDX23 and bcMAVS. Furthermore, co-expressed bcDDX23 significantly inhibited bcMAVS-mediated antiviral ability against SVCV in EPC cells, and knockdown of bcDDX23 enhanced the resistance of host cells against SVCV. Overall, our results conclude that bcDDX23 targets bcMAVS and suppresses MAVS-mediated IFN signaling, which sheds light on the regulation of IFN signaling in teleost fish.

Role of CD14+ monocyte-derived oxidised mitochondrial DNA in the inflammatory interferon type 1 signature in juvenile dermatomyositis

OBJECTIVES

To define the host mechanisms contributing to the pathological interferon (IFN) type 1 signature in Juvenile dermatomyositis (JDM).

METHODS

RNA-sequencing was performed on CD4+, CD8+, CD14+ and CD19+ cells sorted from pretreatment and on-treatment JDM (pretreatment n=10, on-treatment n=11) and age/sex-matched child healthy-control (CHC n=4) peripheral blood mononuclear cell (PBMC). Mitochondrial morphology and superoxide were assessed by fluorescence microscopy, cellular metabolism by 13C glucose uptake assays, and oxidised mitochondrial DNA (oxmtDNA) content by dot-blot. Healthy-control PBMC and JDM pretreatment PBMC were cultured with IFN-α, oxmtDNA, cGAS-inhibitor, TLR-9 antagonist and/or n-acetyl cysteine (NAC). IFN-stimulated gene (ISGs) expression was measured by qPCR. Total numbers of patient and controls for functional experiments, JDM n=82, total CHC n=35.

RESULTS

Dysregulated mitochondrial-associated gene expression correlated with increased ISG expression in JDM CD14+ monocytes. Altered mitochondrial-associated gene expression was paralleled by altered mitochondrial biology, including 'megamitochondria', cellular metabolism and a decrease in gene expression of superoxide dismutase (SOD)1. This was associated with enhanced production of oxidised mitochondrial (oxmt)DNA. OxmtDNA induced ISG expression in healthy PBMC, which was blocked by targeting oxidative stress and intracellular nucleic acid sensing pathways. Complementary experiments showed that, under in vitro experimental conditions, targeting these pathways via the antioxidant drug NAC, TLR9 antagonist and to a lesser extent cGAS-inhibitor, suppressed ISG expression in pretreatment JDM PBMC.

CONCLUSIONS

These results describe a novel pathway where altered mitochondrial biology in JDM CD14+ monocytes lead to oxmtDNA production and stimulates ISG expression. Targeting this pathway has therapeutical potential in JDM and other IFN type 1-driven autoimmune diseases.

[Principles of the diagnostics of inborn errors of immunity]

Inborn errors of immunity (IEI) are a heterogeneous group of nearly 500 diseases characterized by a congenital dysfunction of the immune system. The vast majority of IEIs are rare diseases but all IEIs share a cumulative prevalence of 1:1200-1:2000. In addition to a pathological susceptibility to infections, IEIs can also present with lymphoproliferative, autoimmune or autoinflammatory manifestations. There is often an overlap with classical rheumatic and inflammatory disease patterns. Therefore, a basic knowledge of the clinical presentation and the diagnostics of IEIs is also relevant for the practicing rheumatologist.

Negatively regulation of MAVS-mediated antiviral innate immune response by E3 ligase RNF5 in black carp

Mitochondrial antiviral signaling protein (MAVS) is as an adaptor in RIG-I like receptor (RLR) signaling, which plays the key role in interferon (IFN) production during host antiviral innate immune activation. MAVS is fine tuned to avoid excess IFN production, which have been extensively studied in human and mammals. However, the regulation of MAVS in teleost still remains obscure. In this manuscript, we cloned ring finger protein 5 (bcRNF5) of black carp (Mylopharyngodon piceus) and characterized this teleost E3 ubiquitin ligase as a negative regulator of MAVS. The coding region of bcRNF5 consists of 615 nucleotides which encode 205 amino acids, containing two trans-membrane domain (TM) and a ring-finger domain (RING). The transcription regulation of bcRNF5 varies in host cells in response to stimulations of LPS, poly (I:C), grass carp reovirus (GCRV) and spring viremia of carp virus (SVCV). bcRNF5 migrates around 22 KDa in immunoblot (IB) assay and distributes mainly in cytoplasm by immunofluorescent (IF) staining test. Moreover, bcRNF5 significantly inhibits bcMAVS-mediated IFN promoter transcription. In addition, both IF and co-immunoprecipitation assay showed that bcRNF5 interacts with bcMAVS. Furthermore, bcMAVS-mediated antiviral ability is distinctly impaired by bcRNF5. Taken together, these results conclude that bcRNF5, as a negative regulator of the MAVS-mediated IFN signaling, may play a key role in host protection upon virus infection in black carp.

Association between type I interferon pathway activation and clinical outcomes in rheumatic and musculoskeletal diseases: a systematic literature review informing EULAR points to consider

BACKGROUND

Type I interferons (IFN-I) contribute to a broad range of rheumatic and musculoskeletal diseases (RMDs). Compelling evidence suggests that the measurement of IFN-I pathway activation may have clinical value. Although several IFN-I pathway assays have been proposed, the exact clinical applications are unclear. We summarise the evidence on the potential clinical utility of assays measuring IFN-I pathway activation.

METHODS

A systematic literature review was conducted across three databases to evaluate the use of IFN-I assays in diagnosis and monitor disease activity, prognosis, response to treatment and responsiveness to change in several RMDs.

RESULTS

Of 366 screened, 276 studies were selected that reported the use of assays reflecting IFN-I pathway activation for disease diagnosis (n=188), assessment of disease activity (n=122), prognosis (n=20), response to treatment (n=23) and assay responsiveness (n=59). Immunoassays, quantitative PCR (qPCR) and microarrays were reported most frequently, while systemic lupus erythematosus (SLE), rheumatoid arthritis, myositis, systemic sclerosis and primary Sjögren's syndrome were the most studied RMDs. The literature demonstrated significant heterogeneity in techniques, analytical conditions, risk of bias and application in diseases. Inadequate study designs and technical heterogeneity were the main limitations. IFN-I pathway activation was associated with disease activity and flare occurrence in SLE, but their incremental value was uncertain. IFN-I pathway activation may predict response to IFN-I targeting therapies and may predict response to different treatments.

CONCLUSIONS

Evidence indicates potential clinical value of assays measuring IFN-I pathway activation in several RMDs, but assay harmonisation and clinical validation are urged. This review informs the EULAR points to consider for the measurement and reporting of IFN-I pathway assays.

Immunological, Clinical, and Epidemiological Features of Guillain-Barré Syndrome Associated with SARS-CoV-2 Infection

Objectives. There is a growing interest in understanding the association between Guillain-Barré syndrome (GBS) and SARS-CoV-2 infection. The aim of this study was to analyse various characteristics of GBS before and after the pandemic outbreak and thus identify possible distinctive features of GBS associated with SARS-CoV-2 (GBS-S). Material and Methods. In our centre, we retrospectively reviewed the records of patients diagnosed with GBS between January 2018 and March 2022. Epidemiological, clinical, and immunological data were analysed and compared between patients with GBS according to the time of diagnosis and antecedent events. Results. Thirty-nine patients with GBS were included: nine (23.1%) were diagnosed with GBS-S. GBS-S was most frequent in 2020 (6/13, 46.1%). Most of these patients developed a postinfectious classic demyelinating variant (4/9, 44.4%) with frequent bilateral facial paralysis (4/9, 44.4%). Serum antiganglioside antibodies (AGAs) were found in 1/9 patients with GBS-S. Serum anti-SSA/Ro60 antibodies were highly prevalent in GBS-S (7/9 (77.8%) vs. 3/11 (27.3%), $p=0.019$ ). Three cases associated with SARS-CoV-2 vaccination (GBS-V) were detected. Of note, two had bilateral facial paralysis and anti-SSA/Ro60 antibodies. Conclusion. Our findings suggest that SARS-CoV-2 has become an important antecedent event associated with GBS in our setting. GBS-S shows a postinfectious demyelinating immune-mediated profile with negative serological testing for AGAs. Serum anti-SSA/Ro60 antibodies were found frequently in these patients. Bilateral facial paralysis stands out as a possible characteristic clinical feature both in GBS-S and GBS-V. Larger, prospective studies are needed for a better understanding of its immunopathogenesis.

Reticulocytes in donor RBC units enhance RBC alloimmunization

Although red blood cell (RBC) transfusions save lives, some patients develop clinically-significant alloantibodies against donor blood group antigens, which then have adverse effects in multiple clinical settings. Few effective measures exist to prevent RBC alloimmunization and/or eliminate alloantibodies in sensitized patients. Donor-related factors may influence alloimmunization; thus, there is an unmet clinical need to identify which RBC units are immunogenic. Repeat volunteer blood donors and donors on iron supplements have elevated reticulocyte counts compared to healthy non-donors. Early reticulocytes retain mitochondria and other components, which may act as danger signals in immune responses. Herein, we tested whether reticulocytes in donor RBC units could enhance RBC alloimmunization. Using a murine model, we demonstrate that transfusing donor RBC units with increased reticulocyte frequencies dose-dependently increase RBC alloimmunization rates and alloantibody levels. Transfusing reticulocyte-rich RBC units was associated with increased RBC clearance from the circulation and a robust proinflammatory cytokine response. As compared to previously reported post-transfusion RBC consumption patterns, erythrophagocytosis from reticulocyte-rich units was increasingly performed by splenic B cells. These data suggest that reticulocytes in a donated RBC unit impact the quality of blood transfused, are targeted to a distinct compartment, and may be an underappreciated risk factor for RBC alloimmunization.

Novel insight into miRNA biology and its role in the pathogenesis of systemic lupus erythematosus

MicroRNAs(miRNAs) have emerged as key regulators that control and influence gene expression as well as multiple biological processes depending on their potential binding sites in human-protein coding genes and other unconventional patterns, including coding for peptides, activating Toll-like receptors as a ligand, and other manners. Accumulating evidence has demonstrated that microRNA expression is tightly regulated during phases of development, differentiation, and effector functions of immune cells, immunological disorders of systemic lupus erythematosus (SLE). This review outlines the biogenesis of miRNAs and their unconventional functions as well as underlying cellular and molecular mechanisms. It then summarizes our current knowledge about how the biogenesis of miRNAs is regulated. Moreover, an overview was provided concerning the role of abnormal expression of miRNAs in lupus immune cells. In particular, we will shed some light on the recent advances in the role of miRNAs and exosome-derived miRNAs in immunological and epigenetic pathways in the pathogenesis of SLE.

The expression of Ets-1 and Fli-1 is associated with interferon-inducible genes in peripheral blood mononuclear cells from Japanese patients with systemic lupus erythematosus

Transcription factors E26 transformation-specific-1 (Ets-1) and Friend leukemia insertion site-1 (Fli-1) and type I interferon (IFN) have been implicated in systemic lupus erythematosus (SLE). We examined the expression of these genes in peripheral blood mononuclear cells (PBMCs) from Japanese patients with SLE and analyzed their association with SLE. We enrolled 53 Japanese patients with SLE, 42 patients with rheumatoid arthritis (RA), and 30 healthy donors (HDs) (as controls) in this study. PBMCs were collected from all participants, and the expressions of Ets-1, Fli-1, and three interferon-inducible genes (IFIGs) (interferon-inducible protein with tetratricopeptide 1 [IFIT1], interferon-inducible protein 44 [IFI44], and eukaryotic translation initiation factor 2 alpha kinase 2 [EIF2AK2]) were measured using real-time polymerase chain reaction (PCR). The relationships of each molecule with clinical symptoms, laboratory data, and treatments were analyzed. The expression of Ets-1 and Fli-1 was significantly lower in the PBMCs from patients with SLE than that in the PBMCs from patients with RA and HDs. The expression of the three IFIGs was significantly higher in the PBMCs from patients with SLE than that in the PBMCs from patients with RA and HDs. For patients with SLE, significantly positive correlations were found between Ets-1 and three IFIGs; a similar trend was observed between Fli-1 and IFIGs. IFIG expression in the PBMCs was significantly higher in patients with SLE than that in other participants, and the expression of Ets-1 and Fli-1 was positively associated with IFN expression. Therefore, it was suggested that Ets-1 and Fli-1 were associated with the pathophysiology of SLE by regulating the type I IFN pathway.

Disturbed natural killer cell homeostasis in the salivary gland enhances autoimmune pathology via IFN-γ in a mouse model of primary Sjögren's syndrome

OBJECTIVE

Innate lymphoid cells (ILCs), including natural killer (NK) cells, ILC1, ILC2, lymphoid tissue-inducer (LTi) cells, and ILC3 cell, play a key role in various immune responses. Primary Sjögren's syndrome (pSS) is an autoimmune disease characterized by chronic inflammation of exocrine glands, such as the lacrimal and salivary glands (SGs). The role of NK cells among ILCs in the pathogenesis of pSS is still unclear. In this study, the characteristics and subsets of NK cells in the salivary gland (SG) tissue were analyzed using a murine model of pSS.

METHODS

Multiple phenotypes and cytotoxic signature of the SG NK cells in control and pSS model mice were evaluated by flow cytometric analysis. Intracellular expression of interferon-γ (IFN-γ) among T cells and NK cells from the SG tissues was compared by in vitro experiments. In addition, pathological analysis was performed using anti-asialo-GM1 (ASGM1) antibody (Ab)-injected pSS model mice.

RESULTS

The number of conventional NK (cNK) cells in the SG of pSS model mice significantly increased compared with that in control mice at 6 weeks of age. The production level of IFN-γ was significantly higher in SG NK cells than in SG T cells. The depletion of NK cells by ASGM1 Ab altered the ratio of tissue resident NK (rNK) cells to cNK cells, which inhibited the injury to SG cells with the recovery of saliva secretion in pSS model mice.

CONCLUSION

The results indicate that SG cNK cells may enhance the autoreactive response in the target organ by upregulating of IFN-γ, whereas SG rNK cells protect target cells against T cell cytotoxicity. Therefore, the activation process and multiple functions of NK cells in the target organ could be helpful to develop potential markers for determining autoimmune disease activity and target molecules for incurable immune disorders.

The role of activated monocyte IFN/SIGLEC1 signalling in Graves' disease

Graves' disease (GD) is characterized by dysregulation of the immune system with aberrant immune cell function. However, there have been few previous studies on the role of monocytes in the pathology of GD. The object of this study was to investigate whether and how monocytes participate in GD pathology. CD14+ monocytes were isolated from untreated initial GD patients and healthy controls. Then, RNA-seq was performed to investigate changes in global mRNA expression in monocytes and found that type I interferon (IFN) signalling was among the top upregulated signalling pathways in GD monocytes. Type I IFN-induced sialic acid-binding immunoglobulin-like lectin1 (SIGLEC1) expression was significantly upregulated in untreated GD patients and correlated with thyroid parameters. Patient serum SIGLEC1 concentrations were reduced after anti-thyroid drug treatment. Inhibiting SIGLEC1 expression could inhibit proinflammatory cytokine (IL-1β, IL-6, IL-8, IL-10 and M-CSF) expression in monocytes. In conclusion, our study suggested that type I IFN-mediated monocyte activation could have a deleterious effect on the pathogenesis of GD. These observations indicated that the inhibition of type I IFN-activated monocytes/macrophages could have a therapeutic effect on GD remission.

Assessment of type I interferon signatures in undifferentiated inflammatory diseases: A Japanese multicenter experience

Purpose

Upregulation of type I interferon (IFN) signaling has been increasingly detected in inflammatory diseases. Recently, upregulation of the IFN signature has been suggested as a potential biomarker of IFN-driven inflammatory diseases. Yet, it remains unclear to what extent type I IFN is involved in the pathogenesis of undifferentiated inflammatory diseases. This study aimed to quantify the type I IFN signature in clinically undiagnosed patients and assess clinical characteristics in those with a high IFN signature.

Methods

The type I IFN signature was measured in patients’ whole blood cells. Clinical and biological data were collected retrospectively, and an intensive genetic analysis was performed in undiagnosed patients with a high IFN signature.

Results

A total of 117 samples from 94 patients with inflammatory diseases, including 37 undiagnosed cases, were analyzed. Increased IFN signaling was observed in 19 undiagnosed patients, with 10 exhibiting clinical features commonly found in type I interferonopathies. Skin manifestations, observed in eight patients, were macroscopically and histologically similar to those found in proteasome-associated autoinflammatory syndrome. Genetic analysis identified novel mutations in the PSMB8 gene of one patient, and rare variants of unknown significance in genes linked to type I IFN signaling in four patients. A JAK inhibitor effectively treated the patient with the PSMB8 mutations. Patients with clinically quiescent idiopathic pulmonary hemosiderosis and A20 haploinsufficiency showed enhanced IFN signaling.

Conclusions

Half of the patients examined in this study, with undifferentiated inflammatory diseases, clinically quiescent A20 haploinsufficiency, or idiopathic pulmonary hemosiderosis, had an elevated type I IFN signature.

IFI44 is an immune evasion biomarker for SARS-CoV-2 and Staphylococcus aureus infection in patients with RA

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a global pandemic of severe coronavirus disease 2019 (COVID-19). Staphylococcus aureus is one of the most common pathogenic bacteria in humans, rheumatoid arthritis (RA) is among the most prevalent autoimmune conditions. RA is a significant risk factor for SARS-CoV-2 and S. aureus infections, although the mechanism of RA and SARS-CoV-2 infection in conjunction with S. aureus infection has not been elucidated. The purpose of this study is to investigate the biomarkers and disease targets between RA and SARS-CoV-2 and S. aureus infections using bioinformatics analysis, to search for the molecular mechanisms of SARS-CoV-2 and S. aureus immune escape and potential drug targets in the RA population, and to provide new directions for further analysis and targeted development of clinical treatments.

Methods

The RA dataset (GSE93272) and the S. aureus bacteremia (SAB) dataset (GSE33341) were used to obtain differentially expressed gene sets, respectively, and the common differentially expressed genes (DEGs) were determined through the intersection. Functional enrichment analysis utilizing GO, KEGG, and ClueGO methods. The PPI network was created utilizing the STRING database, and the top 10 hub genes were identified and further examined for functional enrichment using Metascape and GeneMANIA. The top 10 hub genes were intersected with the SARS-CoV-2 gene pool to identify five hub genes shared by RA, COVID-19, and SAB, and functional enrichment analysis was conducted using Metascape and GeneMANIA. Using the NetworkAnalyst platform, TF-hub gene and miRNA-hub gene networks were built for these five hub genes. The hub gene was verified utilizing GSE17755, GSE55235, and GSE13670, and its effectiveness was assessed utilizing ROC curves. CIBERSORT was applied to examine immune cell infiltration and the link between the hub gene and immune cells.

Results

A total of 199 DEGs were extracted from the GSE93272 and GSE33341 datasets. KEGG analysis of enrichment pathways were NLR signaling pathway, cell membrane DNA sensing pathway, oxidative phosphorylation, and viral infection. Positive/negative regulation of the immune system, regulation of the interferon-I (IFN-I; IFN-α/β) pathway, and associated pathways of the immunological response to viruses were enriched in GO and ClueGO analyses. PPI network and Cytoscape platform identified the top 10 hub genes: RSAD2, IFIT3, GBP1, RTP4, IFI44, OAS1, IFI44L, ISG15, HERC5, and IFIT5. The pathways are mainly enriched in response to viral and bacterial infection, IFN signaling, and 1,25-dihydroxy vitamin D3. IFI44, OAS1, IFI44L, ISG15, and HERC5 are the five hub genes shared by RA, COVID-19, and SAB. The pathways are primarily enriched for response to viral and bacterial infections. The TF-hub gene network and miRNA-hub gene network identified YY1 as a key TF and hsa-mir-1-3p and hsa-mir-146a-5p as two important miRNAs related to IFI44. IFI44 was identified as a hub gene by validating GSE17755, GSE55235, and GSE13670. Immune cell infiltration analysis showed a strong positive correlation between activated dendritic cells and IFI44 expression.

Conclusions

IFI144 was discovered as a shared biomarker and disease target for RA, COVID-19, and SAB by this study. IFI44 negatively regulates the IFN signaling pathway to promote viral replication and bacterial proliferation and is an important molecular target for SARS-CoV-2 and S. aureus immune escape in RA. Dendritic cells play an important role in this process. 1,25-Dihydroxy vitamin D3 may be an important therapeutic agent in treating RA with SARS-CoV-2 and S. aureus infections.

A cluster of type II interferon-regulated genes associates with disease activity in patients with systemic lupus erythematosus

Upregulation of interferon-regulated genes (IRGs), denoted IFN signature, in peripheral blood has been used as an indirect measure of IFN pathway activation in patients with systemic lupus erythematosus (SLE). However, it has not been determined, which IFN signatures that optimally reflect clinical disease activity. In this study, we determined an IFN signature based on the expression of 128 IRGs in whole blood from 34 SLE patients in a cross-sectional (CS) study, 11 with active lupus nephritis followed longitudinally (LS) and 15 healthy controls. Blood samples were collected in PAXgene tubes and RNA was extracted and purified using a PAXgene blood RNA kit (Qiagen). Gene expression was measured using the NanoString nCounter Gene Expression platform. The CS SLE patients with higher disease activity displayed thrice as many upregulated IRGs (n = 46) as the rest. These IRGs clustered in three groups, consisting of IRGs known to be predominantly stimulated by type I (gene cluster K1) and type II (gene clusters K2 and 3) IFNs. SLEDAI-2K scores associated with the K2 and K3 gene scores (β = 0.372 and β = 0.419, both p < 0.015) but not with K1. In the longitudinal study, the mean SLEDAI-2K score decreased after an average follow-up of 360 days (β = -2.08, P = 5.09 × 10^-12). The mean K1, K2 and K3 gene scores did not change over time, however longitudinal changes in SLEDAI-2K and K3 scores were associated (β = 0.814, p = 0.007). This study validates the presence of type I IRG subsets that do not associate with disease activity in SLE patients. The novel finding in this study is the association between a type II IRG subset and disease activity. Both findings may have significant implications for choosing IRGs defining clinically relevant IFN signatures.

Molecular Mimicry, Hyperactive Immune System, And SARS-COV-2 Are Three Prerequisites of the Autoimmune Disease Triangle Following COVID-19 Infection

SARS-CoV-2 infection can produce a variety of clinical manifestations, which are either directly related to viral tissue damage or indirectly induced by the antiviral immune response. Molecular mimicry enables this virus to undermine self-tolerance in a host's immune system also immune system's attempts to eliminate SARS-COV-2 may trigger autoimmunity by hyper-activating the innate and adaptive immune systems. Auto immune diseases include Systemic lupus erythematosus, autoimmune thyroid diseases, Guillain‐Barre syndrome, Immune thrombocytopenic purpura, and the detection of autoantibodies are the cues to the discovery of the potential of COVID‐19 in inducing autoimmunity. As COVID-19 and autoimmune diseases share a common pathogenesis, autoimmune drugs may be an effective treatment option. Susceptible patients must be monitored for autoimmune symptoms after contracting CVID-19. In light of the SARS-COV-2 virus' ability to induce autoimmunity in susceptible patients, will the various COVID-19 vaccines that are the only way to end the pandemic induce autoimmunity?

Jak Inhibitors for Treatment of Autoimmune Diseases: Lessons from Systemic Sclerosis and Systemic Lupus Erythematosus

Systemic sclerosis and systemic lupus erythematosus represent two distinct autoimmune diseases belonging to the group of connective tissue disorders. Despite the great progress in the basic science, this progress has not been translated to the development of novel therapeutic approaches that can radically change the face of these diseases. The discovery of JAK kinases, which are tyrosine kinases coupled with cytokine receptors, may open a new chapter in the treatment of so far untreatable diseases. Small synthetic compounds that can block Janus kinases and interact directly with cytokine signalling may provide therapeutic potential in these diseases. In this review, we discuss the therapeutic potential of Jak kinases in light of the cytokine network that JAK kinases are able to interact with. We also provide the theoretical background for the rationale of blocking cytokines with specific JAK inhibitors.

Inflammation and Interferon Signatures in Peripheral B-Lymphocytes and Sera of Individuals With Fibromyalgia

Fibromyalgia (FM) is an idiopathic chronic disease characterized by widespread musculoskeletal pain, hyperalgesia and allodynia, often accompanied by fatigue, cognitive dysfunction and other symptoms. Autoimmunity and neuroinflammatory mechanisms have been suggested to play important roles in the pathophysiology of FM supported by recently identified interferon signatures in affected individuals. However, the contribution of different components in the immune system, such as the B-lymphocytes, in the progression to FM are yet unknown. Furthermore, there is a great need for biomarkers that may improve diagnostics of FM. Herein, we investigated the gene expression profile in peripheral B-cells, as well as a panel of inflammatory serum proteins, in 30 FM patients and 23 healthy matched control individuals. RNA sequence analysis revealed 60 differentially expressed genes when comparing the two groups. The group of FM patients showed increased expression of twenty-five interferon-regulated genes, such as S100A8 and S100A9, VCAM, CD163, SERPINA1, ANXA1, and an increased interferon score. Furthermore, FM was associated with elevated levels of 19 inflammatory serum proteins, such as IL8, AXIN1, SIRT2 and STAMBP, that correlated with the FM severity score. Together, the results shows that FM is associated with an interferon signature in B-cells and increased levels of a set of inflammatory serum proteins. Our findings bring further support for immune activation in the pathogenesis of FM and highlight candidate biomarkers for diagnosis and intervention in the management of FM.

Metabolic Reprogramming of Innate Immune Cells as a Possible Source of New Therapeutic Approaches in Autoimmunity

Immune cells undergo different metabolic pathways or immunometabolisms to interact with various antigens. Immunometabolism links immunological and metabolic processes and is critical for innate and adaptive immunity. Although metabolic reprogramming is necessary for cell differentiation and proliferation, it may mediate the imbalance of immune homeostasis, leading to the pathogenesis and development of some diseases, such as autoimmune diseases. Here, we discuss the effects of metabolic changes in autoimmune diseases, exerted by the leading actors of innate immunity, and their role in autoimmunity pathogenesis, suggesting many immunotherapeutic approaches.

Lipid Metabolism: Immune Regulation and Therapeutic Prospectives in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a heterogeneous disease characterized by the production of abnormal autoantibodies and immune complexes that can affect the organ and organ systems, particularly the kidneys and the cardiovascular system. Emerging evidence suggests that dysregulated lipid metabolism, especially in key effector cells, such as T cells, B cells, and innate immune cells, exerts complex effects on the pathogenesis and progression of SLE. Beyond their important roles as membrane components and energy storage, different lipids can also modulate different cellular processes, such as proliferation, differentiation, and survival. In this review, we summarize altered lipid metabolism and the associated mechanisms involved in the pathogenesis and progression of SLE. Furthermore, we discuss the recent progress in the role of lipid metabolism as a potential therapeutic target in SLE.

Expression of PD-1, PD-L1 and PD-L2 in Lymphomas in Patients with Pre-Existing Rheumatic Diseases-A Possible Association with High Rheumatoid Arthritis Disease Activity

Current research seeks to identify subgroups of non-Hodgkin lymphoma (NHL) patients responsive to PD-1 blocking agents. Whether patients with pre-existing rheumatic diseases might constitute such a subgroup is unknown. We determined intratumoral expression of PD-1 and its ligands in lymphoma patients with pre-existing rheumatic diseases. We included 215 patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) or Sjögren's syndrome with subsequent lymphoma and 74 diffuse large B-cell lymphoma (DLBCL) controls without rheumatic disease. PD-1 and PD-ligand immunohistochemical markers were applied on tumor tissue microarrays. The number of PD-1+ tumor infiltrating leukocytes (TILs) and proportions of PD-L1+ and PD-L2+ tumor cells and TILs were calculated and correlated with clinical data. Expression of PD-L1 in tumor cells and TILs was highest in classical Hodgkin lymphoma and DLBCL. In DLBCLs, expression of PD-1 in TILs and PD-L1 in tumor cells was similar in RA, SLE and controls. In RA-DLBCL, high expression of PD-L1 in tumor cells was significantly more common in patients with the most severe RA disease and was associated with inferior overall survival in multivariable analysis.

Interferon signature in giant cell arteritis aortitis

OBJECTIVES

Molecular mechanisms underlying large-vessel involvement in giant cell arteritis (LV-GCA) are largely unknown. Herein, we explore the critical involvement of pro-inflammatory signaling pathways in both aorta and T cells from patients with LV-GCA.

METHODS

We analyzed transcriptome and interferon gene signature in inflamed aortas from LV-GCA patients and compared them to non-inflammatory control aorta. Differential transcriptomic analyses of circulating CD4⁺ and CD8⁺ T cells were also performed between patients with active GCA (not under any immunosuppressants or corticosteroid doses higher than 10 mg/day by the time of blood collection) and healthy donors. Interferon-alpha serum levels were measured using ultra-sensitive technique (HD-X Simoa Planar Technology) in GCA patients according to disease activity status.

RESULTS

Transcriptomic analyses revealed 1042, 1479 and 2075 significantly dysregulated genes for aortas, CD4⁺ and CD8⁺ cells from LV-GCA patients, respectively, as compared to controls. A great enrichment for pathways linked to interferons (type I, II and III), JAK/STAT signaling, cytokines and chemokines was seen across aortas and circulating T cells. A type I interferon signature was identified as significantly upregulated in the aorta of patients with LV-GCA, notably regarding EPSTI1 and IFI44L genes. STAT3 was significantly upregulated in both aorta and T cells and appeared as central in related gene networks from LV-GCA patients. Interferon-alpha serum levels were higher in patients with active GCA when compared to those in remission (0.024 vs. 0.011 pg/mL; p = 0.028).

CONCLUSION

LV-GCA presents a clear type I interferon signature in aortas, which paves the way for tailored therapeutical targeting.

Managing Antiphospholipid Syndrome in Children and Adolescents: Current and Future Prospects

Pediatric antiphospholipid syndrome (APS) is a rare acquired multisystem autoimmune thromboinflammatory condition characterized by thrombotic and non-thrombotic clinical manifestations. APS in children and adolescents typically presents with large-vessel thrombosis, thrombotic microangiopathy, and, rarely, obstetric morbidity. Non-thrombotic clinical manifestations are frequently seen in pediatric APS and may be present even before the vascular thrombotic events occur. We review insights into the pathogenesis of APS and discuss potential targets for therapy. The identification of multiple immunologic abnormalities in patients with APS reveals molecular targets for current or future treatment. Management strategies, especially for APS in adolescents, require screening for additional prothrombotic risk factors and consideration of counseling regarding contraceptive strategies, lifestyle recommendations, treatment adherence, and mental health issues associated with this autoimmune thrombophilia. The main goal of therapy in pediatric APS is the prevention of thrombosis. The management of acute thrombosis events in children and adolescents is the same as for primary APS, which involves isolated occurrences, and secondary APS, which is seen in association with another autoimmune disease, e.g., systemic lupus erythematosus. A pediatric hematologist should be consulted so other differential thrombophilic conditions can be eliminated. Therapy includes unfractionated heparin or low-molecular-weight heparin followed by vitamin K antagonists. Treatment of catastrophic APS involves triple therapy (anticoagulation, intravenous corticosteroid pulse therapy, and plasma exchange) and may include intravenous immunoglobulin for children and adolescents with this condition. New drugs such as eculizumab and sirolimus seem to be promising drugs for APS.

HIV-1 Nef Protein Affects Cytokine and Extracellular Vesicles Production in the GEN2.2 Plasmacytoid Dendritic Cell Line

Plasmacytoid dendritic cells (pDCs) are a unique dendritic cell subset specialized in type I interferon production, whose role in Human Immunodeficiency Virus (HIV) infection and pathogenesis is complex and not yet well defined. Considering the crucial role of the accessory protein Nef in HIV pathogenicity, possible alterations in intracellular signalling and extracellular vesicle (EV) release induced by exogenous Nef on uninfected pDCs have been investigated. As an experimental model system, a human plasmacytoid dendritic cell line, GEN2.2, stimulated with a myristoylated recombinant Nef_SF2 protein was employed. In GEN2.2 cells, Nef treatment induced the tyrosine phosphorylation of STAT-1 and STAT-2 and the production of a set of cytokines, chemokines and growth factors including IP-10, MIP-1β, MCP-1, IL-8, TNF-α and G-CSF. The released factors differed both in type and amount from those released by macrophages treated with the same viral protein. Moreover, Nef treatment slightly reduces the production of small EVs, and the protein was found associated with the small (size < 200 nm) but not the medium/large vesicles (size > 200 nm) collected from GEN2.2 cells. These results add new information on the interactions between this virulence factor and uninfected pDCs, and may provide the basis for further studies on the interactions of Nef protein with primary pDCs.

The Clinical and Immunological Activity Depending on the Presence of Interferon γ in Primary Sjögren’s Syndrome—A Pilot Study

The upregulation of IFN pathways and their stimulated genes is associated with primary Sjögren’s syndrome (pSS). The recent studies also indicate the involvement of interferon γ (IFNγ) in the pathogenesis of pSS. The study aimed to assess the clinical and immunological activity depending on the concentration of IFNγ in the peripheral blood in pSS patients. Methods: The study group consisted of patients over 18 years of age with a confirmed diagnosis of pSS. Based on the collected data, disease activity was assessed using the EULAR Sjögren’s syndrome disease activity index (ESSDAI) and the EULAR Sjögren’s syndrome patient reported index (ESSPRI). Results: Among 40 pSS patients, 33 (82%) showed increased levels of IFNγ. The group with positive IFNγ was younger (43 years) than the group with negative IFNγ (57 years) (p < 0.05). In the positive IFNγ group, the time to diagnosis was shorter (p < 0.05). There was a difference in ESSDAI among patients with and without IFNγ (p < 0.05). There were no differences between the groups in ESSPRI and the presence of cryoglobulins, specific anti-SSA, and anti-SSB antibodies and in C3 and C4 hypocomplementemia. RF occurred in both groups with a similar frequency (p = 0.6), but in patients with IFNγ presence, significantly higher RF titers were observed (34.9 vs. 10.5; p < 0.05). Conclusion: In the group of patients with positive IFNγ, the mean value of RF and ESSDAI was higher. This group was also younger than patients with pSS without IFNγ.

The Complex Role of C-Reactive Protein in Systemic Lupus Erythematosus

C-reactive protein (CRP) is well-known as a sensitive albeit unspecific biomarker of inflammation. In most rheumatic conditions, the level of this evolutionarily highly conserved pattern recognition molecule conveys reliable information regarding the degree of ongoing inflammation, driven mainly by interleukin-6. However, the underlying causes of increased CRP levels are numerous, including both infections and malignancies. In addition, low to moderate increases in CRP predict subsequent cardiovascular events, often occurring years later, in patients with angina and in healthy individuals. However, autoimmune diseases characterized by the Type I interferon gene signature (e.g., systemic lupus erythematosus, primary Sjögren’s syndrome and inflammatory myopathies) represent exceptions to the general rule that the concentrations of CRP correlate with the extent and severity of inflammation. In fact, adequate levels of CRP can be beneficial in autoimmune conditions, in that they contribute to efficient clearance of cell remnants and immune complexes through complement activation/modulation, opsonization and phagocytosis. Furthermore, emerging data indicate that CRP constitutes an autoantigen in systemic lupus erythematosus. At the same time, the increased risks of cardiovascular and cerebrovascular diseases in patients diagnosed with systemic lupus erythematosus and rheumatoid arthritis are well-established, with significant impacts on quality of life, accrual of organ damage, and premature mortality. This review describes CRP-mediated biological effects and the regulation of CRP release in relation to aspects of cardiovascular disease and mechanisms of autoimmunity, with particular focus on systemic lupus erythematosus.

Immune system activation in polymyalgia rheumatica: Which balance between autoinflammation and autoimmunity? A systematic review

BACKGROUND AND AIM

Polymyalgia rheumatica (PMR) is an inflammatory rheumatic disease that is common in elderly people. Its classification in the spectrum of autoinflammatory and autoimmune diseases is difficult because of its only partially understood immune-mediated mechanisms. The literature concerning the innate and adaptive immune system activation in PMR was systematically reviewed highlighting the relative weight of autoinflammation and autoimmunity in its pathogenesis and disease progression.

METHODS

A literature search on PubMed Central and Embase scientific databases was performed by two independent reviewers. To be eligible, the studies needed to fully satisfy our initial PICO framework: a primary diagnosis of PMR as a population, the search for immune/inflammatory cells, cytokines and autoantibodies as an intervention, a control group consisting in healthy controls, patients with other inflammatory rheumatic diseases or PMR patients in remission after treatment and as outcomes the results of the investigations in the analyzed tissue samples. The most relevant data of the included papers were extracted by using a standardized template.

RESULTS

Of the 933 screened abstracts, 52 papers were included in the systematic review and categorized depending on their primary research objectives. The hyper-activity of neutrophils and monocytes, expressing toll-like receptor 7 in active disease, an impaired phagocytosis and endothelial dysfunction, as well as an increased count of innate T cells in patients with remission emerged among the major derangements of the innate immune response in PMR. Among the cytokines profile, interleukin-6 plays a key role but other pro-inflammatory mediators and angiogenesis markers such as chemokines, B-cell activating factor, vascular endothelial growth factor and angiopoietins seem to be involved in refractory or glucocorticoid-resistant PMR. The aberrant adaptive immune response was documented by tissue and serum findings of polarized T cells towards T helper 1 and 17 phenotypes, an increased expression of immunosenescent surface markers and a downregulated immunoregulatory response. The altered distribution of peripheral B cells, detected during active disease, suggested their peripheral migration towards unidentified sites. The interaction between innate and adaptive immune response was documented by a synovial infiltrate of macrophages and T cells. Despite multiple autoantibodies have been detected in PMR patients, none proved to correlate with disease activity seeming to be reactive to the marked inflammation or antigenic determinants provided by environmental triggers or tissue/cell damage.

CONCLUSIONS

The complex network between innate and adaptive immune system in PMR is supported by findings at molecular and cellular levels. By considering both the ends of the pathophysiological spectrum of immune-mediated rheumatic diseases, PMR may be regarded as an inflammatory immune-mediated disease with mixed mechanisms in a background of genetic and epigenetic factors together with immunological and endocrine senescence.

Potential Effects of Coronaviruses on the Liver: An Update

The coronaviruses that cause notable diseases, namely, severe acute respiratory syndrome (SARS), middle east respiratory syndrome (MERS) and coronavirus disease 2019 (COVID-19), exhibit remarkable similarities in genomic components and pathogenetic mechanisms. Although coronaviruses have widely been studied as respiratory tract pathogens, their effects on the hepatobiliary system have seldom been reported. Overall, the manifestations of liver injury caused by coronaviruses typically involve decreased albumin and elevated aminotransferase and bilirubin levels. Several pathophysiological hypotheses have been proposed, including direct damage, immune-mediated injury, ischemia and hypoxia, thrombosis and drug hepatotoxicity. The interaction between pre-existing liver disease and coronavirus infection has been illustrated, whereby coronaviruses influence the occurrence, severity, prognosis and treatment of liver diseases. Drugs and vaccines used for treating and preventing coronavirus infection also have hepatotoxicity. Currently, the establishment of optimized therapy for coronavirus infection and liver disease comorbidity is of significance, warranting further safety tests, animal trials and clinical trials.

JAK inhibitors: a potential treatment for JDM in the context of the role of interferon-driven pathology

Juvenile Idiopathic Inflammatory Myopathies (IIM) are a group of rare diseases that are heterogeneous in terms of pathology that can include proximal muscle weakness, associated skin changes and systemic involvement. Despite options for treatment, many patients continue to suffer resistant disease and lasting side-effects. Advances in the understanding of the immunopathology and genetics underlying IIM may specify new therapeutic targets, particularly where conventional treatment has not achieved a clinical response. An upregulated type I interferon signature is strongly associated with disease and could be a prime target for developing more specific therapeutics. There are multiple components of the IFN pathway that could be targeted for blockade therapy.Downstream of the cytokine receptor complexes are the Janus kinase-signal transducers and activators of transcription (JAK-STAT) pathway, which consists of JAK1-3, TYK2, and STAT1-6. Therapeutic inhibitors have been developed to target components of this pathway. Promising results have been observed in case studies reporting the use of the JAK inhibitors, Baricitinib, Tofacitinib and Ruxolitinib in the treatment of refractory Juvenile Dermatomyositis (JDM). There is still the question of safety and efficacy for the use of JAK inhibitors in JDM that need to be addressed by clinical trials. Here we review the future for the use of JAK inhibitors as a treatment for JDM.

Innate lymphoid cell dysfunction during long-term suppressive antiretroviral therapy in an African cohort

BACKGROUND

Innate lymphoid cells (ILC) are lymphoid lineage innate immune cells that do not mount antigen-specific responses due to their lack of B and T-cell receptors. ILCs are predominantly found at mucosal surfaces, as gatekeepers against invading infectious agents through rapid secretion of immune regulatory cytokines. HIV associated destruction of mucosal lymphoid tissue depletes ILCs, among other immune dysfunctions. Studies have described limited restoration of ILCs during the first three years of combined antiretroviral therapy (cART). Little is known about restoration of ILCs during long-term cART, particularly in sub-Saharan Africa which hosts increasing numbers of adults with at least a decade of cART.

RESULTS

We examined phenotypes and function of ILCs from peripheral blood mononuclear cells after 12 years of suppressive cART. We report that ILC1 frequencies (T-BET + CD127 + and CD161 +) were higher in cART-treated HIV-infected relative to age-matched health HIV-negative adults; P = 0.04 whereas ILC precursors (ILCP) were comparable in the two groups (P = 0.56). Interferon gamma (IFN-γ) secretion by ILC1 was higher among cART-treated HIV-infected relative to HIV-negative adults (P = 0.03).

CONCLUSION

HIV associated alteration of ILC persisted during cART and may likely affect the quality of host innate and adaptive immune responses during long-term cART.

Type I Interferon Induction in Cutaneous DNA Damage Syndromes

Type I interferons (IFNs) as part of the innate immune system have an outstanding importance as antiviral defense cytokines that stimulate innate and adaptive immune responses. Upon sensing of pattern recognition particles (PRPs) such as nucleic acids, IFN secretion is activated and induces the expression of interferon stimulated genes (ISGs). Uncontrolled constitutive activation of the type I IFN system can lead to autoinflammation and autoimmunity, which is observed in autoimmune disorders such as systemic lupus erythematodes and in monogenic interferonopathies. They are caused by mutations in genes which are involved in sensing or metabolism of intracellular nucleic acids and DNA repair. Many authors described mechanisms of type I IFN secretion upon increased DNA damage, including the formation of micronuclei, cytosolic chromatin fragments and destabilization of DNA binding proteins. Hereditary cutaneous DNA damage syndromes, which are caused by mutations in proteins of the DNA repair, share laboratory and clinical features also seen in autoimmune disorders and interferonopathies; hence a potential role of DNA-damage-induced type I IFN secretion seems likely. Here, we aim to summarize possible mechanisms of IFN induction in cutaneous DNA damage syndromes with defects in the DNA double-strand repair and nucleotide excision repair. We review recent publications referring to Ataxia teleangiectasia, Bloom syndrome, Rothmund–Thomson syndrome, Werner syndrome, Huriez syndrome, and Xeroderma pigmentosum. Furthermore, we aim to discuss the role of type I IFN in cancer and these syndromes.

Shared Pathogenetic Features Between Common Variable Immunodeficiency and Sjögren's Syndrome: Clues for a Personalized Medicine

Common variable immunodeficiency disorders (CVID) are a group of rare diseases of the immune system and the most common symptomatic primary antibody deficiency in adults. The “variable” aspect of CVID refers to the approximately half of the patients who develop non-infective complications, mainly autoimmune features, in particular organ specific autoimmune diseases including thyroiditis, and cytopenias. Among these associated conditions, the incidence of lymphoma, including mucosal associated lymphoid tissue (MALT) type, is increased. Although these associated autoimmune disorders in CVID are generally attributed to Systemic Lupus Erythematosus (SLE), we propose that Sjogren’s syndrome (SS) is perhaps a better candidate for the associated disease. SS is an autoimmune disorder characterized by the lymphocytic infiltrates of lacrimal and salivary glands, leading to dryness of the eyes and mouth. Thus, it is a lymphocyte aggressive disorder, in contrast to SLE where pathology is generally attributed to auto-antibody and complement activation. Although systemic lupus erythematosus (SLE) shares these features with SS, a much higher frequency of MALT lymphoma distinguishes SS from SLE. Also, the higher frequency of germ line encoded paraproteins such as the monoclonal rheumatoid factor found in SS patients would be more consistent with the failure of B-cell VDJ switching found in CVID; and in contrast to the hypermutation that characterizes SLE autoantibodies. Thus, we suggest that SS may fit as a better “autoimmune” association with CVID. Examining the common underlying biologic mechanisms that promote lymphoid infiltration by dysregulated lymphocytes and lymphoma in CVID may provide new avenues for treatment in both the diseases. Since the diagnosis of SLE or rheumatoid arthritis is usually based on specific autoantibodies, the associated autoimmune features of CVID patients may not be recognized in the absence of autoantibodies.

A comprehensive database for integrated analysis of omics data in autoimmune diseases

BACKGROUND

Autoimmune diseases are heterogeneous pathologies with difficult diagnosis and few therapeutic options. In the last decade, several omics studies have provided significant insights into the molecular mechanisms of these diseases. Nevertheless, data from different cohorts and pathologies are stored independently in public repositories and a unified resource is imperative to assist researchers in this field.

RESULTS

Here, we present Autoimmune Diseases Explorer ( https://adex.genyo.es ), a database that integrates 82 curated transcriptomics and methylation studies covering 5609 samples for some of the most common autoimmune diseases. The database provides, in an easy-to-use environment, advanced data analysis and statistical methods for exploring omics datasets, including meta-analysis, differential expression or pathway analysis.

CONCLUSIONS

This is the first omics database focused on autoimmune diseases. This resource incorporates homogeneously processed data to facilitate integrative analyses among studies.

In Vitro Effects of Sulforaphane on Interferon-Driven Inflammation and Exploratory Evaluation in Two Healthy Volunteers

Interferonopathies are rare genetic conditions defined by systemic inflammatory episodes caused by innate immune system activation in the absence of pathogens. Currently, no targeted drugs are authorized for clinical use in these diseases. In this work, we studied the contribution of sulforaphane (SFN), a cruciferous-derived bioactive molecule, in the modulation of interferon-driven inflammation in an immortalized human hepatocytes (IHH) line and in two healthy volunteers, focusing on STING, a key-component player in interferon pathway, interferon signature modulation, and GSTM1 expression and genotype, which contributes to SFN metabolism and excretion. In vitro, SFN exposure reduced STING expression as well as interferon signature in the presence of the pro-inflammatory stimulus cGAMP (cGAMP 3 h vs. SFN+cGAMP 3 h p value < 0.0001; cGAMP 6 h vs. SFN+cGAMP 6 h p < 0.001, one way ANOVA), restoring STING expression to the level of unstimulated cells. In preliminary experiments on healthy volunteers, no appreciable variations in interferon signature were identified after SFN assumption, while only in one of them, presenting the GSTM1 wild type genotype related to reduced SFN excretion, could a downregulation of STING be recorded. This study confirmed that SFN inhibits STING-mediated inflammation and interferon-stimulated genes expression in vitro. However, only a trend towards the downregulation of STING could be reproduced in vivo. Results obtained have to be confirmed in a larger group of healthy individuals and in patients with type I interferonopathies to define if the assumption of SFN could be useful as supportive therapy.

Type I Interferon Production of Plasmacytoid Dendritic Cells under Control

One of the most powerful and multifaceted cytokines produced by immune cells are type I interferons (IFNs), the basal secretion of which contributes to the maintenance of immune homeostasis, while their activation-induced production is essential to effective immune responses. Although, each cell is capable of producing type I IFNs, plasmacytoid dendritic cells (pDCs) possess a unique ability to rapidly produce large amounts of them. Importantly, type I IFNs have a prominent role in the pathomechanism of various pDC-associated diseases. Deficiency in type I IFN production increases the risk of more severe viral infections and the development of certain allergic reactions, and supports tumor resistance; nevertheless, its overproduction promotes autoimmune reactions. Therefore, the tight regulation of type I IFN responses of pDCs is essential to maintain an adequate level of immune response without causing adverse effects. Here, our goal was to summarize those endogenous factors that can influence the type I IFN responses of pDCs, and thus might serve as possible therapeutic targets in pDC-associated diseases. Furthermore, we briefly discuss the current therapeutic approaches targeting the pDC-type I IFN axis in viral infections, cancer, autoimmunity, and allergy, together with their limitations defined by the Janus-faced nature of pDC-derived type I IFNs.