Disease status in human and experimental arthritis, and response to TNF blockade, is associated with MHC class II invariant chain (CD74) isoform expression.

Splice variants of CD74 differentially modulate the activity of cathepsin L (CTSL). As CD74 and CTSL participate in the pathogenesis of inflammatory diseases such as rheumatoid arthritis (RA), we determined whether splice variants of CD74 could be biomarkers of disease activity. Gene expression was measured in mice with collagen-induced arthritis using quantitative PCR (qPCR). In vitro studies using murine macrophage/DC-lineage cells determined the relative influence of macrophage phenotype on isoform expression and the potential to produce CTSL in response to TNF. CD74 splice variants were measured in human RA synovium and RA patients' monocytes. In arthritic mice, the expression of the p41 CD74 isoform was significantly higher in severely affected paws compared with unaffected paws or the paws of naïve mice; the p41 isoform significantly correlated with the expression of TNF in arthritic paws. Compared with M2-like macrophages, M1-like macrophages expressed increased levels of CD74 and had higher expression, secretion and activity of CTSL. RA patients that responded to TNF blockade had significantly higher expression levels of CD74 in circulating monocytes after treatment, compared with non-responders. The expression of the human CD74 isoform a was significantly higher in RA synovia, compared with osteoarthritis synovia, and was associated with CSTL enzymatic activity. This study is the first to demonstrate differential expression of the CD74 p41 isoform in an auto-immune disorder and in response to therapy. The differential expression of CD74 splice variants indicates an association, and potentially a mechanistic role, in the pathogenesis of RA.

SARS-CoV-2 outbreak in immune-mediated inflammatory diseases: the Euro-COVIMID multicentre cross-sectional study.

BACKGROUND: The COVID-19 pandemic has raised numerous questions among patients with immune-mediated inflammatory diseases regarding potential reciprocal effects of COVID-19 and their underlying disease, and potential effects of immunomodulatory therapy on outcomes related to COVID-19. The seroprevalence of SARS-CoV-2 and factors associated with symptomatic COVID-19 in patients with immune-mediated inflammatory diseases are still unclear. The Euro-COVIMID study aimed to determine the serological and clinical prevalence of COVID-19 among patients with immune-mediated inflammatory diseases, as well as factors associated with COVID-19 occurrence and the impact of the pandemic in its management. METHODS: In this multicentre cross-sectional study, patients aged 18 years or older with a clinical diagnosis of rheumatoid arthritis, axial spondyloarthritis, systemic lupus erythematosus, Sjögren's syndrome, or giant cell arteritis were recruited from six tertiary referral centres in France, Germany, Italy, Portugal, Spain, and the UK. Demographics, comorbidities, treatments, and recent disease flares, as well as information on COVID-19 symptoms, were collected through a questionnaire completed by participants. SARS-CoV-2 serology was systematically tested. The main outcome was the serological and clinical prevalence of COVID-19. Factors associated with symptomatic COVID-19 were assessed by multivariable logistic regression, and incidence of recent disease flares, changes in treatments for underlying disease, and the reasons for treatment changes were also assessed. This study is registered with ClinicalTrials.gov, NCT04397237. FINDINGS: Between June 7 and Dec 8, 2020, 3136 patients with an immune-mediated inflammatory disease answered the questionnaire. 3028 patients (median age 58 years [IQR 46-67]; 2239 [73·9%] women and 789 [26·1%] men) with symptomatic COVID-19, serological data, or both were included in analyses. SARS-CoV-2 antibodies were detected in 166 (5·5% [95% CI 4·7-6·4]) of 3018 patients who had serology tests. Symptomatic COVID-19 occurred in 122 (4·0% [95% CI 3·4-4·8]) of 3028 patients, of whom 24 (19·7%) were admitted to hospital and four (3·3%) died. Factors associated with symptomatic COVID-19 were higher concentrations of C-reactive protein (odds ratio 1·18, 95% CI 1·05-1·33; p=0·0063), and higher numbers of recent disease flares (1·27, 1·02-1·58; p=0·030), whereas use of biological therapy was associated with reduced risk (0·51, 0·32-0·82; p=0·0057). At least one disease flare occurred in 654 (21·6%) of 3028 patients. Over the study period, 519 (20·6%) of 2514 patients had treatment changes, of which 125 (24·1%) were due to the pandemic. INTERPRETATION: This study provides key insights into the epidemiology and risk factors of COVID-19 among patients with immune-mediated inflammatory diseases. Overall, immunosuppressants do not seem to be deleterious in this scenario, and the control of inflammatory activity seems to be key when facing the pandemic. FUNDING: Pfizer, Sanofi, Amgen, Galapagos, and Lilly.

Dissecting the Role of BET Bromodomain Proteins BRD2 and BRD4 in Human NK Cell Function.

Natural killer (NK) cells are innate lymphocytes that play a pivotal role in the immune surveillance and elimination of transformed or virally infected cells. Using a chemo-genetic approach, we identify BET bromodomain containing proteins BRD2 and BRD4 as central regulators of NK cell functions, including direct cytokine secretion, NK cell contact-dependent inflammatory cytokine secretion from monocytes as well as NK cell cytolytic functions. We show that both BRD2 and BRD4 control inflammatory cytokine production in NK cells isolated from healthy volunteers and from rheumatoid arthritis patients. In contrast, knockdown of BRD4 but not of BRD2 impairs NK cell cytolytic responses, suggesting BRD4 as critical regulator of NK cell mediated tumor cell elimination. This is supported by pharmacological targeting where the first-generation pan-BET bromodomain inhibitor JQ1(+) displays anti-inflammatory effects and inhibit tumor cell eradication, while the novel bivalent BET bromodomain inhibitor AZD5153, which shows differential activity towards BET family members, does not. Given the important role of both cytokine-mediated inflammatory microenvironment and cytolytic NK cell activities in immune-oncology therapies, our findings present a compelling argument for further clinical investigation.

TLR expression profiles are a function of disease status in rheumatoid arthritis and experimental arthritis.

The role of the innate immune system has been established in the initiation and perpetuation of inflammatory disease, but less attention has been paid to its role in the resolution of inflammation and return to homeostasis. Toll-like receptor (TLR) expression profiles were analysed in tissues with differing disease status in rheumatoid arthritis (RA), ankylosing spondylitis (AS), and in experimental arthritis. TLR gene expression was measured in whole blood and monocytes, before and after TNF blockade. In RA and osteoarthritis synovia, the expression of TLRs was quantified by standard curve qPCR. In addition, four distinct stages of disease were defined and validated in collagen-induced arthritis (CIA), the gold standard animal model for RA - pre-onset, early disease, late disease and immunised mice that were resistant to the development of disease. TLR expression was measured in spleens, lymph nodes, blood cells, liver and the paws (inflamed and unaffected). In RA whole blood, the expression of TLR1, 4 and 6 was significantly reduced by TNF blockade but the differences in TLR expression profiles between responders and non-responders were less pronounced than the differences between RA and AS patients. In RA non-responders, monocytes had greater TLR2 expression prior to therapy compared to responders. The expression of TLR1, 2, 4 and 8 was higher in RA synovium compared to control OA synovium. Circulating cytokine levels in CIA resistant mice were similar to naïve mice, but anti-collagen antibodies were similar to arthritic mice. Distinct profiles of inflammatory gene expression were mapped in paws and organs with differing disease status. TLR expression in arthritic paws tended to be similar in early and late disease, with TLR1 and 2 moderately higher in late disease. TLR expression in unaffected paws varied according to gene and disease status but was generally lower in resistant paws. Disease status-specific profiles of TLR expression were observed in spleens, lymph nodes, blood cells and the liver. Notably, TLR2 expression rose then fell in the transition from naïve to pre-onset to early arthritis. TLR gene expression profiles are strongly associated with disease status. In particular, increased expression in the blood precedes clinical manifestation.

Histone H3K27me3 demethylases regulate human Th17 cell development and effector functions by impacting on metabolism.

T helper (Th) cells are CD4+ effector T cells that play a critical role in immunity by shaping the inflammatory cytokine environment in a variety of physiological and pathological situations. Using a combined chemico-genetic approach, we identify histone H3K27 demethylases KDM6A and KDM6B as central regulators of human Th subsets. The prototypic KDM6 inhibitor GSK-J4 increases genome-wide levels of the repressive H3K27me3 chromatin mark and leads to suppression of the key transcription factor RORγt during Th17 differentiation. In mature Th17 cells, GSK-J4 induces an altered transcriptional program with a profound metabolic reprogramming and concomitant suppression of IL-17 cytokine levels and reduced proliferation. Single-cell analysis reveals a specific shift from highly inflammatory cell subsets toward a resting state upon demethylase inhibition. The root cause of the observed antiinflammatory phenotype in stimulated Th17 cells is reduced expression of key metabolic transcription factors, such as PPRC1. Overall, this leads to reduced mitochondrial biogenesis, resulting in a metabolic switch with concomitant antiinflammatory effects. These data are consistent with an effect of GSK-J4 on Th17 T cell differentiation pathways directly related to proliferation and include regulation of effector cytokine profiles. This suggests that inhibiting KDM6 demethylases may be an effective, even in the short term, therapeutic target for autoimmune diseases, including ankylosing spondylitis.

Guillain-Barré syndrome complicated by takotsubo cardiomyopathy: an under-recognised association.

A 41-year-old woman was admitted with progressive paraesthesia and weakness and was diagnosed with Guillain-Barré syndrome. Following an initial period of recovery with intravenous immunoglobulin treatment, she developed acute chest pain associated with electrocardiographic changes. Investigations excluded acute coronary syndrome and instead confirmed a diagnosis of takotsubo cardiomyopathy, which was treated medically. The patient made an excellent neurological and cardiac recovery. Here we discuss the rarely described association between these two conditions and suggest that patients admitted with Guillain-Barré syndrome may benefit from routine screening with echocardiography.

A retrospective series of conditions and mortality associated with extreme hyperferritinaemia in adults.

BACKGROUND: Serum ferritin is commonly used in the diagnosis of iron deficiency anaemia. However, extreme hyperferritinaemia suggests a significant illness, including the differential diagnosis of haemophagocytic lymphohistiocytosis (HLH), which is rare and associated with a high mortality, particularly if untreated. This series aims to identify the causes and associated mortality of severe hyperferritinaemia in patients seen at a teaching hospital in London, UK. METHOD: Demographic and medical data were collected for all patients over 18 years of age with extreme hyperferritinaemia (defined as serum ferritin levels of ≥4000 mcg/L). Conditions associated with hyperferritinaemia and in-hospital mortality were identified from medical records, laboratory data and discharge and death notification. RESULTS: One hundred and fifty-five cases of extreme hyperferritinaemia in adults were identified. Associated conditions included iron overload (35%), malignancy (24%), infectious disease (21%) and hepatocellular disease (12%). Autoimmune disease and HLH resulted in significantly higher median peak ferritin levels compared with all cases (10 616 mcg/L, P < .01 and 19 138 mcg/L, P < .05, respectively). Patients with confirmed HLH had the highest median peak ferritin. Uncommon infections were identified in this series, and included such as dengue, syphilis, HIV and murine typhus. HLH had been confirmed in seven patients (5%). In five patients (3%) no clear cause for raised ferritin was identified. Overall mortality in the whole cohort was 14% (n = 22), but there was a very high mortality of 80% in the group where no cause was found for the hyperferritinaemia, and these patients were significantly more likely to die during the index admission (P < .01). CONCLUSION: Extreme hyperferritinaemia is associated with a broad differential diagnosis of significant medical conditions, including iron overload, infections, cancer and liver disease. Rare infectious causes were also identified, and this series reports a greater proportion of cases of HLH than has previously reported. Unexplained hyperferritinaemia was associated with significant mortality.

Inhibition of histone H3K27 demethylases selectively modulates inflammatory phenotypes of natural killer cells.

Natural killer (NK) cells are innate lymphocytes, important in immune surveillance and elimination of stressed, transformed, or virus-infected cells. They critically shape the inflammatory cytokine environment to orchestrate interactions of cells of the innate and adaptive immune systems. Some studies have reported that NK cell activation and cytokine secretion are controlled epigenetically but have yielded only limited insight into the mechanisms. Using chemical screening with small-molecule inhibitors of chromatin methylation and acetylation, further validated by knockdown approaches, we here identified Jumonji-type histone H3K27 demethylases as key regulators of cytokine production in human NK cell subsets. The prototypic JMJD3/UTX (Jumonji domain-containing protein 3) H3K27 demethylase inhibitor GSK-J4 increased global levels of the repressive H3K27me3 mark around transcription start sites of effector cytokine genes. Moreover, GSK-J4 reduced IFN-γ, TNFα, granulocyte-macrophage colony-stimulating factor (GM-CSF), and interleukin-10 levels in cytokine-stimulated NK cells while sparing their cytotoxic killing activity against cancer cells. The anti-inflammatory effect of GSK-J4 in NK cell subsets, isolated from peripheral blood or tissue from individuals with rheumatoid arthritis (RA), coupled with an inhibitory effect on formation of bone-resorbing osteoclasts, suggested that histone demethylase inhibition has broad utility for modulating immune and inflammatory responses. Overall, our results indicate that H3K27me3 is a dynamic and important epigenetic modification during NK cell activation and that JMJD3/UTX-driven H3K27 demethylation is critical for NK cell function.

Diagnosing water security in the rural North with an environmental security framework.

This study explores the nature of water security challenges in rural Alaska, using a framework for environmental security that entails four interrelated concepts: availability, access, utility, and stability of water resources. Many researchers and professionals agree that water insecurity is a problem in rural Alaska, although the scale and nature of the problem is contested. Some academics have argued that the problem is systemic, and rooted in an approach to water security by the state that prioritizes economic concerns over public health concerns. Health practitioners and state agencies, on the other hand, contend that much progress has been made, and that nearly all rural households have access to safe drinking water, though many are still lacking 'modern' in-home water service. Here, we draw on a synthesis of ethnographic research alongside data from state agencies to show that the persistent water insecurity problems in rural Alaska are not a problem of access to or availability of clean water, or a lack of 'modern' infrastructure, but instead are rooted in complex human dimensions of water resources management, including the political legacies of state and federal community development schemes that did not fully account for local needs and challenges. The diagnostic approach we implement here helps to identify solutions to these challenges, which accordingly focus on place-based needs and empowering local actors. The framework likewise proves to be broadly applicable to exploring water security concerns elsewhere in the world.

Unusual cause of flare in antineutrophil cytoplasmic antibody-associated vasculitis.

A 53-year-old woman attended for a routine outpatient appointment for follow-up of antineutrophil cytoplasmic antibody-positive vasculitis. Her disease had relapsed despite appropriate medical management with mycophenolate mofetil (MMF), as evidenced by rising acute phase response and antimyeloperoxidase titre with ongoing symptoms. On further questioning, she had been taking oral charcoal as part of a detoxification diet, which we postulate was causing significantly impaired MMF absorption. This case report summarises the presentation and highlights the importance of a thorough drug history, and should prompt the reader to keep an open mind with regard to drug interactions and treatment regimen adherence when treatment is, unexpectedly, seemingly failing.

Methotrexate Restores Regulatory T Cell Function Through Demethylation of the FoxP3 Upstream Enhancer in Patients With Rheumatoid Arthritis.

OBJECTIVE: We have previously shown, in a cohort of untreated rheumatoid arthritis (RA) patients, that the suppressive function of Treg cells is defective. However, other studies in cohorts of patients with established RA have shown that Treg cell function is normal. We hypothesized that treatment may restore Treg cell function and lead to reduced disease activity. The aim of this study was to investigate whether treatment with methotrexate (MTX) can result in epigenetic changes that lead to restoration of the Treg cell suppressive function in RA. METHODS: Peripheral blood samples from RA patients were assessed using (3) H-thymidine incorporation to measure Treg cell suppression of T cell proliferation, and by enzyme-linked immunosorbent assay to determine Treg cell suppression of interferon-γ production. CTLA-4 and FoxP3 expression was measured by flow cytometry and quantitative polymerase chain reaction (qPCR) in Treg cells from healthy individuals and RA patients. CD4+ T cells isolated from healthy individuals were cultured with interleukin-2 (IL-2), IL-6, and tumor necrosis factor α in the presence or absence of MTX, and FoxP3 expression was determined using qPCR and flow cytometry. Methylation of the FOXP3 upstream enhancer was analyzed by bisulfite sequencing PCR. RESULTS: Defective Treg cell function was observed only in RA patients who had not been treated with MTX, whereas Treg cells from MTX-exposed RA patients had restored suppressive function. This restored suppression was associated with increased expression of FoxP3 and CTLA-4 in Treg cells. Bisulfite sequencing PCR of Treg cells cultured in MTX revealed a significant reduction in methylation of the FOXP3 upstream enhancer. CONCLUSION: This study identifies a novel mechanism of action of MTX, in which treatment of RA patients with MTX restores defective Treg cell function through demethylation of the FOXP3 locus, leading to a subsequent increase in FoxP3 and CTLA-4 expression.

Fatal cardiac involvement complicating antisynthetase syndrome.

A 35-year-old Afro-Caribbean woman presented with dyspnoea, urticarial rash and myalgia 1 month after treatment for a community-acquired respiratory tract infection. Investigations revealed raised antisynthetase antibodies, lung fibrosis and an inflammatory myopathy. The patient was diagnosed with antisynthetase syndrome (ASS) and started on immunosuppressive medication. Despite treatment she died 4 weeks after presentation from a fulminant cardiomyopathy. ASS is a rare condition and is not typically associated with a cardiomyopathy. This case report intends to raise awareness that cardiomyopathy is a potentially fatal complication of ASS.

A novel upstream enhancer of FOXP3, sensitive to methylation-induced silencing, exhibits dysregulated methylation in rheumatoid arthritis Treg cells.

Treg-cell function is compromised in rheumatoid arthritis (RA). As the master regulator of Treg cells, FOXP3 controls development and suppressive function. Stable Treg-cell FOXP3 expression is epigenetically regulated; constitutive expression requires a demethylated Treg-specific demethylated region. Here, we hypothesised that methylation of the FOXP3 locus is altered in Treg cells of established RA patients. Methylation analysis of key regulatory regions in the FOXP3 locus was performed on Treg cells from RA patients and healthy controls. The FOXP3 Treg-specific demethylated region and proximal promoter displayed comparable methylation profiles in RA and healthy-donor Treg cells. We identified a novel differentially methylated region (DMR) upstream of the FOXP3 promoter, with enhancer activity sensitive to methylation-induced silencing. In RA Treg cells we observed significantly reduced DMR methylation and lower DNA methyltransferase (DNMT1/3A) expression compared with healthy Treg cells. Furthermore, DMR methylation negatively correlated with FOXP3 mRNA expression, and Treg cells isolated from rheumatoid factor negative RA patients were found to express significantly higher levels of FOXP3 than Treg cells from RhF-positive patients, with an associated decrease in DMR methylation. In conclusion, the novel DMR is involved in the regulation of Treg-cell FOXP3 expression, but this regulation is lost post-transcriptionally in RA Treg cells.

Treg cell function in rheumatoid arthritis is compromised by ctla-4 promoter methylation resulting in a failure to activate the indoleamine 2,3-dioxygenase pathway.

OBJECTIVE: Functionally impaired Treg cells expressing abnormally low levels of CTLA-4 have been well documented in rheumatoid arthritis (RA). However, the molecular defect underlying this reduced expression is unknown. The aims of this study were to assess the role of DNA methylation in regulating CTLA-4 expression in Treg cells isolated from RA patients and to elucidate the mechanism of their reduced suppressor function. METHODS: CTLA-4 expression in Treg cells from RA patients and healthy controls was measured by quantitative polymerase chain reaction (PCR) and flow cytometry. Methylation of the CTLA-4 gene promoter was analyzed by bisulfite-specific PCR, followed by sequencing. Methylation-dependent transcriptional activity of the CTLA-4 gene promoter was measured by luciferase assay, and NF-AT binding to the CTLA-4 gene promoter was determined by chromatin immunoprecipitation. The role of CTLA-4 expression in controlling Teff cells was analyzed using an autologous mixed lymphocyte reaction. RESULTS: Down-regulation of CTLA-4 expression in Treg cells from RA patients was caused by methylation of a previously unidentified NF-AT binding site within the CTLA-4 gene promoter. As a consequence, Treg cells were unable to induce expression and activation of the tryptophan-degrading enzyme indoleamine 2,3-dioxygenase (IDO), which in turn resulted in a failure to activate the immunomodulatory kynurenine pathway. CONCLUSION: We show for the first time that epigenetic modifications contribute to defective Treg cell function in RA through an inability to activate the IDO pathway. Therefore, this study sets a precedent for investigating potential therapeutic strategies aimed at reinforcing the IDO pathway in RA patients.