Gene Expression and Pharmacodynamic Changes in 1,760 Systemic Lupus Erythematosus Patients From Two Phase III Trials of BAFF Blockade With Tabalumab

B- and T-Lymphocyte Attenuator in Systemic Lupus Erythematosus Disease Pathogenesis

B- and T-lymphocyte attenuator (BTLA; CD272) is an immunoglobulin superfamily member and part of a family of checkpoint inhibitory receptors that negatively regulate immune cell activation. The natural ligand for BTLA is herpes virus entry mediator (HVEM; TNFRSF14), and binding of HVEM to BTLA leads to attenuation of lymphocyte activation. In this study, we evaluated the role of BTLA and HVEM expression in the pathogenesis of systemic lupus erythematosus (SLE), a multisystem autoimmune disease. Peripheral blood mononuclear cells from healthy volunteers (N = 7) were evaluated by mass cytometry by time-of-flight to establish baseline expression of BTLA and HVEM on human lymphocytes compared with patients with SLE during a self-reported flare (N = 5). High levels of BTLA protein were observed on B cells, CD4+, and CD8+ T cells, and plasmacytoid dendritic cells in healthy participants. HVEM protein levels were lower in patients with SLE compared with healthy participants, while BTLA levels were similar between SLE and healthy groups. Correlations of BTLA-HVEM hub genes' expression with patient and disease characteristics were also analyzed using whole blood gene expression data from patients with SLE (N = 1,760) and compared with healthy participants (N = 60). HVEM, being one of the SLE-associated genes, showed an exceptionally strong negative association with disease activity. Several other genes in the BTLA-HVEM signaling network were strongly (negative or positive) correlated, while BTLA had a low association with disease activity. Collectively, these data provide a clinical rationale for targeting BTLA with an agonist in SLE patients with low HVEM expression.

Emerging biologic therapies for systemic lupus erythematosus

PURPOSE OF REVIEW

The approval of belimumab and anifrolumab has expanded the scope of treatment for systemic lupus erythematosus (SLE) patients. However, many patients remain refractory to currently available therapies and suffer from drug toxicities. This review will discuss approved and target-specific therapeutics in development that bring hope for better SLE treatments.

RECENT FINDINGS

Since the last review on this subject in the journal, the FDA has approved anifrolumab and belimumab for SLE and lupus nephritis (LN), respectively. A fully humanized anti-CD20, obinutuzumab, met the primary end point in a phase II trial in LN. A Tyk2 inhibitor, deucravacitinib, and an antibody targeting plasmacytoid dendritic cells, litifilimab, met the primary end point in phase II trials in SLE and cutaneous lupus erythematosus (CLE). Ustekinumab and baricitinib met the primary end point in phase II but not in phase III trials.

SUMMARY

While many drug candidates which met the end points in phase II trials have failed phase III trials, the number of target-specific therapies for SLE has continued to expand.

The Link Between Dysregulated Immunometabolism and Vascular Damage: Implications for the Development of Atherosclerosis in Systemic Lupus Erythematosus and Other Rheumatic Diseases

A bimodal pattern of mortality in systemic lupus erythematosus (SLE) exists. Early-stage deaths are predominantly caused by infection, whereas later-stage deaths are mainly caused by atherosclerotic disease. Further, although SLE-related mortality has reduced considerably in recent years, cardiovascular (CV) events remain one of the leading causes of death in people with SLE. Accelerated atherosclerosis in SLE is attributed to both an increase in traditional CV risk factors and the inflammatory effects of SLE itself. Many of these changes occur within the microenvironment of the vascular-immune interface, the site of atherosclerotic plaque development. Here, an intimate interaction between endothelial cells, vascular smooth muscle cells, and immune cells dictates physiological vs pathological responses to a chronic type 1 interferon environment. Low-density neutrophils (LDNs) have also been implicated in eliciting vasculature-damaging effects at such lesion sites. These changes are thought to be governed by dysfunctional metabolism of immune cells in this niche due at least in part to the chronic induction of type 1 interferons. Understanding these novel pathophysiological mechanisms and metabolic pathways may unveil potential innovative pharmacological targets and therapeutic opportunities for atherosclerosis, as well as shed light on the development of premature atherosclerosis in patients with SLE who develop CV events.

Effect of BAFF blockade on the B cell receptor repertoire and transcriptome in a mouse model of systemic lupus erythematosus

Introduction

Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disease. Anti-B-cell-activating factor (BAFF) therapy effectively depletes B cells and reduces SLE disease activity. This research aimed to evaluate the effect of BAFF blockade on B cell receptor (BCR) repertoire and gene expression.

Methods

Through next-generation sequencing, we analyzed gene expression and BCR repertoire in MRL/lpr mice that received long-term anti-BAFF therapy. Based on gene expression profiles, we predicted the relative proportion of immune cells using ImmuCellAI-mouse, validating our predictions via flow cytometry and FluoroSpot.

Results

The loss of BCR repertoire diversity and richness, along with increased clonality and differential frequency distribution of the immunoglobulin heavy chain variable (IGHV) segment gene usage, were observed in BAFF-blockade mice. Meanwhile, the distribution of complementarity-determining region 3 (CDR3) length and CDR3 amino acid usage remained unaffected. BAFF blockade resulted in extensive changes in gene expression, particularly that of genes related to B cells and immunoglobulins. Besides, the tumor necrosis factor (TNF)-α responses and interferon (IFN)-α/γ were downregulated, consistent with the decrease in IFN-γ and TNF-α serum levels following anti-BAFF therapy. In addition, BAFF blockade significantly reduced B cell subpopulations and plasmacytoid dendritic cells, and caused the depletion of antibody-secreting cells.

Discussion

Our comparative BCR repertoire and transcriptome analyses of MRL/lpr mice subjected to BAFF blockade provide innovative insights into the molecular pathophysiology of SLE.

Efficacy and safety of baricitinib in treatment of systemic lupus erythematosus: a systematic review and meta-analysis

BACKGROUND

SLE is an autoimmune disease marked by broad immunological dysregulation and multi-system inflammation. Baricitinib is one of the novel treatments for SLE. We conducted this meta-analysis to evaluate its safety and effectiveness in treating SLE.

METHOD

We looked for all published randomized controlled trials in PubMed, Scopus, Web of Science, and Cochrane and included all RCTs comparing baricitinib and placebo in the treatment of SLE. Review Manager 5.4 program was used for data analysis.

RESULTS

Three trials with a total of 1849 individuals were included. Participants in the baricitinib group were significantly more likely to attain SRI-4 response than those in the placebo group [RR = 1.11, 95% CI (1.02, 1.21), P = 0.01]. Additionally, baricitinib performed better than the placebo in terms of reduction of ≥ 4 points from baseline in SLEDAI-2 K score [RR = 1.13, 95% CI (1.04, 1.22), P = 0.004]. In terms of SLEDAI-2 K remission of arthritis or rash, baricitinib was also superior to placebo [RR = 1.08, 95% CI (1.00, 1.17), P = 0.04]. Treatment-emergent adverse events did not differ significantly [RR = 1.01, 95% CI (0.97, 1.05), P = 0.61].

CONCLUSION

Baricitinib is potentially safe and effective in the treatment of SLE. It has successfully met the study's primary endpoint and some secondary endpoints highlighting its potential to improve the outcomes of SLE. Despite achieving an SRI-4 response, glucocorticoids sparing and some other secondary outcomes weren't reached by baricitinib.

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.

IL17A Blockade with Ixekizumab Suppresses MuvB Signaling in Clinical Psoriasis

Unbiased informatics approaches have the potential to generate insights into uncharacterized signaling pathways in human disease. In this study, we generated longitudinal transcriptomic profiles of plaque psoriasis lesions from patients enrolled in a clinical trial of the anti-IL17A antibody ixekizumab (IXE). This dataset was then computed against a curated matrix of over 700 million data points derived from published psoriasis and signaling node perturbation transcriptomic and chromatin immunoprecipitation-sequencing datasets. We observed substantive enrichment within both psoriasis-induced and IXE-repressed gene sets of transcriptional targets of members of the MuvB complex, a master regulator of the mitotic cell cycle. These gene sets were similarly enriched for pathways involved in the regulation of the G2/M transition of the cell cycle. Moreover, transcriptional targets for MuvB nodes were strongly enriched within IXE-repressed genes whose expression levels correlated strongly with the extent and severity of the psoriatic disease. In models of human keratinocyte proliferation, genes encoding MuvB nodes were transcriptionally repressed by IXE, and depletion of MuvB nodes reduced cell proliferation. Finally, we made the expression and regulatory networks that supported this study available as a freely accessible, cloud-based hypothesis generation platform. Our study positions inhibition of MuvB signaling as an important determinant of the therapeutic impact of IXE in psoriasis.

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.

Safety profile of baricitinib in patients with systemic lupus erythematosus: an integrated analysis

OBJECTIVES

To assess the safety of the oral Janus kinase inhibitor baricitinib in adult patients with systemic lupus erythematosus (SLE) receiving stable background therapy. Topics of special interest included infections and cardiovascular and thromboembolic events.

METHODS

This analysis included integrated safety data from three randomised, placebo-controlled studies (one phase 2 and two phase 3) and one long-term extension study. Data are reported in three data sets: placebo-controlled, extended exposure and all-baricitinib. Outcomes include treatment-emergent adverse events (AEs), AEs of special interest and abnormal laboratory changes. Proportions of patients with events and incidence rates (IRs) were calculated.

RESULTS

A total of 1655 patients received baricitinib for up to 3.5 years (median duration 473 days). With baricitinib 4 mg, baricitinib 2 mg and placebo, respectively, 50.8%, 50.7% and 49.0% of patients reported at least one infection and 4.4%, 3.4% and 1.9% of patients had a serious infection. The most common treatment-emergent infections included urinary tract infection, COVID-19, upper respiratory tract infection and nasopharyngitis. Herpes zoster was more common with baricitinib 4 mg (4.7%) vs baricitinib 2 mg (2.7%) and placebo (2.8%). Among baricitinib-4 mg, 2 mg and placebo-treated patients, respectively, 4 (IR=0.9), 1 (IR=0.2) and 0 experienced at least one positively adjudicated major adverse cardiovascular event, and 0, 3 (IR=0.6) and 2 (IR=0.4) reported at least one positively adjudicated venous thromboembolism.

CONCLUSIONS

The results of this integrated safety analysis in patients with SLE are not substantially different to the established safety profile of baricitinib. No increased venous thromboembolism was found.

Clinical Pharmacokinetics, Pharmacodynamics, and Immunogenicity of Anifrolumab

The type I interferon (IFN) signaling pathway is implicated in the pathogenesis of systemic lupus erythematosus (SLE). Anifrolumab is a monoclonal antibody that targets the type I IFN receptor subunit 1. Anifrolumab is approved in several countries for patients with moderate to severe SLE receiving standard therapy. The approved dosing regimen of anifrolumab is a 300-mg dose administered intravenously every 4 weeks; this was initially based on the results of the Phase 2b MUSE and further confirmed in the Phase 3 TULIP-1 and TULIP-2 trials, in which anifrolumab 300-mg treatment was associated with clinically meaningful improvements in disease activity with an acceptable safety profile. There have been several published analyses of the pharmacokinetic and pharmacodynamic profile of anifrolumab, including a population-pharmacokinetic analysis of 5 clinical studies of healthy volunteers and patients with SLE, in which body weight and type I IFN gene expression were significant covariates identified for anifrolumab exposure and clearance. Additionally, the pooled Phase 3 SLE population has been used to evaluate how serum exposure may be related to clinical responses, safety risks, and pharmacodynamic effects of the 21-gene type I IFN gene signature (21-IFNGS). The relevance of 21-IFNGS with regard to clinical efficacy outcomes has also been analyzed. Herein, the clinical pharmacokinetics, pharmacodynamics, and immunogenicity of anifrolumab as well as results of population-pharmacokinetics and exposure-response analyses are reviewed.

Distinct gene dysregulation patterns herald precision medicine potentiality in systemic lupus erythematosus

OBJECTIVES

We aimed at investigating the whole-blood transcriptome, expression quantitative trait loci (eQTLs), and levels of selected serological markers in patients with SLE versus healthy controls (HC) to gain insight into pathogenesis and identify drug targets.

METHODS

We analyzed differentially expressed genes (DEGs) and dysregulated gene modules in a cohort of 350 SLE patients and 497 HC from the European PRECISESADS project (NTC02890121), split into a discovery (60%) and a replication (40%) set. Replicated DEGs qualified for eQTL, pathway enrichment, regulatory network, and druggability analysis. For validation purposes, a separate gene module analysis was performed in an independent cohort (GSE88887).

RESULTS

Analysis of 521 replicated DEGs identified multiple enriched interferon signaling pathways through Reactome. Gene module analysis yielded 18 replicated gene modules in SLE patients, including 11 gene modules that were validated in GSE88887. Three distinct gene module clusters were defined i.e., "interferon/plasma cells", "inflammation", and "lymphocyte signaling". Predominant downregulation of the lymphocyte signaling cluster denoted renal activity. By contrast, upregulation of interferon-related genes indicated hematological activity and vasculitis. Druggability analysis revealed several potential drugs interfering with dysregulated genes within the "interferon" and "PLK1 signaling events" modules. STAT1 was identified as the chief regulator in the most enriched signaling molecule network. Drugs annotated to 15 DEGs associated with cis-eQTLs included bortezomib for its ability to modulate CTSL activity. Belimumab was annotated to TNFSF13B (BAFF) and daratumumab was annotated to CD38 among the remaining replicated DEGs.

CONCLUSIONS

Modulation of interferon, STAT1, PLK1, B and plasma cell signatures showed promise as viable approaches to treat SLE, pointing to their importance in SLE pathogenesis.

Baricitinib for systemic lupus erythematosus: a double-blind, randomised, placebo-controlled, phase 3 trial (SLE-BRAVE-I)

BACKGROUND

Baricitinib is an oral selective inhibitor of Janus kinase 1 and 2 approved for the treatment of rheumatoid arthritis, atopic dermatitis, and alopecia areata. In a 24-week phase 2 study in patients with systemic lupus erythematosus (SLE), baricitinib 4 mg significantly improved SLE disease activity compared with placebo. The objective of this trial was to evaluate the efficacy and safety of baricitinib in patients with active SLE in a 52-week phase 3 study.

METHODS

In a multicentre, double-blind, randomised, placebo-controlled, parallel-group, phase 3 study, SLE-BRAVE-I, patients (aged ≥18 years) with active SLE receiving stable background therapy were randomly assigned 1:1:1 to baricitinib 4 mg, 2 mg, or placebo once daily for 52 weeks with standard of care. Glucocorticoid tapering was encouraged but not required per protocol. The primary endpoint was the proportion of patients reaching an SLE Responder Index (SRI)-4 response at week 52 in the baricitinib 4 mg treatment group compared with placebo. The primary endpoint was assessed by logistic regression analysis with baseline disease activity, baseline corticosteroid dose, region, and treatment group in the model. Efficacy analyses were done on a modified intention-to-treat population, comprising all participants who were randomly assigned and received at least one dose of investigational product. Safety analyses were done on all randomly assigned participants who received at least one dose of investigational product and who did not discontinue from the study for the reason of lost to follow-up at the first post-baseline visit. This study is registered with ClinicalTrials.gov, NCT03616912.

FINDINGS

760 participants were randomly assigned and received at least one dose of baricitinib 4 mg (n=252), baricitinib 2 mg (n=255), or placebo (n=253). A significantly greater proportion of participants who received baricitinib 4 mg (142 [57%]; odds ratio 1·57 [95% CI 1·09 to 2·27]; difference with placebo 10·8 [2·0 to 19·6]; p=0·016), but not baricitinib 2 mg (126 [50%]; 1·14 [0·79 to 1·65]; 3·9 [-4·9 to 12·6]; p=0·47), reached SRI-4 response compared with placebo (116 [46%]). There were no significant differences between the proportions of participants in either baricitinib group reaching any of the major secondary endpoints compared with placebo, including glucocorticoid tapering and time to first severe flare. 26 (10%) participants receiving baricitinib 4 mg had serious adverse events, 24 (9%) participants receiving baricitinib 2 mg, and 18 (7%) participants receiving placebo. The safety profile of baricitinib in participants with SLE was consistent with the known baricitinib safety profile.

INTERPRETATION

The primary endpoint in this study was met for the 4 mg baricitinib group. However, key secondary endpoints were not. No new safety signals were observed.

FUNDING

Eli Lilly and Company.

Baricitinib for systemic lupus erythematosus: a double-blind, randomised, placebo-controlled, phase 3 trial (SLE-BRAVE-II)

BACKGROUND

Baricitinib is an oral selective inhibitor of Janus kinase 1 and 2 approved for the treatment of rheumatoid arthritis, atopic dermatitis, and alopecia areata. In a 24-week phase 2 study in patients with systemic lupus erythematosus (SLE), baricitinib 4 mg significantly improved SLE disease activity compared with placebo. In this Article, we report the evaluation of efficacy and safety of baricitinib in patients with SLE in a 52-week phase 3 study.

METHODS

In this phase 3 double-blind, randomised, placebo-controlled study, SLE-BRAVE-II, patients (aged ≥18 years) with active SLE receiving stable background therapy were randomly assigned 1:1:1 to baricitinib 4 mg, baricitinib 2 mg, or placebo once daily for 52 weeks. The primary endpoint was the proportion of patients with an SLE Responder Index (SRI)-4 response at week 52 in the baricitinib 4 mg treatment group compared with placebo. Glucocorticoid tapering was encouraged but not required per protocol. The primary endpoint was assessed by logistic regression analysis with baseline disease activity, baseline corticosteroid dose, region, and treatment group in the model. Efficacy analyses were done on an intention-to-treat population, comprising all participants who were randomly assigned and received at least one dose of investigational product and who did not discontinue from the study for the reason of lost to follow-up at the first post-baseline visit. Safety analyses were done on all randomly assigned participants who received at least one dose of investigational product and who did not discontinue. This study is registered with ClinicalTrials.gov, NCT03616964, and is complete.

FINDINGS

A total of 775 patients were randomly assigned and received at least one dose of baricitinib 4 mg (n=258), baricitinib 2 mg (n=261), or placebo (n=256). There was no difference in the primary efficacy outcome of the proportion of SRI-4 responders at week 52 between participants who received baricitinib 4mg (121 [47%]; odds ratio 1·07 [95% CI 0·75 to 1·53]; difference with placebo 1·5 [95% CI -7·1 to 10·2]), 2 mg (120 [46%]; 1·05 [0·73 to 1·50]; 0·8 [-7·9 to 9·4]) and placebo (116 [46%]). None of the major secondary endpoints, including glucocorticoid tapering and time to first severe flare, were met. Serious adverse events were observed in 29 (11%) participants in the baricitinib 4 mg group, 35 (13%) in the baricitinib 2 mg group, and 22 (9%) in the placebo group. The safety profile of baricitinib in patients with SLE was consistent with the known baricitinib safety profile.

INTERPRETATION

Although phase 2 data suggested baricitinib as a potential treatment for patients with SLE, which was supported in SLE-BRAVE-I, this result was not replicated in SLE-BRAVE-II. No new safety signals were observed.

FUNDING

Eli Lilly and Company.

Type I interferon pathway assays in studies of rheumatic and musculoskeletal diseases: a systematic literature review informing EULAR points to consider

OBJECTIVES

To systematically review the literature for assay methods that aim to evaluate type I interferon (IFN-I) pathway activation and to harmonise-related terminology.

METHODS

Three databases were searched for reports of IFN-I and rheumatic musculoskeletal diseases. Information about the performance metrics of assays measuring IFN-I and measures of truth were extracted and summarised. A EULAR task force panel assessed feasibility and developed consensus terminology.

RESULTS

Of 10 037 abstracts, 276 fulfilled eligibility criteria for data extraction. Some reported more than one technique to measure IFN-I pathway activation. Hence, 276 papers generated data on 412 methods. IFN-I pathway activation was measured using: qPCR (n=121), immunoassays (n=101), microarray (n=69), reporter cell assay (n=38), DNA methylation (n=14), flow cytometry (n=14), cytopathic effect assay (n=11), RNA sequencing (n=9), plaque reduction assay (n=8), Nanostring (n=5), bisulphite sequencing (n=3). Principles of each assay are summarised for content validity. Concurrent validity (correlation with other IFN assays) was presented for n=150/412 assays. Reliability data were variable and provided for 13 assays. Gene expression and immunoassays were considered most feasible. Consensus terminology to define different aspects of IFN-I research and practice was produced.

CONCLUSIONS

Diverse methods have been reported as IFN-I assays and these differ in what elements or aspects of IFN-I pathway activation they measure and how. No 'gold standard' represents the entirety of the IFN pathway, some may not be specific for IFN-I. Data on reliability or comparing assays were limited, and feasibility is a challenge for many assays. Consensus terminology should improve consistency of reporting.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Type 1 interferon suppresses expression and glucocorticoid induction of glucocorticoid-induced leucine zipper (GILZ)

SLE is a systemic multi-organ autoimmune condition associated with reduced life expectancy and quality of life. Glucocorticoids (GC) are heavily relied on for SLE treatment but are associated with detrimental metabolic effects. Type 1 interferons (IFN) are central to SLE pathogenesis and may confer GC insensitivity. Glucocorticoid-induced leucine zipper (GILZ) mediates many effects of GC relevant to SLE pathogenesis, but the effect of IFN on GC regulation of GILZ is unknown. We performed in vitro experiments using human PBMC to examine the effect of IFN on GILZ expression. JAK inhibitors tofacitinib and tosylate salt were used in vivo and in vitro respectively to investigate JAK-STAT pathway dependence of our observations. ChiP was performed to examine glucocorticoid receptor (GR) binding at the GILZ locus. Several public data sets were mined for correlating clinical data. High IFN was associated with suppressed GILZ and reduced GILZ relevant to GC exposure in a large SLE population. IFN directly reduced GILZ expression and suppressed the induction of GILZ by GC in vitro in human leukocytes. IFN actions on GILZ expression were dependent on the JAK1/Tyk2 pathway, as evidenced by loss of the inhibitory effect of IFN on GILZ in the presence of JAK inhibitors. Activation of this pathway led to reduced GR binding in key regulatory regions of the GILZ locus. IFN directly suppresses GILZ expression and GILZ upregulation by GC, indicating a potential mechanism for IFN-induced GC resistance. This work has important implications for the ongoing development of targeted GC-sparing therapeutics in SLE.

Scoring personalized molecular portraits identify Systemic Lupus Erythematosus subtypes and predict individualized drug responses, symptomatology and disease progression

OBJECTIVES

Systemic Lupus Erythematosus is a complex autoimmune disease that leads to significant worsening of quality of life and mortality. Flares appear unpredictably during the disease course and therapies used are often only partially effective. These challenges are mainly due to the molecular heterogeneity of the disease, and in this context, personalized medicine-based approaches offer major promise. With this work we intended to advance in that direction by developing MyPROSLE, an omic-based analytical workflow for measuring the molecular portrait of individual patients to support clinicians in their therapeutic decisions.

METHODS

Immunological gene-modules were used to represent the transcriptome of the patients. A dysregulation score for each gene-module was calculated at the patient level based on averaged z-scores. Almost 6100 Lupus and 750 healthy samples were used to analyze the association among dysregulation scores, clinical manifestations, prognosis, flare and remission events and response to Tabalumab. Machine learning-based classification models were built to predict around 100 different clinical parameters based on personalized dysregulation scores.

RESULTS

MyPROSLE allows to molecularly summarize patients in 206 gene-modules, clustered into nine main lupus signatures. The combination of these modules revealed highly differentiated pathological mechanisms. We found that the dysregulation of certain gene-modules is strongly associated with specific clinical manifestations, the occurrence of relapses or the presence of long-term remission and drug response. Therefore, MyPROSLE may be used to accurately predict these clinical outcomes.

CONCLUSIONS

MyPROSLE (https://myprosle.genyo.es) allows molecular characterization of individual Lupus patients and it extracts key molecular information to support more precise therapeutic decisions.

Mechanism of action of baricitinib and identification of biomarkers and key immune pathways in patients with active systemic lupus erythematosus

OBJECTIVES

To elucidate the mechanism of action of baricitinib, a Janus kinase (JAK) 1/2 inhibitor, and describe immunological pathways related to disease activity in adults with systemic lupus erythematosus (SLE) receiving standard background therapy in a phase II trial.

METHODS

Patients with SLE were treated with baricitinib 2 mg or 4 mg in a phase II randomised, placebo-controlled study. Sera from 239 patients (baricitinib 2 mg: n=88; baricitinib 4 mg: n=82; placebo: n=69) and 49 healthy controls (HCs) were collected at baseline and week 12 and analysed using a proximity extension assay (Target 96 Inflammation Panel (Olink)). Interferon (IFN) scores were determined using an mRNA panel. Analytes were compared in patients with SLE versus HCs and in changes from baseline at week 12 between baricitinib 2 mg, 4 mg and placebo groups using a restricted maximum likelihood-based mixed models for repeated measures. Spearman correlations were computed for analytes and clinical measurements.

RESULTS

At baseline, SLE sera had strong cytokine dysregulation relative to HC sera. C-C motif chemokine ligand (CCL) 19, C-X-C motif chemokine ligand (CXCL) 10, tumour necrosis factor alpha (TNF-α), TNF receptor superfamily member (TNFRSF)9/CD137, PD-L1, IL-6 and IL-12β were significantly reduced in patients treated with baricitinib 4 mg versus placebo at week 12. Inflammatory biomarkers indicated correlations/associations with type I IFN (CCL19, CXCL10, TNF-α and PD-L1), anti-double stranded DNA (dsDNA) (TNF-α, CXCL10) and Systemic Lupus Erythematosus Disease Activity Index-2000, tender and swollen joint count and worst joint pain (CCL19, IL-6 and TNFRSF9/CD137).

CONCLUSION

These results suggest that baricitinib 4 mg downregulated key cytokines that are upregulated in patients with SLE and may play a role in a multitargeted mechanism beyond the IFN signature although clinical relevance remains to be further delineated.

TRIAL REGISTRATION NUMBER

NCT02708095.

Emerging Therapies in Cutaneous Lupus Erythematosus

Cutaneous lupus erythematosus (CLE) is an autoimmune disease that can occur with or without underlying systemic lupus erythematosus (SLE) and often has a profoundly negative impact on patient quality of life. There is substantial need for new and more effective therapies to treat CLE. CLE has a multifactorial pathogenesis that involves several key immune cells and pathways, including abnormalities in innate (e.g., type 1 interferon pathways) and adaptive immune responses (e.g., B and T cell autoreactivity), presenting multiple opportunities for more targeted therapies that do not require immunosuppression. Here we review several emerging therapies and their efficacy in CLE. Anifrolumab and belimumab have both been approved for the treatment of SLE in recent years, and clinical trial evidence suggests some forms of CLE may improve with these agents. Therapies currently in development that are being evaluated with CLE-specific outcome measures include BIIB059 and VIB7734, which target plasmacytoid dendritic cells (pDCs), and iberdomide, a cereblon modulator. These novel therapies all have previously demonstrated clinical benefit in some forms of CLE. Other therapies which target molecules believed to play a role in CLE pathogenesis, such as Janus kinases (JAKs), spleen tyrosine kinase (SYK), interferon γ (IFNγ), IL-12, and IL-23, have been evaluated in lupus clinical trials with skin-specific outcomes but failed to meet their primary endpoints.

Biological impact of iberdomide in patients with active systemic lupus erythematosus

OBJECTIVES

Iberdomide is a high-affinity cereblon ligand that promotes proteasomal degradation of transcription factors Ikaros (IKZF1) and Aiolos (IKZF3). Pharmacodynamics and pharmacokinetics of oral iberdomide were evaluated in a phase 2b study of patients with active systemic lupus erythematosus (SLE).

METHODS

Adults with autoantibody-positive SLE were randomised to placebo (n=83) or once daily iberdomide 0.15 mg (n=42), 0.3 mg (n=82) or 0.45 mg (n=81). Pharmacodynamic changes in whole blood leucocytes were measured by flow cytometry, regulatory T cells (Tregs) by epigenetic assay, plasma cytokines by ultrasensitive cytokine assay and gene expression by Modular Immune Profiling.

RESULTS

Iberdomide exhibited linear pharmacokinetics and dose-dependently modulated leucocytes and cytokines. Compared with placebo at week 24, iberdomide 0.45 mg significantly (p<0.001) reduced B cells, including those expressing CD268 (TNFRSF13C) (-58.3%), and plasmacytoid dendritic cells (-73.9%), and increased Tregs (+104.9%) and interleukin 2 (IL-2) (+144.1%). Clinical efficacy was previously reported in patients with high IKZF3 expression and high type I interferon (IFN) signature at baseline and confirmed here in those with an especially high IFN signature. Iberdomide decreased the type I IFN gene signature only in patients with high expression at baseline (-81.5%; p<0.001) but decreased other gene signatures in all patients.

CONCLUSION

Iberdomide significantly reduced activity of type I IFN and B cell pathways, and increased IL-2 and Tregs, suggesting a selective rebalancing of immune abnormalities in SLE. Clinical efficacy corresponded to reduction of the type I IFN gene signature.

TRIAL REGISTRATION NUMBER

NCT03161483.

A Narrative Literature Review Comparing the Key Features of Musculoskeletal Involvement in Rheumatoid Arthritis and Systemic Lupus Erythematosus

Although the clinical approach to the management of musculoskeletal manifestations in systemic lupus erythematosus (SLE) is often similar to that of rheumatoid arthritis (RA), there are distinct differences in immunopathogenesis, structural and imaging phenotypes and therapeutic evidence. Additionally, there are few published comparisons of these diseases. The objective of this narrative literature review is to compare the immunopathogenesis, structural features, magnetic resonance imaging (MRI) and musculoskeletal ultrasound (MSUS) studies and management of joint manifestations in RA and SLE. We highlight the key similarities and differences between the two diseases. Overall, the literature evaluated indicates that synovitis and radiographical progression are the key features in RA, while inflammation without swelling, tendinitis and tenosynovitis are more prominent features in SLE. In addition, the importance of defining patients with RA by the presence or absence of autoantibodies and categorizing patients with SLE by synovitis detected by musculoskeletal ultrasound and by structural phenotype (non-deforming, non-erosive arthritis, Jaccoud’s arthropathy and ‘Rhupus’) with respect to joint manifestations will also be discussed. An increased understanding of the joint manifestations in RA and SLE may inform evidence-based clinical decisions for both diseases.

Phase 2 Trial of Iberdomide in Systemic Lupus Erythematosus

BACKGROUND

Iberdomide, a cereblon modulator promoting degradation of the transcription factors Ikaros and Aiolos, which affect leukocyte development and autoimmunity, is being evaluated for the treatment of systemic lupus erythematosus (SLE).

METHODS

In this phase 2 trial, we randomly assigned patients in a 2:2:1:2 ratio to receive oral iberdomide (at a dose of 0.45, 0.30, or 0.15 mg) or placebo once daily for 24 weeks, in addition to standard medications. The primary end point at week 24 was a response on the SLE Responder Index (SRI-4), which was defined as a reduction of at least 4 points in the Systemic Lupus Erythematosus Disease Activity Index 2000 score (a 24-item weighted score of lupus activity that ranges from 0 to 105, with higher scores indicating greater disease activity), no new disease activity as measured on the British Isles Lupus Assessment Group 2004 index, and no increase of 0.3 points or more in the Physician's Global Assessment score (on a visual-analogue scale ranging from 0 [no disease activity] to 3 [maximal disease]).

RESULTS

A total of 288 patients received the assigned intervention: 81 received iberdomide at a dose of 0.45 mg, 82 received iberdomide at a dose of 0.30 mg, 42 received iberdomide at a dose of 0.15 mg, and 83 received placebo. At week 24, the percentages of patients with an SRI-4 response were 54% in the iberdomide 0.45-mg group, 40% in the iberdomide 0.30-mg group, 48% in the iberdomide 0.15-mg group, and 35% in the placebo group (adjusted difference between the iberdomide 0.45-mg group and the placebo group, 19.4 percentage points; 95% confidence interval, 4.1 to 33.4; P = 0.01), with no significant differences between the groups that received the lower doses of iberdomide and the group that received placebo. Iberdomide-associated adverse events included urinary tract and upper respiratory tract infections and neutropenia.

CONCLUSIONS

In this 24-week, phase 2 trial involving patients with SLE, iberdomide at a dose of 0.45 mg resulted in a higher percentage of patients with an SRI-4 response than did placebo. Data from larger, longer trials are needed to determine the efficacy and safety of iberdomide in SLE. (Funded by Bristol Myers Squibb; ClinicalTrials.gov number, NCT03161483; EudraCT number, 2016-004574-17.).

Anti-RNP antibodies are associated with the interferon gene signature but not decreased complement levels in SLE

OBJECTIVES

The goals of these studies were to elucidate the inter-relationships of specific anti-nuclear antibody (ANA), complement, and the interferon gene signature (IGS) in the pathogenesis of systemic lupus erythematosus (SLE).

METHODS

Data from the Illuminate trials were analysed for antibodies to dsDNA as well as RNA-binding proteins (RBP), levels of C3, C4 and various IGS. Statistical hypothesis testing, linear regression analyses and classification and regression trees analysis were employed to assess relationships between the laboratory features of SLE.

RESULTS

Inter-relationships of ANAs, complement and the IGS differed between patients of African Ancestry (AA) and European Ancestry (EA); anti-RNP and multiple autoantibodies were more common in AA patients and, although both related to the presence of the IGS, relationships between autoantibodies and complement differed. Whereas, anti-dsDNA had an inverse relationship to C3 and C4, levels of anti-RNP were not related to these markers. The IGS was only correlated with anti-dsDNA in EA SLE and complement was more correlated to the IGS in AA SLE. Finally, autoantibodies occurred in the presence and absence of the IGS, whereas the IGS was infrequent in anti-dsDNA/anti-RBP-negative SLE patients.

CONCLUSION

There is a complex relationship between autoantibodies and the IGS, with anti-RNP associated in AA and both anti-dsDNA and RNP associated in EA. Moreover, there was a difference in the relationship between anti-dsDNA, but not anti-RBP, with complement levels. The lack of a relationship of anti-RNP with C3 and C4 suggests that anti-RNP immune complexes (ICs) may drive the IGS without complement fixation, whereas anti-dsDNA ICs involve complement consumption.

Sub-setting systemic lupus erythematosus by combined molecular phenotypes defines divergent populations in two phase III randomized trials

OBJECTIVES

Heterogeneity of SLE patients in clinical trials remains a challenge for developing new therapies. This study used a combinatorial analysis of four molecular biomarkers to define key sources of heterogeneity.

METHODS

Combinations of IFN (high/low), anti-dsDNA (+/-) and C3 and C4 (low/normal) were used to subset n = 1747 patients from two randomized phase III trials. A dichotomous classification scheme defined SLE (+) as: IFN (high), anti-dsDNA (+), C3 (low) and/or C4 (low). SLE (-) required all of the following: IFN (low), anti-dsDNA (-), C3 (normal) and C4 (normal). Additional analyses subset the data further by IFN, anti-dsDNA and complement.

RESULTS

The trials enrolled n = 2262 patients of which n = 1747 patients had data for IFN, anti-dsDNA, C3 and C4 at baseline. There were n = 247 patients in the SLE (-) population and n = 1500 patients in the SLE (+) population. The SLE (-) population had more mucocutaneous and musculoskeletal disease at baseline, while SLE (+) had more haematological, renal and vascular involvement. There was lower concomitant medication use in the SLE (-) population for corticosteroids and immunosuppressants, except for MTX. Time to severe flare was significantly longer in SLE (-) vs SLE (+) (P < 0.0001) and SRI-4 response rate was significantly lower in SLE (-) vs SLE (+) (P = 0.00016). The USA had more SLE (-) patients (22%) than Mexico/Central America/South America (10%), Europe (7%) and the rest of the world (5%).

CONCLUSION

Combinatorial analysis of four molecular biomarkers revealed subsets of SLE patients that discriminated by disease manifestations, concomitant medication use, geography, time to severe flare and SRI-4 response. These data may be useful for designing clinical trials and identifying subsets of patients for analysis. Rheumatology key messages SLE patients from a P3 trial were categorized by IFN, anti-dsDNA, C3 and C4 status. Patients lacking molecular markers of SLE distinguished from biomarker positive patients on multiple clinical parameters. Biomarker negative patients have distinct disease characteristics that may impact clinical trial outcomes.

Glucocorticoid gene signatures in systemic lupus erythematosus and the effects of type I interferon: a cross-sectional and in-vitro study

BACKGROUND

Glucocorticoids, used as a therapy in systemic lupus erythematosus (SLE), interact with the cytoplasmic glucocorticoid receptor to modulate gene transcription. Minimising the use of glucocorticoids is a goal in SLE; however, pharmacological measures to support clinical guidelines are scarce. We evaluated glucocorticoid-regulated genes for their potential use as biomarkers of glucocorticoid exposure in SLE. We examined interactions between changes in gene expression that are induced by glucocorticoids and type I interferon.

METHODS

Genes regulated by glucocorticoids and type I interferon were analysed in relation to glucocorticoid exposure in adult patients meeting the American College of Rheumatology criteria for SLE from three cross-sectional cohorts: a local cohort from a tertiary hospital in Melbourne, VIC, Australia, and two public datasets (GSE49454, Hospital de la Conception, Marseille, France, and GSE88884, patients enrolled in a large, multicentre clinical trial). RNA sequencing was done using RNA from healthy donor leucocytes treated with the glucocorticoid dexamethasone, or type I interferon, or both.

FINDINGS

Glucocorticoid-regulated genes were analysed in a local SLE cohort (n=18) and public dataset GSE49454 (n=62). Five genes correlated with glucocorticoid dose in both cohorts and were combined to make a glucocorticoid gene signature. Validity of the glucocorticoid gene signature was tested in the public dataset GSE88884 (n=1756). A dose-dependent association was observed with glucocorticoid dose (p<0·0001), and the glucocorticoid gene signature had moderate ability to identify patients taking high-dose glucocorticoid (area under the curve [AUC]=0·77) although was less discriminatory when including all doses (AUC=0·69). We saw no effect of glucocorticoid dose on type I interferon -regulated gene expression. Patients with a high type I interferon gene signature had reduced glucocorticoid gene signature expression compared with patients with a low type I interferon gene signature matched for glucocorticoid dose, suggesting type I interferon inhibits glucocorticoid-stimulated gene expression. In RNA sequencing experiments, type I interferon impaired the expression of glucocorticoid-induced genes, whereas dexamethasone had minimal effect on the expression of type I interferon-stimulated genes. We identified genes regulated by dexamethasone but not affected by type I interferon; combined signatures using these genes also showed moderate ability to distinguish patients taking glucocorticoids.

INTERPRETATION

A gene signature for glucocorticoid exposure was identified, but the substantial effect of type I interferon on glucocorticoid-induced genes might limit its application in SLE. These data confirm the insensitivity of type I interferon-regulated genes to glucocorticoids, and together support the concept that type I interferon has a role in glucocorticoid resistance in SLE.

FUNDING

Lupus Research Alliance and Australian National Health and Medical Research Council.

Biologics in refractory idiopathic inflammatory myositis (IIM): What experience in juvenile vs adult myositis tells us about the use of biologics in pediatric IIM

Juvenile dermatomyositis (JDM) is an extremely heterogeneous orphan disease with limited amount of dedicated research on the subject matter. Recent research suggests that JDM may not just be the classic antibody driven complements mediated microangiopathy as was thought to be in the past. The etiopathogenesis of JDM also involves inappropriate stimulation of innate immune system followed by dysregulation of the adaptive immune response through dendritic cells. Many variable immune factors such as genetics, major histocompatibility complex expressions, immunohistochemical variabilities, and diversity in specific and associated autoantibodies may make individual IIM and JDM cases unique. The diversity in IIM and JDM also explains individual variability in response to specific therapies. Classifying and matching the right patients to the right treatment is crucial to the successful treatment of these patients with better outcomes. Sub-type specific biologic therapy may be the best current treatment that can match the patient to the best treatment options. A PubMed search was performed to find all the available cases of refractory myositis patients treated with biologics up to July 2020. Using this search this article reviews all the current biologic treatment options and experiences for both adults and children in the context of recent basic science to assist pediatric rheumatologists in choosing the optimal biologic therapy for a child with recalcitrant JDM.

GILZ Regulates the Expression of Pro-Inflammatory Cytokines and Protects Against End-Organ Damage in a Model of Lupus

Glucocorticoid-induced leucine zipper (GILZ) mimics many of the anti-inflammatory effects of glucocorticoids, suggesting it as a point of therapeutic intervention that could bypass GC adverse effects. We previously reported that GILZ down-regulation is a feature of human SLE, and loss of GILZ permits the development of autoantibodies and lupus-like autoimmunity in mice. To further query the contribution of GILZ to protection against autoimmune inflammation, we studied the development of the lupus phenotype in Lyn-deficient (Lyn^-/-) mice in which GILZ expression was genetically ablated. In Lyn^-/- mice, splenomegaly, glomerulonephritis, anti-dsDNA antibody titres and cytokine expression were exacerbated by GILZ deficiency, while other autoantibody titres and glomerular immune complex deposition were unaffected. Likewise, in patients with SLE, GILZ was inversely correlated with IL23A, and in SLE patients not taking glucocorticoids, GILZ was also inversely correlated with BAFF and IL18. This suggests that at the onset of autoimmunity, GILZ protects against tissue injury by modulating pro-inflammatory pathways, downstream of antibodies, to regulate the cycle of inflammation in SLE.

Novel signatures associated with systemic lupus erythematosus clinical response to IFN-α/-ω inhibition

OBJECTIVES

We aimed to identify transcriptional gene signatures predictive of clinical response, for pharmacodynamic evaluation, and to provide mechanistic insight into JNJ-55920839, a human IgG1κ neutralizing mAb targeting IFN-α/IFN-ω, in participants with systemic lupus erythematosus (SLE).

METHODS

Blood samples were obtained from SLE participants at baseline and up to Day 130, who received six 10 mg/kg IV doses of JNJ-55920839/placebo every 2 weeks. Participants with mild-to-moderate SLE who achieved clinical responses using SLE Disease Activity Index 2000 Responder Index 4-point change were considered responders. Transcriptional signatures from longitudinally collected blood were generated by RNA-Seq; signatures were generated by microarray from baseline blood samples exposed in vitro to JNJ-55920839 versus untreated.

RESULTS

Two gene signatures (IFN-I Signaling and Immunoglobulin Immune Response) exhibited pharmacodynamic changes among JNJ-55920839 responders. The Immunoglobulin signature, but not the IFN-I signature, was elevated at baseline in JNJ-55920839 responders. A gene cluster associated with neutrophil-mediated immunity was reduced at baseline in JNJ-55920839 responders, substantiated by lower neutrophil counts in responders. An IFN-I signature was suppressed by JNJ-55920839 in vitro treatment versus untreated blood to a greater extent in responders before in vivo dosing.

CONCLUSIONS

These signatures may enable enrichment for treatment responders when using IFN-I-suppressing treatments in SLE.

Identification of highly active systemic lupus erythematosus by combined type I interferon and neutrophil gene scores vs classical serologic markers

OBJECTIVES

In SLE, heterogeneous clinical expression and activity may reflect diverse pathogenic and/or effector mechanisms. We investigated SLE heterogeneity by assessing the expression of three gene sets representative of type I IFN (IFN-I), polymorphonuclear neutrophil (PMN) and plasmablast (PB) signatures in a well-characterized, multidisciplinary cohort of SLE patients. We further assessed whether individual gene products could be representative of these three signatures.

METHODS

Whole blood, serum and clinical data were obtained from 140 SLE individuals. Gene expression was assessed by NanoString technology, using a panel of 37 probes to compute six IFN-I, one PMN and one PB scores. Protein levels were measured by ELISA.

RESULTS

Depending on the score, 45-50% of SLE individuals showed high IFN-I gene expression. All six IFN-I scores were significantly associated with active skin involvement, and two of six were associated with arthritis. IFN-induced Mx1 protein (MX1) level was correlated with IFN-I score (P < 0.0001) and associated with a similar clinical phenotype. In all, 25% of SLE individuals showed high PMN gene expression, associated with SLE fever, serositis, leukopoenia and glucocorticoid use. PB gene expression was highly affected by immunosuppressant agents, with no association with SLE features. Combined IFN-I and PMN gene scores were significantly associated with high disease activity and outperformed anti-dsDNA and anti-C1q autoantibody and complement levels for predicting SLE activity.

CONCLUSION

IFN-I and PMN gene scores segregate with distinct SLE clinical features, and their combination may identify high disease activity. MX1 protein level performed similar to IFN-I gene expression.

Low G0S2 gene expression levels in peripheral blood may be a genetic marker of acute myocardial infarction in patients with stable coronary atherosclerotic disease: A retrospective clinical study

BACKGROUND

The G0/G1 switch 2 (G0S2) gene is closely related to lipolysis, cell proliferation, apoptosis, oxidative phosphorylation, and the development of a variety of tumors. The aim of the present study was to expand the sample size to confirm the relationship between the expression of the G0S2 gene in peripheral blood and acute myocardial infarction (AMI) based on previous gene chip results.

METHODS

Three hundred patients were initially selected, of which 133 were excluded in accordance with the exclusion criteria. Peripheral blood leukocytes were collected from 92 patients with AMI and 75 patients with stable coronary atherosclerotic disease (CAD). mRNA expression levels of G0S2 in peripheral blood leukocytes was measured by RT-PCR, and protein expression levels by Western blot analysis. The results of these assays in the 2 groups were compared.

RESULTS

mRNA expression levels of GOS2 in the peripheral blood leukocytes of patients with AMI were 0.41-fold lower than those of patients with stable CAD (P < .05), and GOS2 protein expression levels were 0.45-fold lower. Multivariate logistic regression analysis indicated that low expression levels of the G0S2 gene increased the risk of AMI by 2.08-fold in stable CAD patients.

CONCLUSIONS

G0S2 gene expression in the peripheral blood leukocytes of AMI patients was lower than that of stable CAD patients. Low G0S2 gene expression in peripheral blood leukocytes is an independent risk factor for AMI in stable CAD patients.

B Cells and Antibodies as Targets of Therapeutic Intervention in Neuromyelitis Optica Spectrum Disorders

The first description of neuromyelitis optica by Eugène Devic and Fernand Gault dates back to the 19th century, but only the discovery of aquaporin-4 autoantibodies in a major subset of affected patients in 2004 led to a fundamentally revised disease concept: Neuromyelits optica spectrum disorders (NMOSD) are now considered autoantibody-mediated autoimmune diseases, bringing the pivotal pathogenetic role of B cells and plasma cells into focus. Not long ago, there was no approved medication for this deleterious disease and off-label therapies were the only treatment options for affected patients. Within the last years, there has been a tremendous development of novel therapies with diverse treatment strategies: immunosuppression, B cell depletion, complement factor antagonism and interleukin-6 receptor blockage were shown to be effective and promising therapeutic interventions. This has led to the long-expected official approval of eculizumab in 2019 and inebilizumab in 2020. In this article, we review current pathogenetic concepts in NMOSD with a focus on the role of B cells and autoantibodies as major contributors to the propagation of these diseases. Lastly, by highlighting promising experimental and future treatment options, we aim to round up the current state of knowledge on the therapeutic arsenal in NMOSD.

Pharmacokinetics and Pharmacodynamics of JNJ-55920839, an Antibody Targeting Interferon α/ω, in Healthy Subjects and Subjects with Mild-to-Moderate Systemic Lupus Erythematosus

BACKGROUND

The interferon (IFN) pathway has been correlated with clinical and serological markers of disease activity in patients with systemic lupus erythematosus (SLE).

OBJECTIVE

The pharmacokinetics and pharmacodynamics of JNJ-55920839, a fully human immunoglobulin G1κ antibody targeting IFNα/ω, were investigated.

METHODS

In a double-blind, first-in-human study, Part A enrolled 48 healthy adults who received a single dose of placebo/JNJ-55920839 between 0.3 and 15 mg/kg intravenous (IV) or at 1 mg/kg subcutaneous (SC). Part B enrolled 26 adults with SLE who received placebo or JNJ-55920839 10 mg/kg IV 6 times biweekly. Pharmacokinetic parameters were calculated by noncompartmental analysis (NCA) and estimated by nonlinear mixed-effects modeling.

RESULTS

JNJ-55920839 pharmacokinetics following a single IV infusion exhibited a biphasic disposition in healthy subjects. Maximum plasma concentration (C_max) and area under the concentration-time curve values increased dose-proportionally. Mean clearance (CL) after a single IV infusion ranged between 2.28 and 3.09 mL/kg/day. Absolute bioavailability after a single SC injection was ≥ 80.0%. Mean terminal elimination half-life (t_1/2) was similar after IV (20.7 to 24.6 days) and SC administration (22.6 days). Steady state of JNJ-55920839 was achieved 6 weeks after multiple 10 mg/kg IV doses in subjects with SLE. Mean steady-state CL and t_1/2 were 4.73 mL/kg/day and 14.8 days, respectively. A linear 2-compartment population pharmacokinetic model with 1st-order absorption and elimination adequately characterized the pharmacokinetics; parameters were consistent with NCA estimates. Higher CL was estimated in subjects with SLE compared with healthy subjects, after correcting for body weight. A trend of increased total IFNα/ω levels was observed after treatment with JNJ-55920839.

CONCLUSION

Pharmacokinetic and pharmacodynamic analyses of the data from this study demonstrated that there was biphasic disposition in both healthy subjects and subjects with SLE, CL was faster in subjects with SLE, and increases in total IFNα/ω levels were observed in both healthy subjects and subjects with SLE after treatment with JNJ-55920839, thus further development is supported. The study is registered at ClinicalTrials.gov NCT02609789.

Baricitinib-associated changes in global gene expression during a 24-week phase II clinical systemic lupus erythematosus trial implicates a mechanism of action through multiple immune-related pathways

OBJECTIVE

To characterise the molecular pathways impacted by the pharmacologic effects of the Janus kinase (JAK) 1 and JAK2 inhibitor baricitinib in SLE.

METHODS

In a phase II, 24-week, randomised, placebo-controlled, double-blind study (JAHH), RNA was isolated from whole blood in 274 patients and analysed using Affymetrix HTA2.0 array. Serum cytokines were measured using ultrasensitive quantitative assays.

RESULTS

Gene expression profiling demonstrated an elevation of STAT1, STAT2 and multiple interferon (IFN) responsive genes at baseline in patients with SLE. Statistical and gene network analyses demonstrated that baricitinib treatment reduced the mRNA expression of functionally interconnected genes involved in SLE including STAT1-target, STAT2-target and STAT4-target genes and multiple IFN responsive genes. At baseline, serum cytokines IFN-α, IFN-γ, interleukin (IL)-12p40 and IL-6 were measurable and elevated above healthy controls. Treatment with baricitinib significantly decreased serum IL-12p40 and IL-6 cytokine levels at week 12, which persisted through week 24.

CONCLUSION

Baricitinib treatment induced significant reduction in the RNA expression of a network of genes associated with the JAK/STAT pathway, cytokine signalling and SLE pathogenesis. Baricitinib consistently reduced serum levels of two key cytokines implicated in SLE pathogenesis, IL-12p40 and IL-6.

First-in-Human study of JNJ-55920839 in healthy volunteers and patients with systemic lupus erythematosus: a randomised placebo-controlled phase 1 trial

BACKGROUND

Activation of the type I interferon (IFN) pathway is associated with systemic lupus erythematosus (SLE). We assessed the safety and tolerability of JNJ-55920839, a human monoclonal antibody that selectively neutralises most human IFNα subtypes and IFNω, in healthy participants and those with SLE.

METHODS

This was a two-part, first-in-human, phase 1, randomised, double-blind, placebo-controlled, multicentre study of single-ascending intravenous doses of 0·3-15 mg/kg or a single subcutaneous dose of 1 mg/kg JNJ-55920839 administered to healthy participants (part A) and multiple intravenous doses of 10 mg/kg JNJ-55920839 administered to participants with SLE (part B). Healthy men and women (women had to be postmenopausal or surgically sterile) aged 18-55 years; bodyweight of 50-90 kg; and body-mass index (BMI) of 18-30 kg/m2 were eligible for inclusion in part A. Men and women with SLE were recruited to part B, fertile female participants were required to have a negative pregnancy test result before and during the study and be using two highly effective methods of birth control. The inclusion criteria for participants with SLE in part B matched part A, except for bodyweight (40-100 kg). In both parts, participants were randomly assigned (3:1) to receive JNJ-55920839 or placebo; a computer-generated randomisation schedule was used in part A, and randomisation was stratified by racial and ethnic subpopulation and elevated levels of serological disease activity in part B. The primary outcome was evaluation of safety and tolerability of the study regimen assessed using clinical and laboratory tests compared with placebo. This study is registered with ClinicalTrials.gov, NCT02609789.

FINDINGS

Between Dec 11, 2015, and Sept 20, 2018, 48 healthy participants from a single site and 28 participants with mild-to-moderate SLE from 19 participating centres in seven countries were enrolled in the study. 12 healthy volunteers in part A and eight participants with SLE in part B received placebo. The most common treatment-emergent adverse events in both part A and B were in the system organ class of infections and infestations with a higher percentage of participants administered JNJ-55920839 with infections (ten [28%] of 36 in part A and nine [50%] of 18 in part B) than those exposed to placebo (two [17%] of 12 in part A and one [13%] of eight in part B). Particpants in part B were permitted to continue on defined ongoing standard of care medications. In two participants with SLE, locally disseminated herpes zoster of the skin was reported. No other clinically significant safety or tolerability issues were identified beyond the infections observed in participants treated with JNJ-55920839.

INTERPRETATION

JNJ-55920839 was well tolerated and safe. Additional studies are warranted to determine optimal dosing of patients and further explore safety.

FUNDING

Janssen.

New era of therapy for endocrine autoimmune disorders

The new era of immune and reconstitution therapy of autoimmune disorders is ongoing. However, endocrine autoimmune diseases comprise a group of elaborating pathologies where the development of new treatment strategies remains slow. Substitution of the missing hormones is still standard practice, taking care of the devastating symptoms but not the cause of disease. As our knowledge of the genetic contribution to the aetiology of endocrine disorders increases and early diagnostic tools are available, it is now possible to identify persons at risk before they acquire full-blown disease. This review summarizes current knowledge and treatment of endocrine autoimmune disorders, focusing on type 1 diabetes, Addison's disease, autoimmune thyroid diseases and primary ovarian insufficiency. We explore which new therapies might be used in the different stages of the disease, focus on legalized therapy and elaborate on the ongoing clinical studies for these diseases and the research front, before hypothesizing on the way ahead.

Patient ancestry significantly contributes to molecular heterogeneity of systemic lupus erythematosus

Gene expression signatures can stratify patients with heterogeneous diseases, such as systemic lupus erythematosus (SLE), yet understanding the contributions of ancestral background to this heterogeneity is not well understood. We hypothesized that ancestry would significantly influence gene expression signatures and measured 34 gene modules in 1566 SLE patients of African ancestry (AA), European ancestry (EA), or Native American ancestry (NAA). Healthy subject ancestry-specific gene expression provided the transcriptomic background upon which the SLE patient signatures were built. Although standard therapy affected every gene signature and significantly increased myeloid cell signatures, logistic regression analysis determined that ancestral background significantly changed 23 of 34 gene signatures. Additionally, the strongest association to gene expression changes was found with autoantibodies, and this also had etiology in ancestry: the AA predisposition to have both RNP and dsDNA autoantibodies compared with EA predisposition to have only anti-dsDNA. A machine learning approach was used to determine a gene signature characteristic to distinguish AA SLE and was most influenced by genes characteristic of the perturbed B cell axis in AA SLE patients.

Transcriptional profiling of lupus patients and healthy controls reveals ancestry-related differences and transcriptional heterogeneity among lupus patients.

Genome-wide whole blood transcriptome profiling in a large European cohort of systemic sclerosis patients

Objectives

The analysis of annotated transcripts from genome-wide expression studies may help to understand the pathogenesis of complex diseases, such as systemic sclerosis (SSc). We performed a whole blood (WB) transcriptome analysis on RNA collected in the context of the European PRECISESADS project, aiming at characterising the pathways that differentiate SSc from controls and that are reproducible in geographically diverse populations.

Methods

Samples from 162 patients and 252 controls were collected in RNA stabilisers. Cases and controls were divided into a discovery (n=79+163; Southern Europe) and validation cohort (n=83+89; Central-Western Europe). RNA sequencing was performed by an Illumina assay. Functional annotations of Reactome pathways were performed with the Functional Analysis of Individual Microarray Expression (FAIME) algorithm. In parallel, immunophenotyping of 28 circulating cell populations was performed. We tested the presence of differentially expressed genes/pathways and the correlation between absolute cell counts and RNA transcripts/FAIME scores in regression models. Results significant in both populations were considered as replicated.

Results

Overall, 15 224 genes and 1277 functional pathways were available; of these, 99 and 225 were significant in both sets. Among replicated pathways, we found a deregulation in type-I interferon, Toll-like receptor cascade, tumour suppressor p53 protein function, platelet degranulation and activation. RNA transcripts or FAIME scores were jointly correlated with cell subtypes with strong geographical differences; neutrophils were the major determinant of gene expression in SSc-WB samples.

Conclusions

We discovered a set of differentially expressed genes/pathways validated in two independent sets of patients with SSc, highlighting a number of deregulated processes that have relevance for the pathogenesis of autoimmunity and SSc.

Integrated, multicohort analysis reveals unified signature of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disease that follows an unpredictable disease course and affects multiple organs and tissues. We performed an integrated, multicohort analysis of 7,471 transcriptomic profiles from 40 independent studies to identify robust gene expression changes associated with SLE. We identified a 93-gene signature (SLE MetaSignature) that is differentially expressed in the blood of patients with SLE compared with healthy volunteers; distinguishes SLE from other autoimmune, inflammatory, and infectious diseases; and persists across diverse tissues and cell types. The SLE MetaSignature correlated significantly with disease activity and other clinical measures of inflammation. We prospectively validated the SLE MetaSignature in an independent cohort of pediatric patients with SLE using a microfluidic quantitative PCR (qPCR) array. We found that 14 of the 93 genes in the SLE MetaSignature were independent of IFN-induced and neutrophil-related transcriptional profiles that have previously been associated with SLE. Pathway analysis revealed dysregulation associated with nucleic acid biosynthesis and immunometabolism in SLE. We further refined a neutropoiesis signature and identified underappreciated transcripts related to immune cells and oxidative stress. In our multicohort, transcriptomic analysis has uncovered underappreciated genes and pathways associated with SLE pathogenesis, with the potential to advance clinical diagnosis, biomarker development, and targeted therapeutics for SLE.

A Bayesian gene network reveals insight into the JAK-STAT pathway in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic, remitting, and relapsing, inflammatory disease involving multiple organs, which exhibits abnormalities of both the innate and adaptive immune responses. A limited number of transcriptomic studies have characterized the gene pathways involved in SLE in an attempt to identify the key pathogenic drivers of the disease. In order to further advance our understanding of the pathogenesis of SLE, we used a novel Bayesian network algorithm to hybridize knowledge- and data-driven methods, and then applied the algorithm to build an SLE gene network using transcriptomic data from 1,760 SLE patients’ RNA from the two tabalumab Phase III trials (ILLUMINATE-I & -II), the largest SLE RNA dataset to date. Further, based on the gene network, we carried out hub- and key driver-gene analyses for gene prioritization. Our analyses identified that the JAK-STAT pathway genes, including JAK2, STAT1, and STAT2, played essential roles in SLE pathogenesis, and reaffirmed the recent discovery of pathogenic relevance of JAK-STAT signaling in SLE. Additionally, we showed that other genes, such as IRF1, IRF7, PDIA4, FAM72C, TNFSF10, DHX58, SIGLEC1, and PML, may be also important in SLE and serve as potential therapeutic targets for SLE. In summary, using a hybridized network construction approach, we systematically investigated gene-gene interactions based on their transcriptomic profiles, prioritized genes based on their importance in the network structure, and revealed new insights into SLE activity.

The pathogenesis of systemic lupus erythematosus: Harnessing big data to understand the molecular basis of lupus

Systemic lupus erythematosus (SLE) is a chronic, systemic autoimmune disease that causes damage to multiple organ systems. Despite decades of research and available murine models that capture some aspects of the human disease, new treatments for SLE lag behind other autoimmune diseases such as Rheumatoid Arthritis and Crohn's disease. Big data genomic assays have transformed our understanding of SLE by providing important insights into the molecular heterogeneity of this multigenic disease. Gene wide association studies have demonstrated more than 100 risk loci, supporting a model of multiple genetic hits increasing SLE risk in a non-linear fashion, and providing evidence of ancestral diversity in susceptibility loci. Epigenetic studies to determine the role of methylation, acetylation and non-coding RNAs have provided new understanding of the modulation of gene expression in SLE patients and identified new drug targets and biomarkers for SLE. Gene expression profiling has led to a greater understanding of the role of myeloid cells in the pathogenesis of SLE, confirmed roles for T and B cells in SLE, promoted clinical trials based on the prominent interferon signature found in SLE patients, and identified candidate biomarkers and cellular signatures to further drug development and drug repurposing. Gene expression studies are advancing our understanding of the underlying molecular heterogeneity in SLE and providing hope that patient stratification will expedite new therapies based on personal molecular signatures. Although big data analyses present unique interpretation challenges, both computationally and biologically, advances in machine learning applications may facilitate the ability to predict changes in SLE disease activity and optimize therapeutic strategies.

BAFF inhibition in SLE-Is tolerance restored?

The B cell activating factor (BAFF) inhibitor, belimumab, is the first biologic drug approved for the treatment of SLE, and exhibits modest, but durable, efficacy in decreasing disease flares and organ damage. BAFF and its homolog APRIL are TNF-like cytokines that support the survival and differentiation of B cells at distinct developmental stages. BAFF is a crucial survival factor for transitional and mature B cells that acts as rheostat for the maturation of low-affinity autoreactive cells. In addition, BAFF augments innate B cell responses via complex interactions with the B cell receptor (BCR) and Toll like receptor (TLR) pathways. In this manner, BAFF impacts autoreactive B cell activation via extrafollicular pathways and fine tunes affinity selection within germinal centers (GC). Finally, BAFF and APRIL support plasma cell survival, with differential impacts on IgM- and IgG-producing populations. Therapeutically, BAFF and combined BAFF/APRIL inhibition delays disease onset in diverse murine lupus strains, although responsiveness to BAFF inhibition is model dependent, in keeping with heterogeneity in clinical responses to belimumab treatment in humans. In this review, we discuss the mechanisms whereby BAFF/APRIL signals promote autoreactive B cell activation, discuss whether altered selection accounts for therapeutic benefits of BAFF inhibition, and address whether new insights into BAFF/APRIL family complexity can be exploited to improve human lupus treatments.

Granulocytic myeloid-derived suppressor cells contribute to IFN-I signaling activation of B cells and disease progression through the lncRNA NEAT1-BAFF axis in systemic lupus erythematosus

Activation of interferon (IFN)-I signaling in B cells contributes to the pathogenesis of systemic lupus erythematosus (SLE). Recent studies have shown that myeloid-derived suppressor cells (MDSCs) significantly expand in SLE patients and lupus-prone MRL/lpr mice and contribute to the pathogenesis of SLE. However, the role of SLE-derived MDSCs in regulating IFN-I signaling activation of B cells remains unknown. Here, we demonstrate that expansions of MDSCs, including granulocyte (G)-MDSCs and monocytic (M)-MDSCs, during the progression of SLE were correlated with the IFN-I signature of B cells. Interestingly, G-MDSCs from MRL/lpr mice, but not M-MDSCs, could significantly promote IFN-I signaling activation of B cells and contribute to the pathogenesis of SLE. Mechanistically, we identified that the long non-coding RNA NEAT1 was over-expressed in G-MDSCs from MRL/lpr mice and could induce the promotion of G-MDSCs on IFN-I signaling activation of B cells through B cell-activating factor (BAFF) secretion. Importantly, NEAT1 deficiency significantly attenuated the lupus symptoms in pristane-induced lupus mice. In addition, there was a positive correlation between NEAT1 and BAFF with the IFN signature in SLE patients. In conclusion, G-MDSCs may contribute to the IFN signature in SLE B cells through the NEAT1-BAFF axis, highlighting G-MDSCs as a potential therapeutic target to treat SLE.

Spotlight on anifrolumab and its potential for the treatment of moderate-to-severe systemic lupus erythematosus: evidence to date

Previous reports have described the appearance of systemic lupus erythematosus (SLE) cases following interferon-α (IFN-α) therapy, IFN-regulated gene expression is significantly increased in SLE, and an association between SLE and gene variants belonging to IFN downstream pathways has been shown. Based on this, targeting of IFN and of their signaling pathways has appeared to be interesting developments within the field of SLE therapy. Different specific type I IFN antagonists have been studied in clinical trials and some of those have already reached Phase III. A potential approach would be to target IFN receptors rather than IFN themselves. Anifrolumab (previously MEDI-546) is a fully human monoclonal antibody (Ab) that binds to subunit 1 of the type I IFN receptor (IFNAR1), blocking the action of different type I IFNs (IFN-α, IFN-β and IFN-ω). This drug has been assessed in 11 clinical studies: 9 in SLE, 1 in systemic sclerosis and 1 in rheumatoid arthritis. In SLE, clinical development reached Phase I for 1 study and Phases II and III for 5 and 3 trials, respectively. The Phase IIb, randomized control trial (RCT), double-blind, placebo-controlled study of adults with moderate-to-severe SLE (MUSE trial) showed positive results on the composite primary endpoint SRI-4. Greater efficacy was seen in patients with high baseline IFN gene signature compared with those with low baseline IFN gene signature. Anifrolumab also demonstrated promising results on cutaneous and arthritic manifestations, especially among patients with a high IFN gene signature. The pivotal Treatment of Uncontrolled Lupus via the Interferon IFN Pathway (TULIP 1 and 2 studies are now completed. In August 2018, the promoter announced that the TULIP 1 Phase III trial did not reach its primary endpoint. The release of the completed but not yet published Phase II studies and of the TULIP pivotal trials results will further inform us on the actual therapeutic potential of anifrolumab.

Aberrant expression of alternative splicing variants in multiple sclerosis - A systematic review

OBJECTIVE

Alternative splicing is an important form of RNA processing that affects nearly all human genes. The differential expression of specific transcript and protein isoforms holds the potential of novel biomarkers for complex diseases. In this systematic review, we compiled the existing literature on aberrant alternative splicing events in multiple sclerosis (MS).

METHODS

A systematic literature search in the PubMed database was carried out and supplemented by screening the reference lists of the identified articles. We selected only MS-related original research studies which compared the levels of different isoforms of human protein-coding genes. A narrative synthesis of the research findings was conducted. Additionally, we performed a case-control analysis using high-density transcriptome microarray data to reevaluate the genes that were examined in the reviewed studies.

RESULTS

A total of 160 records were screened. Of those, 36 studies from the last two decades were included. Most commonly, peripheral blood samples were analyzed (32 studies), and PCR-based techniques were usually employed (27 studies) for measuring the expression of selected genes. Two studies used an exploratory genome-wide approach. Overall, 27 alternatively spliced genes were investigated. Nine of these genes appeared in at least two studies (CD40, CFLAR, FOXP3, IFNAR2, IL7R, MOG, PTPRC, SP140 and TNFRSF1A). The microarray data analysis confirmed differential alternative pre-mRNA splicing for 19 genes.

CONCLUSIONS

An altered RNA processing of genes mediating immune signaling pathways has been repeatedly implicated in MS. The analysis of individual exon-level expression patterns is stimulated by the advancement of transcriptome profiling technologies. In particular, the examination of genes encoded in MS-associated genetic regions may provide important insights into the pathogenesis of the disease and help to identify new biomarkers.

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

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

Superiority of combining two independent trials in interim futility analysis

Traditionally, statistical methods for futility analysis are developed based on a single study. To establish a drug's effectiveness, usually at least two adequate and well-controlled studies need to demonstrate convincing evidence on its own. Therefore, in a standard clinical development program in chronic diseases, two independent studies are generally conducted for drug registration. This paper proposes a statistical method to combine interim data from two independent and similar studies for interim futility analysis and shows that the conditional power approach based on combined interim data has better operating characteristics compared to the approach based on single-trial interim data, even with small to moderate heterogeneity on the treatment effects between the two studies.

Galectin-9 is an easy to measure biomarker for the interferon signature in systemic lupus erythematosus and antiphospholipid syndrome

Objective

The interferon (IFN) signature is related to disease activity and vascular disease in systemic lupus erythematosus (SLE) and antiphospholipid syndrome (APS) and represents a promising therapeutic target. Quantification of the IFN signature is currently performed by gene expression analysis, limiting its current applicability in clinical practice. Therefore, the objective of this study was to establish an easy to measure biomarker for the IFN signature.

Methods

Serum levels of galectin-9, CXCL-10 (IP-10) and tumour necrosis factor receptor type II (TNF-RII) were measured in patients with SLE, SLE+APS and primary APS (PAPS) and healthy controls (n=148) after an initial screening of serum analytes in a smaller cohort (n=43). Analytes were correlated to measures of disease activity and the IFN signature. The performance of galectin-9, CXCL-10 and TNF-RII as biomarkers to detect the IFN signature was assessed by receiver operating characteristic curves.

Results

Galectin-9, CXCL-10 and TNF-RII were elevated in patients with SLE, SLE+APS and PAPS (p<0.05) and correlated with disease activity and tissue factor expression. Galectin-9 correlated stronger than CXCL-10 or TNF-RII with the IFN score (r=0.70, p<0.001) and was superior to CXCL-10 or TNF-RII in detecting the IFN signature (area under the curve (AUC) 0.86). Importantly, in patients with SLE(±APS), galectin-9 was also superior to anti-dsDNA antibody (AUC 0.70), or complement C3 (AUC 0.70) and C4 (AUC 0.78) levels in detecting the IFN signature.

Conclusion

Galectin-9 is a novel, easy to measure hence clinically applicable biomarker to detect the IFN signature in patients with systemic autoimmune diseases such as SLE and APS.