Single-cell transcriptomic analysis of hematopoietic progenitor cells from patients with systemic lupus erythematosus reveals interferon-inducible reprogramming in early progenitors

Introduction

Immune cells that contribute to the pathogenesis of systemic lupus erythematosus (SLE) derive from adult hematopoietic stem and progenitor cells (HSPCs) within the bone marrow (BM). For this reason, we reasoned that fundamental abnormalities in SLE can be traced to a BM-derived HSPC inflammatory signature.

Methods

BM samples from four SLE patients, six healthy controls, and two umbilical cord blood (CB) samples were used. CD34+ cells were isolated from BM and CB samples, and single-cell RNA-sequencing was performed.

Results

A total of 426 cells and 24,473 genes were used in the analysis. Clustering analysis resulted in seven distinct clusters of cell types. Mutually exclusive markers, which were characteristic of each cell type, were identified. We identified three HSPC subpopulations, one of which consisted of proliferating cells (MKI67 expressing cells), one T-like, one B-like, and two myeloid-like progenitor subpopulations. Differential expression analysis revealed i) cell cycle-associated signatures, in healthy BM of HSPC clusters 3 and 4 when compared with CB, and ii) interferon (IFN) signatures in SLE BM of HSPC clusters 3 and 4 and myeloid-like progenitor cluster 5 when compared with healthy controls. The IFN signature in SLE appeared to be deregulated following TF regulatory network analysis and differential alternative splicing analysis between SLE and healthy controls in HSPC subpopulations.

Discussion

This study revealed both quantitative-as evidenced by decreased numbers of non-proliferating early progenitors-and qualitative differences-characterized by an IFN signature in SLE, which is known to drive loss of function and depletion of HSPCs. Chronic IFN exposure affects early hematopoietic progenitors in SLE, which may account for the immune aberrancies and the cytopenias in SLE.

Enhanced medullary and extramedullary granulopoiesis sustain the inflammatory response in lupus nephritis

OBJECTIVES

In SLE, deregulation of haematopoiesis is characterised by inflammatory priming and myeloid skewing of haematopoietic stem and progenitor cells (HSPCs). We sought to investigate the role of extramedullary haematopoiesis (EMH) as a key player for tissue injury in systemic autoimmune disorders.

METHODS

Transcriptomic analysis of bone marrow (BM)-derived HSPCs from patients with SLE and NZBW/F1 lupus-prone mice was performed in combination with DNA methylation profile. Trained immunity (TI) was induced through β-glucan administration to the NZBW/F1 lupus-prone model. Disease activity was assessed through lupus nephritis (LN) histological grading. Colony-forming unit assay and adoptive cell transfer were used to assess HSPCs functionalities.

RESULTS

Transcriptomic analysis shows that splenic HSPCs carry a higher inflammatory potential compared with their BM counterparts. Further induction of TI, through β-glucan administration, exacerbates splenic EMH, accentuates myeloid skewing and worsens LN. Methylomic analysis of BM-derived HSPCs demonstrates myeloid skewing which is in part driven by epigenetic tinkering. Importantly, transcriptomic analysis of human SLE BM-derived HSPCs demonstrates similar findings to those observed in diseased mice.

CONCLUSIONS

These data support a key role of granulocytes derived from primed HSPCs both at medullary and extramedullary sites in the pathogenesis of LN. EMH and TI contribute to SLE by sustaining the systemic inflammatory response and increasing the risk for flare.

The SYSCID map: a graphical and computational resource of molecular mechanisms across rheumatoid arthritis, systemic lupus erythematosus and inflammatory bowel disease

Chronic inflammatory diseases (CIDs), including inflammatory bowel disease (IBD), rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) are thought to emerge from an impaired complex network of inter- and intracellular biochemical interactions among several proteins and small chemical compounds under strong influence of genetic and environmental factors. CIDs are characterised by shared and disease-specific processes, which is reflected by partially overlapping genetic risk maps and pathogenic cells (e.g., T cells). Their pathogenesis involves a plethora of intracellular pathways. The translation of the research findings on CIDs molecular mechanisms into effective treatments is challenging and may explain the low remission rates despite modern targeted therapies. Modelling CID-related causal interactions as networks allows us to tackle the complexity at a systems level and improve our understanding of the interplay of key pathways. Here we report the construction, description, and initial applications of the SYSCID map (https://syscid.elixir-luxembourg.org/), a mechanistic causal interaction network covering the molecular crosstalk between IBD, RA and SLE. We demonstrate that the map serves as an interactive, graphical review of IBD, RA and SLE molecular mechanisms, and helps to understand the complexity of omics data. Examples of such application are illustrated using transcriptome data from time-series gene expression profiles following anti-TNF treatment and data from genome-wide associations studies that enable us to suggest potential effects to altered pathways and propose possible mechanistic biomarkers of treatment response.

Flares in Lupus Nephritis: Risk Factors and Strategies for Their Prevention

PURPOSE OF REVIEW

Discuss the prognostic significance of kidney flares in patients with lupus nephritis, associated risk factors, and possible preventative strategies.

RECENT FINDINGS

Recently performed clinical trials and observational cohort studies underscore the high frequency of relapses of kidney disease, following initial response, in patients with proliferative and/or membranous lupus nephritis. Analysis of hard disease outcomes such as progression to chronic kidney disease or end-stage kidney disease, coupled with histological findings from repeat kidney biopsy studies, have drawn attention to the importance of renal function preservation that should be pursued as early as lupus nephritis is diagnosed. In this respect, non-randomized and randomized evidence have suggested a number of factors associated with reduced risk of renal flares such as attaining a very low level of proteinuria (< 700-800 mg/24 h by 12 months), using mycophenolate over azathioprine, adding belimumab to standard therapy, maintaining immunosuppressive/biological treatment for at least 3 to 5 years, and using hydroxychloroquine. Other factors that warrant further clarification include serological activity and the use of repeat kidney biopsy to guide the intensity and duration of treatment in selected cases. The results from ongoing innovative studies integrating kidney histological and clinical outcomes, together with an expanding spectrum of therapies in lupus nephritis, are expected to facilitate individual medical care and long-term disease and patient prognosis.

Transcriptomic and proteomic profiling reveals distinct pathogenic features of peripheral non-classical monocytes in systemic lupus erythematosus

Peripheral blood monocytes propagate inflammation in systemic lupus erythematosus (SLE). Three major populations of monocytes have been recognized namely classical (CM), intermediate (IM) and non-classical monocytes (NCM). Herein, we performed a comprehensive transcriptomic, proteomic and functional characterization of the three peripheral monocytic subsets from active SLE patients and healthy individuals. Our data demonstrate extensive molecular disruptions in circulating SLE NCM, characterized by enhanced inflammatory features such as deregulated DNA repair, cell cycle and heightened IFN signaling combined with differentiation and developmental cues. Enhanced DNA damage, elevated expression of p53, G0 arrest of cell cycle and increased autophagy stress the differentiation potential of NCM in SLE. This immunogenic profile is associated with an activated macrophage phenotype of NCM exhibiting M1 characteristics in the circulation, fueling the inflammatory response. Together, these findings identify circulating SLE NCM as a pathogenic cell type in the disease that could represent an additional therapeutic target.

Combinatorial targeting of a specific EMT/MET network by macroH2A variants safeguards mesenchymal identity

Generation of induced pluripotent stem cells from specialized cell types provides an excellent model to study how cells maintain their stability, and how they can change identity, especially in the context of disease. Previous studies have shown that chromatin safeguards cell identity by acting as a barrier to reprogramming. We investigated mechanisms by which the histone macroH2A variants inhibit reprogramming and discovered that they work as gate keepers of the mesenchymal cell state by blocking epithelial transition, a step required for reprogramming of mouse fibroblasts. More specifically, we found that individual macroH2A variants regulate the expression of defined sets of genes, whose overall function is to stabilize the mesenchymal gene expression program, thus resisting reprogramming. We identified a novel gene network (MSCN, mesenchymal network) composed of 63 macroH2A-regulated genes related to extracellular matrix, cell membrane, signaling and the transcriptional regulators Id2 and Snai2, all of which function as guardians of the mesenchymal phenotype. ChIP-seq and KD experiments revealed a macroH2A variant-specific combinatorial targeting of the genes reconstructing the MSCN, thus generating robustness in gene expression programs to resist cellular reprogramming.

A network-based approach reveals long non-coding RNAs associated with disease activity in lupus nephritis: key pathways for flare and potential biomarkers to be used as liquid biopsies

Objective

A blood-based biomarker is needed to assess lupus nephritis (LN) disease activity, minimizing the need for invasive kidney biopsies. Long non-coding RNAs (lncRNAs) are known to regulate gene expression, appear to be stable in human plasma, and can serve as non-invasive biomarkers.

Methods

Transcriptomic data of whole blood samples from 74 LN patients and 20 healthy subjects (HC) were analyzed to identify differentially expressed (DE) lncRNAs associated with quiescent disease and flares. Weighted gene co-expression network analysis (WGCNA) was performed to uncover lncRNAs with a central role (hub lncRNAs) in regulating key biological processes that drive LN disease activity. The association of hub lncRNAs with disease activity was validated using RT-qPCR on an independent cohort of 15 LN patients and 9 HC. cis- and trans-targets of validated lncRNAs were explored in silico to examine potential mechanisms of their action.

Results

There were 444 DE lncRNAs associated with quiescent disease and 6 DE lncRNAs associated with flares (FDR <0.05). WGCNA highlighted IFN signaling and B-cell activity/adaptive immunity as the most significant processes contributing to nephritis activity. Four disease-activity-associated lncRNAs, namely, NRIR, KLHDC7B-DT, MIR600HG, and FAM30A, were detected as hub genes and validated in an independent cohort. NRIR and KLHDC7B-DT emerged as potential key regulators of IFN-mediated processes. Network analysis suggests that FAM30A and MIR600HG are likely to play a central role in the regulation of B-cells in LN through cis-regulation effects and a competing endogenous RNA mechanism affecting immunoglobulin gene expression and the IFN-λ pathway.

Conclusions

The expression of lncRNAs NRIR, KLHDC7B-DT, FAM30A, and MIR600HG were associated with disease activity and could be further explored as blood-based biomarkers and potential liquid biopsy on LN.

Restoration of aberrant gene expression of monocytes in systemic lupus erythematosus via a combined transcriptome-reversal and network-based drug repurposing strategy

BACKGROUND

Monocytes -key regulators of the innate immune response- are actively involved in the pathogenesis of systemic lupus erythematosus (SLE). We sought to identify novel compounds that might serve as monocyte-directed targeted therapies in SLE.

RESULTS

We performed mRNA sequencing in monocytes from 15 patients with active SLE and 10 healthy individuals. Disease activity was assessed with the Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2 K). Leveraging the drug repurposing platforms iLINCS, CLUE and L1000CDS², we identified perturbagens capable of reversing the SLE monocyte signature. We identified transcription factors and microRNAs (miRNAs) that regulate the transcriptome of SLE monocytes, using the TRRUST and miRWalk databases, respectively. A gene regulatory network, integrating implicated transcription factors and miRNAs was constructed, and drugs targeting central components of the network were retrieved from the DGIDb database. Inhibitors of the NF-κB pathway, compounds targeting the heat shock protein 90 (HSP90), as well as a small molecule disrupting the Pim-1/NFATc1/NLRP3 signaling axis were predicted to efficiently counteract the aberrant monocyte gene signature in SLE. An additional analysis was conducted, to enhance the specificity of our drug repurposing approach on monocytes, using the iLINCS, CLUE and L1000CDS² platforms on publicly available datasets from circulating B-lymphocytes, CD4⁺ and CD8⁺ T-cells, derived from SLE patients. Through this approach we identified, small molecule compounds, that could potentially affect more selectively the transcriptome of SLE monocytes, such as, certain NF-κB pathway inhibitors, Pim-1 and SYK kinase inhibitors. Furthermore, according to our network-based drug repurposing approach, an IL-12/23 inhibitor and an EGFR inhibitor may represent potential drug candidates in SLE.

CONCLUSIONS

Application of two independent - a transcriptome-reversal and a network-based -drug repurposing strategies uncovered novel agents that might remedy transcriptional disturbances of monocytes in SLE.

The genomic landscape of ANCA-associated vasculitis: Distinct transcriptional signatures, molecular endotypes and comparison with systemic lupus erythematosus

Introduction

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAVs) present with a complex phenotype and are associated with high mortality and multi-organ involvement. We sought to define the transcriptional landscape and molecular endotypes of AAVs and compare it to systemic lupus erythematosus (SLE).

Methods

We performed whole blood mRNA sequencing from 30 patients with AAV (granulomatosis with polyangiitis/GPA and microscopic polyangiitis/MPA) combined with functional enrichment and network analysis for aberrant pathways. Key genes and pathways were validated in an independent cohort of 18 AAV patients. Co-expression network and hierarchical clustering analysis, identified molecular endotypes. Multi-level transcriptional overlap analysis to SLE was based on our published data from 142 patients.

Results

We report here that “Pan-vasculitis” signature contained 1,982 differentially expressed genes, enriched in leukocyte differentiation, cytokine signaling, type I and type II IFN signaling and aberrant B-T cell immunity. Active disease was characterized by signatures linked to cell cycle checkpoints and metabolism pathways, whereas ANCA-positive patients exhibited a humoral immunity transcriptional fingerprint. Differential expression analysis of GPA and MPA yielded an IFN-g pathway (in addition to a type I IFN) in the former and aberrant expression of genes related to autophagy and mRNA splicing in the latter. Unsupervised molecular taxonomy analysis revealed four endotypes with neutrophil degranulation, aberrant metabolism and B-cell responses as potential mechanistic drivers. Transcriptional perturbations and molecular heterogeneity were more pronounced in SLE. Molecular analysis and data-driven clustering of AAV uncovered distinct transcriptional pathways that could be exploited for targeted therapy.

Discussion

We conclude that transcriptomic analysis of AAV reveals distinct endotypes and molecular pathways that could be targeted for therapy. The AAV transcriptome is more homogenous and less fragmented compared to the SLE which may account for its superior rates of response to therapy.

Antiviral Innate Immune Responses in Autoimmunity: Receptors, Pathways, and Therapeutic Targeting

Innate immune receptors sense nucleic acids derived from viral pathogens or self-constituents and initiate an immune response, which involves, among other things, the secretion of cytokines including interferon (IFN) and the activation of IFN-stimulated genes (ISGs). This robust and well-coordinated immune response is mediated by the innate immune cells and is critical to preserving and restoring homeostasis. Like an antiviral response, during an autoimmune disease, aberrations of immune tolerance promote inflammatory responses to self-components, such as nucleic acids and immune complexes (ICs), leading to the secretion of cytokines, inflammation, and tissue damage. The aberrant immune response within the inflammatory milieu of the autoimmune diseases may lead to defective viral responses, predispose to autoimmunity, or precipitate a flare of an existing autoimmune disease. Herein, we review the literature on the crosstalk between innate antiviral immune responses and autoimmune responses and discuss the pitfalls and challenges regarding the therapeutic targeting of the mechanisms involved.

ATR-mediated DNA damage responses underlie aberrant B cell activity in systemic lupus erythematosus

B cells orchestrate autoimmune responses in patients with systemic lupus erythematosus (SLE), but broad-based B cell-directed therapies show only modest efficacy while blunting humoral immune responses to vaccines and inducing immunosuppression. Development of more effective therapies targeting pathogenic clones is a currently unmet need. Here, we demonstrate enhanced activation of the ATR/Chk1 pathway of the DNA damage response (DDR) in B cells of patients with active SLE disease. Treatment of B cells with type I IFN, a key driver of immunity in SLE, induced expression of ATR via binding of interferon regulatory factor 1 to its gene promoter. Pharmacologic targeting of ATR in B cells, via a specific inhibitor (VE-822), attenuated their immunogenic profile, including proinflammatory cytokine secretion, plasmablast formation, and antibody production. Together, these findings identify the ATR-mediated DDR axis as the orchestrator of the type I IFN-mediated B cell responses in SLE and as a potential novel therapeutic target.

Baseline IgG-Fc N-glycosylation profile is associated with long-term outcome in a cohort of early inflammatory arthritis patients

Background

Rheumatoid arthritis (RA) is a chronic autoimmune disease for which prediction of long-term prognosis from disease’s outset is not clinically feasible. The importance of immunoglobulin G (IgG) and its Fc N-glycosylation in inflammation is well-known and studies described its relevance for several autoimmune diseases, including RA. Herein we assessed the association between IgG N-glycoforms and disease prognosis at 2 years in an early inflammatory arthritis cohort.

Methods

Sera from 118 patients with early inflammatory arthritis naïve to treatment sampled at baseline were used to obtain IgG Fc glycopeptides, which were then analyzed in a subclass-specific manner by liquid chromatography coupled to mass spectrometry (LC-MS). Patients were prospectively followed and a favorable prognosis at 2 years was assessed by a combined index as remission or low disease activity (DAS28 < 3.2) and normal functionality (HAQ ≤ 0.25) while on treatment with conventional synthetic DMARDs and never used biologic DMARDs.

Results

We observed a significant association between high levels of IgG2/3 Fc galactosylation (effect 0.627 and adjusted p value 0.036 for the fully galactosylated glycoform H5N4F1; effect −0.551 and adjusted p value 0.04963 for the agalactosylated H3N4F1) and favorable outcome after 2 years of treatment. The inclusion of IgG glycoprofiling in a multivariate analysis to predict the outcome (with HAQ, DAS28, RF, and ACPA included in the model) did not improve the prognostic performance of the model.

Conclusion

Pending confirmation of these findings in larger cohorts, IgG glycosylation levels could be used as a prognostic marker in early arthritis, to overcome the limitations of the current prognostic tools.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13075-022-02897-5.

Cross-species transcriptome analysis for early detection and specific therapeutic targeting of human lupus nephritis

Objectives

Patients with lupus nephritis (LN) are in urgent need for early diagnosis and therapeutic interventions targeting aberrant molecular pathways enriched in affected kidneys.

Methods

We used mRNA-sequencing in effector (spleen) and target (kidneys, brain) tissues from lupus and control mice at sequential time points, and in the blood from 367 individuals (261 systemic lupus erythematosus (SLE) patients and 106 healthy individuals). Comparative cross-tissue and cross-species analyses were performed. The human dataset was split into training and validation sets and machine learning was applied to build LN predictive models.

Results

In murine SLE, we defined a kidney-specific molecular signature, as well as a molecular signature that underlies transition from preclinical to overt disease and encompasses pathways linked to metabolism, innate immune system and neutrophil degranulation. The murine kidney transcriptome partially mirrors the blood transcriptome of patients with LN with 11 key transcription factors regulating the cross-species active LN molecular signature. Integrated protein-to-protein interaction and drug prediction analyses identified the kinases TRRAP, AKT2, CDK16 and SCYL1 as putative targets of these factors and capable of reversing the LN signature. Using murine kidney-specific genes as disease predictors and machine-learning training of the human RNA-sequencing dataset, we developed and validated a peripheral blood-based algorithm that discriminates LN patients from normal individuals (based on 18 genes) and non-LN SLE patients (based on 20 genes) with excellent sensitivity and specificity (area under the curve range from 0.80 to 0.99).

Conclusions

Machine-learning analysis of a large whole blood RNA-sequencing dataset of SLE patients using human orthologs of mouse kidney-specific genes can be used for early, non-invasive diagnosis and therapeutic targeting of LN. The kidney-specific gene predictors may facilitate prevention and early intervention trials.

AB0013 THE COHESIN COMPLEX PROTEIN SMC1A IS A PUTATIVE REGULATOR OF SEX-BIASED INFLAMMATORY RESPONSES IN SYSTEMIC LUPUS ERYTHEMATOSUS

Background

A strong female predisposition is characteristic of Systemic Lupus Erythematosus (SLE), with female-to-male ratio ranging from 7:1 to 15:1. The molecular basis of this gender bias remains incompletely understood. In a previous whole-blood RNA profiling study, we identified genes with differential expression in SLE males versus females but not in their healthy counterparts. Among these genes, the cohesin complex protein SMC1A (Structural Maintenance of Chromosomes 1A) displayed the highest statistical significance [1].

Objectives

To (a) determine the immune cell type that displays the strongest gender-biased SMC1A expression in SLE versus healthy individuals, and (b) elucidate the role of SMC1A in regulating immune/inflammatory responses in the context of SLE.

Methods

Multiple immune cell types (CD19+ B cells, CD4+ T cells, CD14+ monocytes, neutrophils) were purified from peripheral blood specimens of SLE and healthy individuals, followed by Taqman PCR and Western blot to measure SMC1A mRNA and protein levels, respectively. The genome-binding properties of SMC1A were assayed by chromatin immunoprecipitation (ChIP)-sequencing in monocytes cultured under lupus-inducing conditions (lupus-like monocytes) [2]. To recapitulate the female/male difference in SMC1A expression, ex vivo cultured lupus-like monocytes were transfected with si-SMC1A (to downregulate SMC1A) versus si-control reagent, followed by genome-wide transcriptome analysis by RNA-sequencing.

Results

Among the various tested immune cell types, CD14+ monocytes best recapitulated the initial whole blood RNA-seq findings, demonstrating significantly decreased SMC1A mRNA and protein expression in male versus female SLE patients but not in their healthy counterparts. In blood monocytes cultured under lupus-inducing conditions and tested by ChIP-sequencing, SMC1A binding was increased on enhancers and promoters of genes associated with inflammation (including type I/II interferon and other inflammatory cytokines) and cell migration. In accordance, lupus-like monocytes with lowered SMC1A expression (i.e., male-like) displayed significantly reduced expression of inflammatory genes like IL6, GBP5, ADA and IL1A, as compared to monocytes with unaffected SMC1A (i.e., female-like). Furthermore, IL6 mRNA synthesis was significantly enhanced in female versus male monocytes cultured under lupus-inducing conditions.

Conclusion

SMC1A may transcriptionally regulate genes associated with the inflammatory response of monocytes. Our findings of gender-biased SMC1A levels in SLE monocytes raise the hypothesis that differential SMC1A expression and function might contribute to the disease gender bias and/or sexual dimorphism.

References

[1]Panousis NI, et al. Ann Rheum Dis. 2019 Aug;78(8):1079-1089.

[2]Park SH, et al. Nat Immunol. 2017 Oct;18(10):1104-1116.

Acknowledgements

The current work is funded by the Hellenic Foundation for Research & Innovation (HFRI). This research is co-financed by Greece and the European Union (European Social Fund- ESF) through the Operational Programme «Human Resources Development, Education and Lifelong Learning» in the context of the project “Strengthening Human Resources Research Potential via Doctorate Research” (MIS-5000432), implemented by the State Scholarships Foundation (IΚΥ)

Disclosure of Interests

None declared

AB0090 BASELINE IgG-Fc N-GLYCOSYLATION PROFILE IS ASSOCIATED WITH LONG-TERM OUTCOME IN A COHORT OF EARLY INFLAMMATORY ARTHRITIS PATIENTS

Background

Rheumatoid arthritis (RA) is a systemic autoimmune disease which causes chronic joint inflammation and functional limitation1,2. The diagnosis of rheumatoid arthritis (RA) is mainly based on clinical data and RA specific autoantibodies, while the prediction of long-term prognosis from disease outset is not clinically reliable3,4. The importance of immunoglobulin G (IgG) and its Fc N-glycosylation in inflammation of RA has been described, with changes in the glycosylation profiles observed years before the diagnosis of RA5.

Objectives

We herein sought to assess the value of total serum IgG Fc N-glycosylation as a diagnostic and prognostic biomarker in patients with early inflammatory arthritis (EIA). Specifically, we aim to assess whether IgG N-glycoform levels may predict the diagnosis of RA or undifferentiated arthritis (UA) and the long-term disease‘s outcome in patients with EIA arthritis patients naïve to treatment.

Methods

The “Early Arthritis Clinic” of the University Hospital of Heraklion is a prospective cohort of patients with inflammatory arthritis. For the present study, we selected a group of patients naïve to any immunosuppressive treatments with available serum at baseline evaluation (n=118). At baseline, demographics, RA clinical characteristics (DAS28, HAQ-DI) and laboratory tests [autoantibodies (RF and/or ACPA)], were also recorded. The patients were prospectively followed for two years, with clinical, laboratory and disease-related treatments documented. A diagnosis of RA or UA was based on established classification criteria6. In order to assess long-term prognosis we formulated a combined “index” of favourable outcome if the patients fulfilled all the following at 24 months of follow-up: remission or low disease activity (based on DAS28 < 3.2) and normal functionality (based on HAQ ≤ 0.25) while on treatment with csDMARDs and never use bDMARDs. We applied a state-of-the-art liquid chromatography - mass spectrometry (LC-MS) based workflow for analysis of subclass-specific IgG Fc N-glycosylation at the baseline7.

Results

We studied 118 EIA patients [age (mean, SD) (53, 15.6) years, females (80.5%), symptoms duration (53.8, 8.7) years, ACPA positive (16%), DAS28 (4.8, 0.14)]. During the 2 years of follow-up, 60% of the patients were diagnosed with RA and 40% with UA. Although patients with UA had higher relative abundances of galactosylated and sialylated N-glycoforms (H4N4F1, H5N4F1 and H5N4F1S1) in all IgG subclasses at baseline compared to RA patients, differences were not statistically important. Interestingly, we observed a significant association between high levels of IgG2/3 galactosylation for H5N4F1 [effect 0.63, adjusted p=0.036)] and H3N4F1 [effect -0.55122, adjusted p=0.0496) and favorable outcome after two years of treatment.

Conclusion

In our cohort of EIA we found IgG2/3 Fc N-glycoforms to be associated with a favorable prognosis after 2 years of follow-up. Should the present data be confirmed in a larger cohort could be of clinical value. Since currently available prognostic tools have significant limitations, further research should aim to the development of a predictive tool of high specificity and sensitivity based on the combination of clinical, serological data and novel biomarkers.

References

[1]Smolen JS, et al. Lancet (2016) 388(10055):2023-38. doi: 10.1016/S0140-6736(16)30173-8

[2]Firestein GS, McInnes IB. Immunity (2017) 46(2):183-96. doi: 10.1016/j.immuni.2017.02.006.

[3]Scott DL, et al.J. Lancet (2010) 376(9746):1094-108. doi: Doi 10.1016/S0140-6736(10)60826-4.

[4]Weyand CM, Goronzy JJ. Nat Immunol (2021) 22(1):10-8. doi: 10.1038/s41590-020-00816-x.

[5]Ligier S, et al. Br J Rheumatol (1998) 37(12):1307-14. doi: 10.1093/rheumatology/37.12.1307.

[6]Aletaha D, et al. Ann Rheum Dis (2010) 69(9):1580-8. doi: 10.1136/ard.2010.138461.

[7]De Leoz MLA, et al. Molecular & Cellular Proteomics (2020) 19(1):11-30. doi: 10.1074/mcp.RA119.001677.

Acknowledgements

This research was funded by the GlySign and SYSCID – European Union’s Horizon 2020 research and innovation programs under the Marie Skłodowska-Curie, grant numbers 722095 and 733100, respectively.

Disclosure of Interests

Thomas Sénard: None declared, Irini Flouri: None declared, Frano Vučković Employee of: Genos Ltd, Garyfalia Papadaki: None declared, Panagiota Goutakoli: None declared, Aggelos Banos: None declared, Maja Pučić-Baković Employee of: Genos Ltd, Marija Pezer Employee of: Genos Ltd, George Bertsias: None declared, Gordan Lauc Shareholder of: Genos Ltd, a private research organization that specializes in high-throughput glycomic analyses and has several patents in this field., Prodromos Sidiropoulos: None declared

Deformation analysis in post-hospitalised patients with moderate SARS-CoV-2 infection

Funding Acknowledgements

Type of funding sources: None.

Background

SARS-CoV-2 infection is associated with multiple cardiac manifestations (1,2). Global longitudinal strain (GLS) by speckle tracking echocardiography (STE) is a novel transthoracic echocardiography (TTE) measure of myocardial deformation, which could early recognize subclinical cardiac injury in COVID-19 patients (3,4).

Purpose

We aimed to explore GLS profiles in post-hospitalized COVID-19 patients to identify features of eventual subclinical cardiac injury and to investigate the possible correlation with the severity of infection.

Methods

We enrolled 33 patients (mean age 59.2 ± 13, 64% men) with positive SARS-CoV-2 RT-PCR, hospitalized for moderate COVID-19 disease, with no admission to intensive care unit. Patients were submitted to TTE 1-2 months after discharge.  Images were anonymised and analysed offline by two accredited cardiologists. Clinical parameters and laboratory findings from hospitalization were also collected.  Acute myocardial infarction and pulmonary embolism were exclusion criteria.

Results

Mean duration of hospitalization was 12.9 ± 8.0 days. Study population had normal systolic function with a mean LV ejection fraction 58.6% (±3.6) while the majority of patients had relative low values of LV global longitudinal strain, mean 15.2% (±2.3). Arterial hypertension was present in 51.5% of patients and a history of previous myocardial infarction was referred in 6.1% of the population. Only 24.2% of patients had elevated troponin levels during the previous in-hospital period (mean maximal value of hs-troponin  was 18.1 ±16.6 pg/mL) whereas  81.8% had abnormal D-Dimers values (mean 2424 μg /L, range ±2825) and 93.1% had high hs-CRP values (138.2 ±92.0 mg/L) . Duration of hospitalization had strong significant correlation with D-Dimers (rho: 0.708, p: &lt;0.001) and hs CRP (rho:0383, p:0.028) and  marginal association with troponin ( rho: 0.335, p:0.056). Moreover, global longitudinal strain showed significant association with duration of hospitalization (rho:-0.545, p: 0.007). Traditional systolic indices as LVEF and the various diastolic parameters  showed no significant association with severity of disease reflected by the duration of hospitalization and the other clinical and laboratory biomarkers.

Conclusion

Cardiac manifestations of SARS-CoV-2 infections could be present in mild to moderate disease and seems to associate with the severity of infection. The novel echocardiographic parameters such as GLS could add valuable information and identify  possible subclinical cardiac injury often unrecognized by traditional TTE examination.

Unraveling the complexities of psoriatic arthritis by the use of -Omics and their relevance for clinical care

-Omic technologies represent a novel approach to unravel ill-defined aspects of psoriatic arthritis (PsA). Large-scale information can be acquired from analysis of affected tissues in PsA via high-throughput studies in the domains of genomics, transcriptomics, epigenetics, proteomics and metabolomics. This is a critical overview of the current knowledge of -omics in PsA, with emphasis on the pathophysiological insights of diagnostic and therapeutic relevance, the advent of novel biomarkers and their potential use for precision medicine in PsA.

POS0418 SPLENIC EXTRAMEDULLARY HEMATOPOIESIS IS OMNIPRESENT AND CORRELATES WITH DISEASE SEVERITY IN THE LUPUS NZB/W F1 MURINE MODEL

Background:

Extramedullary hematopoiesis (EMH) is increasingly recognized as an integral component of systemic inflammatory diseases; compared to their bone marrow counterparts, hematopoietic progenitors of EMH have an enhanced role in target organ damage1,2. We have found that β-glucan -a non-specific inducer of reprograming of innate immunity- results in dramatic EMH with marked increase in Long-Term (LT)-HSCs, massive splenomegaly and worsening of nephritis in the NZB/W F1 lupus murine model (unpublished data).

Objectives:

To investigate EMH’s time course and contribution to inflammatory target-organ damage (kidney) in the NZB/W F1 lupus murine model.

Methods:

Spleens and kidneys were isolated from female NZB/W F1, at pre-nephritic stage (3-month-old) and nephritic stage (>6-month-old), and age/sex matched C57BL/6 (WT controls). Single-cell suspensions of spleens were analyzed by flow cytometry for Hematopoietic Stem and progenitor cells (HSPCs) phenotyping. Formalin-fixed and paraffin-embedded sections of spleens and kidneys were stained with conventional histological stains (H&E, Silver, Trichrome Masson). Spleens were histologically assessed for the presence of ΕΜΗ and kidneys were assessed for activity and chronicity through the NIH Lupus nephritis scoring system.

Results:

Histological analysis revealed that NZW/B F1 mice at the nephritic stage display massive splenomegaly with concomitant expansion of the red pulp, increased presence of megakaryocytes and disorganized splenic architecture. This is further corroborated by the flow cytometry analysis which demonstrated a significant increase of all HSPCs subsets (Long-term/Short-term Hematopoietic Stem Cells and Multipotent progenitors) compared to the C57BL/6 WT controls at nephritic stage. The degree of HSPC expansion and splenic architecture disorganization correlates strongly with the activity of lupus nephritis as quantified by the NIH scoring system. Of note, evidence of splenic EMH were present even in 3-month-old animals before overt nephritis ensues.

Conclusion:

Extramedullary hematopoiesis is present before overt nephritis and is dramatically expanded at the nephritic stage of the NZW/B F1 mouse model. The degree of EMH positively correlates with the severity of lupus nephritis. These data support a pathogenic role of EMH, and spleen derived HSPCs, in driving lupus nephritis.

References:

[1]Regan-Komito, D., Swann, J.W., Demetriou, P., Cohen, E.S., Horwood, N.J., Sansom, S.N., Griseri, T., 2020. GM-CSF drives dysregulated hematopoietic stem cell activity and pathogenic extramedullary myelopoiesis in experimental spondyloarthritis. Nature Communications 11, 155.

[2]Griseri, T., McKenzie, B.S., Schiering, C., Powrie, F., 2012. Dysregulated Hematopoietic Stem and Progenitor Cell Activity Promotes Interleukin-23-Driven Chronic Intestinal Inflammation. Immunity 37, 1116–1129.

Acknowledgements:

This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 742390)

Disclosure of Interests:

None declared

An assessment of contamination pickup on ground robotic vehicles for nuclear surveying application

Ground robotic vehicles are often deployed to inspect areas where radioactive floor contamination is a prominent risk. However, the accuracy of detection could be adversely affected by enhanced radiation signal through self-contamination of the robot occurring over the course of the inspection. In this work, it was hypothesised that a six-legged robot could offer advantages over the more conventional ground robotic devices such as wheeled and tracked rovers. To investigate this, experimental contamination testing and computational Monte Carlo simulation techniques (GEANT4) were employed to understand how radioactive contamination pick-up on three different robotic vehicles would affect their detection accuracy. Two robotic vehicles were selected for comparison with the hexapod robot based on their type of locomotion; a wheeled rover and a tracked rover. With the aid of a non-toxic fluorescent tracer dust, the contamination received by the all three vehicles when traversing a contaminated area was initially compared through physical inspection using high definition cameras. The parametric results from these tests where used in the computational study carried out in GEANT4. A cadmium zinc telluride detector was simulated at heights ranging from 10 to 50 cm above each contaminated vehicle, as if it were mounted on a plinth. Assuming a uniform activity of 60 Bq cm^-2on all contaminated surfaces, the results suggested that due to the hexapod's small ground-contacting surface area and geometry, radiation detection rates using an uncollimated detector are likely to be overestimated by between only 0.07%-0.12%, compared with 3.95%-8.43% and 1.75%-14.53% for the wheeled and tracked robot alternatives, respectively.

Transition to severe phenotype in systemic lupus erythematosus initially presenting with non-severe disease: implications for the management of early disease

Objective

Changes in the care of patients with SLE dictate a re-evaluation of its natural history and risk factors for disease deterioration and damage accrual. We sought to decipher factors predictive of a deterioration in phenotype (‘transition’) in patients initially presenting with non-severe disease.

Methods

Patients from the ‘Attikon’ cohort with disease duration ≥1 year were included. Disease at diagnosis was categorised as mild, moderate or severe, based on the British Isles Lupus Assessment Group manifestations and physician judgement. ‘Transition’ in severity was defined as an increase in category of severity at any time from diagnosis to last follow-up. Multivariable logistic regression was performed to identify baseline factors associated with this transition.

Results

462 patients were followed for a median (IQR) of 36 (120) months. At diagnosis, more than half (56.5%) had a mild phenotype. During disease course, transition to more severe forms was seen in 44.2%, resulting in comparable distribution among severity patterns at last follow-up (mild 28.4%, moderate 33.1%, severe 38.5%). Neuropsychiatric involvement at onset (OR 6.33, 95% CI 1.22 to 32.67), male sex (OR 4.53, 95% CI 1.23 to 16.60) and longer disease duration (OR 1.09 per 1 year, 95% CI 1.04 to 1.14) were independently associated with transition from mild or moderate to severe disease. Patients with disease duration ≥3 years who progressed to more severe disease had more than 20-fold increased risk to accrue irreversible damage.

Conclusion

Almost half of patients with initially non-severe disease progress to more severe forms of SLE, especially men and patients with positive anti-double-stranded DNA or neuropsychiatric involvement at onset. These data may have implications for the management of milder forms of lupus.

Regulatory T-cell Transcriptomic Reprogramming Characterizes Adverse Events by Checkpoint Inhibitors in Solid Tumors

Immune checkpoint inhibitors (ICI), which target immune regulatory pathways to unleash antitumor responses, have revolutionized cancer immunotherapy. Despite the remarkable success of ICI immunotherapy, a significant proportion of patients whose tumors respond to these treatments develop immune-related adverse events (irAE) resembling autoimmune diseases. Although the clinical spectrum of irAEs is well characterized, their successful management remains empiric. This is in part because the pathogenic mechanisms involved in the breakdown of peripheral tolerance and induction of irAEs remain elusive. Herein, we focused on regulatory T cells (Treg) in individuals with irAEs because these cells are vital for maintenance of peripheral tolerance, appear expanded in the peripheral blood of individuals with cancer, and abundantly express checkpoint molecules, hence representing direct targets of ICI immunotherapy. Our data demonstrate an intense transcriptomic reprogramming of CD4⁺CD25⁺CD127^- Tregs in the blood of individuals with advanced metastatic melanoma who develop irAEs following ICI immunotherapy, with a characteristic inflammatory, apoptotic, and metabolic signature. This inflammatory signature was shared by Tregs from individuals with different types of cancer developing irAEs and individuals with autoimmune diseases. Our findings suggest that inflammatory Treg reprogramming is a feature of immunotherapy-induced irAEs, and this may facilitate translational approaches aiming to induce robust antitumor immunity without disturbing peripheral tolerance.

A review of the reaction rates of uranium corrosion in water

This work conducts a review on the kinetics of the uranium and water reaction system by gathering all available kinetic data and across a wide range of reaction conditions. Temperature and pressure dependent kinetic equations that describe the reaction are derived for the uraniumwater vapour and uranium-liquid water systems. Detailed tables which provide information about the reaction conditions and other parameters for each rate point are constructed. From evaluation of the tables, the effects of underlying parameters on the reaction kinetics are discussed. It is suggested that these parameters contribute to the reported discrepancies between reaction rate values under similar conditions. Better prediction of the corrosion rate and rate behaviour can be achieved by combining the kinetic rate equations with the effect of these underlying parameters.

Mitophagy Balance in Various Cell Subsets in Patients with ANCA-Associated Vasculitis and Correlation with the Presence of Anti-Neutrophil Cytoplasmic Antibodies

ANCA-associated vasculitides (AAVs) are characterised by heterogeneous molecular and pathophysiological traits, causing ambiguous differential diagnosis and taxonomy. Response to therapy has proven far from successful, contributing to high mortality. Transcriptome analysis of different vasculitis subtypes adds new leads in elucidating mechanisms of disease and the role of specific cell subsets to them. Recent findings have shown that mitophagy is a procedure whose imbalance could lead to immune dysregulation with certain involvement to autoimmunity. Inflammatory response related mitophagy is yet to be described in AAVs. We here describe a research protocol to investigate mitophagy in monocytes, neutrophils, and T cells in AAV patients, and the relationship of disturbed mitophagy with ANCA seropositivity.

FRI0155 Α MULTICENTER “AT-RISK” COHORT FOR THE DISCOVERY OF ENVIRONMENTAL, CLINICAL AND MOLECULAR PREDICTORS FOR THE TRANSITION INTO SYSTEMIC LUPUS ERYTHEMATOSUS (SLE)

Background:

SLE onset is preceded by a preclinical phase evidenced by the presence of anti-nuclear and other autoantibodies (autoAbs), which however, have low predictive value for development of clinical SLE.

Objectives:

To define the subgroup of autoAbs-positive individuals who are at high risk for progression into SLE by integrating environmental, clinical/serological, genetic and transcriptome data.

Methods:

A multicenter, across five European countries, inception cohort of autoAbs-positive individuals or first-degree relatives (FDRs) of SLE patients who are monitored prospectively over five years for possible transition to SLE according to the classification criteria. Structured data collection on demographics, family and medical history, clinical (criteria and selected non-criteria manifestations) and serological parameters, use of medications, hydroxyvitamin D levels and lifestyle (tobacco, alcohol use, physical activity, adherence to Mediterranean diet). Blood samples are stored for RNA-sequencing and genotyping.

Results:

A total 254 at-risk individuals (93% women, 99% Caucasians, aged [mean ± standard deviation] 36 ± 12 years) have been included and enrolment/monitoring is still ongoing. Forty individuals (16%) have FDR with SLE and 88 individuals (35%) have FDR with another autoimmune disorder. The frequency of active and past use of tobacco was 28% and 20%, respectively. Sedentary lifestyle (moving only for necessary chores or outdoor activity 1-2 times/week) was reported by 54% and adherence to the Mediterranean diet was low (3.4 ± 2.3, maximum score: 9). At enrolment, individuals had 1.9 ± 1.1 ACR-1997 classification criteria, with anti-nuclear antibodies (ANA) being the most frequent (88%), followed by synovitis (39%), photosensitivity (33%) and immunologic disorder (30%) (Table 1). During follow-up of 15.2 ± 7.2 months, a total 15 individuals (5.9%) have progressed into classified SLE, including cases with severe hematological and neurological disease.

Table 1.

Baseline characteristics of the at-risk for SLE cohort

N (%) or mean ± SDACR 1997 classification criteria1.9 ± 1.1 Malar rash68 (27%) Discoid rash29 (11%) Photosensitivity83 (33%) Mucosal ulcers49 (19%) Synovitis100 (39%) Serositis30 (12%) Renal disorder28 (11%) Neurologic disorder31 (12%) Hematologic disorder58 (23%) Immunologic disorder77 (30%) ANA222 (88%)SLICC 2012 classification criteria Clinical criteria1.0 ± 0.9 Immunological criteria1.3 ± 0.9

Conclusion:

Among individuals with positive autoAbs or FDRs with SLE, the short-term risk for transition into clinical SLE is low. Following the study completion, clinical and lifestyle data will be combined with blood transcriptome to define a high-risk subgroup of individuals for progression into SLE.

Acknowledgments:

The study is supported by the Foundation for Research in Rheumatology (FOREUM; preclin016)

Disclosure of Interests:

Christina Adamichou: None declared, Dionysis Nikolopoulos: None declared, Myrto Nikoloudaki: None declared, Zahra Rahme: None declared, Micaela Fredi: None declared, Antigoni Pieta: None declared, ARGYRO REPA: None declared, Alice Parma: None declared, Eleni Kalogiannaki: None declared, Nestor Avgustidis: None declared, Nikolaos Kougkas: None declared, Aggelos Banos: None declared, Anastasios Eskitzis: None declared, Alessandra Bortoluzzi: None declared, Søren Jacobsen: None declared, Prodromos Sidiropoulos: None declared, Emmanouil Dermitzakis: None declared, Marta Mosca: None declared, Luís Inês: None declared, Laura Andreoli: None declared, Angela Tincani: None declared, Antonis Fanouriakis Paid instructor for: Paid instructor for Enorasis, Amgen, Speakers bureau: Paid speaker for Roche, Genesis Pharma, Mylan, George Bertsias Grant/research support from: GSK, Consultant of: Novartis

THU0014 COMPARATIVE TRANSCRIPTOME ANALYSES ACROSS TISSUES AND SPECIES IDENTIFY TARGETABLE GENES FOR HUMAN SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) AND LUPUS NEPHRITIS (LN)

Background:

Systemic Lupus Erythematosus (SLE) is a complex disease associated with the dysfunction of multiple tissues and cells. The causal tissue for each disease phenotype is not known a priori. Despite improvements in diagnosis and treatment, major organ involvement (such as the kidneys) contributes significantly to morbidity and mortality that still remain increased. There is an unmet need for timely targeted therapy.

Objectives:

RNA-sequencing was performed to investigate the patterns of transcription variation across tissues between healthy and lupus-prone mice at different stages of lupus, and how these patterns associate with human Systemic Lupus Erythematosus (SLE).

Methods:

NZB/W-F1 lupus prone mice were sacrificed at the pre-puberty, pre-autoimmunity and nephritic stage. Age-matched C57BL/6 were used as controls. An “effector” tissue (spleen) and “end-organs” (kidneys, brain) were collected. Total RNA was isolated, and mRNA-sequencing was performed. A time-series analysis was developed and differentially expressed genes (DEGs) were analyzed with DESeq. Hierarchical clustering and functional enrichment analysis were performed with gProfiler. Human orthologs of mouse tissue DEGs were identified in the whole-blood RNA-sequencing dataset comprised of 55 lupus-nephritis (LN), 65 non-LN SLE patients and 58 healthy individuals (HI). Human orthologs were compared to human DEGs. Using machine learning, human orthologs identified in the mouse dataset were used to predict kidney involvement in the human dataset, which was split in training and validation sets.

Results:

Lupus susceptibility and progression signatures at different tissues and different stages of the disease were identified. Tissue-specific signatures and a common cross-tissue signature were also described. Previously described and novel biological processes and pathways were revealed. The comparative murine-human transcriptome analysis identified human orthologs from the mouse spleen-signature (including CCL5, IFIT and HLA genes) that are involved in systemic autoimmunity. It also identified human orthologs from the kidney- and brain-signature (including FCGR2A, C1Q, JAK1 and APOA2) that are involved in major “end-organ” damage and response mechanisms. Using a neural network model, 193 human orthologs accurately predicted LN patients vs HI (accuracy=0.86, sensitivity=0.82, specificity=0.91 in the validation set). Using a support vector machine model, 30 human orthologs and age and gender were the best predictors of LN vs non-LN SLE patients (accuracy=0.71, sensitivity=0.73, specificity=0.69 in the validation set).

Conclusion:

Murine tissue gene signatures identified by RNA-sequencing analysis revealed biological processes and pathways that could be potentially used as biomarkers or therapeutic targets in human SLE. Comparison of the murine tissue-transcriptome with the whole-blood human-transcriptome revealed common gene signatures, demonstrating similar biological processes and pathways. Machine learning identified a murine kidney lupus signature that can accurately predict kidney involvement in human SLE. Validation in other datasets is ongoing.

References:

[1]Panousis NI, et al. Ann Rheum Dis 2019;78:1079

Acknowledgments:

This work was supported by FOREUM, SYSCID and ERC -Advanced Grant

Disclosure of Interests:

Eleni Frangou: None declared, Panayiotis Garantziotis: None declared, Maria Grigoriou: None declared, Aggelos Banos: None declared, Nikolaos Panousis: None declared, Emmanouil Dermitzakis: None declared, George Bertsias Grant/research support from: GSK, Consultant of: Novartis, Dimitrios Boumpas: None declared, Anastasia Filia: None declared

Evolving phenotype of systemic lupus erythematosus in Caucasians: low incidence of lupus nephritis, high burden of neuropsychiatric disease and increased rates of late-onset lupus in the 'Attikon' cohort

OBJECTIVE

This study aimed to analyse the phenotype of systemic lupus erythematosus (SLE) at first presentation and during follow-up in a newly established SLE cohort based at 'Attikon' University Hospital. The hospital combines primary, secondary and tertiary care for the region of Western Attica, Greece.

METHODS

This study comprised a mixed prevalent and incident cohort of 555 Caucasian patients diagnosed with SLE according to American College of Rheumatology 1997 criteria and/or the Systemic Lupus Erythematosus International Collaborating Clinics (SLICC) 2012 criteria. Demographic and clinical characteristics, patterns of severity, treatments and SLICC damage index were recorded for each patient at the time of diagnosis and at last evaluation.

RESULTS

The mean age at lupus diagnosis was 38.3 years (standard deviation = 15.6 years), with a median disease duration at last follow-up of two years (interquartile range 1-11). At initial presentation, the most common 'classification' manifestations were arthritis (73.3%), acute cutaneous lupus (65%) and unexplained fever (25%), while among symptoms not included in any criteria set, Raynaud's phenomenon (33%) was the most common. Kidney and neuropsychiatric involvement as presenting manifestations were present in 10.3% and 11.5% cases, respectively. Irreversible damage accrual was present in 17.8% within six months of disease diagnosis, attributed mainly to thrombotic and neuropsychiatric disease. At last evaluation, 202 (36.4%) patients had developed severe disease, of whom more than half were treated with pulse cyclophosphamide.

CONCLUSION

In this cohort of Caucasian patients, lupus nephritis is not as common as in older cohorts, while neuropsychiatric disease is emerging as a major frontier in lupus prevention and care. These data may help to document changes in the natural history and treatment of SLE over time and may have implications for its early recognition and management.

An intrinsic role of IL-33 in Treg cell-mediated tumor immunoevasion

Regulatory T (T_reg) cells accumulate into tumors hindering the success of cancer immunotherapy. Yet, therapeutic targeting of T_reg cells shows limited efficacy or leads to autoimmunity. The molecular mechanisms that guide T_reg cell stability in tumors, remain elusive. Herein, we identify a cell-intrinsic role of the alarmin IL-33 in the functional stability of T_reg cells. Specifically, IL-33-deficient T_reg cells demonstrated attenuated suppressive properties in vivo and facilitated tumor regression in an ST2 (IL-33 receptor)-independent fashion. Upon activation, Il33^–/– T_reg cells exhibited epigenetic reprogramming with increased chromatin accessibility of the Ifng locus leading to elevated interferon-γ (IFN-γ) production in an NF-κB–T-bet-dependent manner. IFN-γ was essential for T_reg cell defective function since its ablation restored Il33^–/– T_reg cell suppressive properties. Importantly, genetic ablation of Il33 potentiated the therapeutic effect of immunotherapy. Our findings reveal a novel and therapeutically important intrinsic role of IL-33 in T_reg cell stability in cancer.

Transcriptome reprogramming and myeloid skewing in haematopoietic stem and progenitor cells in systemic lupus erythematosus

Objectives

Haematopoietic stem and progenitor cells (HSPCs) are multipotent cells giving rise to both myeloid and lymphoid cell lineages. We reasoned that the aberrancies of immune cells in systemic lupus erythematosus (SLE) could be traced back to HSPCs.

Methods

A global gene expression map of bone marrow (BM)-derived HSPCs was completed by RNA sequencing followed by pathway and enrichment analysis. The cell cycle status and apoptosis status of HSPCs were assessed by flow cytometry, while DNA damage was assessed via immunofluorescence.

Results

Transcriptomic analysis of Lin⁻Sca-1⁺c-Kit⁺ haematopoietic progenitors from diseased lupus mice demonstrated a strong myeloid signature with expanded frequencies of common myeloid progenitors (CMPs)—but not of common lymphoid progenitors—reminiscent of a ‘trained immunity’ signature. CMP profiling revealed an intense transcriptome reprogramming with suppression of granulocytic regulators indicative of a differentiation arrest with downregulation trend of major regulators such as Cebpe, Cebpd and Csf3r, and disturbed myelopoiesis. Despite the differentiation arrest, frequencies of BM neutrophils were markedly increased in diseased mice, suggesting an alternative granulopoiesis pathway. In patients with SLE with severe disease, haematopoietic progenitor cells (CD34⁺) demonstrated enhanced proliferation, cell differentiation and transcriptional activation of cytokines and chemokines that drive differentiation towards myelopoiesis, thus mirroring the murine data.

Conclusions

Aberrancies of immune cells in SLE can be traced back to the BM HSPCs. Priming of HSPCs and aberrant regulation of myelopoiesis may contribute to inflammation and risk of flare.

Trial registration number

4948/19-07-2016.

Aryl Hydrocarbon Receptor Contributes to the Transcriptional Program of IL-10-Producing Regulatory B Cells

Regulatory B cells (Bregs) play a critical role in the control of autoimmunity and inflammation. IL-10 production is the hallmark for the identification of Bregs. However, the molecular determinants that regulate the transcription of IL-10 and control the Breg developmental program remain unknown. Here, we demonstrate that aryl hydrocarbon receptor (AhR) regulates the differentiation and function of IL-10-producing CD19+CD21hiCD24hiBregs and limits their differentiation into B cells that contribute to inflammation. Chromatin profiling and transcriptome analyses show that loss of AhR in B cells reduces expression of IL-10 by skewing the differentiation of CD19+CD21hiCD24hiB cells into a pro-inflammatory program, under Breg-inducing conditions. B cell AhR-deficient mice develop exacerbated arthritis, show significant reductions in IL-10-producing Bregs and regulatory T cells, and show an increase in T helper (Th) 1 and Th17 cells compared with B cell AhR-sufficient mice. Thus, we identify AhR as a relevant contributor to the transcriptional regulation of Breg differentiation.

Development of an ANCA-Associated Vasculitides Patient Registry in Greece

Despite the recent advances in treatment, antineutrophil cytoplasmic antibody (ANCA) associated vasculitides (AAV) are among the rheumatic diseases with the highest morbidity and mortality. These outcomes are affected by a variety of factors apart from the disease itself, and are driven by infections, cardiovascular disease and drug toxicity. Even after the induction of remission, patients and their treating physicians are challenged by frequent relapses, accrual of chronic damage and impaired quality of life. Given their rarity along with their heterogeneous disease spectrum, patient registries are of utmost need for the study of all aspects of AAV. Already established AAV registries have a significant contribution in the apprehension of these diseases outside the strict context of clinical trials, and are becoming increasingly important as new drugs and treatment strategies are about to be introduced in daily practice. We here describe the design of a contemporary, web-based and easy-to-use patient registry specifically for patients with AAV, including all the necessary domains suggested by international working groups. This project is anticipated to contribute in better understanding of AAV in our country, with a future prospect of contributing to and sharing data with other international registries.

Sexual dimorphism in SLE: above and beyond sex hormones

Systemic lupus erythematosus (SLE) is characterized by aberrant production of auto-antibodies and a sexual dimorphism both in the phenotypic expression and frequency of the disease between males and females. The striking female predominance was initially attributed primarily to sex hormones. However, recent data challenge this simplistic view and point more towards genetic and epigenetic factors accounting for this difference. More specifically, several SLE-associated single-nucleotide polymorphisms (SNPs) have been found to play an important role in the gender predilection in SLE. Their effect is mediated through their involvement in sex-hormone and immune system signalling and dysregulation of the expression of genes and miRNAs pertinent to the immune system. Additionally, the genetic factors are interchangeably associated with epigenetic modifications such as DNA methylation and histone modification, thus revealing a highly complex network of responsible mechanisms. Of importance, disturbance in the epigenetic process of X chromosome inactivation in females as well as in rare X chromosome abnormalities leads to increased expression of X-linked immune-related genes and miRNAs, which might predispose females to SLE. Microbiota dysbiosis has also been implicated in the sexual dimorphism by the production of oestrogens within the gut and the regulation of oestrogen-responsive immune-related genes. Sexual dimorphism in SLE is an area of active research, and elucidation of its molecular basis may facilitate ongoing efforts towards personalized care.

Autophagy orchestrates the regulatory program of tumor-associated myeloid-derived suppressor cells

Myeloid-derived suppressor cells (MDSCs) densely accumulate into tumors and potently suppress antitumor immune responses, promoting tumor development. Targeting MDSCs in tumor immunotherapy has been hampered by lack of understanding of the molecular pathways that govern MDSC differentiation and function. Herein, we identify autophagy as a crucial pathway for MDSC-mediated suppression of antitumor immunity. Specifically, MDSCs in patients with melanoma and mouse melanoma exhibited increased levels of functional autophagy. Ablation of autophagy in myeloid cells markedly delayed tumor growth and endowed antitumor immune responses. Notably, tumor-infiltrating autophagy-deficient monocytic MDSCs (M-MDSCs) demonstrated impaired suppressive activity in vitro and in vivo, whereas transcriptome analysis revealed substantial differences in genes related to lysosomal function. Accordingly, autophagy-deficient M-MDSCs exhibited impaired lysosomal degradation, thereby enhancing surface expression of MHC class II molecules, resulting in efficient activation of tumor-specific CD4+ T cells. Finally, targeting of the membrane-associated RING-CH1 (MARCH1) E3 ubiquitin ligase that mediates the lysosomal degradation of MHC II in M-MDSCs attenuated their suppressive function, and resulted in markedly decreased tumor volume followed by development of a robust antitumor immunity. Collectively, these findings depict autophagy as a molecular target of MDSC-mediated suppression of antitumor immunity.

In-situ, time resolved monitoring of uranium in BFS:OPC grout. Part 2: Corrosion in water

To reflect potential conditions in a geological disposal facility, uranium was encapsulated in grout and submersed in de-ionised water for time periods between 2-47 weeks. Synchrotron X-ray Powder Diffraction and X-ray Tomography were used to identify the dominant corrosion products and measure their dimensions. Uranium dioxide was observed as the dominant corrosion product and time dependent thickness measurements were used to calculate oxidation rates. The effectiveness of physical and chemical grout properties to uranium corrosion and mobilisation is discussed and Inductively Coupled Plasma Mass Spectrometry was used to measure ²³⁸U_(aq) content in the residual water of several samples.

Tregs restrain dendritic cell autophagy to ameliorate autoimmunity

Design of efficacious Treg-based therapies and establishment of clinical tolerance in autoimmune diseases have proven to be challenging. The clinical implementation of Treg immunotherapy has been hampered by various impediments related to the stability and isolation procedures of Tregs as well as the specific in vivo targets of Treg modalities. Herein, we have demonstrated that Foxp3+ Tregs potently suppress autoimmune responses in vivo through inhibition of the autophagic machinery in DCs in a cytotoxic T-lymphocyte-associated protein 4-dependent (CTLA4-dependent) manner. Autophagy-deficient DCs exhibited reduced immunogenic potential and failed to prime autoantigen-specific CD4+ T cells to mediate autoimmunity. Mechanistically, CTLA4 binding promoted activation of the PI3K/Akt/mTOR axis and FoxO1 nuclear exclusion in DCs, leading to decreased transcription of the autophagy component microtubule-associated protein 1 light chain 3β (Lc3b). Human DCs treated with CTLA4-Ig, a fusion protein composed of the Fc region of IgG1 and the extracellular domain of CTLA4 (also known as abatacept, marketed as Orencia), demonstrated reduced levels of autophagosome formation, while DCs from CTLA4-Ig-treated rheumatoid arthritis patients displayed diminished LC3B transcripts. Collectively, our data identify the canonical autophagy pathway in DCs as a molecular target of Foxp3+ Treg-mediated suppression that leads to amelioration of autoimmune responses. These findings may pave the way for the development of therapeutic protocols that exploit Tregs for the treatment of autoimmunity as well as diseases in which disturbed tolerance is a common denominator.

Safe and prolonged survival with long-term exposure to pomalidomide in relapsed/refractory myeloma

BACKGROUND

The IFM2009-02 trial studied pomalidomide (4 mg daily, 21/28 versus 28/28) and dexamethasone in very advanced relapsed or refractory multiple myeloma (RRMM). We observed that 40% of patients had a prolonged progression-free survival (PFS) and subsequently overall survival (OS). We sought to analyze the characteristics of these patients and study the effect of long exposure to pomalidomide.

DESIGN

We separated the studied population into two groups: 3 months to 1 year (<1 year) and more than 1 year (≥1 year) of treatment with pomalidomide and dexamethasone based on clinical judgment and historical control studies. We then analyzed the characteristics of patients according to duration of treatment.

RESULTS

The overall response rate (ORR) for the <1-year group was 43%, the median PFS 4.6 months [95% confidence interval (95% CI) 3.8-6.4] with only 6% at 12 months, and the median OS was 15 months (11.7-20.3) and 40% at 18 months. For the ≥1-year group, the response rate and survival were strikingly different, ORR at 83%, median PFS 20.7 months (14.7-35.4), median OS not reached, and 91% at 18 months.

CONCLUSION

Pomalidomide and dexamethasone favored prolonged and safe exposure to treatment in 40% of heavily treated and end-stage RRMM, a paradigm shift in the natural history of RRMM characterized with a succession of shorter disease-free intervals and ultimately shorter survival. Although an optimization of pomalidomide-dexamethasone regimen is warranted in advanced RRMM, we claim that pomalidomide has proven once more to change the natural history of myeloma in this series, which should be confirmed in a larger study.

Lenalidomide with or without erythropoietin in transfusion-dependent erythropoiesis-stimulating agent-refractory lower-risk MDS without 5q deletion

After failure of erythropoiesis-stimulating agents (ESAs), lenalidomide (LEN) yields red blood cell (RBC) transfusion independence (TI) in 20-30% of lower-risk non-del5q myelodysplastic syndrome (MDS). Several observations suggest an additive effect of ESA and LEN in this situation. We performed a randomized phase III study in 131 RBC transfusion-dependent (TD, median transfusion requirement six RBC units per 8 weeks) lower-risk ESA-refractory non-del5q MDS. Patients received LEN alone, 10 mg per day, 21 days per 4 weeks (L arm) or LEN (same schedule) + erythropoietin (EPO) beta, 60,000 U per week (LE arm). In an intent-to-treat (ITT) analysis, erythroid response (HI-E, IWG 2006 criteria) after four treatment cycles (primary end point) was 23.1% (95% CI 13.5-35.2) in the L arm and 39.4% (95% CI 27.6-52.2) in the LE arm (P=0.044), while RBC-TI was reached in 13.8 and 24.2% of the patients in the L and LE arms, respectively (P=0.13). Median response duration was 18.1 and 15.1 months in the L and LE arms, respectively (P=0.47). Side effects were moderate and similar in the two arms. Low baseline serum EPO level and a G polymorphism of CRBN gene predicted HI-E. Combining LEN and EPO significantly improves erythroid response over LEN alone in lower-risk non-del5q MDS patients with anemia resistant to ESA.

An Investigation on the Persistence of Uranium Hydride during Storage of Simulant Nuclear Waste Packages

Synchrotron X-rays have been used to study the oxidation of uranium and uranium hydride when encapsulated in grout and stored in de-ionised water for 10 months. Periodic synchrotron X-ray tomography and X-ray powder diffraction have allowed measurement and identification of the arising corrosion products and the rates of corrosion. The oxidation rates of the uranium metal and uranium hydride were slower than empirically derived rates previously reported for each reactant in an anoxic water system, but without encapsulation in grout. This was attributed to the grout acting as a physical barrier limiting the access of oxidising species to the uranium surface. Uranium hydride was observed to persist throughout the 10 month storage period and industrial consequences of this observed persistence are discussed.

Nuclear waste viewed in a new light; a synchrotron study of uranium encapsulated in grout

How do you characterise the contents of a sealed nuclear waste package without breaking it open? This question is important when the contained corrosion products are potentially reactive with air and radioactive. Synchrotron X-rays have been used to perform micro-scale in-situ observation and characterisation of uranium encapsulated in grout; a simulation for a typical intermediate level waste storage packet. X-ray tomography and X-ray powder diffraction generated both qualitative and quantitative data from a grout-encapsulated uranium sample before, and after, deliberately constrained H2 corrosion. Tomographic reconstructions provided a means of assessing the extent, rates and character of the corrosion reactions by comparing the relative densities between the materials and the volume of reaction products. The oxidation of uranium in grout was found to follow the anoxic U+H2O oxidation regime, and the pore network within the grout was observed to influence the growth of uranium hydride sites across the metal surface. Powder diffraction analysis identified the corrosion products as UO2 and UH3, and permitted measurement of corrosion-induced strain. Together, X-ray tomography and diffraction provide means of accurately determining the types and extent of uranium corrosion occurring, thereby offering a future tool for isolating and studying the reactions occurring in real full-scale waste package systems.