Enhancing the repeatability and sensitivity of low-cost PCB, pH-sensitive field-effect transistors

Discrete, extended gate pH-sensitive field-effect transistors (dEGFETs) fabricated on printed circuit boards (PCBs) are a low-cost, simple to manufacture analytical technology that can be applied to a wide range of applications. Electrodeposited iridium oxide (IrOx) films have emerged as promising pH-sensitive layers owing to their theoretically high pH sensitivity and facile deposition, but typically exhibit low pH sensitivity or lack reproducibility. Moreover, to date, a combined IrOx and dEGFET PCB system has not yet been realised. In this study, we demonstrate a dEGFET pH sensor based on an extended gate manufactured on PCB that is rendered pH sensitive through an electrodeposited IrOx film, which can reliably and repeatably display beyond-Nernstian pH response. Using a combination of complementary surface analysis techniques, we show that the high pH sensitivity and repeatability of the dEGFETs are dependent on both the chemical composition and critically the uniformity of the IrOx film. The IrOx film uniformity can be enhanced through electrochemical polishing of the extended gate electrode prior to electrodeposition, leading to dEGFETs that exhibit a median pH sensitivity of 70.7 ± 5 mV/pH (n = 56) compared to only 31.3 ± 14 mV/pH (n = 31) for IrOx electrodeposited on non-polished PCB electrodes. Finally, we demonstrate the applicability of these devices by demonstrating the detection and quantification of ampicillin due to β-Lactamase enzyme activity, thus laying the foundation for cheap and ubiquitous sensors which can be applied to a range of global challenges across healthcare and environmental monitoring.

pH-dependent water permeability switching and its memory in MoS2 membranes

Intelligent transport of molecular species across different barriers is critical for various biological functions and is achieved through the unique properties of biological membranes1-4. Two essential features of intelligent transport are the ability to (1) adapt to different external and internal conditions and (2) memorize the previous state5. In biological systems, the most common form of such intelligence is expressed as hysteresis6. Despite numerous advances made over previous decades on smart membranes, it remains a challenge to create a synthetic membrane with stable hysteretic behaviour for molecular transport7-11. Here we demonstrate the memory effects and stimuli-regulated transport of molecules through an intelligent, phase-changing MoS2 membrane in response to external pH. We show that water and ion permeation through 1T' MoS2 membranes follows a pH-dependent hysteresis with a permeation rate that switches by a few orders of magnitude. We establish that this phenomenon is unique to the 1T' phase of MoS2, due to the presence of surface charge and exchangeable ions on the surface. We further demonstrate the potential application of this phenomenon in autonomous wound infection monitoring and pH-dependent nanofiltration. Our work deepens understanding of the mechanism of water transport at the nanoscale and opens an avenue for the development of intelligent membranes.

In-Operando Lithium-Ion Transport Tracking in an All-Solid-State Battery

An all-solid-state battery is a secondary battery that is charged and discharged by the transport of lithium ions between positive and negative electrodes. To fully realize the significant benefits of this battery technology, for example, higher energy densities, faster charging times, and safer operation, it is essential to understand how lithium ions are transported and distributed in the battery during operation. However, as the third lightest element, methods for quantitatively analyzing lithium during operation of an all-solid-state device are limited such that real-time tracking of lithium transport has not yet been demonstrated. Here, the authors report that the transport of lithium ions in an all-solid-state battery is quantitatively tracked in near real time by utilizing a high-intensity thermal neutron source and lithium-6 as a tracer in a thermal neutron-induced nuclear reaction. Furthermore, the authors show that the lithium-ion migration mechanism and pathway through the solid electrolyte can be determined by in-operando tracking. From these results, the authors suggest that the development of all-solid-state batteries has entered a phase where further advances can be carried out while understanding the transport of lithium ions in the batteries.

AB0034 INVESTIGATING THE ROLE OF ACCELERATED IMMUNESENESCENCE IN THE PATHOGENESIS OF RHEUMATOID ARTHRITIS

Background

Advancing age is recognised as a major risk factor for autoimmune inflammatory conditions, such as Rheumatoid Arthritis (RA). Despite strong associations with older age we understand little of the role ageing processes play in disease pathogenesis in RA. The immune system undergoes a dramatic remodelling with age, termed immunesenescence, which contributes towards increased risk of autoimmunity1. Previous research in patients with established RA has shown certain features of immunesenescence, such as thymic atrophy and telomere shortening in T cells, at a younger age2,3.

Objectives

In this study we aimed to determine if immunesenescence is seen in the very earliest stages of RA and therefore might be a contributor to RA pathogenesis rather than a result of the disease.

Methods

We have assessed aspects of the aged immune phenotype by immunostaining and flow cytometry4 in adults with arthralgia (n=25), undifferentiated arthritis (UA; n=41), confirmed RA of less than 3 months (n=25) and more than 3 months duration (n=78) and compared these to age and sex matched healthy controls (n=38). Nanostring methodology was used to determine gene expression changes associated with the development of RA.

Results

We observed increased features of T and B cell immunesenescence in DMARD-naïve recently diagnosed RA patients driven by reduced naïve T cells (p<0.01) and B cells (p<0.01), increased senescent (CD28-ve, CD57+ve, KLRG1+ve) T cells (p<0.01), an increased Th17/Treg ratio (p<0.01) and increased frequency of age-associated B cells (p<0.01). With the exception of naïve T cell frequency, which was reduced in UA patients (p<0.05), these changes were not seen in the very early stages of RA, namely patients with arthralgia and UA. These data suggest that immunesenescence only occurs once disease is established. Furthermore, using nanostring we have identified several biological ageing processes (DNA damage, autophagy) associated with this state of immunesenescence in RA.

Conclusion

Accelerated immune ageing is an early feature of RA and biological ageing processes represent novel targets to modulate disease progression.

References

[1]Duggal NA, Upton JA, Phillips AC, Sapey E, Lord JM (2013) An age-related numerical and functional deficit in CD19+CD24hiCD38hi B cells is associated with an increase in systemic autoimmunity. Aging Cell 12:873-881.

[2]Goronzy, J.J. and Weyand CM (2001). Thymic function and peripheral T-cell homeostasis in rheumatoid arthritis. Trends Immunol. 22(5):251-5.

[3]Steer SE, Williams FMK, Kato B, Gardner JP, Norman PJ, Hall MA, Kimra M, Vaughan R, Aviv A, Spector T (2007) Reduced telomere length in rheumatoid arthritis in independent of disease activity and duration. Ann Rheum Dis 66:476-480.

[4]Duggal NA, Pollock RD, Lazarus NR, Harridge S, Lord JM (2018). Major features of immunesenescence, including reduced thymic output, are ameliorated by high levels of physical activity in adulthood. Aging Cell 17:e12750

Disclosure of Interests

None declared

AB0091 INCREASED BIOLOGICAL AGE IN MALE PARTICIPANTS OF SWEDISH AND UK RHEUMATOID ARTHRITIS COHORTS IS NOT LINKED TO DISEASE

Background

Immunesenescence in the adaptive immune system, subsequent to thymic involution, results in compromised immunity and increased susceptibility to autoimmune disease and chronic inflammation. There are reports in the literature that immunesenescence, including thymic atrophy and telomere shortening, is accelerated in patients with rheumatoid arthritis (RA)1. What is unclear is whether RA includes accelerated biological ageing overall in addition to immune ageing which may help to explain the increased risk of age-related diseases in RA2. Recent studies have identified a set of DNA methylated sites across the genome that are highly correlated with chronological age and mortality, termed epigenetic clocks3,4 or DNAm age (DNAma), and can be used to determine an individual’s biological age.

Objectives

The aim of our study is to determine if the biological epigenetic clocks of RA patients are accelerated.

Methods

We evaluated the Horvath3 and Hannum4 epigenetic clocks of control and RA patients using published DNAm data sets, accessions GSE42861 (EIRA, Swedish cohort of 342 RA patients and 328 non-RA controls) and E-MTAB-6988 (77 RA discordant monozygotic twins).

Results

We did not detect significant differences between DNAma of RA and non-RA twins. Similarly, there were no significant differences between the DNAma of RA patients and controls from the Swedish EIRA cohort. However, we detected a significant acceleration in DNAma of male discordant twins, both RA and non-RA, by 5.4 years (p=3.29e-5) and 2.8 years (p=0.04) using the Hannum and Horvath clocks, respectively. Male participants, both control and RA patients, from the EIRA cohort also exhibited an accelerated DNAma, by 1.5 years (p=7.55e-5) using the Hannum clock but using the Horvath clock a significant DNAma acceleration, by 1.4 years (p=0.002) was detected in male RA patients from the EIRA cohort.

Conclusion

Overall, we detected a significant biological age acceleration in male participants from both RA and control groups and only found a significant difference between DNAma of Non-RA controls and RA patients for one of the epigenetic clocks. Further analysis using additional cohort data and biological clock algorithms is needed to confirm our findings.

References

[1]Goronzy, J.J. and Weyand CM (2001). Thymic function and peripheral T-cell homeostasis in rheumatoid arthritis. Trends Immunol. 22(5):251-5.

[2]Meune C, et al. (2009) Trends in cardiovascular mortality in patients with rheumatoid arthritis over 50 years: a systematic review and meta-analysis of cohort studies. Rheumatol 48:1309-1313.

[3]Horvath S (2013) DNA methylation age of human tissues and cell types. Genome Biol 14:R115.

[4]Hannum G, et al (2013) Genome-wide Methylation Profiles Reveal Quantitative Views of Human Aging Rates. Mol Cell 49:359-367.

Acknowledgements

The study was funded by FOREUM

Disclosure of Interests

None declared

OP0074 DISTINCT CIRCULATING LYMPHOCYTE SUBSETS DISTINGUISH FLARE FROM DRUG-FREE REMISSION IN RHEUMATOID ARTHRITIS

Background

Rheumatoid arthritis (RA) is characterised by relapsing joint and systemic inflammation, yet the immunopathological basis of these disease flares and their clinical prediction remain uncertain.

Objectives

Using mass cytometry and single cell RNA sequencing, we aimed to identify circulating lymphocyte subsets associated with RA flare, and identify potential cellular biomarkers to predict flare versus drug-free remission (DFR).

Methods

We analysed peripheral blood mononuclear cells (PBMCs) from patients recruited to the BioRRA study (Figure 1), a prospective clinical trial of conventional synthetic disease-modifying anti-rheumatic drug (csDMARD) cessation.[1] Patients with RA in clinical (DAS28-CRP < 2.4) and ultrasound (absence of power Doppler signal in 7 joints) remission stopped csDMARDs, with flare defined as DAS28-CRP ≥ 2.4 during 6 month follow-up. A 44-marker mass cytometry panel was used to profile PBMCs from 36 patients (20 flare, 16 DFR) at two time points each (baseline, and flare onset / month 6 DFR). In a subset of patients (n = 12: 8 flare, 4 DFR), fluorescence-activated cell sorting of T and B cells was followed by single cell sequencing (n = 81,923 cells) incorporating 320 immune genes, 34 oligo-tagged surface protein antibodies, and TCR/BCR CDR3 sequence. Clones were defined as ≥2 cells with identical CDR3 nucleotide sequence, and clonal expansion as a significant increase in proportion from baseline to final study visit. Statistical significance was assessed after Benjamini-Hochberg multiple test correction (adj p < 0.05).

Figure 1.

Results

Mass cytometry revealed 31 distinct cell clusters: notably, greater proportions of memory (CD45RO+/PD1hi) CD4+ and CD8+ T cells, and memory (CD27+/CD21-) B cells, were observed at onset of flare versus baseline (Table 1).

Table 1.Mass cytometry (n = 20 flare + 16 DFR)ContrastClusterMedian %Adj. p (GLMM)Flare onset vs baseline: Flare patientsCD4+/CD45RO+/PD1+ memory T cells2.14 vs 0.24<0.001CD8+/CD45RO+/PD1+ memory T cells6.64 vs 0.07<0.001CD19+/CD27+/CD21- memory B cells2.39 vs 0.03<0.001Single cell RNAseq (n = 8 flare + 4 DFR)ContrastClusterMedian %Adj. p (Wilcoxon)Flare onset vs baseline: Flare patientsIgA+ plasma cells0.37 vs 0.210.020Flare vs DFR patients: BaselineCD4+/CD25+/Foxp3+ Treg cells0.55 vs 1.270.022

To better characterise these flare-associated subsets, single cell sequencing of CD45RO+/PD1hi CD4+ and CD8+ T cells, and CD19+ B cells, was performed and identified 21 distinct clusters. CDR3 sequencing revealed significant clonal expansion (Fisher exact, adj. p < 0.05) at flare onset within five unique CD8+ clones (4 patients), one CD4+ clone (1 patent), and no B clones. Overall, there was a significantly greater proportion of IgA+ plasma cells at flare onset versus baseline. In contrast, a significantly lower proportion of CD25+/FoxP3+ regulatory T cells were present at csDMARD cessation (baseline) in subsequent flare versus DFR patients (Table 1), suggesting biomarker potential.

To further assess the predictive performance of CD4+ Tregs as a biomarker for flare versus DFR, we analysed PBMCs from an independent cohort of 50 patients (25 flare, 25 DFR) stopping csDMARDs in the ongoing BIO-FLARE study.[2] By flow cytometry, we confirmed a lower proportion of CD4+/CD25hi Tregs at baseline in flare vs DFR (median 4.74 versus 6.37%, Wilcoxon p = 0.037; AUC: 0.67). In this cohort, stopping csDMARDs only in patients with elevated (> 6.11% total CD4) baseline Tregs would have prevented drug cessation in 18/25 (72%) of flare patients; 9/25 (36%) of DFR patients would have continued csDMARDs unnecessarily.

Conclusion

We present a detailed longitudinal characterisation of circulating lymphocyte surface phenotype, gene expression, and clonal expansion in RA flare vs DFR. Furthermore our data, across two independent cohorts, suggests a role for CD4+ Tregs in promoting drug-free remission meriting further investigation, with potential for future clinical biomarker development.

References

[1]Baker et al; J Autoimmunity; 105:102298

[2]Rayner et al; BMC Rheumatology; 5:22

Acknowledgements

This work was funded by research grants from Wellcome Trust [102595/Z/13/A to KFB], Newcastle NIHR Biomedical Research Centre [BH136167/PD0045 to KFB], British Society for Rheumatology [KFB], Academy of Medical Sciences [SGL022\1074 to KFB], Newcastle University Wellcome Trust Translational Partnership [KFB], Newcastle Hospitals Charity [8033 to KFB], and a National Institute for Health Research Clinical Lectureship [CL-2017-01-004 to KFB]. Our work is supported by the Research into Inflammatory Arthritis Centre Versus Arthritis (RACE) (grant number 20298), and Rheuma Tolerance for Cure (European Union Innovative Medicines Initiative 2, grant number 777357). AGP and JDI are named as inventors on a patent application by Newcastle University (“Prediction of Drug-Free Remission in Rheumatoid Arthritis”; International Patent Application Number PCT/GB2019/050902). The views expressed are those of the authors and not necessarily those of the NHS, the NIHR, or the Department of Health and Social Care.

Disclosure of Interests

Kenneth F Baker Consultant of: Modern Biosciences Ltd, Grant/research support from: Pfizer, Genentech, Fiona Rayner: None declared, Henrique Lemos: None declared, David McDonald: None declared, Gillian Hulme: None declared, Rafiqul Hussain: None declared, Jonathan Coxhead Speakers bureau: Tesaro, Arthur Pratt Grant/research support from: Pfizer, Gilead, Amy E. Anderson: None declared, Andrew Filby Grant/research support from: Becton Dickinson, John Isaacs Speakers bureau: Abbvie, Gilead, Roche, UCB, Grant/research support from: GSK, Janssen, Pfizer.

OP0012 INTERFERON-α MEDIATED THERAPEUTIC RESISTANCE IN EARLY RA IMPLICATES EPIGENETIC REPROGRAMMING

Background

An interferon gene signature (IGS) is present in approximately 50% of early, treatment naive rheumatoid arthritis (eRA) patients. We previously demonstrated it negatively impacts on initial disease outcomes.

Objectives

To 1) reproduce previous findings demonstrating the harmful effects of the IGS on early RA clinical outcomes, 2) identify which IFN class is responsible for the IGS and 3) seek evidence that IFN-α exposure contributes to harmful epigenetic footprint at disease onset.

Methods

In a large multicentre inception cohort (n=190) of eRA patients (RA-MAP TACERA) whole blood transcriptome, IGS (MxA, IFI44L, OAS1, ISG15, IFI6) and circulating interferons (IFN)-α, -β, -γ and -λ was examined at baseline and 6 months in conjunction with disease activity and clinical characteristics. A separate eRA cohort of paired methylome and transcriptome from CD4 T and CD19 B cells (n=41 for each) was used to explore any epigenetic influence of the IGS.

Results

The baseline IGS reproducibly and significantly negatively impacts on 6-month clinical outcomes. In the high IGS cohort there was increased DAS-28 (p=0.025) and reduced probability of achieving a good EULAR response (p=0.034) at 6-months. In addition, the IGS in eRA is shown for the first time to predominantly reflect raised circulating IFN-α protein, not other classes of IFN and examination of whole blood upstream nucleic acid sensors expression suggest a RNA trigger. Both the IGS and IFN-α significantly fell in parallel at 6 months (p<0.0001), whereas other classes of IFN remained statistically static. There was a significant association with IFN-α and RF titre but not ACPA. Comparison of CD4 T and CD19 B cells between IGS high and low eRA patients demonstrated differentially methylated CPG sites and altered transcript expression of disease relevant genes e.g. PARP9, STAT1, EPTSI1 which was similarly, and persistently, altered 6 months in the separate TACERA cohort. Differentially methylated CPGs implicated altered transcription factor binding in B cells (GATA3, ETSI, NFATC2, EZH2) and T cells (p300, HIF1α) which cumulatively suggested IFN-α induced epigenetic changes promoting increased, and sustained, lymphocyte activation, proliferation and loss of anergy in the IGS high cohort.

Conclusion

We validate that the IGS is a robust prognostic biomarker in eRA predicting poor therapeutic response. Its persistent harmful effects may be driven via epigenetic modifications. These data have relevance for other IFN-α states, such as COVID-19, but also provide a rationale for the initial therapeutic targeting of IFN-α signalling, such as with JAKi, at disease onset in stratified eRA subsets.

References

nil

Acknowledgements

JDI is a National Institute for Health Research (NIHR) Senior Investigator. The authors acknowledge the support of TACERA Principal Investigators from all contributing NHS sites and the members of the TACERA Study Steering and Data Monitoring Committee. Additional acknowledgements include patient volunteers and administrative support from Ben Hargreaves. Newcastle researchers received infrastructural support via the Versus Arthritis Research into Inflammatory Arthritis Centre (Ref 22072), funding from The Medical Research Council; Academy of Medical Sciences; British Society of Rheumatology; The Wellcome Trust; JGW Patterson Foundation; Immune-Mediated Inflammatory Disease Biobank in the UK (IMID-Bio-UK), ANR and RTCure. This work was supported by the NIHR Newcastle Biomedical Research Centre at Newcastle Hospitals Foundation Trust and Newcastle University; views expressed are the authors’ and not necessarily those of the National Health Service, the National Institute of Health Research or the Department of Health.

Disclosure of Interests

Faye Cooles Speakers bureau: Astrazeneca: December 2021, Jessica Tarn: None declared, Dennis Lendrem: None declared, Najib Naamane: None declared, Alice Lin: None declared, Ben Millar: None declared, Nicola Maney: None declared, Nishanthi Thalayasingam: None declared, Vincent Bondet: None declared, Darragh Duffy: None declared, Michael Barnes: None declared, Graham Smith: None declared, Sandra Ng: None declared, David Watson: None declared, Rafael Henkin: None declared, Andrew Cope: None declared, Louise Reynard: None declared, Arthur Pratt: None declared, RA-MAP Consortium: None declared, John Isaacs Speakers bureau: speaker/consulting fees from AbbVie, Gilead, Roche and UCB., Grant/research support from: JDI discloses research grants from Pfizer, Janssen and GSK.

TRAFIC: statistical design and analysis plan for a pragmatic early phase 1/2 Bayesian adaptive dose escalation trial in rheumatoid arthritis

Background

Adaptive model-based dose-finding designs have demonstrated advantages over traditional rule-based designs but have increased statistical complexity but uptake has been slow especially outside of cancer trials. TRAFIC is a multi-centre, early phase trial in rheumatoid arthritis incorporating a model-based design.

Methods

A Bayesian adaptive dose-finding phase I trial rolling into a single-arm, single-stage phase II trial. Model parameters for phase I were chosen via Monte Carlo simulation evaluating objective performance measures under clinically relevant scenarios and incorporated stopping rules for early termination. Potential designs were further calibrated utilising dose transition pathways.

Discussion

TRAFIC is an MRC-funded trial of a re-purposed treatment demonstrating that it is possible to design, fund and implement a model-based phase I trial in a non-cancer population within conventional research funding tracks and regulatory constraints. The phase I design allows borrowing of information from previous trials, all accumulated data to be utilised in decision-making, verification of operating characteristics through simulation, improved understanding for management and oversight teams through dose transition pathways. The rolling phase II design brings efficiencies in trial conduct including site and monitoring activities and cost.

TRAFIC is the first funded model-based dose-finding trial in inflammatory disease demonstrating that small phase I/II trials can have an underlying statistical basis for decision-making and interpretation.

Trial registration

Trials Registration: ISRCTN, ISRCTN36667085. Registered on September 26, 2014.

OP0033 REGULATORY T CELL CD39 EXPRESSION AS A PREDICTOR OF EARLY REMISSION-INDUCTION WITH METHOTREXATE IN NEW-ONSET RHEUMATOID ARTHRITIS

Background:

The long term outcomes for patients with rheumatoid arthritis (RA) depend on early and effective disease control. Methotrexate remains the key first line disease modifying therapy for the majority of patients, with 40% achieving an ACR50 on monotherapy(1). There are at present no effective biomarkers to predict treatment response, preventing effective personalisation of therapy. A putative mechanism of action of methotrexate, the potentiation of anti-inflammatory adenosine signalling, may inform biomarker discovery. By antagonism of the ATIC enzyme in the purine synthesis pathway, methotrexate has been proposed to increase the release of adenosine moieties from cells, which exert an anti-inflammatory effect through interaction with ADORA2 receptors(2). Lower expression of CD39 (a cell surface 5-’ectonucleotidase required for the first step in the conversion of ATP to adenosine) on circulating regulatory T-Lymphocytes (Tregs) was previously identified in patients already established on methotrexate who were not responding (DAS28 >4.0 vs <3.0)(3). We therefore hypothesised that pre-treatment CD39 expression on these cells may have clinical utility as a predictor of early methotrexate efficacy.

Objectives:

To characterise CD39 expression in peripheral blood mononuclear cells in RA patients naïve to disease modifying therapy commencing methotrexate, and relate this expression to 4 variable DAS28CRP remission (<2.6) at 6 months.

Methods:

68 treatment naïve early RA patients starting methotrexate were recruited from the Newcastle Early Arthritis Clinic and followed up for 6 months. Serial blood samples were taken before and during methotrexate therapy with peripheral blood mononuclear cells isolated by density centrifugation. Expression of CD39 by major immune subsets (CD4+ and CD8+ T-cells, B-lymphocytes, natural killer cells and monocytes) was determined by flow cytometry. The statistical analysis used was binomial logistic regression with baseline DAS28CRP used as a covariate due to the significant association of baseline disease activity with treatment response.

Results:

Higher pre-treatment CD39 expression was observed in circulating CD4+ T-cells of patients who subsequently achieved clinical remission at 6 months versus those who did not (median fluorescence 4854.0 vs 3324.2; p = 0.0108; Figure 1-A). This CD39 expression pattern was primarily accounted for by the CD4+CD25 high sub-population (median fluorescence 9804.7 vs 6455.5; p = 0.0065; Figure 1-B). These CD25 high cells were observed to have higher FoxP3 and lower CD127 expression than their CD39 negative counterparts, indicating a Treg phenotype. No significant associations were observed with any other circulating subset. A ROC curve demonstrates the discriminative utility of differential CD39 expression in the CD4+CD25 high population for the prediction of DAS28CRP remission in this cohort, showing greater specificity than sensitivity for remission prediction(AUC: 0.725; 95% CI: 0.53 - 0.92; Figure 1-C). Longitudinally, no significant induction or suppression of the CD39 marker was observed amongst patients who did or did not achieve remission over the 6 months follow-up period.

Figure 1.

Six month DAS28CRP remission versus pre-treatment median fluorescence of CD39 expression on CD4+ T-cells (A); CD25 High expressing CD4+ T-cells (B); and ROC curve of predictive utility of pre-treatment CD39 expression on CD25 High CD4+ T-cells (C).

Conclusion:

These findings support the potential role of CD39 in the mechanism of methotrexate response. Expression of CD39 on circulating Tregs in treatment-naïve RA patients may have particular value in identifying early RA patients likely to respond to methotrexate, and hence add value to evolving multi-parameter discriminatory algorithms.

References:

[1]Hazlewood GS, et al. BMJ. 2016 21;353:i1777

[2]Brown PM, et al. Nat Rev Rheumatol. 2016;12(12):731-742

[3]Peres RS, et al. Proc Natl Acad Sci U S A. 2015;112(8):2509-2514

Disclosure of Interests:

None declared

AB0025 CITRULLINATED-PEPTIDE SPECIFIC CD4+ T CELL RESPONSES IN RHEUMATOID ARHRITIS

Background:

CD4+ T cells reacting to post-translationally modified, citrullinated self-antigens are thought to play a central role in the pathogenesis of rheumatoid arthritis (RA)1. This is evidenced by a strong HLA class II association, the success of therapeutic co-stimulation blockade and the detection of autoantigen specific T-cells using HLA class II multimers2. These cells may represent a target for antigen-specific, tolerogenic therapies and their in-depth phenotyping may provide the means by which to monitor such treatment.

Objectives:

To identify the citrullinated-peptide (cit-peptide) induced cytokine repertoire of antigen-specific memory CD4+ T cells in both healthy controls (HCs) and ACPA positive RA patients using intracellular cytokine staining and flow cytometry. Of note, the HLA-types of both HCs and RA patients were not known.

Methods:

Cryopreserved peripheral blood mononuclear cells (PBMC) from both HCs (n = 8) and RA patients (n = 13) with both early (untreated) and established disease were thawed and labelled with a proliferation tracking dye (PTD). Labelled PBMC were then either incubated alone or with a pool of cit-peptides for 9-days, followed by a 5-hour restimulation with PMA and ionomycin, where cytokine secretion was blocked for the final 4-hours using brefeldin-A. Cells were then harvested, permeabilised and stained for T cell surface markers and intracellular cytokines including IFN-γ, IL-4, IL-21 and IL-17. Stained cells were immediately acquired using a BD Fortessa X20, where antigen-specific CD4+ T cells were identified as the viable CD45RO+ (memory) CD4+ T cell population that had proliferated (PTDlow) in response to the cit-peptides. Stimulation indices (SI) were calculated as the percentage of proliferated memory CD4+ T cells in the stimulated wells divided by the percentage in the unstimulated conditions, and cit-peptide responders were defined as those with an SI > 2.0. Net cytokine production was measured by subtracting the percentage cytokine production from unstimulated CD4+ CD45RO+ PTDlow cells, from those stimulated with the cit-peptides.

Results:

Comparable proliferative responses were observed in both donor groups in response to stimulation with the cit-peptide pool, where 37 % of HCs and 31 % of RA patients responded with an SI > 2.0 (Fig. 1A). While little cytokine production was observed in the cit-peptide responding HC T cells, for responding RA donors, cit-peptide responsive CD4+ memory T cells were predominantly IFN-γ and IL-21 producing (Fig. 1B and 1C). In contrast, these donors did not produce significant levels of either IL-17 or IL-4 (Fig. 1D and 1E).

Conclusion:

Cit-peptides were able to induce proliferation in both HCs and RA memory CD4+ T cells which, amongst the RA donors only, were of a Th1/Tfh subtype. In contrast, and while based only on a small sample, cit-peptides did not induce either IL-17 or IL-4 production in either donor group, suggesting a lack of Th17/Th2 responses. Not all donors responded to the peptide pool, possibly reflecting the limited number of pooled cit-peptides or to a lack of confirmed HLA-DRB1*04:01 positive donors, as peptides were selected for their specificity on this basis. Future work will therefore include HLA-typing, as well as the inclusion of additional citrullinated-epitopes to demonstrate autoreactivity in a wider cross-section of patients. Further phenotyping of the cit-peptide specific T cells will be performed, and future plans will be to study the assay data alongside clinical outcomes to assess its value for immune monitoring.

References:

[1]Malmström, V et al Nat Rev Immunol. 2017; 17(1):60-75.

[2]Gerstner, C et al BMC Immunol. 2020; 21(27):1-14.

Disclosure of Interests:

Jessica Swift: None declared, James Stanway: None declared, Ioana Nicorescu: None declared, Catharien Hilkens: None declared, Frederik Stevenaert Employee of: Janssen, Amy Anderson Grant/research support from: Pfizer, GSK and Janssen, Arthur Pratt Grant/research support from: Pfizer, GSK and Janssen, John D Isaacs Speakers bureau: Abbvie, Gilead, Roche, UC, Consultant of: Abbvie, Gilead, Roche, UC, Grant/research support from: Pfizer, GSK and Janssen

Figure 1.

Citrullinated-peptide specific memory CD4+ T cell proliferation (A) and net % cytokine production of IFN-γ (B), IL-21 (C), IL-17 (D) and IL-4 (E) positive cells.

POS0348 GENETIC SUSCEPTIBILITY VARIANTS FOR RHEUMATOID ARTHRITIS ARE NOT ASSOCIATED WITH EARLY REMISSION; A MULTI-COHORT STUDY

Background:

Patients who achieve remission promptly could have a specific genetic risk profile that supports regaining immune tolerance. The identification of these genes could provide novel drug targets.

Objectives:

To test the association between RA genetic risk variants with achieving remission at 6 months.

Methods:

We computed genetic risk scores (GRS) comprising of the RA susceptibility variants1 and HLA-SE status separately in 4425 patients across eight datasets from inception cohorts. Remission was defined as DAS28CRP<2.6 at 6 months. Missing DAS28CRP values in patients were imputed using predictive mean matching by MICE. We first tested whether baseline DAS28CRP changed with increasing GRS using linear regression. Next, we calculated odds ratios for GRS and HLA-SE on remission using logistic regression. Heterogeneity of the outcome between datasets was mitigated by running inverse variance meta-analysis.

Results:

Evaluation of the complete dataset, baseline clinical variables did not differ between patients achieving remission and those who did not (Table 1). Distribution of GRS was consistent between datasets. Neither GRS nor HLA-SE was associated with baseline DAS2DAS (OR1.01; 95% CI 0.99-1.04). A fixed effect meta-analysis (Figure 1.) showed no significant effect of the GRS (OR 0.99; 95% CI 0.94-1.03) or HLA-SE (OR 0.8CRP87; 95% CI 0.75-1.01) on remission at 6 months.

Table 1.

Summary of the data separated by disease activity after 6 months.

allRemission at 6 monthsNo remission at 6 monthsN4425*15582430Age, mean (sd)55.38 (13.87)5517 (14.09)55.62 (13.59)Female %68.98%65.43%70.73%ACPA+ %61.94%63.53%61.67%Baseline DAS28, mean (sd)4.76 (1.22)4.47 (1.23)5.1 (1.15)

*not all patients had 6 months data

Conclusion:

In these combined cohorts, RA genetics risk variants are not associated with early disease remission. At baseline there was no difference in genetic risk between patients achieving remission or not. Studies encompassing other genetic variants are needed to elucidate the genetics of RA remission.

References:

[1]Knevel R et al. Sci Transl Med. 2020;12(545):eaay1548.

Acknowledgements:

This project has received funding from the Innovative Medicines Initiative 2 Joint Undertaking under grant agreement No 777357, RTCure.

This project has received funding from Pfizer Inc.

Disclosure of Interests:

Samantha Jurado Zapata: None declared, Marc Maurits: None declared, Yann Abraham Employee of: Pfizer, Erik van den Akker: None declared, Anne Barton: None declared, Philip Brown: None declared, Andrew Cope: None declared, Isidoro González-Álvaro: None declared, Carl Goodyear: None declared, Annette van der Helm - van Mil: None declared, Xinli Hu Employee of: Pfizer, Thomas Huizinga: None declared, Martina Johannesson: None declared, Lars Klareskog: None declared, Dennis Lendrem: None declared, Iain McInnes: None declared, Fraser Morton: None declared, Caron Paterson: None declared, Duncan Porter: None declared, Arthur Pratt: None declared, Luis Rodriguez Rodriguez: None declared, Daniela Sieghart: None declared, Paul Studenic: None declared, Suzanne Verstappen: None declared, Leonid Padyukov: None declared, Aaron Winkler Employee of: Pfizer, John D Isaacs: None declared, Rachel Knevel Grant/research support from: Pfizer

AB0021 CHARACTERISATION OF AGE-ASSOCIATED B CELLS IN EARLY, DRUG NAÏVE RHEUMATOID ARTHRITIS

Background:

Rheumatoid arthritis (RA) is a chronic inflammatory disease of immune dysregulation affecting the joints. While T cells play a recognised role in disease pathogenesis, the presence of autoantibodies years before the clinical onset of disease, and the efficacy of the B cell-depleting therapy rituximab, highlight a pathogenic role for these functionally diverse lymphocytes. A novel subset, termed age-associated B cells (ABCs), are described as CD19high CD21- CD11c+, with a high proportion expressing the transcription factor T-bet; they are elevated in murine models of autoimmunity and produce autoantibodies characteristic of autoimmune disease. A detailed characterisation of ABCs in early, drug naïve RA has not yet been conducted.

Objectives:

We aimed to characterise peripheral blood (PB) and synovial fluid (SF) ABCs in patients suffering from early drug naïve RA. As a secondary objective we sought to determine whether this population differs between RA patients and age-matched early psoriatic arthritis (PsA; disease controls) and healthy controls.

Methods:

Newly presenting early RA and other inflammatory arthritis patients, naïve to immunomodulatory treatment, were recruited from the Newcastle Early Arthritis Clinic. Patients with established RA (≥1 year duration on treatment and age-matched healthy controls were recruited in parallel. B cell subsets (naïve (CD19+IgD+CD27-), switched memory (CD19+IgD-CD27+) and ABC (CD19+CD21-CD11c+)) in PB and SF were characterised by flow cytometry. FACS sorted PB B cell subset gene expression profiles were assessed using a customised NanoString nCounter Human Immunology v2 Panel.

Results:

Transcriptionally, ABC differed from both naïve and switched memory B cells. In keeping with published studies ABCs had an activated memory phenotype, exemplified by elevated expression of CD69, CD80, and CD86, as well as Ki67, HLA-DR, IgG and T-bet. Interestingly, ABC had high expression of the Fc Receptor Like (FcRL) family (FcRL1-5), and an inflammatory homing profile (high levels of CXCR3 and low levels of CXCR4 and CXCR5). We found no difference in the proportion of PB ABC between RA patients and control groups, and no association of ABC frequencies with age. Focussing on RA ABCs specifically, we observed elevated ABC frequencies in females, but no association with disease activity. In keeping with their chemokine receptor profile, cross-sectional analysis also demonstrated ABC enrichment in SF compared to PB, with SF frequencies higher in established than early disease. The transcriptome of ABCs from early RA patients differed from both age-matched disease controls and healthy donors (Figure 1 next page).

Conclusion:

These data demonstrate that ABCs have a unique, activated, class-switched proliferative phenotype that is transcriptionally distinct from switched memory and naïve B cells. Interestingly, at the transcriptome level early RA ABCs differ to their counterparts in health and other inflammatory arthritides, suggesting they may differ functionally and contribute to pathogenesis. Of note, their high expression of MHC class II (HLA-DR) and co-stimulatory (CD80 and CD86) molecules suggests an important antigen-presentation function of ABC, which together with their unique FcRL family expression pattern, warrants further functional characterisation.

Figure 1.

Differential gene expression in ABCs from early RA patients compared to early PsA patients (A) and healthy controls (B). A NanoString nCounter Technologies chip was used to assess gene expression. Raw counts were normalised to the housekeeping genes. Sample quality was then assessed using the arrayQualityMetrics package. Gene expression profiles between different donor groups was assessed using the DESeq2 R package. In both hierarchical clustering heatmaps gene expression intensities were log2 transformed and their z-scores are displayed as colours ranging from yellow (low expression) to red (high expression) as shown in the key.

Disclosure of Interests:

Gemma Vidal-Pedrola: None declared, Najib Naamane: None declared, Dagmar Scheel-Toellner: None declared, Arthur Pratt Grant/research support from: GSK, Pfizer and Janssen, Andrew Mellor: None declared, John D Isaacs Speakers bureau: Abbvie, Gilead, Roche, UC, Consultant of: Abbvie, Gilead, Roche, UC, Grant/research support from: Pfizer, GSK and Janssen, Amy E. Anderson Grant/research support from: Pfizer, GSK and Janssen

Magnetically Triggered Release of Entrapped Bioactive Proteins from Thermally Responsive Polymer-Coated Iron Oxide Nanoparticles for Stem-Cell Proliferation

Nanoparticles could conceal bioactive proteins during therapeutic delivery, avoiding side effects. Superparamagnetic iron oxide nanoparticles (SPIONs) coated with a temperature-sensitive polymer were tested for protein release. We show that coated SPIONs can entrap test proteins and release them in a temperature-controlled manner in a biological system. Magnetically heating SPIONs triggered protein release at bulk solution temperatures below the polymer transition. The entrapped growth factor Wnt3a was inactive until magnetically triggered release, upon which it could increase mesenchymal stem cell proliferation. Once the polymer transition will be chemically adjusted above body temperature, this system could be used for targeted cell stimulation in model animals and humans.

AB0356 TARGETING THE RHEUMATOID ARTHRITIS SYNOVIAL FIBROBLAST VIA CYCLIN DEPENDENT KINASE INHIBITION (TRAFIC): A PHASE 1B STUDY TO DETERMINE THE MAXIMUM TOLERATED DOSE OF SELICICLIB FOR REPURPOSING IN RHEUMATOID ARTHRITIS

Background:

Current rheumatoid arthritis (RA) therapeutics target immune inflammation and are subject to ceiling effects, with non-response observed in a third of recipients together with low remission rates. Synovial fibroblasts (SFs) are stromal cells not yet targeted in RA, whose hyperplastic and proliferative properties drive inflammation and tissue destruction. Seliciclib (R-roscovitine) is an orally available cyclin-dependent kinase (CDK) inhibitor that suppresses SF proliferation and ameliorates inflammatory arthritis in rodents.

Objectives:

To determine the maximum tolerated dose (MTD) of seliciclib in patients with active RA despite anti-TNF, with or without background conventional disease modifying anti-rheumatic drugs (cDMARDs). Safety and pharmacokinetics (PK) were also evaluated.

Methods:

A restricted, one-stage Bayesian continual reassessment method (CRM) determined MTD based on a target dose-limiting toxicity (DLT) probability of 35%. RA patients (DAS28 ≥3.2) were recruited sequentially to cohorts of 3 subjects each. Cohort 1 received 400mg seliciclib daily for 4 consecutive days each week for 4 weeks, added to existing therapy. Each subsequent cohort received a dose determined by the toxicity-based CRM algorithm, calculated upon conclusion of the previous cohort. Safety was assessed through adverse event (AE) monitoring. Associations with relevant PK parameters were sought.

Results:

15 anti-TNF recipients were enrolled, 10 of whom were also taking cDMARDs (median DAS28 4.9). Application of the CRM algorithm prompted one dose increment during the study (to 600mg for cohort 2), but reversion to 400mg for subsequent cohorts (Figure 1A). After treatment of 5 cohorts, 400mg was determined the MTD, with a DLT probability of 0.35 (CI 0.18-0.52; Figure 1B). 6 patients experienced DLTs, of which two were classified as serious AEs (SAEs) in keeping with the safety profile of seliciclib; these are summarised in Table 1. Of 43/65 total AEs reported at any dose that didnotcontribute to a DLT, 26 were possibly, probably or definitely related to seliciclib; 19 of these 26 were mild, 7 moderate and none severe. The most frequent AE was mild nausea. No relationship of safety and/or tolerability with concomitant cDMARD use or PK was seen.

Table 1.

Characteristics of patients who developed HZ at initiation of baricitinib

DLTSeliciclib dose (mg)Doses receivedContributing AEsContributing SAEsDescriptionOutcomeA1400830Constipation, N+V, liver injury; fatigue.Resolved2600430Constipation, N+V.Resolved3600101BFever, N+V, renal injury.Resolved4400831BConstipation, N+V, jaundice, liver injury.Resolved5400840Fever, dizziness, liver injury.Resolved6400890Dizziness, N+V, liver injury, bilirubin rise.Persistent AST rise

Conclusion:

The MTD of seliciclib has been defined for RA. No unexpected safety concerns were identified to preclude ongoing evaluation in patients, which focuses on clinical, radiological and biological indicators of efficacy.

Disclosure of Interests:

Arthur Pratt Grant/research support from: Pfizer, GlaxoSmithKlein, Stefan Siebert Grant/research support from: BMS, Boehringer Ingelheim, Celgene, GlaxoSmithKline, Janssen, Novartis, Pfizer, UCB, Consultant of: AbbVie, Boehringer Ingelheim, Janssen, Novartis, Pfizer, UCB, Speakers bureau: AbbVie, Celgene, Janssen, Novartis, Michael Cole: None declared, Deborah Stocken: None declared, Stephen Kelly: None declared, Muddassir Shaikh: None declared, Amy Cranston: None declared, Miranda Morton: None declared, Jennifer Walker: None declared, Sheelagh Frame Employee of: Cyclacel Ltd., Wan-fai Ng: None declared, Chris Buckley Consultant of: Janssen, Pfizer, GSK, Galapagos, Gillead, Iain McInnes Grant/research support from: Bristol-Myers Squibb, Celgene, Eli Lilly and Company, Janssen, and UCB, Consultant of: AbbVie, Bristol-Myers Squibb, Celgene, Eli Lilly and Company, Gilead, Janssen, Novartis, Pfizer, and UCB, Andrew Filer: None declared, John D Isaacs Consultant of: AbbVie, Bristol-Myers Squibb, Eli Lilly, Gilead, Janssen, Merck, Pfizer, Roche

THU0026 CLONAL HAEMATOPOIESIS ASSOCIATED SOMATIC MUTATIONS IN RHEUMATOID ARTHRITIS

Background:

Clonal haematopoiesis of indeterminate potential (CHIP) occurs when somatic mutations arise in myeloid neoplasia driver genes of haematopoietic progenitor cells, in the absence of overt cytopenia or dysplasia. The prevalence of CHIP increases with age. The most common genes affected by CHIP mutations in unselected populations are DNMT3A, ASXL1, and TET2. The presence of CHIP is linked to increased basal level of inflammation and a high risk of cardiovascular disease and all-cause mortality. Rheumatoid arthritis (RA) is one of the most common and debilitating multi-system autoimmune disorders, affecting up to 1% of adults in developed countries. The role of somatic mutations in the pathogenesis of autoimmune diseases is an unexplored area; therefore, we aimed to test the hypothesis that clonal haematopoiesis (CH) is associated with the incidence and severity of RA.

Objectives:

To evaluate the association of CH somatic mutation with severity of RA.

Methods:

163 RA patients were recruited from the following cohorts: (i)Early RA/treatment naive (n=31), (ii)Refractory RA - non-responders to Disease-Modifying Anti-Rheumatic Drugs (DMARDs) and biologics (n=48), (ii)Flare (n=41) vsRemission patients (n=43) –patients treated with DMARDs and withdrawn from treatment on achieving remission. Six months later, 50% relapse and 50% sustain remission. Single molecule molecular inversion probes (smMIPs) were used to screen for somatic mutations in 40 loci known to carry clonal haematopoiesis driver mutations (CHDMs). Whole exome sequencing was also performed on Flare/Remission patients (n = 84) to screen for CHDMs and other somatic mutations. In-house bioinformatics pipelines were used to call mutations from both the datasets.

Results:

We identified CH in RA with an overall prevalence of 14%. Twenty-four unique variants with a variant allele frequency (VAF) of 2-35% were found in ten genes including ASXL1, CBL, DNMT3A, GNAS, GNB1, PTPN11, PTPN12, SF3B1, TET2, and TP53. The number of unique patients carrying mutations in these genes are follows:refractory: n=12/48, flare: n=6/41,remission: n=4/43 andearly RA: n=2/31. The majority of the mutations occurred in DNMT3A (n=6) followed by TP53 (N=4) and TET2 (n=3). Two variants with VAF of 15% were identified in two patients under the age of 30, both with clinically severe disease. In patients between the ages of 50-59 yrs., 60-69 yrs., and 70-79 yrs., CH was observed at 11% (4/35), 23% (11/46) and 17%(7/41), respectively.

Conclusion:

We here report the prevalence of CH in RA, affecting more patients with clinically advanced/refractory disease compared to those with early/less severe disease.

Further study will be conducted to confirm the results.

References:

[1]Acuna-Hidalgo, R., Sengul, H., Steehouwer, M., van de Vorst, M., Vermeulen, S., & Kiemeney, L. et al. (2017). Ultra-sensitive Sequencing Identifies High Prevalence of Clonal Hematopoiesis-Associated Mutations throughout Adult Life.The American Journal Of Human Genetics,101(1), 50-64. doi: 10.1016/j.ajhg.2017.05.013

[2]NRAS - National Rheumatoid Arthritis Society. (2020). Retrieved 30 January 2020, fromhttps://www.nras.org.uk/what-is-ra-article

[3]Steensma, D., Bejar, R., Jaiswal, S., Lindsley, R., Sekeres, M., Hasserjian, R., & Ebert, B. (2015). Clonal hematopoiesis of indeterminate potential and its distinction from myelodysplastic syndromes.Blood,126(1), 9-16. doi: 10.1182/blood-2015-03-631747

Acknowledgments:

National Institute for Health Research, United Kingdom

Disclosure of Interests:

Fareeha Tariq: None declared, Bilal Alobaidi: None declared, Miguel Xavier: None declared, Michael McCorkindale: None declared, Joris Veltman: None declared, John Isaacs Consultant of: AbbVie, Bristol-Myers Squibb, Eli Lilly, Gilead, Janssen, Merck, Pfizer, Roche, Arthur Pratt Grant/research support from: Pfizer, GSK, Amy Anderson: None declared, Matthew Collin: None declared

SAT0013 PIM-1 KINASE IS A MEASURABLE MEDIATOR OF CD4+ T CELL DYSREGULATION AND THERAPEUTIC TARGET IN EARLY RHEUMATOID ARTHRITIS

Background:

As well as being an established oncoprotein and a therapeutic target in cancer,Proviral Integration site for murine Moloney leukemia virus-1(pim-1) has been implicated in human autoimmunity. We previously confirmed this serine-threonine protein kinase to be strikingly upregulated in circulating CD4+ T cells of untreated rheumatoid arthritis (RA) patients as a consequence of IL-6 signalling1-2. Evidence for the relevance of pim-1 signalling in the disruption of RA synovial fibroblast (RASF) homeostasis3further supports its candidacy as a therapeutic target.

Objectives:

To investigate PIM1 and its family members (PIM2 and PIM3) as potential candidates for drug repurposing in RA.

Methods:

A flow cytometric assay for PIM1 transcript measurement in circulating CD4+ T cells of early arthritis patients was validated against real-time PCR in paired cells isolated by bead selection. Synovial protein expression in tissue from the same cohort of untreated RA patients and disease controls was determined by quantitative multiplex immunofluorescence. The functional consequences of manipulating pim kinase family expression in freshly purified T cell receptor (TCR)-stimulated CD4+ T cells from early RA patients was explored. The impact of pim-1 specific and pim-1-3 (pan-pim) kinase inhibition on progression of the IL-6 dependent collagen-induced arthritis (CIA) model was assessed.

Results:

The percentage of circulating CD4+ T cells positive forPIM1transcript by flow cytometry proved a faithful surrogate for gene expression in early arthritis (Figure 1A), distinguishing RA from other pathologies (Figure 1B). Pim-1 protein expression was increased in the synovium of untreated RA compared with disease controls, including amongst infiltrating CD4+ T cells (Figure 1C-D).In vitro, exposure of TCR-stimulated early RA CD4+ T cells to pim kinase inhibitors restrained their activation and proliferative capacity; diminished pro-inflammatory cytokine production (IFN-g and IL-17) and an expanded CD25hiFoxP3+ regulatory T cell (Treg) fraction were also observed in treatedversusun-treated cells. Finally, administration of pim inhibitors robustly attenuated clinical scores of arthritis in the CIA model, with reduced cartilage loss observed in animals treated with a pan-PIM inhibitor compared with vehicle control (Figure 2).

Conclusion:

Our data highlight pim kinases as plausible therapeutic targets for a subgroup of early RA patients that may be identifiable using tractable in vitro assays. Pim kinase inhibitors could simultaneously target immune inflammation and RASF dysregulation; consideration should now be given to their repurposing for this condition.

References:

[1] Anderson AE et al Annals of the Rheumatic Diseases 2016; 75:466-73.

[2] Anderson AE et al Rheumatology 2019; 58:1250-1258

[3] Ha YJ et al Rheumatology 2019; 58:154-64

Disclosure of Interests:

Nicola Maney Consultant of: Current employee of Eli Lilly, Henrique De Paula-Lemos: None declared, Ben Barron-Millar: None declared, Andrew Mellor Shareholder of: NewLink Genetics PLC, and has received patent licensing income from this source., John D Isaacs Consultant of: AbbVie, Bristol-Myers Squibb, Eli Lilly, Gilead, Janssen, Merck, Pfizer, Roche, Amy Anderson: None declared, Arthur Pratt Grant/research support from: Pfizer, GlaxoSmithKlein

AB0220 TENOSYNOVITIS AS THE PRESENTING FEATURE OF FLARE IN RHEUMATOID ARTHRITIS

Background:

The importance and relevance of tenosynovitis (TS) has long been recognised in rheumatoid arthritis (RA), but it is not usually considered in disease activity assessments. The significance of TS in early arthritis (EA) has also been recognised and, using ultrasound (US) it has recently been identified as a precursor to RA1. The ongoing BIO-FLARE (BIOlogical Factors that Limit sustAined Remission in rhEumatoid arthritis) observational study aims to investigate the pathogenesis of flare in RA. Patients with RA in remission stop their disease modifying anti-rheumatic drug medication (DMARDs: methotrexate, sulfasalazine and/or hydroxychloroquine) and are closely followed for 6 months, in anticipation that approximately 50% will experience a flare. We investigated whether TS occurrence was a frequent herald of flare in this cohort.

Objectives:

To review the case notes of 49 patients in the BIO-FLARE study with confirmed flare to date, seeking evidence of US tenosynovitis prior to or concurrent with flare.

Methods:

Patients in the study who are deemed to be in remission based on a disease activity score (DAS28-CRP) < 2.4 stop their DMARD medication and attend regularly for review over 6 months, with provision for ad-hoc appointments if symptoms return between visits. Patients are defined as having a flare if their DAS28-CRP ≥ 3.2 at any point or two consecutive DAS28-CRP ≥ 2.4. Targeted US assessment occurs at baseline only for patients that consent to an optional baseline ultrasound-guided synovial biopsy. If a flare occurs, US of symptomatic joints is undertaken, to assess suitability for a synovial biopsy. Following this, the patient receives a steroid injection and restarts their DMARD medication.

Results:

To January 2020, 120 patients had been recruited into the study and 49 experienced a flare. Seven patients had a flare predominantly or initially characterised by TS or paratenonitis, the results of which are summarised in Table 1.

Table 1.

Tenosynovitis in BIO-FLARE

DMARD stoppedTime to TS, weeksTendon involvedTime to flare, weeksJoints involved1Methotrexate, sulfasalazine, hydroxychloroquine12Extensor carpi ulnaris12Shoulders and PIPJs, no synovitis suitable to biopsy2Methotrexate7Bilateral extensor carpi ulnaris7Shoulders, wrists, knees, PIPJ with no accompanying synovitis3Methotrexate5Tibialis posterior5No joints flared, no synovitis but treated as a flare due to severity of TS4Methotrexate8Tibialis posterior – attributed to increase in patient activity22MCPJ, PIPJs, mid tarsal and MTPJ5Methotrexate and hydroxychloroquine7Extensor policis longus8Polyarticular flare6Methotrexate and hydroxychloroquine2Extensor carpi ulnaris – attributed to overuse6Polyarticular flare7Methotrexate12Extensor paratenonitis at PIPJ4 & 512MCPJ synovitis

Conclusion:

Although highlighted as a precursor of RA in early arthritis1, the occurrence of TS in the context of flare – and the prodrome heralding this – has not been studied. Our findings show that TS in early flare is reminiscent of the features sometimes seen in EA or clinically suspect arthralgia2. Further data are required to determine the role of periarticular inflammatory phenomena, such as TS, as risk factors for joint synovitis. Our study did not entail formal US assessments, therefore the rate of TS in this population may be under estimated. Careful study of RA patients in early phase of disease flare may pose an opportunity to characterise the nature and chronology of this association in greater depth.

References:

[1]Sahbudin I et al. Rheumatology. 2018;57(7):1243-1252

[2]Mankia K et al. Ann rheum dis. 2019;78(6):781-786

Acknowledgments:

The Research was funded by the Medical Research Council and supported by NIHR Newcastle Biomedical Research Centre

Disclosure of Interests:

Fiona Rayner: None declared, Sean Kerrigan: None declared, Bernard Dyke: None declared, Andrew McGucken: None declared, Mark Maybury: None declared, Andrew Filer: None declared, Arthur Pratt Grant/research support from: Pfizer, GlaxoSmithKlein, John Isaacs Consultant of: AbbVie, Bristol-Myers Squibb, Eli Lilly, Gilead, Janssen, Merck, Pfizer, Roche

OP0129 AUTOREACTIVE, CITRULLINATED PEPTIDE-SPECIFIC T CELLS IN RHEUMATOID ARTHRITIS

Background:

Self-reactive CD4+ T cells are thought to play a key role in the pathogenesis of rheumatoid arthritis (RA) and represent a target for antigen-specific, tolerogenic therapies1. Phenotyping such cells could provide the means with which to monitor these treatments. Here, we aimed to demonstrate antigen-induced T cell responses to RA relevant epitopes using peptide stimulation of peripheral blood mononuclear cells (PBMC). Several autoantigens have been described in RA, including various citrullinated peptide (cit-peptide) epitopes2; here we have used a combination of cit-peptides that will be used to load tolerogenic dendritic cells in a forthcoming experimental medicine study (AuToDeCRA II).

Objectives:

To detect peripheral blood T cell proliferation in response to candidate autoantigens in RA patients and healthy controls (HCs) using flow cytometry.

Methods:

PBMC from RA patients and HCs were obtained following informed consent and were cryopreserved. Prior to use, cells were thawed in medium supplemented with human serum and were labelled with a proliferation tracking dye (PTD). 2x105labelled cells were plated into 96 well plates with a minimum of 7 replicates per condition and were either cultured alone or stimulated with individual peptides at varying concentrations or a peptide pool. On day 9, cells from replicate wells were harvested, pooled and stained for surface markers and viability. Samples were acquired on a BD Fortessa X20 and analysis was performed in FlowJo version 10. A manual gating strategy was used to identify CD45RO+ (memory) CD4+ T cells and amongst this population, activated/proliferated cells were defined as CD25+ PTD low. Stimulation indices (SI) were calculated as the percentage of activated/proliferated cells from stimulated wells divided by the percentage from unstimulated wells.

Results:

Ten RA patients (including early and established disease) were recruited alongside seven HCs. Cit-peptides were initially titrated on an individual basis to determine the optimum concentration for use (n = 2). We then compared stimulation with either single peptides or a pool (n = 2), and found that PBMC stimulated with the pooled cit-peptides had a higher proliferative response. Both single and pooled cit-peptide induced T cell proliferation was observed in both RA and HC samples (Figure 1); the largest responses were seen amongst RA patients, with a maximum stimulation index of 52.4 compared to a maximum of 6.75 in the HC group. Only 1 HC sample responded with an SI greater than 3.0, whereas 50 % of RA patients elicited responses above this. Two of the RA patients failed to respond to the peptide pool (SI < 1.0). Of note, RA patients were not selected on the basis of tissue type whereas selected peptides bind preferentially to class II HLA containing the shared epitope (SE).

Figure 1

Antigen-specific CD4+ CD45RO+ responses of citrullinated peptide stimulated PBMC from HCs and RA patients.

Conclusion:

In non-HLA typed individuals, cit-peptide induced proliferative T cell responses were detectable in both RA patients and HCs, and although SIs overall were higher amongst RA patients this did not reach statistical significance in this small sample. Not all RA patients responded to the peptide pool which may be due to the limited number of citrullinated epitopes used, or to RA patients with a non-SE HLA type. Additional work should establish the need for HLA typing in this assay; around half of seropositive RA patients would be expected to be SE positive3. Furthermore, a wider array of cit-peptides may be needed to demonstrate autoreactivity in a broader cross-section of RA patients. Our future plans are to further phenotype the cellular subsets responding to the peptide pool and to study assay data in the context of clinical outcomes, to assess its utility for immune monitoring.

References:

[1]McInnes, I. B. & Schett, G. N Engl J Med. 2011; 365(23):2205-2219

[2]James, E. Aet al. Arthritis Rheum. 2014; 66(7):1712-1722

[3]Thomson, Wet al. Arthritis Rheum. 1999; 42(4):757-762

Disclosure of Interests:

Jessica Swift: None declared, James Stanway: None declared, Catharien Hilkens: None declared, Amy Anderson: None declared, Arthur Pratt Grant/research support from: Pfizer, GlaxoSmithKlein, John Isaacs Consultant of: AbbVie, Bristol-Myers Squibb, Eli Lilly, Gilead, Janssen, Merck, Pfizer, Roche

THU0005 VARIABILITY OF DNA METHYLATION IS A DRIVER OF LYMPHOCYTE DYSREGULATION IN EARLY RHEUMATOID ARTHRITIS

Background:

DNA methylation patterns differ between leukocyte subsets and mediate the impact of environmental exposures on the molecular and functional phenotype of immune cells. Besides differences in mean methylation of CpG positions amongst patients with immune mediated diseases, recent evidence indicates variability of site-specific DNA methylation also contributes to pathogenesis1,2.

Objectives:

To seek evidence of altered DNA methylation patterns in RA, controlling for systemic inflammation and immunotherapy use.

Methods:

Patients with confirmed clinical diagnoses were enrolled from the Northeast Early Arthritis Cohort (NEAC). CD4+and CD19+lymphocytes were isolated from fresh blood by positive selection prior to therapeutic immune modulation. Methylation was quantified in cell subset-specific DNA (Infinium MethylationEPIC BeadChip, Illumina)3. Differentially methylated positions and regions (DMPs, DMRs) between RA and non-RA patients were identified (linear modelling, filtering on 5% pairwise difference in mean DNA methylation, and DMRcate package). Next, to identify instances where methylation variance differed between comparator groups, Bartlett’s test was performed using the iEVORA package, which accounts for outlier values4. Findings were controlled for technical confounders and subject to multiple test correction (FDR). A validated hypergeometric test was used to annotate enriched pathways.

Results:

After sample- and probe-level quality control, CD4+ and B lymphocyte specific data were respectively available for 45 and 49 RA patients, and 64 and 81 disease controls matched for systemic inflammation (CRP, ESR). No DMPs were identified in either cell type at FDR < 0.05 and Δβ ≥0.05. Only following relaxation of multiple test correction was it possible to identify DMRs in either cell type, most notably encapsulating 10 CpGs relatively hypomethylated at the promoter of the endosome protein-encodingRUFY1gene in CD4+ lymphocytes of RA patients (Δβ = 0.076). By contrast, striking evidence for differential variation in DNA methylation was observed at 291 and 601 CpGs of CD4+ and B lymphocytes, respectively (exemplars depicted in Figure 1). Only 15 of these differentially variable positions (DVPs) were common to both cell types. Pathway analysis highlighted potential functional consequences of DVP associations; for example, RA-specific hypervariability implicates prostaglandinsignalling in CD4+ lymphocytes.

Conclusion:

We highlight a role for altered variability in DNA methylation during the molecular pathogenesis of RA, and emphasise the importance of its study in relevant cell subsets.

References:

[1]Paul DSet al. Nature Communications 7, 13555 doi: 10.1038/ncomms13555 (2016).

[2]Webster AP et al. Genome Medicine 10, 64 (2018)doi:10.1186/s13073-018-0575-9.

[3]Clark AD et al. Journal of Allergy and Clinical Immunology 2019; doi: 10.1016/j.jaci.2019.12.910

[4]Teschendorff AE et al. Nature Communications 2016; 7:12.

Disclosure of Interests:

Alexander Clark: None declared, Najib Naamane: None declared, Nisha Nair: None declared, Amy Anderson: None declared, Nishanthi Thalayasingam: None declared, Julie Diboll: None declared, Anne Barton Consultant of: AbbVie, Stephen Eyre: None declared, John D Isaacs Consultant of: AbbVie, Bristol-Myers Squibb, Eli Lilly, Gilead, Janssen, Merck, Pfizer, Roche, Louise Reynard: None declared, Arthur Pratt Grant/research support from: Pfizer, GlaxoSmithKlein

Aldehyde-Mediated Protein-to-Surface Tethering via Controlled Diazonium Electrode Functionalization Using Protected Hydroxylamines

We report a diazonium electro-grafting method for the covalent modification of conducting surfaces with aldehyde-reactive hydroxylamine functionalities that facilitate the wiring of redox-active (bio)molecules to electrode surfaces. Hydroxylamine near-monolayer formation is achieved via a phthalimide-protection and hydrazine-deprotection strategy that overcomes the multilayer formation that typically complicates diazonium surface modification. This surface modification strategy is characterized using electrochemistry (electrochemical impedance spectroscopy and cyclic voltammetry), X-ray photoelectron spectroscopy, and quartz crystal microbalance with dissipation monitoring. Thus-modified glassy carbon, boron-doped diamond, and gold surfaces are all shown to ligate to small molecule aldehydes, yielding surface coverages of 150-170, 40, and 100 pmol cm^-2, respectively. Bioconjugation is demonstrated via the coupling of a dilute (50 μM) solution of periodate-oxidized horseradish peroxidase enzyme to a functionalized gold surface under biocompatible conditions (H₂O solvent, pH 4.5, 25 °C).

Aire is not essential for regulating neuroinflammatory disease in mice transgenic for human autoimmune-diseases associated MHC class II genes HLA-DR2b and HLA-DR4

The human autoimmune disease-associated HLA alleles HLA-DR2b (DRB1*1501) and HLA-DR4 (DRB1*0401) are strongly linked to increased susceptibility for multiple sclerosis (MS) and rheumatoid arthritis (RA), respectively. The underlying mechanisms are not fully understood, but these MHC alleles may shape the repertoire of pathogenic T cells via central tolerance. The transcription factor autoimmune regulator (AIRE) promotes central T cell tolerance via ectopic expression of tissue-specific antigens (TSAs). Aire deficiency in humans causes autoimmune polyendocrinopathy syndrome type 1 (APS1), and Aire knockout mice (Aire-/-) develop spontaneous autoimmune pathology characterized by multi-organ lymphocytic infiltrates. Here, we asked whether impaired TSAs gene expression in the absence of Aire promoted spontaneous MS- or RA-like autoimmune pathology in the context of human HLA alleles in HLA-DR2b or HLA-DR4 transgenic (tg) mice. The results show that reduced TSAs gene expression in the thymus of Aire-deficient HLA-DR2b or HLA-DR4 tg mice corresponded to mild spontaneous inflammatory infiltrates in salivary glands, liver, and pancreas. Moreover, Aire-deficiency modestly enhanced experimental autoimmune encephalomyelitis (EAE) in HLA-DR tg mice, but the animals did not show signs of spontaneous neuroinflammation or arthritis. No significant changes were observed in CD4+ T cell numbers, T cell receptor (TCR) distribution, regulatory T cells (Treg), or antigen-induced cytokine production. Abrogating Treg function by treatment with anti-CTLA-4 or anti-CD25 mAb in Aire-deficient HLA-DR tg mice did not trigger EAE or other autoimmune pathology. Our results suggest a redundant role for Aire in maintaining immune tolerance in the context of autoimmune disease-associated human HLA alleles.

Enhancement of the spin polarization of an Fe3O4(100) surface by nitric oxide adsorption

The geometric, electronic and magnetic properties of a nitric oxide (NO) adsorbed Fe3O4(100) surface have been investigated using density functional theory (DFT) calculations. NO molecules preferentially bond with surface Fe(B) atoms via their N atoms. The generalized gradient approximation (GGA) is not recommended to be used in such a strongly correlated system since it provides not only an overestimation of the adsorption energy and an underestimation of the Fe(B)-N bond length, but also magnetic quenching of the adsorbate and the bonded Fe(B) atoms. In contrast, a tilted geometry and magnetization of the adsorbate and the bonded Fe(B) atom are obtained after including the strong on-site Coulomb interactions through a Hubbard term (GGA+U). The spin-down 2π* states of the NO molecule are filled and broadened due to the adsorbate-substrate interaction and the molecule-molecule interaction. The surface spin polarization close to the Fermi level is expected to be greatly enhanced by the NO adsorption which has significance for interface design in spintronic devices.

Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

Reversible switching of the spin state in a manganese phthalocyanine molecule by atomic nitrogen

Reversible control of the spin state of an organic molecule is significant for the development of molecular spintronic devices. Here, density functional theory calculations have been performed to study the adsorption of atomic nitrogen on a single manganese phthalocyanine (MnPc) molecule, three-layered MnPc, and MnPc on an Fe(100) surface. For all three cases, the N atom strongly adsorbs on top of the Mn atom and induces a significant variation of the geometric, electronic and magnetic properties. After N adsorption, an energy gap appears and the electronic states become unpolarized. Different functionals including three hybrid functionals are used in these calculations, and all yield a switchable spin state.

Ultrathin graphene-based membrane with precise molecular sieving and ultrafast solvent permeation

Graphene oxide (GO) membranes continue to attract intense interest due to their unique molecular sieving properties combined with fast permeation. However, their use is limited to aqueous solutions because GO membranes appear impermeable to organic solvents, a phenomenon not yet fully understood. Here, we report efficient and fast filtration of organic solutions through GO laminates containing smooth two-dimensional (2D) capillaries made from large (10-20 μm) flakes. Without modification of sieving characteristics, these membranes can be made exceptionally thin, down to ∼10 nm, which translates into fast water and organic solvent permeation. We attribute organic solvent permeation and sieving properties to randomly distributed pinholes interconnected by short graphene channels with a width of 1 nm. With increasing membrane thickness, organic solvent permeation rates decay exponentially but water continues to permeate quickly, in agreement with previous reports. The potential of ultrathin GO laminates for organic solvent nanofiltration is demonstrated by showing >99.9% rejection of small molecular weight organic dyes dissolved in methanol. Our work significantly expands possibilities for the use of GO membranes in purification and filtration technologies.

Half-metallicity induced by boron adsorption on an Fe3O4(100) surface

Spin polarization of the Fe₃O₄(100) surface is enhanced by B adsorption through the opening of the spin-up band gap.

Ultrahigh vacuum and low-temperature cleaning of oxide surfaces using a low-concentration ozone beam

We present a novel method of delivering a low-concentration (<15%) ozone beam to an ultra-high vacuum environment for the purpose of cleaning and dosing experimental samples through oxidation processing. The system described is safe, low-cost, and practical and overcomes the limitations of ozone transport in the molecular flow environment of high or ultrahigh vacuum whilst circumventing the use of pure ozone gas which is potentially highly explosive. The effectiveness of this method in removing surface contamination is demonstrated through comparison of high-temperature annealing of a simple oxide (MgO) in ozone and oxygen environments as monitored using quadrupole mass spectroscopy and Auger electron spectroscopy. Additionally, we demonstrate the potential of ozone for obtaining clean complex oxide surfaces without the need for high-temperature annealing which may significantly alter surface structure.

Significant variation of surface spin polarization through group IV atom (C, Si, Ge, Sn) adsorption on Fe3O4(100)

The adsorption of group IV atoms (C, Si, Ge, Sn) on the magnetite Fe3O4(100) surface is investigated by density functional theory calculations. All these atoms prefer to bond to the surface oxygen atom which has no tetrahedral Fe(A) neighbor. The spin-up surface states of clean Fe3O4(100) are completely removed and half-metallicity is recovered by C adsorption. The spin-up band gap of the C-adsorbed Fe3O4(100) surface is wider than that of the H-adsorbed one and closer to the value of bulk Fe3O4. For the adsorption of other group IV atoms, the adsorbate-substrate interaction decreases and the adsorbate-adsorbate interaction increases with the increase of atomic number Z. As a consequence, the spin polarization varies from -99.4% (C adsorption) to +44.2% (Sn adsorption) for the electronic states of the adsorbed atom integrated from -0.5 eV to the Fermi level. The ability to tune the surface spin polarization by the choice of adsorbate is of significance for magnetite-based spintronic devices.

Enhanced oxidation of nanoparticles through strain-mediated ionic transport

Geometry and confinement effects at the nanoscale can result in substantial modifications to a material's properties with significant consequences in terms of chemical reactivity, biocompatibility and toxicity. Although benefiting applications across a diverse array of environmental and technological settings, the long-term effects of these changes, for example in the reaction of metallic nanoparticles under atmospheric conditions, are not well understood. Here, we use the unprecedented resolution attainable with aberration-corrected scanning transmission electron microscopy to study the oxidation of cuboid Fe nanoparticles. Performing strain analysis at the atomic level, we reveal that strain gradients induced in the confined oxide shell by the nanoparticle geometry enhance the transport of diffusing species, ultimately driving oxide domain formation and the shape evolution of the particle. We conjecture that such a strain-gradient-enhanced mass transport mechanism may prove essential for understanding the reaction of nanoparticles with gases in general, and for providing deeper insight into ionic conductivity in strained nanostructures.

Analysis of 14,008 uroliths from dogs in the UK over a 10-year period

OBJECTIVES

To identify breed-associated risk factors for urolithiasis in dogs from the UK.

METHODS

Records of all canine uroliths submitted to Hills Pet Nutrition UK for analysis at the University of Minnesota Urolith Centre over 10 years (1997 to 2006) were reviewed. The results, along with the request forms completed by the submitting veterinarian, were analysed. The most commonly affected breeds, age and gender of the dogs were identified for each of the most common types of uroliths (struvite, calcium oxalate, urate, cystine and mixed). Pearson's chi-squared tests were performed to assess whether certain breeds of dogs were over-represented relative to a reference population (from an insurance database).

RESULTS

The records of 14,008 urolith submissions were analysed. The relative frequency of struvite remained stable over time, whereas calcium oxalate decreased over the study period. Breeds found to be significantly over-represented for calcium oxalate uroliths included the Chihuahua, miniature poodle and Yorkshire terrier. Staffordshire bull terriers and English bulldogs were at increased risk for cystine uroliths.

CLINICAL SIGNIFICANCE

Associations between breed, gender, age and urolith formation were similar to those reported elsewhere. However, temporal trends and novel breed predispositions were identified.

Building HIA approaches into strategies for green space use: an example from Plymouth's (UK) Stepping Stones to Nature project

The health and well-being benefits of access to green space are well documented. Research suggests positive findings regardless of social group, however barriers exist that limit access to green space, including proximity, geography and differing social conditions. Current public health policy aims to broaden the range of environmental public health interventions through effective partnership working, providing opportunities to work across agencies to promote the use of green space. Health Impact Assessment (HIA) is a combination of methods and procedures to assess the potential health and well-being impacts of policies, developments and projects. It provides a means by which negative impacts can be mitigated and positive impacts can be enhanced, and has potential application for assessing green space use. This paper describes the application of a HIA approach to a multi-agency project (Stepping Stones to Nature--SS2N) in the UK designed to improve local green spaces and facilitate green space use in areas classified as having high levels of deprivation. The findings suggest that the SS2N project had the potential to provide significant positive benefits in the areas of physical activity, mental and social well-being. Specific findings for one locality identified a range of actions that could be taken to enhance benefits, and mitigate negative factors such as anti-social behaviour. The HIA approach proved to be a valuable process through which impacts of a community development/public health project could be enhanced and negative impacts prevented at an early stage; it illustrates how a HIA approach could enhance multi-agency working to promote health and well-being in communities.

Use of Monte Carlo modeling to aid interpretation and quantification of the low energy-loss electron yield at low primary energies

Experimental low-loss electron (LLE) yields were measured as a function of loss energy for a range of elemental standards using a high-vacuum scanning electron microscope operating at 5 keV primary beam energy with losses from 0 to 1 keV. The resulting LLE yield curves were compared with Monte Carlo simulations of the LLE yield in the particular beam/sample/detector geometry employed in the experiment to investigate the possibility of modeling the LLE yield for a series of elements. Monte Carlo simulations were performed using both the Joy and Luo [Joy, D.C. & Luo, S., Scanning 11(4), 176988 (2005)] to assess the influence of the more recent stopping power data on the simulation results. Further simulations have been conducted to explore the influence of sample/detector geometry on the LLE signal in the case of layered samples consisting of a thin C overlayer on an elemental substrate. Experimental LLE data were collected from a range of elemental samples coated with a thin C overlayer, and comparisons with Monte Carlo simulations were used to establish the overlayer thickness.

Strengthening emergency obstetric care in Nepal: The Women's Right to Life and Health Project (WRLHP)

INTRODUCTION

The Women's Right to Life and Health Project contributes to Nepal's National Safe Motherhood Program and maternal mortality reduction efforts by working to improve the availability, quality and utilization of emergency obstetric care services in public health facilities.

METHODS

The project upgraded 8 existing public health facilities through infrastructure, equipment, training, data collection, policy advocacy, and community information activities. The total cost of the project was approximately US$1.6 million.

RESULTS

In 5 years, 3 comprehensive and 4 basic emergency obstetric care (EmOC) facilities were established in an area where adequate EmOC services were previously lacking. From 2000 to 2004, met need for EmOC improved from 1.9 to 16.9%; the proportion of births in EmOC project facilities increased from 3.8 to 8.3%; and the case fatality rate declined from 2.7 to 0.3%.

DISCUSSION

While the use of maternity services is still low in Nepal, improving availability and quality of EmOC together with community empowerment can increase utilization by women with complications, even in low-resource settings. Partnerships with government and donors were key to the project's success. Similar efforts should be replicated throughout Nepal to expand the availability of essential life-saving services for pregnant women.

New multichannel electron energy analyzer with cylindrically symmetrical electrostatic field

This article discusses an electron energy analyzer with a cylindrically symmetrical electrostatic field, designed for rapid Auger analysis. The device was designed and built. The best parameters of the analyzer were estimated and then experimentally verified.