Chimeric antigens displaying GPR65 extracellular loops on a soluble scaffold enabled the discovery of antibodies, which recognized native receptor

GPR65 is a proton-sensing G-protein coupled receptor associated with multiple immune-mediated inflammatory diseases, whose function is relatively poorly understood. With few reagents commercially available to probe the biology of receptor, generation of an anti-GPR65 monoclonal antibody was desired. Using soluble chimeric scaffolds, such as ApoE3, displaying the extracellular loops of GPR65, together with established phage display technology, native GPR65 loop-specific antibodies were identified. Phage-derived loop-binding antibodies recognized the wild-type native receptor to which they had not previously been exposed, generating confidence in the use of chimeric soluble proteins to act as efficient surrogates for membrane protein extracellular loop antigens. This technique provides promise for the rational design of chimeric antigens in facilitating the discovery of specific antibodies to GPCRs.

Type I interferon blockade with anifrolumab in patients with systemic lupus erythematosus modulates key immunopathological pathways in a gene expression and proteomic analysis of two phase 3 trials

INTRODUCTION

Anifrolumab is a type I interferon (IFN) receptor 1 (IFNAR1) blocking antibody approved for treating patients with systemic lupus erythematosus (SLE). Here, we investigated the immunomodulatory mechanisms of anifrolumab using longitudinal transcriptomic and proteomic analyses of the 52-week, randomised, phase 3 TULIP-1 and TULIP-2 trials.

METHODS

Patients with moderate to severe SLE were enrolled in TULIP-1 and TULIP-2 and received intravenous anifrolumab or placebo alongside standard therapy. Whole-blood expression of 18 017 genes using genome-wide RNA sequencing (RNA-seq) (pooled TULIP; anifrolumab, n=244; placebo, n=258) and 184 plasma proteins using Olink and Simoa panels (TULIP-1; anifrolumab, n=124; placebo, n=132) were analysed. We compared treatment groups via gene set enrichment analysis using MetaBase pathway analysis, blood transcriptome modules, in silico deconvolution of RNA-seq and longitudinal linear mixed effect models for gene counts and protein levels.

RESULTS

Compared with placebo, anifrolumab modulated >2000 genes by week 24, with overlapping results at week 52, and 41 proteins by week 52. IFNAR1 blockade with anifrolumab downregulated multiple type I and II IFN-induced gene modules/pathways and type III IFN-λ protein levels, and impacted apoptosis-associated and neutrophil extracellular traps-(NET)osis-associated transcriptional pathways, innate cell activating chemokines and receptors, proinflammatory cytokines and B-cell activating cytokines. In silico deconvolution of RNA-seq data indicated an increase from baseline of mucosal-associated invariant and γδT cells and a decrease of monocytes following anifrolumab treatment.

DISCUSSION

Type I IFN blockade with anifrolumab modulated multiple inflammatory pathways downstream of type I IFN signalling, including apoptotic, innate and adaptive mechanisms that play key roles in SLE immunopathogenesis.

Characterization of the genetic determinants of context-specific DNA methylation in primary monocytes

To better understand inter-individual variation in sensitivity of DNA methylation (DNAm) to immune activity, we characterized effects of inflammatory stimuli on primary monocyte DNAm (n = 190). We find that monocyte DNAm is site-dependently sensitive to lipopolysaccharide (LPS), with LPS-induced demethylation occurring following hydroxymethylation. We identify 7,359 high-confidence immune-modulated CpGs (imCpGs) that differ in genomic localization and transcription factor usage according to whether they represent a gain or loss in DNAm. Demethylated imCpGs are profoundly enriched for enhancers and colocalize to genes enriched for disease associations, especially cancer. DNAm is age associated, and we find that 24-h LPS exposure triggers approximately 6 months of gain in epigenetic age, directly linking epigenetic aging with innate immune activity. By integrating LPS-induced changes in DNAm with genetic variation, we identify 234 imCpGs under local genetic control. Exploring shared causal loci between LPS-induced DNAm responses and human disease traits highlights examples of disease-associated loci that modulate imCpG formation.

Targeting DORIS Remission and LLDAS in SLE: A Review

Remission is the established therapeutic goal for patients with systemic lupus erythematosus (SLE) and is currently defined by the widely adopted Definition Of Remission In SLE (DORIS) criteria. Attainment of remission is rare in the clinical setting, thus an alternative, pragmatic treatment target of low disease activity, as defined by the Lupus Low Disease Activity State (LLDAS), provides a less stringent and more attainable treatment goal for a wider proportion of patients compared with DORIS remission. Randomized controlled trials and real-world analyses have confirmed the positive clinical benefits of achieving either DORIS remission or LLDAS. The treat-to-target (T2T) approach utilizes practical clinical targets to proactively tailor individual treatment regimens. Studies in other chronic inflammatory diseases using the T2T approach demonstrated significantly improved clinical outcomes and quality-of-life measures compared with established standard of care. However, such trials have not yet been performed in patients with SLE. Here we review the evolution of DORIS remission and LLDAS definitions and the evidence supporting the positive clinical outcomes following DORIS remission or LLDAS attainment, before discussing considerations for implementation of these outcome measures as potential T2T objectives. Adoption of DORIS remission and LLDAS treatment goals may result in favorable patient outcomes compared with established standard of care for patients with SLE.

Optimising psoriatic arthritis therapy with immunological methods to increase standard evaluation: the protocol of an open-label multicentre, parallel-group, two-arm randomised controlled study evaluation precision medicine approach in the treatment of psoriatic arthritis

INTRODUCTION

Psoriatic arthritis (PsA) affects around 150 000 people in the UK of whom around 50% require treatment with biologics. The most used biologics for PsA target tumour necrosis factor (TNF) or interleukin-17A (IL-17A). About 50% of patients respond to each, but it is not currently possible to predict response for individual patients, necessitating sequential treatment steps. A recent proof of concept study in PsA suggested that using peripheral immunophenotype to choose therapy could improve time to treatment response.This study will test the hypothesis, within an open-label parallel-group biomarker-stratified multicentre randomised controlled trial, which the baseline proportion of CD4+T cells with an activated type 17 immunophenotype (Th17 levels) predicts response to IL-17A or TNF inhibitors in PsA. Additional analyses will identify if the model can be refined by combining additional clinical and immunophenotypic factors. Statistical modelling will be used to predict the likely effectiveness of these approaches compared with standard care.

METHODS AND ANALYSIS

Patients with PsA eligible to start their first biologic as part of standard care are recruited and baseline blood tests are taken for immunophenotyping. Participants are stratified equally by Th17 levels and randomised 1:1 to receive either TNF (adalimumab) or IL-17A (secukinumab) inhibitors. The primary analysis will establish the interaction between baseline immunophenotype and treatment on the primary outcome (achievement of minimal disease activity criteria at week 24). In secondary analysis, modelling will identify if this prediction model can be optimised further by incorporating clinical phenotypes and additional immunophenotyping techniques.

ETHICS AND DISSEMINATION

Ethical approval for the study was granted by the North West Preston Research Ethics Committee (ref 21/NW/0016). Dissemination will be via conference presentations and peer-reviewed publications, aiming to impact on treatment guidelines.

TRIAL REGISTRATION NUMBER

ISRCTN17228602.

The long-term safety and tolerability of anifrolumab for patients with systemic lupus erythematosus in Japan: TULIP-LTE subgroup analysis

OBJECTIVES

Evaluate the long-term safety and tolerability of anifrolumab 300 mg, alongside standard therapy, in patients from Japan with systemic lupus erythematosus (SLE) in the TULIP-LTE trial (NCT02794285).

METHODS

TULIP-LTE was a 3-year, randomized, double-blind, placebo-controlled long-term extension (LTE) of the TULIP trials. The primary safety outcome included serious adverse events (SAEs) and AEs of special interest (AESIs) during the LTE period. Exploratory efficacy outcomes included SLE Disease Activity Index 2000 (SLEDAI-2K) scores and glucocorticoid use. We performed a post hoc subgroup analysis of patients who enrolled in Japan.

RESULTS

Exposure-adjusted incidence rates of SAEs during the LTE and follow-up for patients receiving anifrolumab 300 mg (n=21) were 8.7 per 100 patient-years; AESIs included influenza (6.9) and herpes zoster (3.5). One of three patients receiving placebo had an SAE (13.9). One patient per group discontinued due to an AE. There were no deaths. During the TULIP+LTE period, patients receiving anifrolumab 300 mg (n=24) had sustained reduction from baseline in mean SLEDAI-2K scores and cumulative glucocorticoid dosage.

CONCLUSIONS

Anifrolumab 300 mg showed a favourable benefit-risk profile for the long-term treatment of adult patients with moderate to severe SLE from Japan, with safety, tolerability, and efficacy profiles consistent with the overall population.

Differential regulation of IL-17A and IL-17F via STAT5 contributes to psoriatic disease

BACKGROUND

IL-17A plays a pivotal pathogenic role in several immune-mediated inflammatory diseases. Despite sharing 50% sequence homology with IL-17A, the role of IL-17F remains less clear. Clinical findings suggest that dual inhibition of IL-17A and IL-17F in psoriatic disease is more efficacious than IL-17A inhibition alone, positing a pathogenic role for IL-17F.

OBJECTIVE

We characterized the regulation of IL-17A and IL-17F in psoriatic disease.

METHODS

Using both in vitro systems and lesional skin tissue from patients, we interrogated the chromosomal, transcriptional, and protein expression landscape of IL-17A+ and IL-17F+ TH17 cells. Alongside established assays such as single-cell RNA sequencing, we developed a novel cytokine-capture technique that was combined with chromatin immunoprecipitation sequencing and RNA sequencing.

RESULTS

We confirm a preferential elevation of IL-17F over IL-17A in psoriatic disease and show that expression of each isoform predominantly occurs in distinct cell populations. The expression of both IL-17A and IL-17F exhibited a high degree of plasticity, with the balance between the 2 isoforms influenced by proinflammatory signaling and by anti-inflammatory drugs such as methylprednisolone. This plasticity was reflected in a broad H3K4me3 region at the IL17A-F locus, while opposing effects of STAT5/IL-2 signaling were observed for each of the 2 genes. Functionally, higher IL17F expression was linked to greater cell proliferation.

CONCLUSION

There are key differences in the regulation of IL-17A and IL-17F in psoriatic disease, leading to distinct inflammatory cell populations. As such, we propose that both IL-17A and IL-17F neutralization may be required to maximally inhibit IL-17-driven pathology.

A Randomized, Placebo-Controlled Phase III Extension Trial of the Long-Term Safety and Tolerability of Anifrolumab in Active Systemic Lupus Erythematosus

OBJECTIVE

To explore long-term safety and tolerability of anifrolumab 300 mg compared with placebo in patients with systemic lupus erythematosus (SLE) who completed a Treatment of Uncontrolled Lupus via the Interferon Pathway (TULIP) trial and enrolled in the placebo-controlled 3-year long-term extension (LTE) study (ClinicalTrials.gov identifier: NCT02794285).

METHODS

In the blinded LTE study, patients continued anifrolumab 300 mg, switched from anifrolumab 150 mg to 300 mg, or were re-randomized from placebo to receive either anifrolumab 300 mg or to continue placebo, administered every 4 weeks. Primary comparisons in the LTE study were between patients who received anifrolumab 300 mg or placebo throughout the TULIP and LTE studies. For rare safety events, comparisons included patients who received any anifrolumab dose during TULIP or LTE. When exposure differed, exposure-adjusted incidence rates (EAIRs) per 100 patient-years were calculated.

RESULTS

In the LTE study, EAIRs of serious adverse events (SAEs) were 8.5 with anifrolumab compared with 11.2 with placebo; likewise, EAIRs of AEs leading to treatment discontinuation were 2.5 versus 3.2, respectively. EAIRs of non-opportunistic serious infections were comparable between groups (3.7 with anifrolumab versus 3.6 with placebo). Exposure-adjusted event rates of COVID-related AEs, including asymptomatic infections, were 15.5 with anifrolumab compared with 9.8 with placebo. No COVID-related AEs occurred in fully vaccinated individuals. EAIRs of malignancy and major acute cardiovascular events were low and comparable between groups. Anifrolumab was associated with lower cumulative glucocorticoid use and greater mean improvement in the SLE Disease Activity Index 2000, compared with placebo.

CONCLUSION

This LTE study represents the longest placebo-controlled clinical trial performed in SLE to date. No new safety findings were identified in the LTE study, supporting the favorable benefit-risk profile of anifrolumab for patients with moderate-to-severe SLE receiving standard therapy.

P168 An enriched population of tissue-resident CD8 memory T cells in young people with juvenile idiopathic arthritis recapitulate findings from mouse models of inflammatory arthritis flares

Background/Aims

Asymmetrical joint inflammation at presentation and during flares of juvenile idiopathic arthritis (JIA) implicates resident cell populations and the microenvironment in disease. Persistent CD8+ tissue-resident cell populations have been identified from murine models, capable of priming the joint towards an exaggerated inflammatory response, which resist systemic treatment. Clonally-expanded enriched populations of these tissue-resident CD8+ memory T cells (TRM) have been identified in synovial fluid of children with JIA.

Methods

We integrate and compare scRNA-seq findings from paired synovial fluid mononuclear cells and blood mononuclear cell (PBMC) samples from children with oligoarticular JIA (n = 2), adults with psoriatic arthritis (n = 3) and blood from healthy adult volunteers (n = 4).

Results

A number of T lymphocyte and myeloid cell populations demonstrated enrichment amongst synovial fluid mononuclear cells (compared to paired PBMCs) that corresponded across arthritic subtypes. A mean of 2.98% of T cells in synovial JIA samples had the CD69+ITGAE+CD8A+ tissue-resident signature compared to a mean of 0.37% in paired JIA PBMCs and 0.24% in other sample types (P <.00001, vs synovial psoriatic samples). These cells recapitulated previously observed traits of tissue-resident CD8+ T cells, including high expression of transcription factor RUNX3, granzymes and the FABP5 fatty acid transporter. In mouse models the chemokine CCL5 was critical for leukocyte recruitment to mediate inflammatory flares and indeed, JIA synovial fluid samples exhibited stronger expression of CCL5 in TRM. Additionally, transcripts for cytokines involved in CD8+ tissue-resident T cell regulation and maintenance were specifically enriched in JIA synovial samples compared to peripheral blood, including IL-15, IL-12, IFN-γ; suggesting an environment conducive to the persistence of this population.

Conclusion

We confirm the existence of previously-described cell populations in synovial fluid from JIA patients and identify the enrichment of CD8 T cells with a tissue-resident signature. Further study is required to identify the significance or functional implications of these populations.

Disclosure

C. Bolton: None. C. Rich-Griffin: None. C. Dendrou: None. C. Brown: None. H. Al-Mossawi: None. A. Croft: None. L. Wedderburn: Consultancies; L.R.W. receieved a consultancy fee from Pfizer unrelated to this work. Grants/research support; L.R.W. declares support from AbbVie, GSK, Pfizer, Sobi, and UCB to the CLUSTER Consortium.

Ex vivo mass cytometry analysis reveals a profound myeloid proinflammatory signature in psoriatic arthritis synovial fluid

OBJECTIVES

A number of immune populations have been implicated in psoriatic arthritis (PsA) pathogenesis. This study used mass cytometry (CyTOF) combined with transcriptomic analysis to generate a high-dimensional dataset of matched PsA synovial fluid (SF) and blood leucocytes, with the aim of identifying cytokine production ex vivo in unstimulated lymphoid and myeloid cells.

METHODS

Fresh SF and paired blood were either fixed or incubated with protein transport inhibitors for 6 hours. Samples were stained with two CyTOF panels: a phenotyping panel and an intracellular panel, including antibodies to both T cell and myeloid cell secreted proteins. Transcriptomic analysis by gene array of key expanded cell populations, single-cell RNA-seq, ELISA and LEGENDplex analysis of PsA SF were also performed.

RESULTS

We observed marked changes in the myeloid compartment of PsA SF relative to blood, with expansion of intermediate monocytes, macrophages and dendritic cell populations. Classical monocytes, intermediate monocytes and macrophages spontaneously produced significant levels of the proinflammatory mediators osteopontin and CCL2 in the absence of any in vitro stimulation. By contrast minimal spontaneous cytokine production by T cells was detected. Gene expression analysis showed the genes for osteopontin and CCL2 to be among those most highly upregulated by PsA monocytes/macrophages in SF; and both proteins were elevated in PsA SF.

CONCLUSIONS

Using multiomic analyses, we have generated a comprehensive cellular map of PsA SF and blood to reveal key expanded myeloid proinflammatory modules in PsA of potential pathogenic and therapeutic importance.

Treating to target in psoriatic arthritis: assessing real-world outcomes and optimising therapeutic strategy for adults with psoriatic arthritis-study protocol for the MONITOR-PsA study, a trials within cohorts study design

Background

The Tight Control of psoriatic arthritis (TICOPA) trial confirmed improved clinical outcomes with a treat to target (T2T) strategy in psoriatic arthritis (PsA). This consisted of 4-weekly review and escalation of ‘step up’ therapy (single disease modifying therapy (DMARD), combination DMARDs and then biologics) based on remission criteria. Based on this, a T2T approach is supported by European PsA treatment recommendations. However, it is not commonly implemented in routine care primarily due to feasibility and cost concerns. In the TICOPA trial, the same treatment regime was used for all participants regardless of their disease profile. Despite the recognition of PsA as a highly heterogeneous condition, no studies have tailored which drugs are used depending on disease severity. The cohort will establish real world outcomes for the T2T approach in PsA and also form the basis of a trials within cohorts (TWiCs) design to test alternative therapeutic approaches within embedded clinical trials providing an evidence base for treatment strategy in PsA.

Methods

The Multicentre Observational Initiative in Treat to target Outcomes in Psoriatic Arthritis (MONITOR-PsA) cohort will apply a T2T approach within routine care. It will recruit newly diagnosed adult patients with PsA starting systemic therapies. The cohort is observational allowing routine therapeutic care within NHS clinics but a T2T approach will be supported when monitoring treatment within the cohort. Eligible participants will be adults (≥18 years) with active PsA with ≥ 1 tender or swollen joints or enthesis who have not previously had treatment with DMARDs for articular disease.

Discussion

This study is the first TWiC designed to support a fully powered randomised drug trial. The results from the observational cohort will be compared with those observed in the TICOPA trial investigating the clinical effectiveness and health care costs of the pragmatic T2T approach. Nested trials will provide definitive RCT evidence establishing the optimal management of PsA within the T2T approach. The TWiCs design allows robust generalizability to routine healthcare, avoids disappointment bias, aids recruitment and in future will allow assessment of longer-term outcomes.

Trial registration

ClinicalTrials.gov NCT03531073. Retrospectively registered on 21 May 2018.

Multi-omic single cell analysis resolves novel stromal cell populations in healthy and diseased human tendon

Tendinopathy accounts for over 30% of primary care consultations and represents a growing healthcare challenge in an active and increasingly ageing population. Recognising critical cells involved in tendinopathy is essential in developing therapeutics to meet this challenge. Tendon cells are heterogenous and sparsely distributed in a dense collagen matrix; limiting previous methods to investigate cell characteristics ex vivo. We applied next generation CITE-sequencing; combining surface proteomics with in-depth, unbiased gene expression analysis of > 6400 single cells ex vivo from 11 chronically tendinopathic and 8 healthy human tendons. Immunohistochemistry validated the single cell findings. For the first time we show that human tendon harbours at least five distinct COL1A1/2 expressing tenocyte populations in addition to endothelial cells, T-cells, and monocytes. These consist of KRT7/SCX+ cells expressing microfibril associated genes, PTX3+ cells co-expressing high levels of pro-inflammatory markers, APOD+ fibro–adipogenic progenitors, TPPP3/PRG4+ chondrogenic cells, and ITGA7+ smooth muscle-mesenchymal cells. Surface proteomic analysis identified markers by which these sub-classes could be isolated and targeted in future. Chronic tendinopathy was associated with increased expression of pro-inflammatory markers PTX3, CXCL1, CXCL6, CXCL8, and PDPN by microfibril associated tenocytes. Diseased endothelium had increased expression of chemokine and alarmin genes including IL33.

Context-specific regulation of surface and soluble IL7R expression by an autoimmune risk allele

IL-7 is a key factor in T cell immunity and common variants at IL7R, encoding its receptor, are associated with autoimmune disease susceptibility. IL7R mRNA is induced in stimulated monocytes, yet a function for IL7R in monocyte biology remains unexplored. Here we characterize genetic regulation of IL7R at the protein level in healthy individuals, and find that monocyte surface and soluble IL7R (sIL7R) are markedly induced by lipopolysaccharide. In monocytes, both surface IL7R and sIL7R expression strongly associate with allelic carriage of rs6897932, a disease-associated IL7R polymorphism. Monocytes produce more sIL7R than CD4 + T cells, and the amount is additionally correlated with the expression of DDX39A, encoding a splicing factor. Synovial fluid-derived monocytes from patients with spondyloarthritis are enriched for IL7R+ cells with a unique transcriptional profile that overlaps with IL-7-induced gene sets. Our data thus suggest a previously unappreciated function for monocytes in IL-7 biology and IL7R-associated diseases.

Precision medicine in psoriatic arthritis: how should we select targeted therapies?

Psoriatic arthritis (PsA) is a heterogeneous inflammatory arthritis associated with psoriasis. Patients manifest variable presentations with potential involvement of peripheral joints, spine, tendons, skin, and nails. There has been a rapid expansion in targeted treatment options for patients with PsA, but typically less than half of those who receive therapy achieve optimal treatment targets. Many patients respond to second-line or third-line biological therapies, but little evidence exists to guide the choice of therapeutics for each individual. At present, choice of therapy is driven by active clinical disease domains, clinician familiarity with existing treatments, and cost. Here, we review recent data that highlight the potential for personalised, or precision, medicine in PsA and other forms of inflammatory arthritis, noting that this research is still at a preliminary stage. In the future, a combination of detailed immunophenotyping and sophisticated statistical analyses should help to facilitate a personalised medicine approach in PsA, following examples from other clinical areas, such as oncology. This change in approach to the treatment of PsA has the potential to maximise outcomes for patients and to provide optimal therapies without delay.

Activation-Induced Killer Cell Immunoglobulin-like Receptor 3DL2 Binding to HLA-B27 Licenses Pathogenic T Cell Differentiation in Spondyloarthritis

Objective

In thespondyloarthritides (SpA), increased numbers of CD4+ T cells express killer cell immunoglobulin‐like receptor 3DL2 (KIR‐3DL2). The aim of this study was to determine the factors that induce KIR‐3DL2 expression, and to characterize the relationship between HLA–B27 and the phenotype and function of KIR‐3DL2–expressing CD4+ T cells in SpA.

Methods

In total, 34 B27+patients with SpA, 28 age‐ and sex‐matched healthy controls (20 B27− and 8 B27+), and 9 patients with rheumatoid arthritis were studied. KIR-3DL2 expression and other phenotypic characteristics of peripheral blood and synovial fluid CD4+ T cells were studied by flow cytometry, quantitative polymerase chain reaction, and Western blotting. T cell receptor clonality was determined by template‐switch anchored reverse transcription–polymerase chain reaction and sequencing analysis. Cytokines were measured by enzyme‐linked immunosorbent assay.

Results

Cellular activation induced KIR‐3DL2 expression on both naive and effector CD4+ T cells. KIR‐3DL2 binding to B27+ cells promoted expression of KIR‐3DL2, the Th17‐specific transcription factor retinoic acid receptor–related orphan nuclear receptor γt, and the antiapoptotic factor B cell lymphoma 2. KIR‐3DL2+CD4+ T cells in patients with ankylosing spondylitis were oligoclonal and enriched for markers of T cell activation and for the gut homing receptor CCR9. In the presence of B27+ antigen‐presenting cells, KIR‐3DL2+CD4+ T cells produced less interleukin‐2 (IL‐2) but more IL‐17. This effect was blocked by HC10, an antibody that inhibits the binding of KIR‐3DL2 to B27 heavy chains.

Conclusion

KIR‐3DL2 binding to HLA–B27 licenses Th17 cell differentiation in SpA. These findings raise the therapeutic potential of targeting HLA–B27–KIR‐3DL2 interactions for the treatment of B27+ patients with SpA.