IFN-α kinoid in systemic lupus erythematosus: results from a phase IIb, randomised, placebo-controlled study

Shared and distinct peripheral blood immune cell landscape in MCTD, SLE, and pSS

BACKGROUND

Mixed connective tissue disease (MCTD) is a rare autoimmune disease, and little is known about its pathogenesis. Furthermore, MCTD, systemic lupus erythematosus (SLE), and primary Sjögren's syndrome (pSS) share many clinical, laboratory, and immunological manifestations. This overlap complicates early diagnosis and accurate treatment.

METHODS

The transcriptomic profiling of peripheral blood mononuclear cells (PBMCs) from MCTD patients was performed using both bulk RNA sequencing and single-cell RNA sequencing (scRNA-seq) for the first time. Additionally, we applied MCTD scRNA-seq data, along with datasets from SLE (GSE135779) and pSS (GSE157278) from the Gene Expression Omnibus database, to characterize and compare the similarities and heterogeneity among MCTD, SLE, and pSS.

RESULTS

We first resolved transcriptomic changes in peripheral blood immune cells of MCTD, and then revealed the shared and unique features among MCTD, SLE, and pSS. Analyses showed that the percentage of CD8+ effector T cells was increased, while mucosal-associated invariant T cells were decreased in all three diseases. Genes related to the 'interferon (IFN) γ response' and 'IFN α response' were significantly upregulated. SCENIC analysis revealed activation of STAT1 and IRF7 in disease states, targeting IFN-related genes. The IFN-II signaling network was notably elevated in all three diseases. Unique features of MCTD, SLE, and pSS were also identified.

CONCLUSION

We dissected the immune landscape of MCTD at single-cell resolution, providing new insights into the development of novel biomarkers and immunotherapies for MCTD. Furthermore, we offer insights into the transcriptomic similarities and heterogeneity across different autoimmune diseases, while highlighting prospective therapeutic targets.

Decoding tryptophan: Pioneering new frontiers in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disease that affects multiple organ systems, with its pathogenesis intricately tied to genetic, environmental, and immune regulatory factors. In recent years, the aberration of tryptophan metabolism has emerged as a key player in the disease, particularly through the activation of the kynurenine pathway and its influence on immune regulation. This review delves into the critical pathways of tryptophan metabolism and its profound impact on the multi-system manifestations of SLE, including its connections to the nervous system, kidneys, skin, and other organs. Additionally, it examines how tryptophan metabolism modulates the function of various immune cell types. The review also explores potential therapeutic avenues targeting tryptophan metabolism, such as dietary interventions, probiotic modulation, IDO expression inhibition, and immunoadsorption techniques. While current research has underscored the pivotal role of tryptophan metabolism in the onset and progression of SLE, its full therapeutic potential remains to be fully elucidated. This review aims to provide a solid scientific foundation for therapeutic strategies based on modulating tryptophan metabolism in SLE, offering a comprehensive overview of both clinical and basic research in this rapidly evolving field.

Exploring the correlation between UVB sensitivity and SLE activity: Insights into UVB-driven pathogenesis in lupus erythematosus

Lupus erythematosus (LE) comprises various autoimmune inflammatory diseases, with significant overlap between cutaneous LE (CLE) and systemic LE (SLE). A key feature of both CLE and SLE is UV photosensitivity, particularly in UV-exposure-related skin inflammation. Despite this, reliable and objective UVB photosensitivity indicators closely correlating with LE activity have yet to be identified, and the underlying cellular and molecular mechanisms linking UVB sensitivity with LE onset and progression remain unclear. We discovered that ultraviolet B minimal erythema dose (UVB-MED), a quantitative photosensitivity measure, is a significant and independent risk factor for SLE activity, demonstrating a negative correlation with SLEDAI (r = -0.58, P < 0.0001). Comprehensive transcriptomic analyses of large-scale CLE and SLE samples (5918 in discovery and 7242 in validation datasets) revealed more pronounced and extensive UVB-response gene dysregulation in skin tissues compared to blood. Additionally, 14 lupus activity-correlated, UVB-response genes (UVBACGs) were identified, including eight type I interferon-stimulated genes (IRF7, ISG20, ISG15, IFI44, IFITM1, MX1, LY6E, OASL) and others (JUN, PTTG1, HLA-F, CAV1, HOPX, RPL3), with dysregulation evident in skin, blood, and affected organs (e.g., kidney and synovium). Immunocytes serve as the primary carriers of this dysregulation. Conventional LE therapies and type I interferon-targeted therapies were found to be associated with these genes and can potentially regulate them, thereby contributing to therapeutic effects. These findings highlight the role of UVB in triggering autoimmune inflammation in the skin, which may subsequently spread to systemic inflammation via immune cells and factors. UVBACGs play a critical role in this process and may serve as targets for precise therapies, providing insight into the link between UVB photosensitivity and LE pathogenesis.

Systemic lupus erythematosus: updated insights on the pathogenesis, diagnosis, prevention and therapeutics

Systemic lupus erythematosus (SLE) is a chronic inflammatory illness with heterogeneous clinical manifestations covering multiple organs. Diversified types of medications have been shown effective for alleviating SLE syndromes, ranging from cytokines, antibodies, hormones, molecular inhibitors or antagonists, to cell transfusion. Drugs developed for treating other diseases may benefit SLE patients, and agents established as SLE therapeutics may be SLE-inductive. Complexities regarding SLE therapeutics render it essential and urgent to identify the mechanisms-of-action and pivotal signaling axis driving SLE pathogenesis, and to establish innovative SLE-targeting approaches with desirable therapeutic outcome and safety. After introducing the research history of SLE and its epidemiology, we categorized primary determinants driving SLE pathogenesis by their mechanisms; combed through current knowledge on SLE diagnosis and grouped them by disease onset, activity and comorbidity; introduced the genetic, epigenetic, hormonal and environmental factors predisposing SLE; and comprehensively categorized preventive strategies and available SLE therapeutics according to their functioning mechanisms. In summary, we proposed three mechanisms with determinant roles on SLE initiation and progression, i.e., attenuating the immune system, restoring the cytokine microenvironment homeostasis, and rescuing the impaired debris clearance machinery; and provided updated insights on current understandings of SLE regarding its pathogenesis, diagnosis, prevention and therapeutics, which may open an innovative avenue in the fields of SLE management.

Understanding the Role of Type I Interferons in Cutaneous Lupus and Dermatomyositis: Toward Better Therapeutics

A 29-year-old female presented to a rheumatology-dermatology clinic with a pruritic rash that began 6 months prior, after a viral illness. She had previously been diagnosed with eczema and treated with antihistamines and topical steroids without improvement. She also noted fatigue, hair loss, and severe scalp pruritus. Physical examination was notable for violaceous periorbital edema, scaly erythematous papules on the metacarpophalangeal joints of bilateral hands, dilated capillaries of the proximal nail folds, scaly plaques on bilateral elbows, and excoriated erythematous plaques on upper chest, back and hips. The patient reported no muscle weakness, and strength testing and creatinine phosphokinase were normal. Magnetic resonance imaging of the thigh showed no evidence of inflammation or edema. Antibody testing was negative. A diagnosis of clinically amyopathic dermatomyositis was made. Computed tomography scans of the chest, abdomen and pelvis, colonoscopy, and mammogram showed no evidence of cancer. The patient was initiated on methotrexate. Her cutaneous manifestations persisted with debilitating intractable pruritus, and thus, she was transitioned to mycophenolate mofetil, again with minimal improvement. Intravenous immunoglobulin was not approved by insurance given the lack of muscle involvement in her disease. This patient's case highlights a common clinical scenario in rheumatology and dermatology and raises several important issues related to the immunologic underpinnings of cutaneous lupus erythematosus (CLE) and dermatomyositis (DM): What is the role of type I interferon (IFN) in triggering skin disease in CLE and DM? What is the role of IFN in the pathogenesis of skin inflammation in CLE and DM? Can we apply what we know about IFN-targeted therapeutics in CLE and DM to develop better treatments for skin disease?

Progressive polyadenylation and m6A modification of Ighg1 mRNA maintain IgG1 antibody homeostasis in antibody-secreting cells

Antigen-specific antibodies are generated by antibody-secreting cells (ASCs). How RNA post-transcriptional modification affects antibody homeostasis remains unclear. Here, we found that mRNA polyadenylations and N6-methyladenosine (m6A) modifications maintain IgG1 antibody production in ASCs. IgG heavy-chain transcripts (Ighg) possessed a long 3' UTR with m6A sites, targeted by the m6A reader YTHDF1. B cell-specific deficiency of YTHDF1 impaired IgG production upon antigen immunization through reducing Ighg1 mRNA abundance in IgG1+ ASCs. Disrupting either the m6A modification of a nuclear-localized splicing intermediate Ighg1 or the nuclear localization of YTHDF1 reduced Ighg1 transcript stability. Single-cell RNA sequencing identified an ASC subset with excessive YTHDF1 expression in systemic lupus erythematosus patients, which was decreased upon therapy with immunosuppressive drugs. In a lupus mouse model, inhibiting YTHDF1-m6A interactions alleviated symptoms. Thus, we highlight a mechanism in ASCs to sustain the homeostasis of IgG antibody transcripts by integrating Ighg1 mRNA polyadenylation and m6A modification.

Biologics in Systemic Lupus Erythematosus: Recent Evolutions and Benefits

INTRODUCTION

Systemic lupus erythematosus (SLE) is a multifaceted autoimmune disorder characterized by significant autoantibodies, particularly targeting nuclear antigens. SLE pathogenesis involves genetic, environmental, and hormonal factors. The disease course includes flares and remission and involves various organs. Recent therapeutic progresses, including biologics, have improved management and prognosis, though the long-term impact of novel therapies remains to be determined. Biologics in SLE: Rituximab, the earliest B-cell-oriented biologic, binds CD20 and depletes CD20+ B cells, leading to remission in some SLE patients. Belimumab is a B-cell-activating factor (BAFF) inhibitor with a recent additional indication for lupus nephritis. The CALIBRATE and BLISS-BELIEVE studies investigated combinations of these drugs with conventional therapies, showing varied efficacy. Ocrelizumab and obinutuzumab, newer CD20-oriented SLE therapies, together with ofatumumab and veltuzumab, are also promising. The latest trials highlight their efficacy and safety. Anifrolumab, targeting type-I interferon receptors, was evaluated in the TULIP 1/2 trials. The ongoing TULIP LTE trial supports the long-term safety and efficacy of anifrolumab. Additionally, the IRIS Phase III trial is exploring anifrolumab for lupus nephritis, showing favorable renal responses. Tocilizumab and secukinumab are being assessed for SLE, with mixed outcomes. Several biologics targeting the C5 complement protein, together with immunomodulators and immunotherapeutics, are also under investigation for potential benefits in SLE.

DISCUSSION

Biologics in SLE target specific immune components, aiming to improve disease control and reduce the side effects of conventional therapy. However, trial outcomes vary due to factors like inclusion criteria and trial design.

CONCLUSIONS

Biotechnology progress enables targeted biologic therapies for SLE, reducing disease activity and improving patients' quality of life.

SPATS2L is a positive feedback regulator of the type I interferon signaling pathway and plays a vital role in lupus

Through genome-wide association studies (GWAS) and integrated expression quantitative trait locus (eQTL) analyses, numerous susceptibility genes ("eGenes", whose expressions are significantly associated with common variants) associated with systemic lupus erythematosus (SLE) have been identified. Notably, a subset of these eGenes is correlated with disease activity. However, the precise mechanisms through which these genes contribute to the initiation and progression of the disease remain to be fully elucidated. In this investigation, we initially identify SPATS2L as an SLE eGene correlated with disease activity. eSignaling and transcriptomic analyses suggest its involvement in the type I interferon (IFN) pathway. We observe a significant increase in SPATS2L expression following type I IFN stimulation, and the expression levels are dependent on both the concentration and duration of stimulation. Furthermore, through dual-luciferase reporter assays, western blot analysis, and imaging flow cytometry, we confirm that SPATS2L positively modulates the type I IFN pathway, acting as a positive feedback regulator. Notably, siRNA-mediated intervention targeting SPATS2L, an interferon-inducible gene, in peripheral blood mononuclear cells (PBMCs) from patients with SLE reverses the activation of the interferon pathway. In conclusion, our research highlights the pivotal role of SPATS2L as a positive-feedback regulatory molecule within the type I IFN pathway. Our findings suggest that SPATS2L plays a critical role in the onset and progression of SLE and may serve as a promising target for disease activity assessment and intervention strategies.

Monoclonal antibodies targeting interleukins for systemic lupus erythematosus: updates in early clinical drug development

INTRODUCTION

The advent of biological therapies has already revolutionized treatment strategies and disease course of several rheumatologic conditions, and monoclonal antibodies (mAbs) targeting cytokines and interleukins represent a considerable portion of this family of drugs. In systemic lupus erythematosus (SLE) dysregulation of different cytokine and interleukin-related pathways have been linked to disease development and perpetration, offering palatable therapeutic targets addressable via such mAbs.

AREAS COVERED

In this review, we provide an overview of the different biological therapies under development targeting cytokines and interleukins, with a focus on mAbs, while providing the rationale behind their choice as therapeutic targets and analyzing the scientific evidence linking them to SLE pathogenesis.

EXPERT OPINION

An unprecedented number of clinical trials on biological drugs targeting different immunological pathways are ongoing in SLE. Their success might allow us to tackle present challenges of SLE management, including the overuse of glucocorticoids in daily clinical practice, as well as SLE heterogenicity in treatment response among different individuals, hopefully paving the way toward precision medicine.

New and emerging therapies for systemic lupus erythematosus

Systemic Lupus Erythematosus (SLE) and lupus nephritis treatment is still based on non-specific immune suppression despite the first biological therapy for the disease having been approved more than a decade ago. Intense basic and translational research has uncovered a multitude of pathways that are actively being evaluated as treatment targets in SLE and lupus nephritis, with two new medications receiving FDA approval in the last 3 years. Herein we provide an overview of targeted therapies for SLE including medications targeting the B lymphocyte compartment, intracellular signaling, co-stimulation, and finally the interferons and other cytokines.

Engaging natural antibody responses for the treatment of inflammatory bowel disease via phosphorylcholine-presenting nanofibres

Inflammatory bowel disease lacks a long-lasting and broadly effective therapy. Here, by taking advantage of the anti-infection and anti-inflammatory properties of natural antibodies against the small-molecule epitope phosphorylcholine (PC), we show in multiple mouse models of colitis that immunization of the animals with self-assembling supramolecular peptide nanofibres bearing PC epitopes induced sustained levels of anti-PC antibodies that were both protective and therapeutic. The strength and type of immune responses elicited by the nanofibres could be controlled through the relative valency of PC epitopes and exogenous T-cell epitopes on the nanofibres and via the addition of the adjuvant CpG. The nanomaterial-assisted induction of the production of therapeutic antibodies may represent a durable therapy for inflammatory bowel disease.

Potential role of RhoA GTPase regulation in type interferon signaling in systemic lupus erythematosus

OBJECTIVE

Systemic lupus erythematosus (SLE) is an autoimmune disorder characterized by abnormal activation of the type I interferon (IFN) pathway, which results in tissue inflammation and organ damage. We explored the role of the RhoA GTPase in the type I IFN activation pathway to provide a potential basis for targeting GTPase signaling for the treatment of SLE.

METHODS

Total RNA was extracted from peripheral blood mononuclear cells (PBMCs) of SLE patients and healthy controls, and the mRNA expression levels of RhoA and IFN-stimulated genes were measured by SYBR Green quantitative reverse transcriptase-polymerase chain reaction. IFN-a-stimulated response element (ISRE)-luciferase reporter gene assays and Western blotting were conducted to assess the biologic function of RhoA. An enzyme-linked immunoassay (ELISA) measured C-X-C motif chemokine ligand 10 (CXCL10) protein expression.

RESULTS

Our studies demonstrate that the expression of RhoA in the PBMCs of SLE subjects was significantly higher than in healthy controls and positively correlated with type I IFN scores and type I IFN-stimulated gene (ISGs) expression levels. SiRNA-mediated knockdown of RhoA and the RhoA/ROCK inhibitor Y27632 reduced the activity of the type I IFN-induced ISRE, the signal transducer and activator of transcription 1 (STAT-1) phosphorylation, and the expression of CXCL10 and 2'-5'-oligoadenylate synthetase 1 (OAS1). Finally, we verified that Y27632 could significantly down-regulate the OAS1 and CXCL10 expression levels in the PBMCs of SLE patients.

CONCLUSION

Our study shows that RhoA positively regulates the activation of the type I IFN response pathway. Reducing the expression level of RhoA inhibits the abnormal activation of the type I IFN system, and the RhoA/ROCK inhibitor Y27632 decreases aberrant type I IFN signaling in SLE PBMCs, suggesting the possibility of targeting the RhoA GTPase for the treatment of SLE.

Anifrolumab: first biologic approved in the EU not restricted to patients with a high degree of disease activity for the treatment of moderate to severe systemic lupus erythematosus

INTRODUCTION

Type 1 interferons (IFNs) play a crucial role in the pathogenesis of systemic lupus erythematosus (SLE) and various type I IFNs targeting therapeutic approaches have been developed. Anifrolumab, a monoclonal antibody that binds to the subunit 1 of the type I IFN receptor, has acquired considerable interest and has entered different clinical human trials willing to evaluate its efficacy and safety.

AREAS COVERED

This review summarizes the data obtained in phases 1, 2, and 3 clinical trials of anifrolumab for SLE patients. A focus is made on data of clinical efficacy and safety obtained in MUSE, TULIP-1 and TULIP-2 trials.

EXPERT OPINION/COMMENTARY

Anifrolumab is a promising therapeutic option for patients with SLE, currently authorized for moderate-to-severe SLE. Extensive real-world use is now going to generate data required to gain experience on the type of patients who benefit the most from the drug, and the exact positioning of anifrolumab in the therapeutic plan.

Emerging immunotherapeutic strategies for cutaneous lupus erythematosus: an overview of recent phase 2 and 3 clinical trials

INTRODUCTION

Cutaneous lupus erythematosus (CLE) is an autoimmune disease that is clinically heterogenous and may occur with or without the presence of systemic lupus erythematosus (SLE). While existing on a spectrum, CLE and SLE present differences in their underlying pathogenesis and therapeutic responses. No new therapies have been approved in recent decades by the U.S. Food and Drug Administration for CLE, although frequently refractory to conventional therapies. There is an unmet need to develop effective drugs for CLE as it significantly impacts patients' quality of life and may leave irreversible disfiguring damage.

AREAS COVERED

This review provides an update on the latest phase 2 and 3 clinical trials performed in CLE or SLE using skin-specific outcome measures. Emergent therapies are presented alongside their mechanism of action as recent translational studies have permitted identification of critical targets among immune cells and/or pathways involved in CLE.

EXPERT OPINION

While the recent literature has few trials for CLE, drugs targeting type I interferon, its downstream signaling and plasmacytoid dendritic cells have shown promising results. Further research is required to develop long-awaited effective therapies, and this review highlights the importance of implementing trials dedicated to CLE to fill the current gap in CLE therapeutics.

A comprehensive analysis of type 1 interferon gene signatures in systematic lupus erythematosus and prediction of the crucial susceptible factor for Sjögren syndrome

This study aimed to determine the role of IFN-1 gene signatures in SLE and their association with Sjögren syndrome (SS). Publicly available data from the Gene Expression Omnibus database were used to construct the models. The random forest tree model was used to screen key IFN-1 gene signatures, and consensus clustering algorithms were used for unsupervised cluster analysis of these signatures. CIBERSORT and gene set variation analyses were used to evaluate the relative immune cell infiltration and enriched molecular pathways of the samples, respectively. Weighted gene co-expression network analysis was used to identify the co-expression modules and hub genes. Finally, univariate and multivariate logistic regression models were used to evaluate differences in clinical and laboratory characteristics between the different groups. The role of IFN-1 gene signatures in SLE was comprehensively assessed, which revealed an IFN-1 gene signature including six genes that could easily distinguish SLE patients and healthy individuals and identified two distinct IFN-1 subtypes exhibiting significant differences in clinical characteristics, immune microenvironment, and biological functional pathways. The SLE disease activity index, lower lymphocyte count, nucleotide oligomerization domain (NOD)-like receptor signaling pathway, and dendritic cell activation were strongly correlated with the IFN-1 gene signatures. In addition, we found that IFN-1 gene signatures in SLE may be an important susceptibility factor for SS, and the NOD-like receptor signaling pathway was identified as a common pathway. This study provides a comprehensive evaluation of the IFN-1 gene signatures, which may provide a new direction for the understanding of SLE and SS and help in the selection of optimal strategies for personalized immunotherapy.

New and future therapies: Changes in the therapeutic armamentarium for SLE

Following better understanding of molecular pathways involved in the pathogenesis of Systemic lupus erythematosus (SLE), pharmaceutical companies have been investigating new targeted drugs for SLE. The purpose of this scoping review is to provide an updated view of the most promising targeted therapies currently in clinical development or recently approved for SLE treatment as well as of the most promising potential future therapeutic strategies in SLE. In the past several years, two new drugs have been developed for lupus treatment along with an extended indication for belimumab. Anifrolumab, the anti-interferon medication, to treat non-renal lupus; voclosporin, a calcineurin inhibitor, for the treatment of lupus nephritis; and belimumab for lupus nephritis. More than 90 investigational drugs are currently in clinical development for SLE treatment, with various targets including inflammatory cytokines and their receptors, intracellular signaling, B cells or plasma cells, co-stimulation molecules, complement fractions, T cells, plasmacytoid dendritic cells as well as various other immunological targets of interest. Researchers are also actively engaged in the development of new therapeutic strategies, including the use of monoclonal antibodies in combination with bispecific monoclonal antibodies, nanobodies and nanoparticles, therapeutic vaccines, utilizing siRNA interference techniques, autologous hematopoietic stem-cell transplantation and Chimeric Antigens Receptor (CAR)-T cells. The therapeutic management and prognosis of SLE have profoundly evolved with changes in the therapeutic armamentarium. With the broad pipeline of targeted treatments in clinical development and new treatment strategies in the future, current challenges are transitioning from the availability of new drugs to the selection of the most appropriate strategy at the patient level.

An interpretable machine learning pipeline based on transcriptomics predicts phenotypes of lupus patients

Machine learning (ML) has the potential to identify subsets of patients with distinct phenotypes from gene expression data. However, phenotype prediction using ML has often relied on identifying important genes without a systems biology context. To address this, we created an interpretable ML approach based on blood transcriptomics to predict phenotype in systemic lupus erythematosus (SLE), a heterogeneous autoimmune disease. We employed a sequential grouped feature importance algorithm to assess the performance of gene sets, including immune and metabolic pathways and cell types, known to be abnormal in SLE in predicting disease activity and organ involvement. Gene sets related to interferon, tumor necrosis factor, the mitoribosome, and T cell activation were the best predictors of phenotype with excellent performance. These results suggest potential relationships between the molecular pathways identified in each model and manifestations of SLE. This ML approach to phenotype prediction can be applied to other diseases and tissues.

Analysis of transcriptomic features reveals molecular endotypes of SLE with clinical implications

BACKGROUND

Systemic lupus erythematosus (SLE) is known to be clinically heterogeneous. Previous efforts to characterize subsets of SLE patients based on gene expression analysis have not been reproduced because of small sample sizes or technical problems. The aim of this study was to develop a robust patient stratification system using gene expression profiling to characterize individual lupus patients.

METHODS

We employed gene set variation analysis (GSVA) of informative gene modules to identify molecular endotypes of SLE patients, machine learning (ML) to classify individual patients into molecular subsets, and logistic regression to develop a composite metric estimating the scope of immunologic perturbations. SHapley Additive ExPlanations (SHAP) revealed the impact of specific features on patient sub-setting.

RESULTS

Using five datasets comprising 2183 patients, eight SLE endotypes were identified. Expanded analysis of 3166 samples in 17 datasets revealed that each endotype had unique gene enrichment patterns, but not all endotypes were observed in all datasets. ML algorithms trained on 2183 patients and tested on 983 patients not used to develop the model demonstrated effective classification into one of eight endotypes. SHAP indicated a unique array of features influential in sorting individual samples into each of the endotypes. A composite molecular score was calculated for each patient and significantly correlated with standard laboratory measures. Significant differences in clinical characteristics were associated with different endotypes, with those with the least perturbed transcriptional profile manifesting lower disease severity. The more abnormal endotypes were significantly more likely to experience a severe flare over the subsequent 52 weeks while on standard-of-care medication and specific endotypes were more likely to be clinical responders to the investigational product tested in one clinical trial analyzed (tabalumab).

CONCLUSIONS

Transcriptomic profiling and ML reproducibly separated lupus patients into molecular endotypes with significant differences in clinical features, outcomes, and responsiveness to therapy. Our classification approach using a composite scoring system based on underlying molecular abnormalities has both staging and prognostic relevance.

Should we be targeting type 1 interferons in antiphospholipid syndrome?

Systemic autoimmune diseases are characterized by increased production of type I interferon (IFN-1) and upregulation of IFN-1-inducible genes, suggesting an important role of the IFN-1 pathway in their pathogenesis. Recent studies have demonstrated increased IFN-1 expression in both primary and secondary antiphospholipid syndrome (APS), along with increased toll-like receptor type 9 activity and plasmacytoid dendritic cell function. The increasing knowledge of the association between IFN-1 and APS pathology may provide a rationale for conducting clinical trials to assess the efficacy of IFN-1-targeting drugs in reducing APS-related complications. In this narrative review, we summarize the current knowledge on the role of IFN-1 in APS pathogenesis, explore its clinical implications, and examine the existing evidence regarding therapeutic options that have been investigated to date.

The RhoA GTPase regulates Type I Interferon Signaling in Systemic lupus erythematosus

Objective

Systemic lupus erythematosus (SLE) is an autoimmune disorder characterized by abnormal activation of the type I interferon (IFN) pathway, which results in tissue inflammation and organ damage. We explored the role of the RhoA GTPase in the type I IFN activation pathway to provide a potential basis for targeting GTPase signaling for the treatment of SLE.

Methods

Total RNA was extracted from peripheral blood mononuclear cells (PBMCs) of SLE patients and healthy controls, and the mRNA expression levels of RhoA and IFN-stimulated genes were measured by SYBR Green quantitative reverse transcriptase-polymerase chain reaction. IFN-stimulated response element (ISRE)-luciferase reporter gene assays and Western blotting were conducted to asssess the biologic function of RhoA. An Enzyme-Linked Immunoassay (ELISA) measured C-X-C motif chemokine ligand 10(CXCL10)protein expression.

Results

Our studies demonstrated that the expression of RhoA in the PBMCs of SLE subjects was significantly higher than healthy controls and positively correlated with type I IFN scores and type I IFN-stimulated gene (ISGs) expression levels. SiRNA-mediated knockdown of RhoA and the RhoA/ROCK inhibitor Y27632 reduced the activity of the type I IFN-induced ISRE, the signal transducer and activator of transcription 1 (STAT-1) phosphorylation, and the expression of CXCL10 and 2'-5'-oligoadenylate synthetase 1(OAS1). Finally,we verified that Y27632 could significantly down-regulate the OAS1 and CXCL10 expression levels in PBMCs of SLE patients.

Conclusion

Our study shows that RhoA positively regulates the activation of the type I IFN response pathway. Reducing the expression level of RhoA inhibits the abnormal activation of the type I IFN system, and the RhoA/ROCK inhibitor Y27632 decreases aberrant type I IFN signaling in SLE PBMCs, suggesting the possibility of targeting the RhoA GTPase for the treatment of SLE.

Heterogeneity and functions of the 13 IFN-α subtypes - lucky for some?

Type I IFNs are critical for host responses to viral infection and are also implicated in the pathogenesis of multiple autoimmune diseases. Multiple subtypes exist within the type I IFN family, in particular 13 distinct IFN-α genes, which signal through the same heterodimer receptor that is ubiquitously expressed by mammalian cells. Both evolutionary genetic studies and functional antiviral assays strongly suggest differential functions and activity between the 13 IFN-α subtypes, yet we still lack a clear understanding of these different roles. This review summarizes the evidence from studies describing differential functions of IFN-α subtypes and highlights potential reasons for discrepancies between the reports. We examine both acute and chronic viral infection, as well as autoimmunity, and integrate a more recent awareness of the importance of anti-IFN-α autoantibodies in shaping the type I IFN responses in these different conditions.

Control of lupus activity during pregnancy via the engagement of IgG sialylation: novel crosstalk between IgG sialylation and pDC functions

Immunoglobulin (IgG) glycosylation affects the effector functions of IgG in a myriad of biological processes and has been closely associated with numerous autoimmune diseases, including systemic lupus erythematosus (SLE), thus underlining the pathogenic role of glycosylation aberration in autoimmunity. This study aims to explore the relationship between IgG sialylation patterns and lupus pregnancy. Relative to that in serum samples from the control cohort, IgG sialylation level was aberrantly downregulated in serum samples from the SLE cohort at four stages (from preconception to the third trimester of pregnancy) and was significantly associated with lupus activity and fetal loss during lupus pregnancy. The type I interferon signature of pregnant patients with SLE was negatively correlated with the level of IgG sialylation. The lack of sialylation dampened the ability of IgG to suppress the functions of plasmacytoid dendritic cells (pDCs). RNA-seq analysis further revealed that the expression of genes associated with the spleen tyrosine kinase (SYK) signaling pathway significantly differed between IgG- and deSia-IgG-treated pDCs. This finding was confirmed by the attenuation of the ability to phosphorylate SYK and BLNK in deSia-IgG. Finally, the coculture of pDCs isolated from pregnant patients with SLE with IgG/deSia-IgG demonstrated the sialylation-dependent anti-inflammatory function of IgG. Our findings suggested that IgG influences lupus activity through regulating pDCs function via the modulation of the SYK pathway in a sialic acid-dependent manner.

Pathogenic cellular and molecular mediators in lupus nephritis

Kidney involvement in patients with systemic lupus erythematosus - lupus nephritis (LN) - is one of the most important and common clinical manifestations of this disease and occurs in 40-60% of patients. Current treatment regimens achieve a complete kidney response in only a minority of affected individuals, and 10-15% of patients with LN develop kidney failure, with its attendant morbidity and considerable prognostic implications. Moreover, the medications most often used to treat LN - corticosteroids in combination with immunosuppressive or cytotoxic drugs - are associated with substantial side effects. Advances in proteomics, flow cytometry and RNA sequencing have led to important new insights into immune cells, molecules and mechanistic pathways that are instrumental in the pathogenesis of LN. These insights, together with a renewed focus on the study of human LN kidney tissue, suggest new therapeutic targets that are already being tested in lupus animal models and early-phase clinical trials and, as such, are hoped to eventually lead to meaningful improvements in the care of patients with systemic lupus erythematosus-associated kidney disease.

Novel therapeutic strategies for autoimmune and inflammatory rheumatic diseases

Drugs of unknown mechanisms of action are no longer being developed because we have largely capitalized on our improved understanding of the immunopathogenesis of immune-mediated inflammatory diseases (IMIDs) to develop therapeutic monoclonal antibodies (mAbs) and targeted treatments. These therapies have profoundly revolutionized the care of IMIDs. However, because of the heterogeneity of IMIDs and the redundancy of the targeted molecular pathways, some patients with IMIDs might not respond to a specific targeted drug or their disease might relapse secondarily. Therefore, there is much at stake in the development of new therapeutic strategies, which include combinations of mAbs or bispecific mAbs (BsMAbs), nanobodies and nanoparticles (NPs), therapeutic vaccines, small interfering RNA (siRNA) interference, autologous hematopoietic stem cell transplantation (aHSCT), or chimeric antigen receptor (CAR)-T cells. With the broad pipeline of targeted treatments in clinical development, the therapeutic paradigm is rapidly evolving from whether new drugs will be available to the complex selection of the most adequate targeted treatment (or treatment combination) at the patient level. This paradigm change highlights the need to better characterize the heterogeneous immunological spectrum of these diseases. Only then will these novel therapeutic strategies be able to fully demonstrate their potential to treat IMIDs.

Inactive disease in patients with lupus is linked to autoantibodies to type I interferons that normalize blood IFNα and B cell subsets

Systemic lupus erythematosus (SLE) is characterized by increased expression of type I interferon (IFN)-regulated genes in 50%-75% of patients. We report that out of 501 patients with SLE analyzed, 73 (14%) present autoantibodies against IFNα (anti-IFN-Abs). The presence of neutralizing-anti-IFN-Abs in 4.2% of patients inversely correlates with low circulating IFNα protein levels, inhibition of IFN-I downstream gene signatures, and inactive global disease score. Hallmarks of SLE pathogenesis, including increased immature, double-negative plasmablast B cell populations and reduction in regulatory B cell (Breg) frequencies, were normalized in patients with neutralizing anti-IFN-Abs compared with other patient groups. Immunoglobulin G (IgG) purified from sera of patients with SLE with neutralizing anti-IFN-Abs impedes CpGC-driven IFNα-dependent differentiation of B cells into immature B cells and plasmablasts, thus recapitulating the neutralizing effect of anti-IFN-Abs on B cell differentiation in vitro. Our findings highlight a role for neutralizing anti-IFN-Abs in controlling SLE pathogenesis and support the use of IFN-targeting therapies in patients with SLE lacking neutralizing-anti-IFN-Abs.

Targeting type I interferons in systemic lupus erythematous

Systemic lupus erythematosus (SLE) is a complex autoimmune disease with systemic clinical manifestations including, but not limited to, rash, inflammatory arthritis, serositis, glomerulonephritis, and cerebritis. Treatment options for SLE are expanding and the increase in our understanding of the immune pathogenesis is leading to the development of new therapeutics. Autoantibody formation and immune complex formation are important mediators in lupus pathogenesis, but an important role of the type I interferon (IFN) pathway has been identified in SLE patients and mouse models of lupus. These studies have led to the development of therapeutics targeting type I IFN and related pathways for the treatment of certain manifestations of SLE. In the current narrative review, we will discuss the role of type I IFN in SLE pathogenesis and the potential translation of these data into strategies using type I IFN as a biomarker and therapeutic target for patients with SLE.

Macrophages in Lupus Nephritis: Exploring a potential new therapeutic avenue

Lupus nephritis (LN) is a serious complication of systemic lupus erythematosus (SLE) that occurs in about half of patients. LN is characterized by glomerular deposition of immune complexes, leading to subendothelial, mesangial and subepithelial electron dense deposits, triggering immune cell infiltration and glomerular as well as tubulointerstitial injury. Monocytes and macrophages are abundantly present in inflammatory lesions, both in glomeruli and the tubulointerstitium. Here we discuss how monocytes and macrophages are involved in this process and how monocytes and macrophages may represent specific therapeutic targets to control LN.

Emerging concepts of type I interferons in SLE pathogenesis and therapy

Type I interferons have been suspected for decades to have a crucial role in the pathogenesis of systemic lupus erythematosus (SLE). Evidence has now overturned several long-held assumptions about how type I interferons are regulated and cause pathological conditions, providing a new view of SLE pathogenesis that resolves longstanding clinical dilemmas. This evidence includes data on interferons in relation to genetic predisposition and epigenetic regulation. Importantly, data are now available on the role of interferons in the early phases of the disease and the importance of non-haematopoietic cellular sources of type I interferons, such as keratinocytes, renal tubular cells, glial cells and synovial stromal cells, as well as local responses to type I interferons within these tissues. These local effects are found not only in inflamed target organs in established SLE, but also in histologically normal skin during asymptomatic preclinical phases, suggesting a role in disease initiation. In terms of clinical application, evidence relating to biomarkers to characterize the type I interferon system is complex, and, notably, interferon-blocking therapies are now licensed for the treatment of SLE. Collectively, the available data enable us to propose a model of disease pathogenesis that invokes the unique value of interferon-targeted therapies. Accordingly, future approaches in SLE involving disease reclassification and preventative strategies in preclinical phases should be investigated.

Tailored treatment strategies and future directions in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) represents a diagnostic and therapeutic challenge for physicians due to its protean manifestations and unpredictable course. The disease may manifest as multisystemic or organ-dominant and severity at presentation may vary according to age at onset (childhood-, adult- or late-onset SLE). Different manifestations may respond variably to different immunosuppressive medications and, even within the same organ-system, the severity of inflammation may vary from mild to organ-threatening. Current "state-of-the-art" in SLE treatment aims at remission or low disease activity in all organ systems. Apart from hydroxychloroquine and glucocorticoids (which should be used with caution), the choice of the appropriate immunosuppressive agent should be individualized and depend on the prevailing manifestation, severity stratification and patient childbearing potential. In this review, we provide an overview of therapeutic options for the various organ manifestations and severity patterns of the disease, different phenotypes (such as multisystem versus organ-dominant disease), as well as specific considerations, including lupus with antiphospholipid antibodies, childhood and late-onset disease, as well as treatment options during pregnancy and lactation.

Measurement of specific organ domains in lupus randomized controlled trials: a scoping review

OBJECTIVE

Randomized controlled trials (RCTs) in SLE (lupus) typically adopt composite responder definitions as primary efficacy endpoints; however, outcomes within individual organ domains are also important to understand. The aim of this scoping review was to evaluate how organ-specific disease activity and therapeutic responses have been measured and reported in lupus RCTs.

METHODS

We searched MEDLINE, EMBASE, Cochrane registry and clinicaltrials.gov. Eligible studies were RCTs investigating efficacy of an immune-directed drug therapy in active SLE, published January 2000-March 2021, excluding studies limited to lupus nephritis. Data were extracted independently in duplicate into a template and summarized descriptively.

RESULTS

Thirty-four RCTs were included, of which 32 (94%) reported activity and/or responses in at least one organ domain. Study populations had a high, although variable, frequency of baseline musculoskeletal and mucocutaneous activity and low, but also variable, representation of other domains. Definitions of organ-specific responses were inconsistent, even within individual instruments. Response in most organ domains were evaluated using BILAG and SLEDAI components but meaningful comparison between treatment arms was limited by small subgroups analysed in a post hoc fashion. Specific mucocutaneous and arthritis instruments were also used, including within pre-specified organ-specific endpoints, which discriminated between treatment arms in some studies.

CONCLUSION

Mucocutaneous and musculoskeletal manifestations predominate in SLE RCTs. Organ-specific outcome measures are commonly reported, but definitions of involvement and response are inconsistent. Research into the development of new outcome measures for key organ domains, and validation and comparison of response definitions using existing instruments, is needed.

Type I Interferons in Autoimmunity

Dysregulated IFN-1 responses play crucial roles in the development of multiple forms of autoimmunity. Many patients with lupus, systemic sclerosis, Sjogren's syndrome, and dermatomyositis demonstrate enhanced IFN-1 signaling. IFN-1 excess is associated with disease severity and autoantibodies and could potentially predict response to newer therapies targeting IFN-1 pathways. In this review, we provide an overview of the signaling pathway and immune functions of IFN-1s in health and disease. We also review the systemic autoimmune diseases classically associated with IFN-1 upregulation and current therapeutic strategies targeting the IFN-1 system.

Type I Interferons in Systemic Lupus Erythematosus: A Journey from Bench to Bedside

Dysregulation of type I interferons (IFNs) has been implicated in the pathogenesis of systemic lupus erythematosus (SLE) since the late 1970s. The majority of SLE patients demonstrate evidence of type I IFN pathway activation; however, studies attempting to address the relationship between type I IFN signature and SLE disease activity have yielded conflicting results. In addition to type I IFNs, type II and III IFNs may overlap and also contribute to the IFN signature. Different genetic backgrounds lead to overproduction of type I IFNs in SLE and contribute to the breakdown of peripheral tolerance by activation of antigen-presenting myeloid dendritic cells, thus triggering the expansion and differentiation of autoreactive lymphocytes. The consequence of the continuous stimulation of the immune system is manifested in different organ systems typical of SLE (e.g., mucocutaneous and cardiovascular involvement). After the discovery of the type I IFN signature, a number of different strategies have been developed to downregulate the IFN system in SLE patients, finally leading to the successful trial of anifrolumab, the second biologic to be approved for the treatment of SLE in 10 years. In this review, we will discuss the bench to bedside translation of the type I IFN pathway and put forward some issues that remain unresolved when selecting SLE patients for treatment with biologics targeting type I IFNs.

Biologic Agents and Other Emerging Therapies for Childhood SLE

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease characterized by remissions and flares. Twenty percent of SLE presents in childhood where the course of SLE is often more severe with significant morbidity and mortality. Several biologic agents have been developed recently for the treatment of lupus, and although some have proven to be safe and efficacious, many have failed to demonstrate significant benefit in clinical trials. There continues to be a desperate need for safe, effective medications that target specific pathway abnormalities seen in SLE. This is an area of intense research that is changing clinical practice in the treatment of childhood SLE. In this article, we discuss the use of B-cell inhibitors, including belimumab and rituximab, as well as the anti-complement drug eculizumab. Promising treatments on the horizon include the jak-stat inhibitors as well as anifrolumab, which targets interferon. [Pediatr Ann. 2022;51(2):e63-e71.].

The interferon gene signature as a clinically relevant biomarker in autoimmune rheumatic disease

The interferon gene signature (IGS) is derived from the expression of interferon-regulated genes and is classically increased in response to type I interferon exposure. A raised whole blood IGS has increasingly been reported in rheumatic diseases as sequencing technology has advanced. Although its role remains unclear, we explore how a raised IGS can function as a clinically relevant biomarker, independent of whether it is a bystander effect or a key pathological process. For example, a raised IGS can act as a diagnostic biomarker when predicting rheumatoid arthritis in patients with arthralgia and anti-citrullinated protein antibodies, or predicting systemic lupus erythematous (SLE) in those with antinuclear antibodies; a theragnostic biomarker when predicting response for patients receiving disease modifying therapy, such as rituximab in rheumatoid arthritis; a biomarker of disease activity (early rheumatoid arthritis, dermatomyositis, systemic sclerosis, SLE); or finally a predictor of clinical characteristics, such as lupus nephritis in SLE or disease burden in primary Sjögren's syndrome. A high IGS does not uniformly predict worse clinical phenotypes across all diseases, as demonstrated by a reduced disease burden in primary Sjögren's syndrome, nor does it predict a universally poorer response to all therapies, as shown in rheumatoid arthritis. This dichotomy highlights both the complexity of type I interferon signalling in vivo and the current lack of standardisation when calculating the IGS. The IGS as a biomarker warrants further exploration, with beneficial clinical applications anticipated in multiple rheumatic diseases.

New developments in systemic lupus erythematosus

In this review, the results of recent and ongoing clinical trials in patients with SLE are discussed. After many unsuccessful trials in the past decade, belimumab was the first biologic specifically designed for SLE that met its primary end point. At the same time, studies on the pathophysiology of SLE have further elucidated the pathways involved in the disease, which has led to the identification of new possible therapeutics and has encouraged the initiation of new trials. These new drugs include biologics that target B cells, T cells and type 1 interferons, and small molecules that inhibit kinases. Other therapeutics aim to restore immunological balance by restoring tolerance. Results from phase II and even phase III trials are promising and it is likely that some of the therapeutics discussed will receive approval in the following years. Hopefully, this will allow for more tailor-made medicine for SLE patients in the future.

Targeted Delivery of Chloroquine to Antigen-Presenting Cells Enhances Inhibition of the Type I Interferon Response

Systemic lupus erythematosus (SLE) causes damaging inflammation in multiple organs via the accumulation of immune complexes. These complexes activate plasmacytoid dendritic cells (pDCs) via toll-like receptors (TLRs), contributing to disease pathogenesis by driving the secretion of inflammatory type I interferons (IFNs). Antimalarial drugs, such as chloroquine (CQ), are TLR antagonists used to alleviate inflammation in SLE. However, they require ∼3 months of continuous use before achieving therapeutic efficacy and can accumulate in the retinal pigment epithelium with chronic use, resulting in retinopathy. We hypothesized that poly(ethylene glycol)-b-poly(propylene sulfide) filamentous nanocarriers, filomicelles (FMs), could directly deliver CQ to pDCs via passive, morphology-based targeting to concentrate drug delivery to specific immune cells, improve drug activity by increased inhibition of type I IFN, and enhance efficacy per dose. Healthy human peripheral blood mononuclear cells were treated with soluble CQ or CQ-loaded FMs, stimulated with TLR agonists or SLE patient sera, and type I IFN secretion was quantified via multi-subtype IFN-α ELISA and MX1 gene expression using real-time reverse transcription-quantitative polymerase chain reaction. Our results showed that 50 μg CQ/mg FM decreased MX1 expression and IFN-α production after TLR activation with either synthetic nucleic acid agonists or immune complex-rich sera from SLE patients. Cellular uptake and biodistribution studies showed that FMs preferentially accumulate in human pDCs and monocytes in vitro and in tissues frequently damaged in SLE patients (i.e., kidneys), while sparing the eye in vivo. These results showed that nanocarrier morphology enables drug delivery, and CQ-FMs may be equally effective and more targeted than soluble CQ at inhibiting SLE-relevant pathways.

Therapeutic Potential of Anti-Interferon α Vaccination on SjS-Related Features in the MRL/lpr Autoimmune Mouse Model

Sjögren’s syndrome (SjS) is a frequent systemic autoimmune disease responsible for a major decrease in patients’ quality of life, potentially leading to life-threatening conditions while facing an unmet therapeutic need. Hence, we assessed the immunogenicity, efficacy, and tolerance of IFN-Kinoid (IFN-K), an anti-IFNα vaccination strategy, in a well-known mouse model of systemic autoimmunity with SjS-like features: MRL/MpJ-Faslpr/lpr (MRL/lpr) mice. Two cohorts (with ISA51 or SWE01 as adjuvants) of 26 female MRL/lpr were divided in parallel groups, “controls” (not treated, PBS and Keyhole Limpet Hemocyanin [KLH] groups) or “IFN-K” and followed up for 122 days. Eight-week-old mice received intra-muscular injections (days 0, 7, 28, 56 and 84) of PBS, KLH or IFN-K, emulsified in the appropriate adjuvant, and blood samples were serially collected. At sacrifice, surviving mice were euthanized and their organs were harvested for histopathological analysis (focus score in salivary/lacrimal glands) and IFN signature evaluation. SjS-like features were monitored. IFN-K induced a disease-modifying polyclonal anti-IFNα antibody response in all treated mice with high IFNα neutralization capacities, type 1 IFN signature’s reduction and disease features’ (ocular and oral sicca syndrome, neuropathy, focus score, glandular production of BAFF) improvement, as reflected by the decrease in Murine Sjögren’s Syndrome Disease Activity Index (MuSSDAI) modelled on EULAR Sjögren’s Syndrome Disease Activity Index (ESSDAI). No adverse effects were observed. We herein report on the strong efficacy of an innovative anti-IFNα vaccination strategy in a mouse model of SjS, paving the way for further clinical development (a phase IIb trial has just been completed in systemic lupus erythematosus with promising results).

The Pathogenesis, Molecular Mechanisms, and Therapeutic Potential of the Interferon Pathway in Systemic Lupus Erythematosus and Other Autoimmune Diseases

Therapeutic success in treating patients with systemic lupus erythematosus (SLE) is limited by the multivariate disease etiology, multi-organ presentation, systemic involvement, and complex immunopathogenesis. Agents targeting B-cell differentiation and survival are not efficacious for all patients, indicating a need to target other inflammatory mediators. One such target is the type I interferon pathway. Type I interferons upregulate interferon gene signatures and mediate critical antiviral responses. Dysregulated type I interferon signaling is detectable in many patients with SLE and other autoimmune diseases, and the extent of this dysregulation is associated with disease severity, making type I interferons therapeutically tangible targets. The recent approval of the type I interferon-blocking antibody, anifrolumab, by the US Food and Drug Administration for the treatment of patients with SLE demonstrates the value of targeting this pathway. Nevertheless, the interferon pathway has pleiotropic biology, with multiple cellular targets and signaling components that are incompletely understood. Deconvoluting the complexity of the type I interferon pathway and its intersection with lupus disease pathology will be valuable for further development of targeted SLE therapeutics. This review summarizes the immune mediators of the interferon pathway, its association with disease pathogenesis, and therapeutic modalities targeting the dysregulated interferon pathway.

Type I interferon detection in autoimmune diseases: challenges and clinical applications

INTRODUCTION

Accumulating data highlights that the dysregulation of type I interferon (IFN) pathways plays a central role in the pathogenesis of several systemic and organ-specific autoimmune diseases. Advances in understanding the role of type I IFNs in these disorders can lead to targeted drug development as well as establishing potential disease biomarkers.

AREAS COVERED

Here, we summarize current knowledge regarding the role of type I IFNs in the major systemic, as well as organ-specific, autoimmune disorders, including prominent inflammatory CNS disorders like multiple sclerosis.

EXPERT OPINION

Type I IFN involvement and its clinical associations in a wide spectrum of autoimmune diseases represents a promising area for research aiming to unveil common pathogenetic pathways in systemic and organ-specific autoimmunity.

Clinician-reported outcome measures in lupus trials: a problem worth solving

Systemic lupus erythematosus (SLE) remains a disease of high unmet clinical need. Because of substantial patient heterogeneity, the execution of clinical trials that successfully determine the efficacy of novel therapeutics compared with placebo is a continuous challenge. Clinician-reported outcome measures of treatment response used in SLE trials have evolved from the use of individual disease activity indices, including the SLE Disease Activity Index (SLEDAI) and British Isles Lupus Assessment Group (BILAG), to composite responder definitions such as the SLE Responder Index (SRI) and BILAG-Based Composite Lupus Assessment (BICLA), which are based on these indices. However, these approaches have notable drawbacks and defining the optimal clinical trial outcome measure for SLE remains a research goal. In this Viewpoint, we explore the strengths and limitations of existing indices and composite assessments, illustrating features which should be investigated in future analysis of trial data. Further, we provide a platform from which to advance new approaches to endpoint design, which is crucial to improve the interpretability and success of subsequent clinical trials in SLE.

IFN-α: A key therapeutic target for multiple autoimmune rheumatic diseases

Interferon (IFN)-α has emerged as a major therapeutic target for several autoimmune rheumatic diseases. In this review, we focus on clinical and preclinical advances in anti-IFN-α treatments in systemic lupus erythematosus (SLE), primary Sjögren syndrome (pSS), systemic sclerosis (SSc), and dermatomyositis (DM), for which a high medical need persists. Promising achievements were obtained following direct IFN-α neutralization, targeting its production through the cytosolic nucleic acid sensor pathways or by blocking its downstream effects through the type I IFN receptor. We further focus on molecular profiling and data integration approaches as crucial steps to select patients most likely to benefit from anti-IFN-α therapies within a precision medicine approach.

Updates on Clinical Trials in Systemic Lupus Erythematosus

PURPOSE OF REVIEW

Because of the complexity of systemic lupus erythematosus (SLE), different approaches are undertaken while investigating potential therapeutic compounds to treat the disease. The purpose of this review is to summarize the results from recent clinical trials, which investigated different compounds for treating SLE.

RECENT FINDINGS

Targeting B cells and type I interferons constitutes the major focus in recent clinical trials. The potential for therapeutic effects of small molecule inhibition such as JAK, Tyk, and Btk is now being investigated for treating SLE. The immunoregulation of T cell activation in SLE is studied using low-dose IL-2 and CD40 ligand inhibition. There are clinical trials that study bispecific antibodies, with binding specificities for 2 different target molecules related to T- and B-cell activation or to different aspects of B cell activation. An approach of combination treatment is also being studied. Clinical trials are underway and new treatment compounds for SLE are being anticipated.

Type I Interferons in the Pathogenesis and Treatment of Autoimmune Diseases

Type I interferons (IFN-Is) are a very important group of cytokines that are produced by innate immune cells but also act on adaptive immune cells. IFN-Is possess antiviral, antitumor, and anti-proliferative effects, as well are associated with the initiation and maintenance of autoimmune disorders. Studies have shown that aberrantly expressed IFN-Is and/or type I IFN-inducible gene signatures in the serum or tissues of patients with autoimmune disorders are linked to their pathogenesis, clinical manifestations, and disease activity. Type I interferonopathies with mutations in genes impacting the type I IFN signaling pathway have shown symptoms and characteristics similar to those of systemic lupus erythematosus (SLE). Furthermore, both interventions in animal models and clinical trials of therapies targeting the type I IFN signaling pathway have shown efficacy in the treatment of autoimmune diseases. Our review aims to summarize the functions and targeted therapies (as well as clinical trials) of IFN-Is in both adult and pediatric autoimmune diseases, such as SLE, pediatric SLE (pSLE), rheumatoid arthritis (RA), juvenile idiopathic arthritis (JIA), juvenile dermatomyositis (JDM), Sjögren syndrome (SjS), and systemic sclerosis (SSc), discussing the potential abnormal regulation of transcription factors and epigenetic modifications and providing a potential mechanism for pathogenesis and therapeutic strategies for future clinical use.

Interferon lambda in inflammation and autoimmune rheumatic diseases

Interferons are potent antiviral cytokines that modulate immunity in response to infection or other danger signals. In addition to their antiviral functions, type I interferons (IFNα and IFNβ) are important in the pathogenesis of autoimmune diseases. Type III interferons (IFNλs) were initially described as a specialized system that inhibits viral replication at epithelial barrier surfaces while limiting inflammatory damage. However, evidence now suggests that type III interferons have complex effects on both innate and adaptive immune responses and might also be pathogenic in systemic autoimmune diseases. Concentrations of IFNλs are increased in blood and tissues in a number of autoimmune rheumatic diseases, including systemic lupus erythematosus, and are further associated with specific clinical and laboratory parameters. This Review is aimed at providing a critical evaluation of the current literature on IFNλ biology and how type III interferons might contribute to immune dysregulation and tissue damage in autoimmunity. The potential effects of type III interferons on treatment strategies for autoimmune rheumatic diseases, such as interferon blockade, are also considered.

Dual vaccination against IL-4 and IL-13 protects against chronic allergic asthma in mice

Allergic asthma is characterized by elevated levels of IgE antibodies, type 2 cytokines such as interleukin-4 (IL-4) and IL-13, airway hyperresponsiveness (AHR), mucus hypersecretion and eosinophilia. Approved therapeutic monoclonal antibodies targeting IgE or IL-4/IL-13 reduce asthma symptoms but require costly lifelong administrations. Here, we develop conjugate vaccines against mouse IL-4 and IL-13, and demonstrate their prophylactic and therapeutic efficacy in reducing IgE levels, AHR, eosinophilia and mucus production in mouse models of asthma analyzed up to 15 weeks after initial vaccination. More importantly, we also test similar vaccines specific for human IL-4/IL-13 in mice expressing human IL-4/IL-13 and the related receptor, IL-4Rα, to find efficient neutralization of both cytokines and reduced IgE levels for at least 11 weeks post-vaccination. Our results imply that dual IL-4/IL-13 vaccination may represent a cost-effective, long-term therapeutic strategy for the treatment of allergic asthma as demonstrated in mouse models, although additional studies are warranted to assess its safety and feasibility.

Asthma is caused by hyperreactivity to benign antigens, with humoral immunity orchestrated by interleukin-4 (IL-4) and IL-13 being the key etiological factor. Here the authors show, in humanized mouse models, that dual vaccination against IL-4 and IL-13 induces their durable suppression ameliorate experimental asthma, and to hint clinical translation.

Biologics in the treatment of Sjogren's syndrome, systemic lupus erythematosus, and lupus nephritis

PURPOSE OF REVIEW

It is an understatement to say that drug approvals in systemic lupus erythematosus (SLE), lupus nephritis, and Sjogren's syndrome have lagged far behind those in other autoimmune diseases, such as rheumatoid arthritis and psoriatic arthritis. Reasons for this are multiple and include the molecular and clinical heterogeneity of these conditions; confounding by background medications, especially corticosteroids; and clinical trial endpoints. However, the tides are changing, and there have been several bright spots in our attempts to bring more efficacious drugs to our patients.

RECENT FINDINGS

Several positive phase II and phase III trials in SLE and lupus nephritis with drugs such as anifrolumab, voclosporin, belimumab, and obinutuzumab will no doubt eventually generate regulatory approvals for most, if not all, of these drugs. Although early in development, the promising results in Sjogren's syndrome with iscalimab and ianalumab should make the Sjogren's syndrome community quite hopeful of future drug approvals.

SUMMARY

In this review, we highlight recent study results in Sjogren's syndrome, SLE, and lupus nephritis, emphasizing investigational therapies in late stage development, but we also provide a glimpse into drugs of the future.

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.

Type I Interferons in Systemic Autoimmune Diseases: Distinguishing Between Afferent and Efferent Functions for Precision Medicine and Individualized Treatment

A sustained increase in type I interferon (IFN-I) may accompany clinical manifestations and disease activity in systemic autoimmune diseases (SADs). Despite the very frequent presence of IFN-I in SADs, clinical manifestations are extremely varied between and within SADs. The present short review will address the following key questions associated with high IFN-I in SADs in the perspective of precision medicine. 1) What are the mechanisms leading to high IFN-I? 2) What are the predisposing conditions favoring high IFN-I production? 3) What is the role of IFN-I in the development of distinct clinical manifestations within SADs? 4) Would therapeutic strategies targeting IFN-I be helpful in controlling or even preventing SADs? In answering these questions, we will underlie areas of incertitude and the intertwined role of autoantibodies, immune complexes, and neutrophils.