Number of days required to measure sedentary time and physical activity using accelerometery in rheumatoid arthritis: a reliability study

This study aimed to determine the minimum number of days required to reliably estimate free-living sedentary time, light-intensity physical activity (LPA) and moderate-intensity physical activity (MPA) using accelerometer data in people with Rheumatoid Arthritis (RA), according to Disease Activity Score-28-C-reactive protein (DAS-28-CRP). Secondary analysis of two existing RA cohorts with controlled (cohort 1) and active (cohort 2) disease was undertaken. People with RA were classified as being in remission (DAS-28-CRP < 2.4, n = 9), or with low (DAS-28-CRP ≥ 2.4-≤ 3.2, n = 15), moderate (DAS-28-CRP > 3.2-≤ 5.1, n = 41) or high (DAS-28-CRP > 5.1, n = 16) disease activity. Participants wore an ActiGraph accelerometer on their right hip for 7 days during waking hours. Validated RA-specific cut-points were applied to accelerometer data to estimate free-living sedentary time, LPA and MPA (%/day). Single-day intraclass correlation coefficients (ICC) were calculated and used in the Spearman Brown prophecy formula to determine the number of monitoring days required to achieve measurement reliability (ICC ≥ 0.80) for each group. The remission group required ≥ 4 monitoring days to achieve an ICC ≥ 0.80 for sedentary time and LPA, with low, moderate and high disease activity groups requiring ≥ 3 monitoring days to reliably estimate these behaviours. The monitoring days required for MPA were more variable across disease activity groups (remission =  ≥ 3 days; low =  ≥ 2 days; moderate =  ≥ 3 days; high =  ≥ 5 days). We conclude at least 4 monitoring days will reliably estimate sedentary time and LPA in RA, across the whole spectrum of disease activity. However, to reliably estimate behaviours across the movement continuum (sedentary time, LPA, MPA), at least 5 monitoring days are required.

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.

BIOlogical Factors that Limit sustAined Remission in rhEumatoid arthritis (the BIO-FLARE study): protocol for a non-randomised longitudinal cohort study

BACKGROUND

Our knowledge of immune-mediated inflammatory disease (IMID) aetiology and pathogenesis has improved greatly over recent years, however, very little is known of the factors that trigger disease relapses (flares), converting diseases from inactive to active states. Focussing on rheumatoid arthritis (RA), the challenge that we will address is why IMIDs remit and relapse. Extrapolating from pathogenetic factors involved in disease initiation, new episodes of inflammation could be triggered by recurrent systemic immune dysregulation or locally by factors within the joint, either of which could be endorsed by overarching epigenetic factors or changes in systemic or localised metabolism.

METHODS

The BIO-FLARE study is a non-randomised longitudinal cohort study that aims to enrol 150 patients with RA in remission on a stable dose of non-biologic disease-modifying anti-rheumatic drugs (DMARDs), who consent to discontinue treatment. Participants stop their DMARDs at time 0 and are offered an optional ultrasound-guided synovial biopsy. They are studied intensively, with blood sampling and clinical evaluation at weeks 0, 2, 5, 8, 12 and 24. It is anticipated that 50% of participants will have a disease flare, whilst 50% remain in drug-free remission for the study duration (24 weeks). Flaring participants undergo an ultrasound-guided synovial biopsy before reinstatement of previous treatment. Blood samples will be used to investigate immune cell subsets, their activation status and their cytokine profile, autoantibody profiles and epigenetic profiles. Synovial biopsies will be examined to profile cell lineages and subtypes present at flare. Blood, urine and synovium will be examined to determine metabolic profiles. Taking into account all generated data, multivariate statistical techniques will be employed to develop a model to predict impending flare in RA, highlighting therapeutic pathways and informative biomarkers. Despite initial recruitment to time and target, the SARS-CoV-2 pandemic has impacted significantly, and a decision was taken to close recruitment at 118 participants with complete data.

DISCUSSION

This study aims to investigate the pathogenesis of flare in rheumatoid arthritis, which is a significant knowledge gap in our understanding, addressing a major unmet patient need.

TRIAL REGISTRATION

The study was retrospectively registered on 27/06/2019 in the ISRCTN registry 16371380 .

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

P117 Rituximab for IgG4-related disease: the Newcastle experience

Background

IgG4-related disease (IgG4-RD) is a multisystem immune mediated fibro-inflammatory condition characterised by the three histopathologic features of IgG4-RD lymphoplasmacytic infiltration, storiform fibrosis and obliterative phlebitis. The condition can be indolent with few symptoms or present with organ or life-threatening disease. First-line treatment with high dose corticosteroids is often effective, however when tapering steroids, the disease can relapse, and second line agents such as methotrexate (MTX), azathioprine (AZA) or mycophenolate (MMF) are not always effective or tolerated. In 2016, following evidence from observational studies, NHS England approved the use of rituximab (RTX) in refractory IgG4-RD according to strict criteria. In our unit we have used rituximab, with or without cyclophosphamide induction, in eight patients with IgG4-RD. Our aim was to assess effectiveness of rituximab treatment and adherence to NHS England guidelines.

Methods

Using our connective tissue disease database, patients with IgG4-RD were identified and their electronic notes were reviewed. Outcome after rituximab treatment was assessed by the evaluation of clinical and radiological responses.

Results

Between August 2017 and September 2019, 15 patients with IgG4-RD were seen in the rheumatology service. 8 patients went on to receive rituximab therapy, 4 with IV cyclophosphamide (CYP). 5/8 patients had head and neck disease and 3/8 had abdominal disease (pancreas, retroperitoneal, renal). By comparison, those patients that did not receive rituximab had a preponderance of abdominal disease (4/7 had abdominal disease, 2/7 head and neck, 1/7 breast). 8/8 patients receiving rituximab were discussed in a designated MDT and met NHS diagnostic guidelines. MDT treatment decisions were made based on ‘refractory’ or ‘organ critical’ disease criteria. In all patients, with available post treatment imaging, radiological response was demonstrated. In one case, imaging showed improvement in some areas and progression in other areas and response was described as ‘partial’.

Conclusion

In the patients treated to date in our unit, rituximab has been shown to be an effective treatment for IgG4-RD. Cyclophosphamide induction has been used in a subset of patients. Patients with head and neck disease were more likely to require escalation to rituximab therapy, compared with those with abdominal disease.

Disclosures

F. Rayner None. B. Griffiths None. M. Nayar None. K. Oppong None. J. Vila None.

Therapeutic tolerance in autoimmune disease

Experimental immune tolerance induction, enabling tissues to be transplanted across animal strains, was first demonstrated in the 1950s. Therapeutic tolerance induction, whereby immune tolerance is used to treat or prevent transplant rejection, and as a treatment for autoimmunity, followed in the 1980s. Clinical translation has been slow but the pace of change is accelerating. Numerous strategies are now being tested clinically, ranging from monoclonal antibodies against T-cells, to peptide therapies, cellular therapies and microbiome manipulation. Furthermore, technology has advanced to the stage where we can start to monitor serological and cellular autoreactivity as biomarkers of response. In terms of autoimmunity, recognition of the prolonged phase of preclinical autoimmunity in several conditions, is leading to debate around treatment of at risk individuals, and trials in patients with prodromal clinical symptoms, such as seropositive arthralgia. Additionally, potent immunomodulatory drugs are achieving a substantial track record of safety. Putting these various factors together suggests that we can soon expect to see more trials of tolerogenic strategies in pre-clinical disease, with intensive immune monitoring to guide therapy.