Continuous flow analysis methods for sodium, magnesium and calcium detection in the Skytrain ice core

AbstractDissolved and particulate sodium, magnesium and calcium are analyzed in ice cores to determine past changes in sea ice extent, terrestrial dust variability and atmospheric aerosol transport efficiency. They are also used to date ice cores if annual layers are visible. Multiple methods have been developed to analyze these important compounds in ice cores. Continuous flow analysis (CFA) is implemented with instruments that sample the meltstream continuously. In this study, CFA with ICP-MS (inductively coupled-plasma mass spectrometry) and fast ion chromatography (FIC) methods are compared for analysis of sodium and magnesium. ICP-MS, FIC and fluorescence methods are compared for analysis of calcium. Respective analysis of a 10 m section of the Antarctic WACSWAIN Skytrain Ice Rise ice core shows that all of the methods result in similar levels of the compounds. The ICP-MS method is the most suitable for analysis of the Skytrain ice core due to its superior precision (relative standard deviation: 1.6% for Na, 1.3% for Mg and 1.2% for Ca) and sampling frequency compared to the FIC method. The fluorescence detection method may be preferred for calcium analysis due to its higher depth resolution (1.4 cm) relative to the ICP-MS and FIC methods (~4 cm).European Research Counci

Rituximab versus tocilizumab and B-cell status in TNF-alpha inadequate-responder rheumatoid arthritis patients: the R4-RA RCT

BackgroundAlthough biological therapies have transformed the outlook for those with rheumatoid arthritis, there is a lack of any meaningful response in approximately 40% of patients. The role of B cells in rheumatoid arthritis pathogenesis is well recognised and is supported by the clinical efficacy of the B-cell-depleting agent rituximab (MabThera, F. Hoffman La-Roche Ltd, Basel, Switzerland). Rituximab is licensed for use in rheumatoid arthritis following failure of conventional synthetic disease-modifying antirheumatic drugs and tumour necrosis factor inhibitor therapy. However, over 50% of patients show low/absent synovial B-cell infiltration, suggesting that, in these patients, inflammation is driven by alternative cell types. This prompted us to test the hypothesis that, in synovial biopsy B-cell-poor patients, tocilizumab (RoActemra, F. Hoffman La-Roche Ltd, Basel, Switzerland) (targeting interleukin 6) is superior to rituximab (targeting CD20+/B cells).DesignThe R4–RA (A Randomised, open-labelled study in anti-TNFalpha inadequate responders to investigate the mechanisms for Response, Resistance to Rituximab versus Tocilizumab in Rheumatoid Arthritis patients) trial is a 48-week Phase IV, open-label, randomised controlled trial conducted in 19 European centres that recruited patients failing on or intolerant to conventional synthetic disease-modifying antirheumatic drug therapy and at least one tumour necrosis factor inhibitor.ParticipantsSynovial tissue was obtained at trial entry and classified histologically as B-cell rich or B-cell poor to inform balanced stratification. Patients were randomised on a 1 : 1 basis to receive standard therapy with rituximab or tocilizumab. B-cell-poor/-rich molecular classification was also carried out. The study was powered to test the superiority of tocilizumab over rituximab at 16 weeks in the B-cell-poor population.Main outcome measuresThe primary end point was defined as an improvement in the Clinical Disease Activity Index (CDAI) score of ≥ 50% from baseline. In addition, patients were considered to be non-responders if they did not reach an improvement in CDAI score of ≥ 50% and a CDAI score of ResultsIn total, 164 patients were randomised: 83 patients received rituximab and 81 received tocilizumab. Eighty-one out of 83 rituximab patients and 73 out of 81 tocilizumab patients completed treatment up to week 16 (primary end point). Baseline characteristics were comparable between the treatment groups. In the histologically classified B-cell-poor population (n = 79), no significant difference was observed in the primary outcome, an improvement in CDAI score of ≥ 50% from baseline (risk ratio 1.25, 95% confidence interval 0.80 to 1.96). A supplementary analysis of the CDAI-MTR, however, did reach statistical significance (risk ratio 1.96, 95% confidence interval 1.01 to 3.78). In addition, when B-cell-poor classification was determined molecularly, both the primary end point and the CDAI-MTR were statistically significant (risk ratio 1.72, 95% confidence interval 1.02 to 2.91, and risk ratio 4.12, 95% confidence interval 1.55 to 11.01, respectively). Moreover, a larger number of secondary end points achieved significance when classified molecularly than when classified histologically. In the B-cell-rich population, there was no significant difference between treatments in the majority of both primary and secondary end points. There were more adverse events and serious adverse events, such as infections, in the tocilizumab group than in the rituximab group.ConclusionTo our knowledge, this is the first biopsy-based, multicentre, randomised controlled trial of rheumatoid arthritis. We were unable to demonstrate that tocilizumab was more effective than rituximab in patients with a B-cell-poor pathotype in our primary analysis. However, superiority was shown in most of the supplementary and secondary analyses using a molecular classification. These analyses overcame possible unavoidable weaknesses in our original study plan, in which the histological method of determining B-cell status may have misclassified some participants and our chosen primary outcome was insufficiently sensitive. Given the significant results observed using the molecular classification, future research will focus on refining this stratification method and evaluating its clinical utility.Trial registrationCurrent Controlled Trials ISRCTN97443826.FundingThis project was funded by the Efficacy and Mechanism Evaluation (EME) programme, a Medical Research Council and National Institute for Health and Care Research (NIHR) partnership. This will be published in full in Efficacy and Mechanism Evaluation; Vol. 9, No. 7. See the NIHR Journals Library website for further project information

Single-cell sequencing reveals clonal expansions of pro-inflammatory synovial CD8 T cells expressing tissue-homing receptors in psoriatic arthritis.

Psoriatic arthritis (PsA) is a debilitating immune-mediated inflammatory arthritis of unknown pathogenesis commonly affecting patients with skin psoriasis. Here we use complementary single-cell approaches to study leukocytes from PsA joints. Mass cytometry demonstrates a 3-fold expansion of memory CD8 T cells in the joints of PsA patients compared to peripheral blood. Meanwhile, droplet-based and plate-based single-cell RNA sequencing of paired T cell receptor alpha and beta chain sequences show pronounced CD8 T cell clonal expansions within the joints. Transcriptome analyses find these expanded synovial CD8 T cells to express cycling, activation, tissue-homing and tissue residency markers. T cell receptor sequence comparison between patients identifies clonal convergence. Finally, chemokine receptor CXCR3 is upregulated in the expanded synovial CD8 T cells, while two CXCR3 ligands, CXCL9 and CXCL10, are elevated in PsA synovial fluid. Our data thus provide a quantitative molecular insight into the cellular immune landscape of psoriatic arthritis

A novel translational assay of response inhibition and impulsivity: effects of prefrontal cortex lesions, drugs used in ADHD, and serotonin 2C receptor antagonism

Animal models are making an increasing contribution to our understanding of the psychology and brain mechanisms underlying behavioral inhibition and impulsivity. The aim here was to develop, for the first time, a mouse analogue of the stop-signal reaction time task with high translational validity in order to be able to exploit this species in genetic and molecular investigations of impulsive behaviours. Cohorts of mice were trained to nose-poke to presentations of visual stimuli. Control of responding was manipulated by altering the onset of an auditory ‘stop-signal’ during the go response. The anticipated systematic changes in action cancellation were observed as stopping was made more difficult by placing the stop-signal closer to the execution of the action. Excitotoxic lesions of medial prefrontal cortex resulted in impaired stopping, whilst the clinically effective drugs methylphenidate and atomoxetine enhanced stopping abilities. The specific 5-HT2C receptor antagonist SB242084 also led to enhanced response control in this task. We conclude that stop-signal reaction time task performance can be successfully modelled in mice and is sensitive to prefrontal cortex dysfunction and drug treatments in a qualitatively similar manner to humans and previous rat models. Additionally, using the model we show novel and highly discrete effects of 5-HT2C receptor antagonism that suggest manipulation of 5-HT2C receptor function may be of use in correcting maladaptive impulsive behaviors and provide further evidence for dissociable contributions of serotonergic transmission to response control

Immune checkpoint inhibitor PD-1 pathway is down-regulated in synovium at various stages of rheumatoid arthritis disease progression.

Immune checkpoint blockade with therapeutic anti-cytotoxic T lymphocyte-associated antigen (CTLA)-4 (Ipilimumab) and anti-programmed death (PD)-1 (Nivolumab and Pembrolizumab) antibodies alone or in combination has shown remarkable efficacy in multiple cancer types, concomitant with immune-related adverse events, including arthralgia and inflammatory arthritis (IA) in some patients. Herein, using Nivolumab (anti-PD-1 antagonist)-responsive genes along with transcriptomics of synovial tissue from multiple stages of rheumatoid arthritis (RA) disease progression, we have interrogated the activity status of PD-1 pathway during RA development. We demonstrate that the expression of PD-1 was increased in early and established RA synovial tissue compared to normal and OA synovium, whereas that of its ligands, programmed death ligand-1 (PD-L1) and PD-L2, was increased at all the stages of RA disease progression, namely arthralgia, IA/undifferentiated arthritis, early RA and established RA. Further, we show that RA patients expressed PD-1 on a majority of synovial tissue infiltrating CD4+ and CD8+ T cells. Moreover, enrichment of Nivolumab gene signature was observed in IA and RA, indicating that the PD-1 pathway was downregulated during RA disease progression. Furthermore, serum soluble (s) PD-1 levels were increased in autoantibody positive early RA patients. Interestingly, most of the early RA synovium tissue sections showed negative PD-L1 staining by immunohistochemistry. Therefore, downregulation in PD-1 inhibitory signaling in RA could be attributed to increased serum sPD-1 and decreased synovial tissue PD-L1 levels. Taken together, these data suggest that agonistic PD1 antibody-based therapeutics may show efficacy in RA treatment and interception

Stratification of biological therapies by pathobiology in biologic-naive patients with rheumatoid arthritis (STRAP and STRAP-EU): two parallel, open-label, biopsy-driven, randomised trials

BACKGROUND: Despite highly effective targeted therapies for rheumatoid arthritis, about 40% of patients respond poorly, and predictive biomarkers for treatment choices are lacking. We did a biopsy-driven trial to compare the response to rituximab, etanercept, and tocilizumab in biologic-naive patients with rheumatoid arthritis stratified for synovial B cell status. METHODS: STRAP and STRAP-EU were two parallel, open-label, biopsy-driven, stratified, randomised, phase 3 trials done across 26 university centres in the UK and Europe. Biologic-naive patients aged 18 years or older with rheumatoid arthritis based on American College of Rheumatology (ACR)–European League Against Rheumatism classification criteria and an inadequate response to conventional synthetic disease-modifying antirheumatic drugs (DMARDs) were included. Following ultrasound-guided synovial biopsy, patients were classified as B cell poor or B cell rich according to synovial B cell signatures and randomly assigned (1:1:1) to intravenous rituximab (1000 mg at week 0 and week 2), subcutaneous tocilizumab (162 mg per week), or subcutaneous etanercept (50 mg per week). The primary outcome was the 16-week ACR20 response in the B cell-poor, intention-to-treat population (defined as all randomly assigned patients), with data pooled from the two trials, comparing etanercept and tocilizumab (grouped) versus rituximab. Safety was assessed in all patients who received at least one dose of study drug. These trials are registered with the EU Clinical Trials Register, 2014-003529-16 (STRAP) and 2017-004079-30 (STRAP-EU). FINDINGS: Between June 8, 2015, and July 4, 2019, 226 patients were randomly assigned to etanercept (n=73), tocilizumab (n=74), and rituximab (n=79). Three patients (one in each group) were excluded after randomisation because they received parenteral steroids in the 4 weeks before recruitment. 168 (75%) of 223 patients in the intention-to-treat population were women and 170 (76%) were White. In the B cell-poor population, ACR20 response at 16 weeks (primary endpoint) showed no significant differences between etanercept and tocilizumab grouped together and rituximab (46 [60%] of 77 patients vs 26 [59%] of 44; odds ratio 1·02 [95% CI 0·47–2·17], p=0·97). No differences were observed for adverse events, including serious adverse events, which occurred in six (6%) of 102 patients in the rituximab group, nine (6%) of 108 patients in the etanercept group, and three (4%) of 73 patients in the tocilizumab group (p=0·53). INTERPRETATION: In this biologic-naive population of patients with rheumatoid arthrtitis, the dichotomic classification into synovial B cell poor versus rich did not predict treatment response to B cell depletion with rituximab compared with alternative treatment strategies. However, the lack of response to rituximab in patients with a pauci-immune pathotype and the higher risk of structural damage progression in B cell-rich patients treated with rituximab warrant further investigations into the ability of synovial tissue analyses to inform disease pathogenesis and treatment response. FUNDING: UK Medical Research Council and Versus Arthritis

Tertiary Lymphoid Organs in Rheumatoid Arthritis.

Rheumatoid Arthritis (RA) is a chronic systemic autoimmune disease. RA mainly affects the joints, with inflammation of the synovial membrane, characterized by hyperplasia, neo-angiogenesis, and immune cell infiltration that drives local inflammation and, if untreated, can lead to joint destruction and disability. In parallel to the well-known clinical heterogeneity, the underlying synovitis can also be significantly heterogeneous. In particular, in about 40% of patients with RA, synovitis is characterized by a dense lymphocytic infiltrate that can acquire the features of fully functional tertiary lymphoid organs (TLO). These structures amplify autoimmunity and inflammation locally associated with worse prognosis and potential implications for treatment response. Here, we will review the current knowledge on TLO in RA, with a focus on their pathogenetic and clinical relevance

The ST22 chronology for the Skytrain Ice Rise ice core - Part 1: A stratigraphic chronology of the last 2000 years

Abstract. A new ice core was drilled in West Antarctica on Skytrain Ice Rise in field season 2018/2019. This 651 m ice core is one of the main targets of the WACSWAIN (WArm Climate Stability of the West Antarctic ice sheet in the last INterglacial) project. A present-day accumulation rate of 13.5 cm w.e. yr−1 was derived. Although the project mainly aims to investigate the last interglacial (115–130 ka), a robust chronology period covering the recent past is needed to constrain the age models for the deepest ice. Additionally, this time period is important for understanding current climatic changes in the West Antarctic region. Here, we present a stratigraphic chronology for the top 184.14 m of the Skytrain ice core based on absolute age tie points interpolated using annual layer counting encompassing the last 2000 years of climate history. Together with a model-based depth–age relationship of the deeper part of the ice core, this will form the ST22 chronology. The chemical composition, dust content, liquid conductivity, water isotope concentration and methane content of the whole core was analysed via continuous flow analysis (CFA) at the British Antarctic Survey. Annual layer counting was performed by manual counting of seasonal variations in mainly the sodium and calcium records. This counted chronology was informed and anchored by absolute age tie points, namely, the tritium peak (1965 CE) and six volcanic eruptions. Methane concentration variations were used to further constrain the counting error. A minimal error of ±1 year at the tie points was derived, accumulating to ± 5 %–10 % of the age in the unconstrained sections between tie points. This level of accuracy enables data interpretation on at least decadal timescales and provides a solid base for the dating of deeper ice, which is the second part of the chronology. </jats:p