High levels of circulating interferons type I, type II and type III associate with distinct clinical features of active systemic lupus erythematosus

Longitudinal analysis at pre- and post-flare of T peripheral helper and T follicular helper subsets in patients with systemic lupus erythematosus

OBJECTIVE

We focused to analyze the time-course changes at pre- and post-flare of T peripheral helper (Tph) cells and circulating T follicular helper (Tfh) cells in the blood of patients with systemic lupus erythematosus (SLE) with lupus low disease activity state (LLDAS) before flare.

METHODS

This study included inactive (n = 29) and active (n = 55) patients with SLE. Tph subsets, Tfh subsets, CD11chi B cells, and plasma cells in the blood were determined by flow cytometry. The blood levels of cytokines including interferons (IFNs) were measured by electrochemiluminescence assay or cytokine beads array.

RESULTS

Active SLE patients exhibited the increased frequency of Tph1, Tph2, Tfh1, and Tfh2 subsets when compared to inactive patients, but no clear changes in the other subsets. During the treatment with medications, Tph1, Tph2, and Tfh2 subsets were significantly reduced along with disease activity and Tph1 and Tph2 subsets were positively correlated with SLE disease activity index (SLEDAI). The time course analysis of patients at pre- and post-flare revealed that in the patients at LLDAS before flare, Tph subsets and Tfh subsets were relatively low levels. At the flare, Tph cells, particularly Tph1 and Tph2 subsets, were increased and correlated with SLEDAI. Furthermore, the blood levels of IFN-α2a, IFN-γ, and IFN-λ1 were low in the patients with LLDAS before flare but these IFNs, particularly IFN-λ1, were increased along with flare.

CONCLUSION

Increased frequency of Tph1 and Tph2 subsets and elevated levels of serum IFN-λ1 are presumably critical for triggering of flare in SLE.

IRF5 Variants Are Risk Factors for Systemic Lupus Erythematosus in Two Mexican Populations

INTRODUCTION

Interferon regulatory factor 5 ( IRF5 ) is one of the pivotal genes implicated in systemic lupus erythematosus (SLE) among diverse ethnic groups, including Europeans, Asians, Hispanics, and Africans. Notably, its significance appears particularly pronounced among Hispanic populations. Previous studies have identified several single-nucleotide variants within IRF5 , such as rs2004640G/T, rs2070197T/C, and rs10954213G/A, as associated with susceptibility to SLE among patients from Mexico City. However, the population of Yucatan, located in the Southeast of Mexico and characterized by a greater Amerindian genetic component, remains largely unexplored in this regard.

OBJECTIVES

Our study aimed to replicate the observed association between IRF5 variants and susceptibility to SLE among patients from Central Mexico and Yucatan. Furthermore, we investigated the impact of IRF5 rs59110799G/T, a variant that has not been previously studied in SLE individuals.

METHOD

Our study included 204 SLE patients and 160 controls from Central Mexico, as well as 184 SLE patients and 184 controls from Yucatan. All participants were females 18 years and older. We employed a TaqMan assay to detect the presence of the following single-nucleotide variants: rs2004640G/T, rs2070197T/C, rs10954213G/A, and rs59110799G/T. Furthermore, we utilized 2 distinct web tools and databases to predict the potential functional implications of IRF5 variants.

RESULTS

In SLE patients from Central Mexico, several IRF5 alleles showed significant associations with the disease following adjustment by the Bonferroni test: the rs2070197C allele (odds ratio [OR], 2.08), the rs10954213A allele (OR, 1.59), and the rs59110799G allele (OR, 1.71). Conversely, among patients from Yucatan, the following alleles showed associations: rs2004640T (OR, 1.51), rs2070197C (OR, 1.62), rs10954213A (OR, 1.67), and rs59110799G (OR, 1.44).

CONCLUSION

Our findings highlight genetic variations between Mexican populations and emphasize the role of IRF5 as a risk factor in SLE patients from both Central Mexico and Yucatan.

Tofacitinib versus thalidomide for mucocutaneous lesions of systemic lupus erythematosus: A real-world CSTAR cohort study XXVII

OBJECTIVE

Thalidomide is an effective medication for refractory mucocutaneous lesions of systemic lupus erythematosus (SLE) and can treat arthritis in some autoimmune diseases, but it has some adverse reactions. Recently, the effectiveness of tofacitinib in treating mucocutaneous lesions of SLE has been reported. We aimed to compare the efficacy and safety of tofacitinib with thalidomide in treating mucocutaneous and musculoskeletal lesions in patients with SLE.

METHODS

This study was a real-world cohort study based on the Chinese SLE Treatment and Research group (CSTAR) registry. SLE patients who manifested mucocutaneous and/or musculoskeletal symptoms and were prescribed tofacitinib or thalidomide were included. We retrospectively conducted comparisons between the tofacitinib and thalidomide groups regarding clinical improvements, SLE disease activity, serological indicators, glucocorticoid doses, and adverse events at the 1, 3, and 6-months time points.

RESULTS

At 3 and 6 months, the tofacitinib group exhibited a higher proportion of patients with improvement in mucocutaneous and musculoskeletal issues. Additionally, a greater percentage of patients in the tofacitinib group achieved remission or a low disease activity state (LLDAS) at these time points. No significant serological improvements were observed in either the tofacitinib or thalidomide groups. Fewer adverse events were observed in the tofacitinib group than in the thalidomide group.

CONCLUSIONS

Tofacitinib might be superior to thalidomide in the improvement of mucocutaneous and musculoskeletal lesions in SLE, and had a good safety profile.

Type I interferon gene expression signature as a marker to predict response to cyclophosphamide based treatment in proliferative lupus nephritis

OBJECTIVES

To assess the longitudinal effect of cyclophosphamide (CYC) treatment on type-I interferon (IFN) signature in proliferative lupus nephritis (LN) and its role in predicting treatment response.

METHODS

Fifty-four biopsy proven proliferative LN patients scheduled to receive high-dose (HD) or low-dose (LD) CYC were recruited and followed up for six months. At six months, patients were classified as clinical responders (CR) or non-responders (NR) to treatment, using the EULAR/EDTA criteria. An IFN-gene based score (IGS) was developed from the mean log-transformed gene expression of MX1, OAS1, IFIT1, OASL, IFIT4, LY6E, IRF7 at baseline, three and six months. Longitudinal changes of IGS within and between groups were assessed and ΔIGS, which is the difference in IGS between baseline and three months was calculated. Independent predictors of non-response were identified and an ROC analysis was performed to evaluate their utility to predict NR.

RESULTS

There was a dynamic change in IGS within the HD, LD, CR, and NR groups. Compared to baseline, there was a significant decrease in IGS at three months in HD and LD groups (HD group: 2.01 to 1.14, p = .001; LD group = 2.01 to 0.81, p < .001), followed by a significant increase from three to six months in LD group (LD: 0.81 to 1.51, p = .03; HD: 1.14 to 1.54, p = .300). A decrease in IGS from baseline to three months was seen in both CR (2.13 to 0.79, p < .001) and NR groups (1.83 to 1.27, p = .046), and a significant increase from three to six months was observed only in the CR group (CR: 0.79 to 1.57, p = .006; NR: 1.27 to 1.46, p = 1). ΔIGS (baseline to three months) was higher in CR compared to NR group (-1.339 vs -0.563, p = .017). ROC analysis showed that the model comprising of 0.81 fold decrease in IGS from baseline to three months, endocapillary hypercellularity and interstitial inflammation on renal histopathology predicted non-response with a sensitivity of 83.3% and specificity of 71.4%.

CONCLUSION

In proliferative LN, treated with HD or LD-CYC, combined model comprising of decrease in IGS score by 0.81 fold from baseline to three months, along with important histopathological features such as endocapillary hypercellularity and interstitial inflammation had better predictive capability for non-response.

Biochemical implication of acetylcholine, histamine, IL-18, and interferon-alpha as diagnostic biomarkers in hepatitis C virus, coronavirus disease 2019, and dual hepatitis C virus-coronavirus disease 2019 patients

Globally, hepatitis C virus (HCV) and coronavirus disease 2019 (COVID-19) are the most common causes of death due to the lack of early predictive and diagnostic tools. Therefore, research for a new biomarker is crucial. Inflammatory biomarkers are critical central players in the pathogenesis of viral infections. IL-18, produced by macrophages in early viral infections, triggers inflammatory biomarkers and interferon production, crucial for viral host defense. Finding out IL-18 function can help understand COVID-19 pathophysiology and predict disease prognosis. Histamine and its receptors regulate allergic lung responses, with H1 receptor inhibition potentially reducing inflammation in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. angiotensin-converting enzyme 2 (ACE-2) receptors on cholangiocytes suggest liver involvement in SARS-CoV-2 infection. The current study presents the potential impact of circulating acetylcholine, histamine, IL-18, and interferon-Alpha as diagnostic tools in HCV, COVID-19, and dual HCV-COVID-19 pathogenesis. The current study was a prospective cross-section conducted on 188 participants classified into the following four groups: Group 1 COVID-19 (n = 47), Group 2 HCV (n = 47), and Group 3 HCV-COVID-19 patients (n = 47), besides the healthy control Group 4 (n = 47). The levels of acetylcholine, histamine, IL-18, and interferon-alpha were assayed using the ELISA method. Liver and kidney functions within all groups showed a marked alteration compared to the healthy control group. Our statistical analysis found that individuals with dual infection with HCV-COVID-19 had high ferritin levels compared to other biomarkers while those with COVID-19 infection had high levels of D-Dimer. The histamine, acetylcholine, and IL-18 biomarkers in both COVID-19 and dual HCV-COVID-19 groups have shown discriminatory power, making them potential diagnostic tests for infection. These three biomarkers showed satisfactory performance in identifying HCV infection. The IFN-Alpha test performed well in the HCV-COVID-19 group and was fair in the COVID-19 group, but it had little discriminative value in the HCV group. Moreover, our findings highlighted the pivotal role of acetylcholine, histamine, IL-18, and interferon-Alpha in HCV, COVID-19, and dual HCV-COVID-19 infection. Circulating levels of acetylcholine, histamine, IL-18, and interferon-Alpha can be potential early indicators for HCV, COVID-19, and dual HCV-COVID-19 infection. We acknowledge that further large multicenter experimental studies are needed to further investigate the role biomarkers play in influencing the likelihood of infection to confirm and extend our observations and to better understand and ultimately prevent or treat these diseases.

Assay for interferon gamma release as a novel marker in pediatric patients with systemic lupus erythematosus

BACKGROUND

The interferon-gamma (IFN-γ) release assay (IGRA) is an important laboratory diagnosis for latent Mycobacterium tuberculosis (TB) infection. The TB-IGRA measures the release of IFN-γ from peripheral blood cells, who are exposed to TB antigen (Ag), mitogen (MT), or negative/nil control (NL) in vitro. While, an exceptional higher TB Ag-NL level will reflect an elevation of peripheral lymphocytes released IFN-γ in a same condition. Therefore, we found that the elevated levels of TB Ag-NL could become a new biomarker for the diagnosis and treatment of pediatric systemic lupus erythematosus (SLE) patients.

METHODS

We have analyzed the clinical data of 776 children who are underwent TB-IGRA testing in the Department of Allergy and Rheumatology of Guangzhou Women and Children's Medical Center from 2018 to 2020. To investigate the association between TB Ag-NL and SLE, we have analyzed the clinical data of 47 SLE patients and TB Ag-NL testing results, and then evaluated the association between TB Ag-NL and SLE disease activity.

RESULTS

The TB Ag-NL levels were significantly higher in patients with active SLE than those in inactive SLE (p = 0.0002). The TB Ag-NL levels were positively correlated with the SLE disease activity index (SLEDAI) and laboratory diagnosis parameters. The mean value of TB Ag-NL in SLE patients (0.04191 ± 0.07955, IU/mL) were significantly higher than those in patients with juvenile dermatomyositis (JDM) (0.0158 ± 0.0337, IU/mL, p = 0.036), juvenile idiopathic arthritis (JIA) (0.0162 ± 0.0388, IU/mL, p = 0.001), and healthy controls (HC) (0.0001 ± 0.0027, IU/mL, p = 0.0003). Therefore, the elevated TB Ag-NL levels could serve as a potential diagnostic biomarker of SLE, especially for the active SLE.

CONCLUSION

The detection of IFN-γ release levels by the TB-IGRA may be useful to assess SLE disease activity in pediatric patients with active SLE.

CD11b suppresses TLR7-driven inflammatory signaling to protect against lupus nephritis

Lupus Nephritis (LN) is a severe complication of systemic lupus erythematosus (SLE) that affects kidney function. Here, we investigated the role of CD11b, a protein encoded by the ITGAM gene, in the development of LN and its functional activation as a therapeutic strategy. Genetic coding variants of ITGAM significantly increase the risk for SLE and LN by producing a less active CD11b and leading to elevated levels of type I interferon (IFN I). However, a molecular mechanism for how these variants increase LN risk has been unclear. Here, we determined that these variants also significantly associate with elevations in soluble urokinase plasminogen activator receptor (suPAR), a known biomarker linked to kidney disease, suggesting a novel molecular connection. Pharmacologic activation of CD11b with a novel, clinical-stage agonist ONT01 significantly suppressed suPAR production in myeloid cells and reduced systemic inflammation and kidney damage in multiple experimental models of LN. Importantly, delaying treatment with ONT01 until after disease onset also significantly reduced serum suPAR and inflammatory cytokines, and decreased immune complex deposition in the glomerulus, glomerulonephritis and albuminuria, suggesting that CD11b activation is therapeutic for LN. Genetic activation of CD11b via a gain-of-function CD11b mutation also showed complete protection from LN, whereas genetic deletion of CD11b worsened the disease in mice, providing further evidence of the role of CD11b activation in regulating LN. Finally, transfer of human LN PBMCs generated human LN like disease in mice that was significantly reduced by ONT01. Together, these data provide strong evidence that ONT01 mediated CD11b activation can therapeutically modulate TLR7-driven inflammation and protect against LN. These findings support clinical development of CD11b agonists as novel therapeutics for treating lupus nephritis in human patients.

Evaluation of the Efficacy and Safety of Anifrolumab in Moderate-to-Severe Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease, which poses significant challenges due to its chronic nature and complex clinical manifestations. For patients with moderate-to-severe SLE, anifrolumab, a monoclonal antibody that targets the type 1 interferon receptor (IFNAR), has emerged as a cutting-edge treatment option that can reduce disease activity, prevent organ damage from the illness or side effects resulting from medications, and enhance the quality of life for those living with SLE. Consequently, this drug has received approval from major regulatory agencies. Anifrolumab's safety, effectiveness, and long-term results are assessed in this systematic review using information from clinical trials, real-world research, and retrospective analysis. In particular, clinical investigations, such as the MUSE Phase II and TULIP Phase III trials, showed that anifrolumab significantly improved important outcomes compared to placebo, including the SLE Responder Index, major clinical response, and disease activity ratings. During extended use, anifrolumab demonstrated significant sustained efficacy and a tolerable safety profile, with controllable side events mostly associated with viral infections. Moreover, subgroup analyses, demonstrating that Asian patients and individuals with a strong interferon gene profile are particularly responsive to anifrolumab, underscore the importance of customized treatment methods. Anifrolumab's safety and effectiveness were further validated by real-world data, particularly in patients who reached the Lupus Low Disease Activity State (LLDAS), where the drug decreased glucocorticoid consumption and disease activity. Overall, anifrolumab shows great promise as a treatment for moderate-to-severe SLE, providing significant efficacy together with a manageable safety profile. To fully explore its therapeutic potential and optimize therapy approaches for the management of SLE, further research is necessary, especially in lupus nephritis and other disease subsets.

Integration of multi-omics analysis reveals metabolic alterations of B lymphocytes in systemic lupus erythematosus

OBJECTIVE

To link changes in the B-cell transcriptome from systemic lupus erythematosus (SLE) patients with those in their macroenvironment, including cellular and fluidic components.

METHODS

Analysis was performed on 363 patients and 508 controls, encompassing transcriptomics, metabolomics, and clinical data. B-cell and whole-blood transcriptomes were analysed using DESeq and GSEA. Plasma and urine metabolomics peak changes were quantified and annotated using Ceu Mass Mediator database. Common sources of variation were identified using MOFA integration analysis.

RESULTS

Cellular macroenvironment was enriched in cytokines, stress responses, lipidic synthesis/mobility pathways and nucleotide degradation. B cells shared these pathways, except nucleotide degradation diverted to nucleotide salvage pathway, and distinct glycosylation, LPA receptors and Schlafen proteins.

CONCLUSIONS

B cells showed metabolic changes shared with their macroenvironment and unique changes directly or indirectly induced by IFN-α signalling. This study underscores the importance of understanding the interplay between B cells and their macroenvironment in SLE pathology.

Double-filtration plasmapheresis reduces type I interferon bioavailability and inducing activity in systemic lupus erythematosus

Type I interferons (IFN-Is) play a significant role in systemic lupus erythematosus (SLE) pathogenesis. Double-filtration plasmapheresis (DFPP) is a treatment option for SLE; however, its effect on IFN-Is remains unclear. Therefore, we investigated the effects of DFPP on IFN-Is. Plasma from patients with SLE (n = 11) who regularly underwent DFPP was analysed using a cell-based reporter system to detect the bioavailability and inducing activity of IFN-I. The concentration of plasma dsDNA was measured, and western blotting analysis was used to assess the phosphorylation of the STING pathway. A higher IFN-I bioavailability and inducing activity were observed in patients compared to healthy controls, and both parameters decreased after DFPP. The reduction in IFN-I-inducing activity was particularly prominent in patients with high disease activity. Notably, this reduction was not observed in STING-knockout reporter cells. Additionally, plasma dsDNA levels decreased after DFPP treatment, suggesting that inhibition of the STING pathway was responsible for the observed decrease in activity. Western blotting analysis revealed suppression of STING pathway phosphorylation after DFPP. DFPP reduced IFN-I bioavailability and the inducing activity of plasma. This reduction is likely attributable to the inhibition of the STING pathway through the elimination of dsDNA.

Variations in the interferon and TLR3 genes may be associated with susceptibility to systemic lupus erythematosus and its clinical presentation

The study aimed to explore the pontential impact of 10 polymorphisms within IFN-α, IFN-β1, IFN-γ and TLR3 genes on SLE phenotype and susceptibility and to study the relationship between specific genotypes and clinics. Whole blood samples from SLE patients and healthy controls was obtained. DNA was extracted from the peripheral blood by the QIAamp DNA Blood Mini Kit (Qiagen). The quality and quantity of isolated DNA was estimated by the Quawell Q5000 spectrophotometer. We genotyped SLE patients and healthy subjects using real-time PCR (QuantStudio 5 thermocycler). The study suggests that IFN-γ rs2069705, IFN-γ rs2069718 and IFN-α rs3758236 polymorphisms have a protective role in SLE. We observed relations between TLR3 rs3775292, IFN-β1 rs7873167, IFN-γ rs2069705, TLR3 rs3775291 and TLR3 rs5743305 polymorphisms and clinical picture of SLE patients. We found associations between the IFN-α rs3758236, IFN-γ rs2069705, IFN-γ rs2069718, IFN-γ rs1861493 and IFN-β1 rs10964831 polymorphisms and the clinical manifestation of the SLE and/or its comorbidities. We perceived links between IFN-γ rs2069705, IFN-γ rs2069718, IFN-γ rs1861493, TLR3 rs3775291, TLR3 rs3775292 and TLR3 rs5743305 polymorphisms and the occurrence of autoantibodies. Our study presented the relationship between IFN and TLR gene polymorphisms with SLE susceptibility, phenotype and autoantibodies profile. This study propose that polymorphisms within interferons and TLR3 genes can be engaged in the SLE pathogenesis and course.

SOCS1 is a critical checkpoint in immune homeostasis, inflammation and tumor immunity

The Suppressor of Cytokine Signaling (SOCS) family proteins are important negative regulators of cytokine signaling. SOCS1 is the prototypical member of the SOCS family and functions in a classic negative-feedback loop to inhibit signaling in response to interferon, interleukin-12 and interleukin-2 family cytokines. These cytokines have a critical role in orchestrating our immune defence against viral pathogens and cancer. The ability of SOCS1 to limit cytokine signaling positions it as an important immune checkpoint, as evidenced by the detection of detrimental SOCS1 variants in patients with cytokine-driven inflammatory and autoimmune disease. SOCS1 has also emerged as a key checkpoint that restricts anti-tumor immunity, playing both a tumor intrinsic role and impacting the ability of various immune cells to mount an effective anti-tumor response. In this review, we describe the mechanism of SOCS1 action, focusing on the role of SOCS1 in autoimmunity and cancer, and discuss the potential for new SOCS1-directed cancer therapies that could be used to enhance adoptive immunotherapy and immune checkpoint blockade.

An interactive atlas of genomic, proteomic, and metabolomic biomarkers promotes the potential of proteins to predict complex diseases

Multiomics analyses have identified multiple potential biomarkers of the incidence and prevalence of complex diseases. However, it is not known which type of biomarker is optimal for clinical purposes. Here, we make a systematic comparison of 90 million genetic variants, 1453 proteins, and 325 metabolites from 500,000 individuals with complex diseases from the UK Biobank. A machine learning pipeline consisting of data cleaning, data imputation, feature selection, and model training using cross-validation and comparison of the results on holdout test sets showed that proteins were most predictive, followed by metabolites, and genetic variants. Only five proteins per disease resulted in median (min-max) areas under the receiver operating characteristic curves for incidence of 0.79 (0.65-0.86) and 0.84 (0.70-0.91) for prevalence. In summary, our work suggests the potential of predicting complex diseases based on a limited number of proteins. We provide an interactive atlas (macd.shinyapps.io/ShinyApp/) to find genomic, proteomic, or metabolomic biomarkers for different complex diseases.

Type I Interferons in Systemic Autoimmune Rheumatic Diseases: Pathogenesis, Clinical Features and Treatment Options

Type I interferon (IFN) pathway dysregulation plays a crucial role in the pathogenesis of several systemic autoimmune rheumatic diseases (SARDs), including systemic lupus erythematosus (SLE), Sjögren's disease (SjD), systemic sclerosis (SSc), dermatomyositis (DM) and rheumatoid arthritis (RA). Genetic and epigenetic alterations have been involved in dysregulated type I IFN responses in systemic autoimmune disorders. Aberrant type I IFN production and secretion have been associated with distinct clinical phenotypes, disease activity, and severity as well as differentiated treatment responses among SARDs. In this review, we provide an overview of the role of type I IFNs in systemic autoimmune diseases including SLE, RA, SjD, SSc, and DM focusing on pathophysiological, clinical, and therapeutical aspects.

Uncoupling interferons and the interferon signature explains clinical and transcriptional subsets in SLE

Systemic lupus erythematosus (SLE) displays a hallmark interferon (IFN) signature. Yet, clinical trials targeting type I IFN (IFN-I) have shown variable efficacy, and blocking IFN-II failed to treat SLE. Here, we show that IFN type levels in SLE vary significantly across clinical and transcriptional endotypes. Whereas skin involvement correlated with IFN-I alone, systemic features like nephritis associated with co-elevation of IFN-I, IFN-II, and IFN-III, indicating additive IFN effects in severe SLE. Notably, while high IFN-II/-III levels without IFN-I had a limited effect on disease activity, IFN-II was linked to IFN-I-independent transcriptional profiles (e.g., OXPHOS and CD8+GZMH+ cells), and IFN-III enhanced IFN-induced gene expression when co-elevated with IFN-I. Moreover, dysregulated IFNs do not explain the IFN signature in 64% of patients or clinical manifestations including cytopenia, serositis, and anti-phospholipid syndrome, implying IFN-independent endotypes in SLE. This study sheds light on mechanisms underlying SLE heterogeneity and the variable response to IFN-targeted therapies in clinical trials.

Anifrolumab for systemic lupus erythematosus: A clinical study of Japanese patients in Kanazawa University Hospital

We investigated the effectiveness of anifrolumab in treating systemic lupus erythematosus (SLE). We treated seven patients with SLE (age range, 31-68 years; median age, 48 years); one male and six females) with anifrolumab between January 2022 and February 2023 at Kanazawa University Hospital. The period between the onset and initiation of anifrolumab treatment was 60-276 months (median, 234 months), and the SLE disease activity index-2000 (SLEDAI-2 K) before treatment was 2-6 months (median, 3 months). Five patients experienced skin rashes or alopecia, and their cutaneous lupus erythematosus disease area and severity index (CLASI) activity scores were 2-9 (median, 4). Six patients continued treatment with anifrolumab, but one did not because of uncontrolled pleurisy and pericarditis. Our results demonstrated that anifrolumab was effective in treating SLE and reducing both SLEDAI-2 K and CLASI activity scores (median decrease, 100%). Furthermore, the oral corticosteroid dosage could be reduced in all patients who were able to continue treatment. Our findings indicate that anifrolumab is effective not only for reducing disease and eruption activities, but also facilitates tapering of corticosteroid dosage.

Low CD4 + T cell count is related to specific anti-nuclear antibodies, IFNα protein positivity and disease activity in systemic lupus erythematosus pregnancy

BACKGROUND

Lymphopenia, autoantibodies and activation of the type I interferon (IFN) system are common features in systemic lupus erythematosus (SLE). We speculate whether lymphocyte subset counts are affected by pregnancy and if they relate to autoantibody profiles and/or IFNα protein in SLE pregnancy.

METHODS

Repeated blood samples were collected during pregnancy from 80 women with SLE and 51 healthy controls (HC). Late postpartum samples were obtained from 19 of the women with SLE. Counts of CD4 + and CD8 + T cells, B cells and NK cells were measured by flow cytometry. Positivity for anti-nuclear antibodies (ANA) fine specificities (double-stranded DNA [dsDNA], Smith [Sm], ribonucleoprotein [RNP], chromatin, Sjögren's syndrome antigen A [SSA] and B [SSB]) and anti-phospholipid antibodies (cardiolipin [CL] and β2 glycoprotein I [β2GPI]) was assessed with multiplexed bead assay. IFNα protein concentration was quantified with Single molecule array (Simoa) immune assay. Clinical data were retrieved from medical records.

RESULTS

Women with SLE had lower counts of all lymphocyte subsets compared to HC throughout pregnancy, but counts did not differ during pregnancy compared to postpartum. Principal component analysis revealed that low lymphocyte subset counts differentially related to autoantibody profiles, cluster one (anti-dsDNA/anti-Sm/anti-RNP/anti-Sm/RNP/anti-chromatin), cluster two (anti-SSA/anti-SSB) and cluster three (anti-CL/anti-β2GPI), IFNα protein levels and disease activity. CD4 + T cell counts were lower in women positive to all ANA fine specificities in cluster one compared to those who were negative, and B cell numbers were lower in women positive for anti-dsDNA and anti-Sm compared to negative women. Moreover, CD4 + T cell and B cell counts were lower in women with moderate/high compared to no/low disease activity, and CD4 + T cell count was lower in IFNα protein positive relative to negative women. Finally, CD4 + T cell count was unrelated to treatment.

CONCLUSION

Lymphocyte subset counts are lower in SLE compared to healthy pregnancies, which seems to be a feature of the disease per se and not affected by pregnancy. Our results also indicate that low lymphocyte subset counts relate differentially to autoantibody profiles, IFNα protein levels and disease activity, which could be due to divergent disease pathways.

SLE serum induces altered goblet cell differentiation and leakiness in human intestinal organoids

Human intestinal epithelial cells are the interface between luminal content and basally residing immune cells. They form a tight monolayer that constantly secretes mucus creating a multilayered protective barrier. Alterations in this barrier can lead to increased permeability which is common in systemic lupus erythematosus (SLE) patients. However, it remains unexplored how the barrier is affected. Here, we present an in vitro model specifically designed to examine the effects of SLE on epithelial cells. We utilize human colon organoids that are stimulated with serum from SLE patients. Combining transcriptomic with functional analyses revealed that SLE serum induced an expression profile marked by a reduction of goblet cell markers and changed mucus composition. In addition, organoids exhibited imbalanced cellular composition along with enhanced permeability, altered mitochondrial function, and an interferon gene signature. Similarly, transcriptomic analysis of SLE colon biopsies revealed a downregulation of secretory markers. Our work uncovers a crucial connection between SLE and intestinal homeostasis that might be promoted in vivo through the blood, offering insights into the causal connection of barrier dysfunction and autoimmune diseases.

Smith-specific regulatory T cells halt the progression of lupus nephritis

Antigen-specific regulatory T cells (Tregs) suppress pathogenic autoreactivity and are potential therapeutic candidates for autoimmune diseases such as systemic lupus erythematosus (SLE). Lupus nephritis is associated with autoreactivity to the Smith (Sm) autoantigen and the human leucocyte antigen (HLA)-DR15 haplotype; hence, we investigated the potential of Sm-specific Tregs (Sm-Tregs) to suppress disease. Here we identify a HLA-DR15 restricted immunodominant Sm T cell epitope using biophysical affinity binding assays, then identify high-affinity Sm-specific T cell receptors (TCRs) using high-throughput single-cell sequencing. Using lentiviral vectors, we transduce our lead Sm-specific TCR into Tregs derived from patients with SLE who are anti-Sm and HLA-DR15 positive. Compared with polyclonal mock-transduced Tregs, Sm-Tregs potently suppress Sm-specific pro-inflammatory responses in vitro and suppress disease progression in a humanized mouse model of lupus nephritis. These results show that Sm-Tregs are a promising therapy for SLE.

Tlr5 deficiency exacerbates lupus-like disease in the MRL/lpr mouse model

Introduction

Leaky gut has been linked to autoimmune disorders including lupus. We previously reported upregulation of anti-flagellin antibodies in the blood of lupus patients and lupus-prone mice, which led to our hypothesis that a leaky gut drives lupus through bacterial flagellin-mediated activation of toll-like receptor 5 (TLR5).

Methods

We created MRL/lpr mice with global Tlr5 deletion through CRISPR/Cas9 and investigated lupus-like disease in these mice.

Result

Contrary to our hypothesis that the deletion of Tlr5 would attenuate lupus, our results showed exacerbation of lupus with Tlr5 deficiency in female MRL/lpr mice. Remarkably higher levels of proteinuria were observed in Tlr5 -/- MRL/lpr mice suggesting aggravated glomerulonephritis. Histopathological analysis confirmed this result, and Tlr5 deletion significantly increased the deposition of IgG and complement C3 in the glomeruli. In addition, Tlr5 deficiency significantly increased renal infiltration of Th17 and activated cDC1 cells. Splenomegaly and lymphadenopathy were also aggravated in Tlr5-/- MRL/lpr mice suggesting impact on lymphoproliferation. In the spleen, significant decreased frequencies of regulatory lymphocytes and increased germinal centers were observed with Tlr5 deletion. Notably, Tlr5 deficiency did not change host metabolism or the existing leaky gut; however, it significantly reshaped the fecal microbiota.

Conclusion

Global deletion of Tlr5 exacerbates lupus-like disease in MRL/lpr mice. Future studies will elucidate the underlying mechanisms by which Tlr5 deficiency modulates host-microbiota interactions to exacerbate lupus.

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.

Burden of systemic lupus erythematosus in clinical practice: baseline data from the SLE Prospective Observational Cohort Study (SPOCS) by interferon gene signature

OBJECTIVE

The longitudinal Systemic Lupus Erythematosus Prospective Observational Cohort Study (SPOCS) aims to assess SLE disease course overall and according to type I interferon 4 gene signature (IFNGS). Here, we describe SPOCS patient characteristics by IFNGS and baseline disease activity.

METHODS

SPOCS (NCT03189875) is an international study of patients with SLE according to Systemic Lupus International Collaborating Clinics (SLICC)/American College of Rheumatology (ACR) criteria. Enrolled patients from 135 centres in 8 countries were followed biannually for ≤3 years from June 2017 to November 2022. Baseline demographics, disease characteristics, organ system involvement/damage and flares were analysed descriptively according to SLE Disease Activity Index-2000 score (SLEDAI-2K <10/≥10) and IFNGS status (high/low).

RESULTS

The study population (n=823) was 93.2% female, with mean (SD) age 45.3 (13.9) years and 11.1 (9.2) years since diagnosis; 52.4% had baseline SLICC/ACR Damage Index score ≥1. Patients with SLEDAI-2K scores ≥10 (241 of 584, 41.3%) vs <10 were younger (mean 42.8 (13.7) vs 46.6 (14.2) years; nominal p=0.001), had shorter SLE duration (10.4 (8.6) vs 12.4 (9.6) years; nominal p=0.012) and more severe flares (12.9% vs 5.3%; nominal p=0.001). IFNGS-high patients (522 of 739, 70.6%) were younger than IFNGS-low patients at first SLE manifestation (30.0 (12.7) vs 36.8 (14.6) years; nominal p<0.001). Proportions of IFNGS-high patients differed according to race (nominal p<0.001), with higher proportions among Asian (83.3%) and black (86.5%) versus white patients (63.5%). Greater proportions of IFNGS-high versus IFNGS-low patients had haematological (12.6% vs 4.1%), immunological (74.4% vs 45.6%) or dermal (69.7% vs 62.2%) involvement.

CONCLUSIONS

We identified key characteristics of patients with high disease activity and/or elevated type I IFN signalling, populations with SLE with high unmet needs. Baseline SLEDAI-2K ≥10 was associated with shorter disease duration and more severe flares. IFNGS-high patients were younger at diagnosis and had distinct patterns of organ involvement, compared with IFNGS-low patients.

Th1-related transcription factors and cytokines in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an inflammatory disorder related to immunity dysfunction. The Th1 cell family including Th1 cells, transcription factor T-bet, and related cytokines IFNγ, TNFα, IL-2, IL-18, TGF-β, and IL-12 have been widely discussed in autoimmunity, such as SLE. In this review, we will comprehensively discuss the expression profile of the Th1 cell family in both SLE patients and animal models and clarify how the family members are involved in lupus development. Interestingly, T-bet-related age-associated B cells (ABCs) and low-dose IL-2 treatment in lupus were emergently discussed as well. Collection of the evidence will better understand the roles of the Th1 cell family in lupus pathogenesis, especially targeting IL-2 in lupus.

Whole blood hydroxychloroquine: Does genetic polymorphism of cytochrome P450 enzymes have a role?

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with a wide range of clinical manifestations and multifactorial etiologies ranging from environmental to genetic. SLE is associated with dysregulated immunological reactions, with increased immune complex formation leading to end-organ damages such as lupus nephritis, cutaneous lupus, and musculoskeletal disorders. Lupus treatment aims to reduce disease activity, prevent organ damage, and improve long-term patient survival and quality of life. Antimalarial, hydroxychloroquine (HCQ) is used as a first-line systemic treatment for lupus. It has shown profound efficacy in lupus and its associated conditions. However, wide variation in terms of clinical response to this drug has been observed among this group of patients. This variability has limited the potential of HCQ to achieve absolute clinical benefits. Several factors, including genetic polymorphisms of cytochrome P450 enzymes, have been stipulated as key entities leading to this inter-individual variation. Thus, there is a need for more studies to understand the role of genetic polymorphisms in CYP450 enzymes in the clinical response to HCQ. Focusing on the role of genetic polymorphism on whole blood HCQ in lupus disorder, this review aims to highlight up-to-date pathophysiology of SLE, the mechanism of action of HCQ, and finally the role of genetic polymorphism of CYP450 enzymes on whole blood HCQ level as well as clinical response in lupus.

Antiviral effects of duck type I and type III interferons against Duck Tembusu virus in vitro and in vivo

Duck Tembusu Virus (DTMUV) is a newly emerging avian flavivirus that causes substantial economic losses to the duck industry in Asia by causing severe egg drop syndrome and fatal encephalitis in domestic ducks. During viral replication, host cells recognize the RNA structures produced by DTMUV, which triggers the production of interferons (IFNs) to inhibit viral replication. However, the function of duck type I and type III IFNs in inhibiting DTMUV infection remains largely unknown. In this study, we expressed and purified recombinant duck IFN-β (duIFN-β) and IFN-λ (duIFN-λ) in Escherichia coli and evaluated their antiviral activity against vesicular stomatitis virus (VSV). Furthermore, we found that both duIFN-β and duIFN-λ activated the ISRE promoter and induced the expression of ZAP, OAS, and RNaseL in duck embryo fibroblasts (DEFs). Notably, duIFN-β showed faster and more potent induction of ISGs in vitro and in vivo compared to duIFN-λ. Moreover, both duIFN-β and duIFN-λ showed high potential to inhibit DTMUV infection in DEFs, with duIFN-β demonstrating better antiviral efficacy than duIFN-λ against DTMUV in ducks. In conclusion, our results revealed that both duIFN-β and duIFN-λ can induce ISGs production and exhibit significant antiviral activity against DTMUV in vitro and in vivo, providing new insights for the development of antiviral therapeutic strategies in ducks.

Differences and similarities in cytokine profiles of macrophage activation syndrome in systemic lupus erythematosus and adult-onset Still's disease

To clarify the differences and similarities in the cytokine profiles of macrophage activating syndrome (MAS) between systemic lupus erythematosus (SLE) and adult-onset Still's disease (AOSD). The study participants included 9 patients with MAS-SLE, 22 with non-MAS-SLE, 9 with MAS-AOSD, and 13 with non-MAS-AOSD. Serum cytokine levels were measured using a multiplex bead assay. Cytokine levels were compared between patients with SLE and AOSD with/without MAS. Moreover, cytokine patterns were examined using principal component analysis (PCA) and cluster analysis. IL-6, IL-8, IL-18, and TNF-α levels were elevated in patients with SLE and AOSD. IFN-α levels were elevated in SLE, whereas IL-1β and IL-18 levels were elevated in AOSD. In SLE, IFN-α and IL-10 levels were higher in MAS than in non-MAS and controls. PCA revealed distinctive cytokine patterns in SLE and AOSD, SLE with IFN-α and IP-10, AOSD with IL-1β, IL-6, and IL-18, and enhanced cytokine production in MAS. PCA and cluster analysis showed no differences in cytokine patterns between the MAS and non-MAS groups. However, serum ferritin levels were correlated with IFN-α levels in SLE. Cytokine profiles differed between SLE and AOSD but not between MAS and non-MAS. MAS is induced by the enhancement of underlying cytokine abnormalities rather than by MAS-specific cytokine profiles. Type I IFN may be involved in MAS development in patients with SLE.

Spatial enrichment of the type 1 interferon signature in the brain of a neuropsychiatric lupus murine model

Among systemic lupus erythematosus (SLE) patients, neuropsychiatric symptoms are highly prevalent, being observed in up to 80% of adult and 95% of pediatric patients. Type 1 interferons, particularly interferon alpha (IFNα), have been implicated in the pathogenesis of SLE and its associated neuropsychiatric symptoms (NPSLE). However, it remains unclear how type 1 interferon signaling in the central nervous system (CNS) might result in neuropsychiatric sequelae. In this study, we validate an NPSLE mouse model and find an elevated peripheral type 1 interferon signature alongside clinically relevant NPSLE symptoms such as anxiety and fatigue. Unbiased single-nucleus sequencing of the hindbrain and hippocampus revealed that interferon-stimulated genes (ISGs) were among the most highly upregulated genes in both regions and that gene pathways involved in cellular interaction and neuronal development were generally repressed among astrocytes, oligodendrocytes, and neurons. Using image-based spatial transcriptomics, we found that the type 1 interferon signature is enriched as spatially distinct patches within the brain parenchyma of these mice. Our results suggest that type 1 interferon in the CNS may play an important mechanistic role in mediating NPSLE behavioral phenotypes by repressing general cellular communication pathways, and that type 1 interferon signaling modulators are a potential therapeutic option for NPSLE.

IFN-γ: An overlooked cytokine in dermatomyositis with anti-MDA5 antibodies

Dermatomyositis with anti-melanoma differentiation-associated gene 5 antibody (anti-MDA5 DM) is a rare autoimmune disease, often complicated by life-threatening, rapidly progressive interstitial lung disease. Additional manifestations of the disease include skin lesions, vascular abnormalities, joints and muscles pain. Despite its clinical significance, the pathogenesis of anti-MDA5 DM remains largely unknown. Currently, the disease is perceived as driven by type I interferon (IFN) whose expression is increased in most of the patients. Importantly, the regulation of IFN-γ is also altered in anti-MDA5 DM as evidenced by the presence of IFN-γ positive histiocytes in the lungs of patients, and the identification of autoantibodies that directly stimulate the production of IFN-γ by mononuclear cells. This review critically examines the pathogenesis of the disease, shedding light on recent findings that emphasize a potential role of IFN-γ. A novel conceptual framework is proposed, which integrates the molecular mechanisms altering IFN-γ regulation in anti-MDA5 DM with the known functional effects of IFN-γ on key tissues affected during the disease, such as the lungs, skin, and vessels. Understanding the precise role and relevance of IFN-γ in the pathogenesis of the disease will not only enhance the selection of available therapies for anti-MDA5 DM patients but also pave the way for the development of new therapeutic approaches targeting the altered molecular pathways.

Potential role of EBV and Toll-like receptor 9 ligand in patients with systemic lupus erythematosus

SLE is a multisystem autoimmune disease characterized by multiple immunological abnormalities including production of autoantibodies. While the etiology of SLE is largely unknown, it is generally accepted that both genetic and environmental factors contribute to disease risk and immune dysregulation. Production of IFN-α is important for protecting the host against infections; however, over stimulation of innate immune pathways can induce autoimmune disease. Environmental factors, particularly Epstein-Barr virus (EBV), have been proposed to play an important role in SLE disease. Improper engagement of Toll-like receptor (TLR) pathways by endogenous or exogenous ligands may lead to the initiation of autoimmune responses and tissue injury. EBV is shown to be a potent stimulant of IFN-α by TLR signaling cascades. Given the highlighted role of IFN-α in SLE pathogenesis and potential role of EBV infection in this disease, the present study is aimed at exploring the in vitro effects of EBV infection and CPG (either alone or in combination) on IFN-α. We also examined the expression level of CD20 and BDCA-4 and CD123 in PBMCs in 32 SLE patients and 32 healthy controls. Our results showed PBMCs treated with CPG-induced higher levels of IFN-α and TLR-9 gene expression fold change compared to cells treated with either EBV or EBV-CPG. Moreover, PBMCs treated with CPG produced significantly higher IFN-α concentration in supernatant compared to cells treated with EBV but not EBV-CPG. Our results further highlight the potential role of EBV infection and TLRs in SLE patients although more studies are warranted to ascertain the global imprint that EBV infection can have on immune signature in patients with SLE.

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.

Functions of double-negative B cells in autoimmune diseases, infections, and cancers

Most mature B cells can be divided into four subtypes based on the expression of the surface markers IgD and CD27: IgD+ CD27- naïve B cells, IgD+ CD27+ unswitched memory B cells, IgD- CD27+ switched memory B cells, and IgD- CD27- double-negative (DN) B cells. Despite their small population size in normal peripheral blood, DN B cells play integral roles in various diseases. For example, they generate autoimmunity in autoimmune conditions, while these cells may generate both autoimmune and antipathogenic responses in COVID-19, or act in a purely antipathogenic capacity in malaria. Recently, DN B cells have been identified in nasopharyngeal carcinoma and non-small-cell lung cancers, where they may play an immunosuppressive role. The distinct functions that DN B cells play in different diseases suggest that they are a heterogeneous B-cell population. Therefore, further study of the mechanisms underlying the involvement of DN B cells in these diseases is essential for understanding their pathogenesis and the development of therapeutic strategies. Further research is thus warranted to characterize the DN B-cell population in detail.

Serum interferon-alpha predicts in-hospital mortality in patients hospitalised with acute severe lupus

OBJECTIVES

Dysregulation of interferon-alpha (IFN-α) is considered central to the immunological abnormalities observed in SLE. Short-term mortality during high disease activity in lupus is up to 30%. Adenovirus vector-introduced IFN-α into a lupus-prone mouse causes the development of glomerulonephritis and death within weeks. We studied serum IFN-α as a biomarker of in-hospital mortality in patients of SLE with high disease activity.

METHODS

Serum IFN-α (ELISA) was measured in patients hospitalised for acute severe lupus in a tertiary care rheumatology unit in India and the levels were compared between survivors and non-survivors. Serum IFN-α was compared with traditional clinical and serological markers associated with disease activity to assess which better prognosticates survival.

RESULTS

In a cohort of 90 patients with a mean Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) of 19.3 (±5.5), the mean serum IFN-α was 88±144 pg/dL. Levels were undetectable in patients with inactive disease. SLEDAI, anti double stranded DNA (dsDNA) antibody titres and serum IFN-α levels were higher and serum complement (C3) lower in non-survivors (p=0.003, p=0.017, p<0.001, p=0.029, respectively). Serum IFN-α level of 140 pg/mL had a sensitivity of 86.7%, specificity of 94.6%, positive predictive value of 76% and negative predictive value of 83.3% (p<0.001) in predicting mortality. The area under the curve for predicting in-hospital mortality was 0.25 for C3, 0.72 for dsDNA, 0.77 for SLEDAI and 0.92 for serum IFN-α.

CONCLUSIONS

Serum IFN-α was better in predicting in-hospital mortality compared with conventional measures of disease activity such as anti-dsDNA, complements and SLEDAI.

Differential regulation of the interferon response in systemic lupus erythematosus distinguishes patients of Asian ancestry

OBJECTIVES

Type I interferon (IFN) plays a role in the pathogenesis of systemic lupus erythematosus (SLE), but insufficient attention has been directed to the differences in IFN responses between ancestral populations. Here, we explored the expression of the interferon gene signatures (IGSs) in SLE patients of European ancestry (EA) and Asian ancestry (AsA).

METHODS

We used gene set variation analysis with multiple IGS encompassing the response to both type 1 and type 2 IFN in isolated CD14+ monocytes, CD19+B cells, CD4+T cells and Natural Killer (NK) cells from patients with SLE stratified by self-identified ancestry. The expression of genes upstream of the IGS and influenced by lupus-associated risk alleles was also examined. Lastly, we employed machine learning (ML) models to assess the most important features classifying patients by disease activity.

RESULTS

AsA patients with SLE exhibited greater enrichment in the IFN core and IFNA2 IGS compared with EA patients in all cell types examined and, in the presence and absence of autoantibodies. Overall, AsA patients with SLE demonstrated higher expression of genes upstream of the IGS than EA counterparts. ML with feature importance analysis indicated that IGS expression in NK cells, anti-dsDNA, complement levels and AsA status contributed to disease activity.

CONCLUSIONS

AsA patients with SLE exhibited higher IGS than EA patients in all cell types regardless of autoantibody status, with enhanced expression of genetically associated genes upstream of the IGS potentially contributing. AsA, along with the IGS in NK cells, anti-dsDNA and complement, independently influenced SLE disease activity.

Bioinformatic analysis of immune-related transcriptome affected by IFIT1 gene in childhood systemic lupus erythematosus

Background

The interferon-induced protein with tetratricopeptide repeats 1 (IFIT1) gene is strongly associated with disease activity index of childhood systemic lupus erythematosus (SLE). However, whether IFIT1-regulated gene expression is the molecular basis of the pathogenesis of SLE has not been fully investigated.

Methods

Dataset GSE11909 was used to analyze the expression profiles of IFIT1 gene in 103 SLE cases and 12 healthy individuals. Differentially expressed genes (DEGs)-affected by IFIT1 gene were screened between the case group and control group, followed by gene function analysis. The clinical diagnostic potential of the least absolute shrinkage and selection operator (LASSO) model, established based on the expression profiles of IFIT1 and IFIFT1-affected DEGs, was evaluated. Analysis of association between IFIFT1-affected DEGs and immune infiltration was performed.

Results

IFIT1 was highly expressed in childhood SLE patients. IFIT1 and IFIT1-affected DEGs showed the potential to serve as a diagnostic marker for childhood SLE with area under the curve (AUC) value of 0.947. Childhood SLE patients showed 826 upregulated DEGs and 4,111 downregulated DEGs compared to the control group. Among them, 208 upregulated DEGs and 214 downregulated DEGs were identified in the IFIT1-high group compared to the IFIT1-low group. The LASSO model for the diagnosis of childhood SLE involved 7 marker genes that were related to immune checkpoint and tertiary lymphoid structure in SLE.

Conclusions

Our results confirmed the clinical diagnostic potential of IFIT1 and IFIT1-affected genes in childhood SLE. Moreover, this study elucidated that IFIT1-induced changes in the transcriptome are involved in immune checkpoint and tertiary lymphoid structure in childhood.

Uncoupling interferons and the interferon signature explain clinical and transcriptional subsets in SLE

Interferons (IFN) are thought to be key players in systemic lupus erythematosus (SLE). The unique and interactive roles of the different IFN families in SLE pathogenesis, however, remain poorly understood. Using reporter cells engineered to precisely quantify IFN-I, IFN-II and IFN-III activity levels in serum/plasma, we found that while IFNs play essential role in SLE pathogenesis and disease activity, they are only significant in specific subsets of patients. Interestingly, whereas IFN-I is the main IFN that governs disease activity in SLE, clinical subsets are defined by the co-elevation of IFN-II and IFN-III. Thus, increased IFN-I alone was only associated with cutaneous lupus. In contrast, systemic features, such as nephritis, were linked to co-elevation of IFN-I plus IFN-II and IFN-III, implying a synergistic effect of IFNs in severe SLE. Intriguingly, while increased IFN-I levels were strongly associated with IFN-induced gene expression (93.5%), in up to 64% of cases, the IFN signature was not associated with IFN-I. Importantly, neither IFN-II nor IFN-III explained IFN-induced gene expression in patients with normal IFN-I levels, and not every feature in SLE was associated with elevated IFNs, suggesting IFN-independent subsets in SLE. Together, the data suggest that, unlike the IFN signature, direct quantification of bioactive IFNs can identify pathogenic and clinically relevant SLE subsets amenable for precise anti-IFN therapies. Since IFN-I is only elevated in a subset of SLE patients expressing the IFN signature, this study explains the heterogeneous response in clinical trials targeting IFN-I, where patients were selected based on IFN-induced gene expression rather than IFN-I levels.

Interferons and systemic lupus erythematosus: Pathogenesis, clinical features, and treatments in interferon-driven disease

Type I interferons (IFNs) have recently received a lot of attention with the elucidation of the pathogenesis of systemic lupus erythematosus (SLE). Type I IFNs are associated with many SLE symptoms and play a role in the pathogenesis of autoimmune diseases that may occur concurrently with SLE, such as Sjögren's syndrome, antiphospholipid syndrome, myositis, scleroderma, and interferonopathy. Type I IFNs could be the link between these diseases. However, direct measurement of type I IFN levels and the IFN gene signature is currently unavailable in clinical practice. This review discusses type I IFN signalling in SLE, investigates the role of type I IFN in the clinical manifestations and symptoms associated with SLE and other IFN-related diseases, and discusses the clinical tests that can be used to diagnose SLE and measure disease activity. In addition, the role of type I IFN-blocking therapies as potential treatments for SLE is discussed.

IFN-γ and androgens disrupt mitochondrial function in murine myocytes

The effect of cytokines on non-traditional immunological targets under conditions of chronic inflammation is an ongoing subject of study. Fatigue is a symptom often associated with autoimmune diseases. Chronic inflammatory response and activated cell-mediated immunity are associated with cardiovascular myopathies which can be driven by muscle weakness and fatigue. Thus, we hypothesize that immune dysfunction-driven changes in myocyte mitochondria may play a critical role in fatigue-related pathogenesis. We show that persistent low-level expression of IFN-γ in designated IFN-γ AU-Rich Element deletion mice (ARE mice) under androgen exposure resulted in mitochondrial and metabolic deficiencies in myocytes from male or castrated ARE mice. Most notably, echocardiography unveiled that low ejection fraction in the left ventricle post-stress correlated with mitochondrial deficiencies, explaining how heart function decreases under stress. We report that inefficiencies and structural changes in mitochondria, with changes to expression of mitochondrial genes, are linked to male-biased fatigue and acute cardiomyopathy under stress. Our work highlights how male androgen hormone backgrounds and active autoimmunity reduce mitochondrial function and the ability to cope with stress and how pharmacological blockade of stress signal protects heart function. These studies provide new insight into the diverse actions of IFN-γ in fatigue, energy metabolism, and autoimmunity. © 2023 The Pathological Society of Great Britain and Ireland. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Low-density granulocytes are related to shorter pregnancy duration but not to interferon alpha protein blood levels in systemic lupus erythematosus

BACKGROUND

An increased risk of pregnancy complications is seen in women with systemic lupus erythematosus (SLE), but the specific immunopathological drivers are still unclear. Hallmarks of SLE are granulocyte activation, type I interferon (IFN) overproduction, and autoantibodies. Here we examined whether low-density granulocytes (LDG) and granulocyte activation increase during pregnancy, and related the results to IFNα protein levels, autoantibody profile, and gestational age at birth.

METHODS

Repeated blood samples were collected during pregnancy in trimesters one, two, and three from 69 women with SLE and 27 healthy pregnant women (HC). Nineteen of the SLE women were also sampled late postpartum. LDG proportions and granulocyte activation (CD62L shedding) were measured by flow cytometry. Plasma IFNα protein concentrations were quantified by single molecule array (Simoa) immune assay. Clinical data were obtained from medical records.

RESULTS

Women with SLE had higher LDG proportions and increased IFNα protein levels compared to HC throughout pregnancy, but neither LDG fractions nor IFNα levels differed during pregnancy compared to postpartum in SLE. Granulocyte activation status was higher in SLE relative to HC pregnancies, and it was increased during pregnancy compared to after pregnancy in SLE. Higher LDG proportions in SLE were associated with antiphospholipid positivity but not to IFNα protein levels. Finally, higher LDG proportions in trimester three correlated independently with lower gestational age at birth in SLE.

CONCLUSION

Our results suggest that SLE pregnancy results in increased peripheral granulocyte priming, and that higher LDG proportions late in pregnancy are related to shorter pregnancy duration but not to IFNα blood levels in SLE.

Immune Phenotype as a Biomarker for Systemic Lupus Erythematosus

The treatment of rheumatoid arthritis was revolutionized with the use of molecular-targeted drugs that target immunoregulatory molecules. The success of treatment with these drugs prompted the development of molecular-targeted drugs for systemic lupus erythematosus. However, systemic lupus erythematosus is a disease with high heterogeneous immune abnormalities, and diverse cells or molecules can be treatment targets. Thus, the identification of subpopulations based on immune abnormalities is essential for the development of effective treatment. One analytical method used to identify subpopulations is the immunophenotyping of peripheral blood samples of patients. This analysis evaluates the validity of target molecules for peripheral blood immune cell subsets, which are expected to be developed as biomarkers for precision medicine in which appropriate treatment targets are set for each subpopulation.

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.

Interferon and autoantigens: intersection in autoimmunity

Interferon (IFN) is a key component of the innate immune response. For reasons that remain incompletely understood, the IFN system is upregulated in several rheumatic diseases, particularly those that feature autoantibody production, such as SLE, Sjögren's syndrome, myositis and systemic sclerosis. Interestingly, many of the autoantigens targeted in these diseases are components of the IFN system, representing IFN-stimulated genes (ISGs), pattern recognition receptors (PRRs), and modulators of the IFN response. In this review, we describe features of these IFN-linked proteins that may underlie their status as autoantigens. Note is also made of anti-IFN autoantibodies that have been described in immunodeficiency states.

Role of Anifrolumab in Refractory Cutaneous Manifestations of Lupus Erythematosus: A Case Series and Literature Review

Lupus erythematosus (LE) is an autoimmune disease that presents either as a systemic (SLE) or an isolated skin disease (CLE). Currently, there is no FDA-approved medication specifically for CLE, and is treated with the same approach as SLE. We present two refractory cases of SLE with severe cutaneous manifestations unresponsive to the first-line therapy treated with anifrolumab. First, a 39-year-old Caucasian female with a known history of SLE with severe subacute CLE presented to the clinic for her refractory cutaneous symptoms. Her current regimen was hydroxychloroquine (HCQ), mycophenolate mofetil (MMF), and s/c belimumab with no improvement. Belimumab was discontinued, and she was started on anifrolumab with significant improvement. Another, a 28-year-old female with no known medical history was referred to a rheumatology clinic for elevated anti-nuclear antibody (ANA) and ribonucleoprotein (RNP) titers. She was diagnosed with SLE, and was treated with HCQ, belimumab, and MMF but failed to produce a reasonably good outcome. Hence belimumab was discontinued and anifrolumab was added instead with significant cutaneous improvement. The treatment spectrum for SLE is wide, which includes antimalarial (HCQ), oral corticosteroids (OCS), and immunosuppressants (Methotrexate-MTX, MMF, azathioprine-AZT). Anifrolumab, a type 1 IFNα receptor subunit 1 (IFNAR1) inhibitor, has been recently approved by the FDA for moderate to severe SLE while on standard therapy in August 2021. Early use of anifrolumab in moderate to severe cutaneous manifestations of SLE or CLE may result in significant improvement in patients.

Targeted Therapy for SLE-What Works, What Doesn't, What's Next

For many years, the failure of randomized controlled trials (RCTs) has prevented patients with systemic lupus erythematosus (SLE) from benefiting from biological drugs that have proved to be effective in other rheumatological diseases. Only two biologics are approved for SLE, however they can only be administered to a restricted proportion of patients. Recently, several phase II RCTs have evaluated the efficacy and safety of new biologics in extra-renal SLE and lupus nephritis. Six drug trials have reported encouraging results, with an improvement in multiple clinical and serological outcome measures. The possibility of combining B-cell depletion and anti-BLyS treatment has also been successfully explored.

Paediatric autoimmune diseases with ELANE mutations associated with neutropenia

OBJECTIVE

To explore the clinical characteristics of autoimmune diseases in children with ELANE mutations.

METHODS

Three cases of children with ELANE mutations manifesting as autoimmune diseases, who were under treatment from April 2020 to May 2021, were retrospectively analysed.

RESULTS

Among the three children, two were boys aged 15 years and 22 months (cases 1 and 3) respectively, and the other one was a 22-month-old girl (case 2). All the cases had recurrent infections. Case 1 presented with cyclic neutropenia and systemic lupus erythematosus (SLE). Case 2 presented with severe neutropenia and autoimmune haemolytic anaemia (AHIA). Case 3 presented with severe neutropenia and anti-neutrophil cytoplasm antibodies (ANCA)-associated small vasculitis. Genetic tests showed that they all had heterozygous mutations in the ELANE gene. Case 1 was treated with methylprednisolone and hydroxychloroquine sulphate for 2 years, making neutrophil level return to normal. Case 2 received allogeneic hematopoietic stem cell transplantation and has stopped taking antibiotics, steroids and all the immunosuppressors. Case 3 received subcutaneous injections of granulocyte colony-stimulating factor, oral prednisone and cyclophosphamide. The boy in case 3 has been followed up for one year, and his absolute neutrophil count has increased to 1.56 × 10⁹/L.

CONCLUSION

Patients with ELANE mutations, combined with autoimmune diseases, may have recurrent infections. Disease-modifying antirheumatic drugs (DMARDs) are effective for autoimmune diseases. Autoimmune diseases with ELANE mutations associated with neutropenia can be cured through allogeneic hematopoietic stem cell transplantation.

Targeted multiomics in childhood-onset SLE reveal distinct biological phenotypes associated with disease activity: results from an explorative study

OBJECTIVE

To combine targeted transcriptomic and proteomic data in an unsupervised hierarchical clustering method to stratify patients with childhood-onset SLE (cSLE) into similar biological phenotypes, and study the immunological cellular landscape that characterises the clusters.

METHODS

Targeted whole blood gene expression and serum cytokines were determined in patients with cSLE, preselected on disease activity state (at diagnosis, Low Lupus Disease Activity State (LLDAS), flare). Unsupervised hierarchical clustering, agnostic to disease characteristics, was used to identify clusters with distinct biological phenotypes. Disease activity was scored by clinical SELENA-SLEDAI (Safety of Estrogens in Systemic Lupus Erythematosus National Assessment-Systemic Lupus Erythematosus Disease Activity Index). High-dimensional 40-colour flow cytometry was used to identify immune cell subsets.

RESULTS

Three unique clusters were identified, each characterised by a set of differentially expressed genes and cytokines, and by disease activity state: cluster 1 contained primarily patients in LLDAS, cluster 2 contained mainly treatment-naïve patients at diagnosis and cluster 3 contained a mixed group of patients, namely in LLDAS, at diagnosis and disease flare. The biological phenotypes did not reflect previous organ system involvement and over time, patients could move from one cluster to another. Healthy controls clustered together in cluster 1. Specific immune cell subsets, including CD11c+ B cells, conventional dendritic cells, plasmablasts and early effector CD4+ T cells, differed between the clusters.

CONCLUSION

Using a targeted multiomic approach, we clustered patients into distinct biological phenotypes that are related to disease activity state but not to organ system involvement. This supports a new concept where choice of treatment and tapering strategies are not solely based on clinical phenotype but includes measuring novel biological parameters.

Optimal Selection of IFN-α-Inducible Genes to Determine Type I Interferon Signature Improves the Diagnosis of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the production of autoantibodies specific to self-molecules in the nucleus, cytoplasm, and cell surface. The diversity of serologic and clinical manifestations observed in SLE patients challenges the development of diagnostics and tools for monitoring disease activity. Elevated type I interferon signature (IFN- I) in SLE leads to dysregulation of innate and adaptive immune function, resulting in autoantibodies production. The most common method to determine IFN-I signature is measuring the gene expression of several IFN-α-inducible genes (IFIGs) in blood samples and calculating a score. Optimal selection of IFIGs improves the sensitivity, specificity, and accuracy of the diagnosis of SLE. We describe the mechanisms of the immunopathogenesis of IFN-I signature (IFNα production) and its clinical consequences in SLE. In addition, we explore the association between IFN-I signature, the presence of autoantibodies, disease activity, medical therapy, and ethnicity. We discuss the presence of IFN-I signature in some patients with other autoimmune diseases, including rheumatoid arthritis, systemic and multiple sclerosis, Sjogren’s syndrome, and dermatomyositis. Prospective studies are required to assess the role of IFIG and the best combination of IFIGs to monitor SLE disease activity and drug treatments.

mTORC2 contributes to systemic autoimmunity

The development of many systemic autoimmune diseases, including systemic lupus erythematosus, is associated with overactivation of the type I interferon (IFN) pathway, lymphopenia and increased follicular helper T (Tfh)-cell differentiation. However, the cellular and molecular mechanisms underlying these immunological perturbations remain incompletely understood. Here, we show that the mechanistic target of rapamycin complex 2 (mTORC2) promotes Tfh differentiation and disrupts Treg homeostasis. Inactivation of mTORC2 in total T cells, but not in Tregs, greatly ameliorated the immunopathology in a systemic autoimmunity mouse model. This was associated with reduced Tfh differentiation, B-cell activation, and reduced T-cell glucose metabolism. Finally, we show that type I IFN can synergize with TCR ligation to activate mTORC2 in T cells, which partially contributes to T-cell lymphopenia. These data indicate that mTORC2 may act as downstream of type I IFN, TCR and costimulatory receptor ICOS, to promote glucose metabolism, Tfh differentiation, and T-cell lymphopenia, but not to suppress Treg function in systemic autoimmunity. Our results suggest that mTORC2 might be a rational target for systemic autoimmunity treatment.