Functional analysis of epilepsy-associated GABAA receptor mutations using Caenorhabditis elegans

OBJECTIVE

GABAA receptor subunit mutations pose a significant risk for genetic generalized epilepsy; however, there are over 150 identified variants, many with unknown or unvalidated pathogenicity. We aimed to develop in vivo models for testing GABAA receptor variants using the model organism, Caenorhabditis elegans.

METHODS

CRISPR-Cas9 gene editing was used to create a complete deletion of unc-49, a C. elegans GABAA receptor, and to create homozygous epilepsy-associated mutations in the endogenous unc-49 gene. The unc-49 deletion strain was rescued with transgenes for either the C. elegans unc-49B subunit or the α1, β3, and γ2 subunits for the human GABAA receptor. All newly created strains were analyzed for phenotype and compared against existing unc-49 mutations.

RESULTS

Nematodes with a full genetic deletion of the entire unc-49 locus were compared with existing unc-49 mutations in three separate phenotypic assays-coordinated locomotion, shrinker frequency and seizure-like convulsions. The full unc-49 deletion exhibited reduced locomotion and increased shrinker frequency and PTZ-induced convulsions, but were not found to be phenotypically stronger than existing unc-49 mutations. Rescue with the unc-49B subunit or creation of humanized worms for the GABAA receptor both showed partial phenotypic rescue for all three phenotypes investigated. Finally, two epilepsy-associated variants were analyzed and deemed to be loss of function, thus validating their pathogenicity.

SIGNIFICANCE

These findings establish C. elegans as a genetic model to investigate GABAA receptor mutations and delineate a platform for validating associated variants in any epilepsy-associated gene.

PLAIN LANGUAGE SUMMARY

Epilepsy is a complex human disease that can be caused by mutations in specific genes. Many possible mutations have been identified, but it is unknown for most of them whether they cause the disease. We tested the role of mutations in one specific gene using a small microscopic worm as an animal model. Our results establish this worm as a model for epilepsy and confirm that the two unknown mutations are likely to cause the disease.

Tissue distribution of cysteine string protein/DNAJC5 in C. elegans analysed by CRISPR/Cas9-mediated tagging of endogenous DNJ-14

Cysteine string protein (CSP) is a member of the DnaJ/Hsp40 family of molecular chaperones. CSP is enriched in neurons, where it mainly localises to synaptic vesicles. Mutations in CSP-encoding genes in flies, worms, mice and humans result in neuronal dysfunction, neurodegeneration and reduced lifespan. Most attention has therefore focused on CSP's neuronal functions, although CSP is also expressed in non-neuronal cells. Here, we used genome editing to fluorescently tag the Caenorhabditis elegans CSP orthologue, dnj-14, to identify which tissues preferentially express CSP and hence may contribute to the observed mutant phenotypes. Replacement of dnj-14 with wrmScarlet caused a strong chemotaxis defect, as seen with other dnj-14 null mutants. In contrast, inserting the reporter in-frame to create a DNJ-14-wrmScarlet fusion protein had no effect on chemotaxis, indicating that C-terminal tagging does not impair DNJ-14 function. WrmScarlet fluorescence appeared most obvious in the intestine, head/pharynx, spermathecae and vulva/uterus in the reporter strains, suggesting that DNJ-14 is preferentially expressed in these tissues. Crossing the DNJ-14-wrmScarlet strain with GFP marker strains confirmed the intestinal and pharyngeal expression, but only a partial overlap with neuronal GFP was observed. DNJ-14-wrmScarlet fluorescence in the intestine was increased in response to starvation, which may be relevant to mammalian CSPα's role in microautophagy. DNJ-14's enrichment in worm reproductive tissues (spermathecae and vulva/uterus) parallels the testis-specific expression of CSPβ and CSPγ isoforms in mammals. Furthermore, CSPα messenger RNA is highly expressed in the human proximal digestive tract, suggesting that CSP may have a conserved, but overlooked, function within the gastrointestinal system.

Proximity labelling reveals effects of disease-causing mutation on the DNAJC5/cysteine string protein α interactome

Cysteine string protein α (CSPα), also known as DNAJC5, is a member of the DnaJ/Hsp40 family of co-chaperones. The name derives from a cysteine-rich domain, palmitoylation of which enables localization to intracellular membranes, notably neuronal synaptic vesicles. Mutations in the DNAJC5 gene that encodes CSPα cause autosomal dominant, adult-onset neuronal ceroid lipofuscinosis (ANCL), a rare neurodegenerative disease. As null mutations in CSP-encoding genes in flies, worms and mice similarly result in neurodegeneration, CSP is evidently an evolutionarily conserved neuroprotective protein. However, the client proteins that CSP chaperones to prevent neurodegeneration remain unclear. Traditional methods for identifying protein-protein interactions such as yeast 2-hybrid and affinity purification approaches are poorly suited to CSP, due to its requirement for membrane anchoring and its tendency to aggregate after cell lysis. Therefore, we employed proximity labelling, which enables identification of interacting proteins in situ in living cells via biotinylation. Neuroendocrine PC12 cell lines stably expressing wild type or L115R ANCL mutant CSP constructs fused to miniTurbo were generated; then the biotinylated proteomes were analysed by liquid chromatographymass spectrometry (LCMS) and validated by western blotting. This confirmed several known CSP-interacting proteins, such as Hsc70 and SNAP-25, but also revealed novel binding proteins, including STXBP1/Munc18-1. Interestingly, some protein interactions (such as Hsc70) were unaffected by the L115R mutation, whereas others (including SNAP-25 and STXBP1/Munc18-1) were inhibited. These results define the CSP interactome in a neuronal model cell line and reveal interactions that are affected by ANCL mutation and hence may contribute to the neurodegeneration seen in patients.

A Caenorhabditis elegans model of autosomal dominant adult-onset neuronal ceroid lipofuscinosis identifies ethosuximide as a potential therapeutic

Autosomal dominant adult-onset neuronal ceroid lipofuscinosis (ANCL) is a rare neurodegenerative disorder characterized by progressive dementia and premature death. Four ANCL-causing mutations have been identified, all mapping to the DNAJC5 gene that encodes cysteine string protein α (CSPα). Here, using Caenorhabditis elegans, we describe an animal model of ANCL in which disease-causing mutations are introduced into their endogenous chromosomal locus, thereby mirroring the human genetic disorder. This was achieved through CRISPR/Cas9-mediated gene editing of dnj-14, the C. elegans ortholog of DNAJC5. The resultant homozygous ANCL mutant worms exhibited reduced lifespans and severely impaired chemotaxis, similar to isogenic dnj-14 null mutants. Importantly, these phenotypes were also seen in balanced heterozygotes carrying one wild-type and one ANCL mutant dnj-14 allele, mimicking the heterozygosity of ANCL patients. We observed a more severe chemotaxis phenotype in heterozygous ANCL mutant worms compared with haploinsufficient worms lacking one copy of CSP, consistent with a dominant-negative mechanism of action. Additionally, we provide evidence of CSP haploinsufficiency in longevity, as heterozygous null mutants exhibited significantly shorter lifespan than wild-type controls. The chemotaxis phenotype of dnj-14 null mutants was fully rescued by transgenic human CSPα, confirming the translational relevance of the worm model. Finally, a focused compound screen revealed that the anti-epileptic drug ethosuximide could restore chemotaxis in dnj-14 ANCL mutants to wild-type levels. This suggests that ethosuximide may have therapeutic potential for ANCL and demonstrates the utility of this C. elegans model for future larger-scale drug screening.

Cysteine string protein alpha accumulates with early pre-synaptic dysfunction in Alzheimer’s disease

In Alzheimer’s disease, synapse loss causes memory and cognitive impairment. However, the mechanisms underlying synaptic degeneration in Alzheimer’s disease are not well understood. In the hippocampus, alterations in the level of cysteine string protein alpha, a molecular co-chaperone at the pre-synaptic terminal, occur prior to reductions in synaptophysin, suggesting that it is a very sensitive marker of synapse degeneration in Alzheimer’s. Here, we identify putative extracellular accumulations of cysteine string alpha protein, which are proximal to beta-amyloid deposits in post-mortem human Alzheimer’s brain and in the brain of a transgenic mouse model of Alzheimer’s disease. Cysteine string protein alpha, at least some of which is phosphorylated at serine 10, accumulates near the core of beta-amyloid deposits and does not co-localize with hyperphosphorylated tau, dystrophic neurites or glial cells. Using super-resolution microscopy and array tomography, cysteine string protein alpha was found to accumulate to a greater extent than other pre-synaptic proteins and at a comparatively great distance from the plaque core. This indicates that cysteine string protein alpha is most sensitive to being released from pre-synapses at low concentrations of beta-amyloid oligomers. Cysteine string protein alpha accumulations were also evident in other neurodegenerative diseases, including some fronto-temporal lobar dementias and Lewy body diseases, but only in the presence of amyloid plaques. Our findings are consistent with suggestions that pre-synapses are affected early in Alzheimer’s disease, and they demonstrate that cysteine string protein alpha is a more sensitive marker for early pre-synaptic dysfunction than traditional synaptic markers. We suggest that cysteine string protein alpha should be used as a pathological marker for early synaptic disruption caused by beta-amyloid.

POS1229 THE IMPACT OF COVID-19 ON MEDICATION NON-ADHERENCE IN A RHEUMATOID AND PSORIATIC ARTHRITIS UK COHORT

Background

In March 2020, as part of the UK’s COVID-19 prevention strategy, those identified as ‘clinically extremely vulnerable’, were advised to shield. This included a number of patients prescribed anti-rheumatic drugs, who were asked to continue their current treatment unless they developed symptoms of infection. Suboptimal treatment adherence (16.0%-81.0%) has been reported in patients with arthritic diseases, and is associated with psychological factors, including anxiety (1). Previous literature in non-UK cohorts has highlighted suboptimal adherence levels in immunosuppressed patients during the pandemic, although many were single centre studies (2,3).

Objectives

The aim of this multi-centre study is to investigate the impact of the COVID-19 pandemic on adherence to anti-rheumatic medications in patients with established rheumatoid (RA) and psoriatic (PsA) arthritis in the UK who had recently commenced a biologic or targeted synthetic DMARD.

Methods

Between September 2020 and May 2021, RA and PsA patients prescribed biologic or targeted synthetic anti-rheumatic drugs from two multi-centre observational studies (BRAGGSS and OUTPASS) were sent a questionnaire on medication usage, adherence, and perceptions to establish the impact of COVID-19 on these parameters. Patients were asked about compliance during the COVID-19 pandemic using a 5-point Likert scale (always, often, sometimes, rarely, and never) and the reason for non-adherence. Adherence was defined as never missing or delaying a dose, unless medically advised. Descriptive summary statistics were calculated, and logistic regression and Pearson’s chi-squared tests were employed to investigate variables associated with self-reported non-adherence.

Results

In total 159 questionnaires were returned (81.1% RA and 18.9% PsA). Methotrexate (53.5%) was the most frequently prescribed agent, followed by etanercept (25.2%), sulfasalazine (22.6%), hydroxychloroquine (21.4%) and adalimumab (19.5%). Furthermore, 68.6% of patients were prescribed ≥2 drugs. During the pandemic, 42.1% of patients reported missing or delaying a treatment dose for any reason. Adherence information was available for 97.5% of patients with 25.8% reporting non-adherence which was not medically advised. Methotrexate non-adherence was 27.1%, with similar levels reported for etanercept (20.0%), sulfasalazine (27.8%), hydroxychloroquine (35.3%) and adalimumab (29.0%). No drugs had significantly different adherence compared to methotrexate. Furthermore, there was no association between disease type or perception of disease control and adherence. Of non-adherent patients, 17.5% reported increased anxiety, fear, and increased risk due to the COVID-19 pandemic as an influencing factor. Meanwhile, 37.5% of non-adherent patients listed non-COVID-19 intentional reasons and 45.0% reported non-intentional reasons, with forgetting and running out of treatment listed most frequently.

Conclusion

In a UK cohort self-reported non-adherence was reported in 25.8% of patients during the COVID-19 pandemic, despite medical advice, with reasons including increased anxiety due to COVID-19.

References

[1]Medication adherence and persistence in patients with rheumatoid arthritis, psoriasis, and psoriatic arthritis: a systematic literature review. Patient Prefer Adherence. 2018;12:1483–503.

[2]Vakirlis E, Bakirtzi K, Papadimitriou I, Vrani F, Sideris N, Lallas A, et al. Treatment adherence in psoriatic patients during COVID-19 pandemic: Real-world data from a tertiary hospital in Greece. J Eur Acad Dermatology Venereol. 2020;34(11):e673–5.

[3]Polat Ekinci A, Pehlivan G, Gökalp MO. Surveillance of psoriatic patients on biologic treatment during the COVID-19 pandemic: A single-center experience. Dermatol Ther. 2020;(December 2020):19–22.

Acknowledgements

on behalf of the BRAGGSS consortium

Disclosure of Interests

Philippa Curry: None declared, Hector Chinoy Speakers bureau: UCB, Biogen, Consultant of: Novartis, Eli Lilly, Orphazyme, Astra Zeneca, Grant/research support from: Eli Lilly, UCB, Meghna Jani: None declared, Darren Plant: None declared, Kimme Hyrich Consultant of: consultancy/honoraria from AbbVie, Grant/research support from: Pfizer, BMS, Ann Morgan Speakers bureau: Roche, Chugai, Consultant of: GSK, Roche, Chugai, AstraZeneka, Regeneron, Sanofi, Vifor, Grant/research support from: Roche, Kiniksa Pharmaceuticals, Anthony G Wilson: None declared, John Isaacs Speakers bureau: Abbvie, Gilead, Roche, UCB, Grant/research support from: GSK, Janssen, Pfizer, Andrew Morris: None declared, Anne Barton Grant/research support from: I have received grant funding from Pfizer, Galapagos, Scipher Medicine and Bristol Myers Squibb., James Bluett Grant/research support from: Pfizer Limited. JB has received travel/conference fees from UCB, Pfizer and Eli Lilly

POS0033 GENETIC INVESTIGATION OF TUMOUR NECROSIS FACTOR INHIBITOR IMMUNOGENICITY IN PATIENTS WITH RHEUMATOID ARTHRITIS

Background

Rheumatoid arthritis (RA) is a chronic inflammatory disease that primarily affects the synovial joints. Tumour Necrosis Factor inhibitor (TNFi) therapy has transformed the clinical management of RA. However, monoclonal antibody derived TNFi is associated with development of immunogenicity and subsequent loss of therapeutic effects. Previous studies have observed associations between certain HLA alleles and TNFi immunogenicity. For example HLA-DQA1 and HLA-DRB1 have been associated with immunogenicity in inflammatory bowel disease 1,2 and RA 3,4, respectively.

Objectives

The aims of this study were to identify associations between HLA alleles and immunogenicity to TNFi in an observational cohort of RA patients and to replicate findings from previous studies.

Methods

Anti-drug antibody titres were measured using radioimmunoassay in serum samples from RA patients participating in Biologics in Rheumatoid Arthritis Genetics and Genomics Study Syndicate (BRAGGSS). An anti-drug antibody titre of ≥12 AU/mL following six months on treatment was used to define positive immunogenicity. Genotype data were generated using Illumina HumanCoreExome Arrays. Standard quality control (QC) was applied prior to HLA imputation using SNP2HLA software before low minor allele frequency markers were removed. Logistic regression was used to study the association between HLA alleles and immunogenicity, whilst the omnibus test was applied to amino acid positions; sex and concurrent conventional synthetic DMARD use were included as a covariate in all the models.

Results

In total, 445 RA patients were analysed, 377 patients (70 immunogenicity events) were underdoing adalimumab therapy and 68 certolizumab (30 immunogenicity events) therapy. Following QC, 162 HLA alleles and 361 amino acids positions were available for analysis. The strongest HLA allele association was observed for HLA-DQA1*03 when all patients were analysed (OR = 0.61; 95% CI = 0.43 – 0.86; p-value = 5e-3). The amino acids positions 187 (p-value = 5e-3) and 26 (p-value = 5e-3) within the HLA-DQA1 gene were significantly associated with immunogenicity events. When both drugs were analysed separately, they produced similar effect size for HLA-DQA1*03 association; patients treated with adalimumab (OR = 0.59; 95% CI = 0.38 – 0.88; p-value = 1e-2) and certolizumab (OR = 0.52; 95% CI = 0.24 – 1.1; p-value = 1e-1). Another strong association was found in HLA-DRB1*04 (OR = 0.62; 95% CI = 0.44 – 0.88; p-value = =7e-3) and the amino acid position of 180 (p-value = 7e-3) and 33 (p-value = 7e-3) of HLA-DRB1 gene. Additionally, the similar protective effect between the two presented alleles suggested possibility of linkage disequilibrium, upon investigation the r2 between the 2 alleles is 0.69.

Conclusion

The current study increases the evidence for association between immunogenicity development with HLA-DQA1 and HLA-DRB1 alleles in patients receiving monoclonal antibody derived TNFi therapy. Further well powered studies are now required to determine the utility of HLA markers as a potential tool to aid the clinical management of RA.

References

[1]Sazonovs, A. et al. HLA-DQA1*05 Carriage Associated With Development of Anti-Drug Antibodies to Infliximab and Adalimumab in Patients With Crohn’s Disease. Gastroenterology158, 189–199 (2020).

[2]Billiet, T. et al. Immunogenicity to infliximab is associated with HLA-DRB1. Gut64, 1344–1345 (2015).

[3]Liu, M. et al. Identification of HLA-DRB1 association to adalimumab immunogenicity. PLoS One13, e0195325 (2018).

[4]Rigby, W. et al. HLA-DRB1 risk alleles for RA are associated with differential clinical responsiveness to abatacept and adalimumab: data from a head-to-head, randomized, single-blind study in autoantibody-positive early RA. Arthritis Res. Ther.23, 245 (2021).

Disclosure of Interests

Chuan Fu Yap: None declared, Nisha Nair: None declared, Kimme Hyrich Speakers bureau: Abbvie, Grant/research support from: Pfizer and BMS, Anthony G Wilson: None declared, John Isaacs Speakers bureau: Abbvie, Gilead, Roche, UCB, Grant/research support from: GSK, Janssen, Pfizer, Ann Morgan Speakers bureau: Roche, Chugai, Consultant of: GSK, Roche, Chugai, AstraZeneca, Regeneron, Sanofi, Vifor, Grant/research support from: Roche, Kiniksa Pharmaceuticals, Anne Barton Grant/research support from: I have received grant funding from Pfizer, Galapagos, Scipher Medicine and Bristol Myers Squibb., Darren Plant: None declared

AB0011 DNA METHYLATION AS A BIOMARKER OF TOCILIZUMAB RESPONSE IN RHEUMATOID ARTHRITIS PATIENTS

Background

Tocilizumab (TCZ) is a disease-modifying antirheumatic biologic drug, which targets the IL-6 signalling pathway and is effective in ameliorating disease activity in rheumatoid arthritis (RA). However, approximately 50% of patients do not respond adequately to TCZ and some patients report adverse events. Considering there is growing evidence that DNA methylation is implicated in RA susceptibility and response to some biologics (1, 2), we investigated DNA methylation as a candidate biomarker for response to TCZ in RA.

Objectives

To identify differential DNA methylation signatures in whole blood associated with TCZ response in patients with RA.

Methods

Epigenome-wide DNA methylation patterns were measured using the Infinium EPIC 850k BeadChip (Illumina) in whole blood-derived DNA samples from patients with RA. DNA was extracted from blood samples taken pre-treatment and following 3 months on therapy, and response was determined at 6 months using the Clinical Disease Activity Index (CDAI). Patients who had good response (n=10) or poor response (n=10) to TCZ by 6 months were selected. Samples from secondary poor responders (n=10) (patients who had an improvement of CDAI and were in remission at 3 months, followed by a worsening of CDAI at 6 months) were also analysed. Differentially methylated positions (DMPs) were identified using linear regression, adjusting for gender, age, cell composition, smoking status, and glucocorticoid use.

Results

In the pre-treatment samples, 20 DMPs were significantly associated with response status at 6 months (unadjusted p-value <10-6), whilst in the 3 month samples, 21 DMPs were associated with response. One DMP, cg03121467, was significantly less methylated in good responders compared to poor responders in the pre-treatment samples. This DMP is close to EPB41L4A and may play a role in β–catenin signalling. Interestingly, cg10136146 was significantly less methylated in secondary poor responders compared to both good and poor responders in the 3 month samples. This DMP maps close to CD81, which plays a role in mediating the development and activation of B and T lymphocytes.

Conclusion

These preliminary results provide evidence that DNA methylation patterns may predict response to TCZ. Further regional and pathway analyses is in progress and validation of these findings in other larger data sets is required.

References

[1]Liu,Y., Aryee,M.J., Padyukov,L., Fallin,M.D., Hesselberg,E., Runarsson,A., Reinius,L., Acevedo,N., Taub,M., Ronninger,M., et al. (2013) Epigenome-wide association data implicate DNA methylation as an intermediary of genetic risk in rheumatoid arthritis. Nat. Biotechnol., 31, 142–147.

[2]Plant,D., Webster,A., Nair,N., Oliver,J., Smith,S.L., Eyre,S., Hyrich,K.L., Wilson,A.G., Morgan,A.W., Isaacs,J.D., et al. (2016) Differential Methylation as a Biomarker of Response to Etanercept in Patients With Rheumatoid Arthritis. Arthritis Rheumatol. (Hoboken, N.J.), 68, 1353–60.

Disclosure of Interests

Nisha Nair: None declared, Darren Plant: None declared, John Isaacs Speakers bureau: Abbvie, Gilead, Roche, UCB, Grant/research support from: GSK, Janssen, Pfizer, Ann Morgan Speakers bureau: Roche/Chugai, Consultant of: GSK, Roche, Chugai, AstraZeneca, Regeneron, Sanofi, Vifor, Grant/research support from: Roche, Kiniksa Pharmaceuticals, Kimme Hyrich Consultant of: AbbVie, Grant/research support from: Pfizer, BMS, Anne Barton Grant/research support from: I have received grant funding from Pfizer, Galapagos, Scipher Medicine and Bristol Myers Squibb., Anthony G Wilson: None declared

AB0148 COULD THE RENIN-ANGIOTENSIN SYSTEM AFFECT THE PROGNOSIS OF GIANT CELL ARTERITIS? SINGLE-CENTRE RETROSPECTIVE OBSERVATIONAL STUDY

Background

About half of patients with giant cell arteritis (GCA) relapse while tapering glucocorticoid therapy1. A previous observational study reported that blockade of the renin-angiotensin system, with angiotensin II receptor blockers (ARBs), was associated with lower relapse risk2.

Objectives

To determine whether angiotensin blockade, with angiotensin converting enzyme inhibitor (ACEi) or ARB, is associated with differential relapse risk in GCA.

Methods

GCA patients from a tertiary centre diagnosed 2012–2020 with two years follow-up were identified from UK GCA Consortium. All provided written informed consent. Retrospective review of medical records included demographics, comorbidities, drug history, inflammatory markers and relapses. Relapse was defined as return of symptoms, raised inflammatory markers, or active vasculitis on imaging confirmed by the treating clinician. Relapse-free survival was analysed using Kaplan Meier (KM) curves and Cox proportional hazards.

Results

111 patients were included (Table 1: demographic data), all were initially treated with 40–60mg Prednisolone. 42% received further immunosuppressants due to relapse or disease severity. 50% patients relapsed in two years, presenting with cranial symptoms (72%), PMR-like symptoms (30%) and/or raised inflammatory markers (48%). There was no association between relapse and age, gender, comorbid HTN/IHD or pre-steroid inflammatory markers and relapse. Rate of steroid taper can affect relapse. EULAR recommend 15–20mg of steroid by three months3. 9 patients relapsed within that time and were excluded, there was no difference in steriod dose at three months between the two groups. KM analysis showed ACEi did not significantly affect time to relapse compared to no angiotensin blockade (HR 0.57, 95% CI 0.28 – 1.18, unadjusted p-value=0.128), and neither did an ARB (HR 0.78, 95% CI 0.31 – 1.98, unadjusted p-value=0.605).

Table 1.

demographic data at baseline.

Relapse (n = 56)No Relapse (n = 55)Patient FactorsAge median (IQR)70 (65-74)73 (67-78)Male Sex n (%)16 (29)20 (36.36)Medications n (%)ACEi9 (15)16 (29)ARB7 (12)7 (13)Comorbidities n (%)CKD4 (7)9 (16)IHD6 (11)5 (9)Prediabetes11 (20)10 (18)DM1 (2)5 (9)HTN22 (40)23 (42)Current Smoker6 (10)2 (4)GCA Factors median (IQR)CRP pre-treatment69 (32 – 131)64 (23 -115)ESR pre-treatment50 (37 -95)4 (22 -72)Steroid dose at 3 months19 (15 -20)15 (10-20)Figure 1.

Unadjusted KM survival curve showing probability of relapse in patients 1) taking ACEi, 2) taking ARB, 3) taking neither ACEi or ARB, 4) with no comorbid HTN or IHD at diagnosis, and 5) experienced comorbid HTN/IHD. There was no significant difference in relapse free survival in patients on an ACEi compared to those taking neither ACEi or ARB.

Conclusion

In the two years following GCA diagnosis 50% relapsed. There was no significant difference in the rate of relapse in patients taking an ACEi or ARB. The main limitation, in this retrospective, observational study was the inability to exclude a reluctance of clinicians to diagnose GCA relapse in the presence of cardiovascular comorbidity. A randomised controlled trial would be needed to determine whether starting an ACEi could reduce relapse risk in patients with new-onset GCA.

References

[1]Mainbourg, S. et al. Prevalence of Giant Cell Arteritis Relapse in Patients Treated With Glucocorticoids: A Meta-Analysis. Arthritis Care Res.72, 838–849 (2020).

[2]Alba, M. A. et al. Treatment with angiotensin II receptor blockers is associated with prolonged relapse-free survival, lower relapse rate, and corticosteroid-sparing effect in patients with giant cell arteritis. Semin. Arthritis Rheum.43, 772–777 (2014).

[3]Hellmich, B. et al. 2018 Update of the EULAR recommendations for the management of large vessel vasculitis. Ann Rheum Dis79, 19–30 (2020).

Disclosure of Interests

Ranjana Venkateswaran: None declared, Karan Gour: None declared, Louise Sorensen: None declared, Charlotte Harden: None declared, Sizheng Steven Zhao: None declared, Ann Morgan Speakers bureau: Roche/Chugai., Consultant of: GSK, Roche, Chugai, AstraZeneca, Regeneron, Sanofi, Vifor., Grant/research support from: Roche, Kiniksa Pharmaceuticals, Sarah Mackie Consultant of: Roche/Chugai, AbbVie, AstraZeneca, Sanofi, Pfizer., Grant/research support from: Attendance at ACR21 supported by Pfizer. Attendance at EULAR2019 supported by Roche.

AB0345 THERAPEUTIC DRUG LEVELS TO ACHIEVE GOOD EULAR RESPONSE IN PATIENTS WITH RHEUMATOID ARTHRITIS RECEIVING ADALIMUMAB: RESULTS FROM THE BIOLOGICS IN RHEUMATOID ARTHRITIS GENETICS AND GENOMICS STUDY SYNDICATE (BRAGGSS) COHORT

Background

Rheumatoid arthritis (RA) is a systemic inflammatory disease often treated with biologic disease-modifying anti-rheumatic drugs (bDMARDs) such as Adalimumab (ADL), a tumour-necrosis factor inhibitor (TNFi). However, it is known that about a third of patients do not respond to ADL treatment. Previous studies have reported associations between poor response, decreased serum drug levels (SDLs) and poor adherence, but a therapeutic SDL has not been defined nor applied in clinical practice.

Objectives

To assess median ADL SDLs in RA European Alliance of Associations for Rheumatology (EULAR) good vs non/moderate responders, and to determine cut-off SDLs associated with a “Good” response in fully adherent RA patients.

Methods

In a prospective observational cohort study, patients with RA were treated with ADL. At baseline, 3-, 6-, and 12-months patients had 4-component DAS28 scores, self-reported treatment adherence data and SDLs measured. Median drug levels and receiver-operator characteristics (ROC) curves were used to compare SDLs between responders and non-responders, and to establish cut-off SDLs in self-reported fully adherent patients. Serum drug levels were measured using a sandwich ELISA produced by Progenika Biopharma. Patients were considered fully adherent if they self-reported never having altered, forgotten or omitted any dose of their biologic drug at follow-up. Between group comparisons were assessed using Fisher’s exact test, with a threshold for significance set at p<0.05. Statistical analyses were performed in R Version 4.1.0 and RStudio Version 1.4.1106.

Results

A total of 283 RA patients taking ADL were included in the analysis. Baseline characteristics are shown in Table 1. Of these patients 93 (32.9%) self-reported being fully adherent to treatment at 3 months follow-up and had SDLs measured.

Table 1.

Baseline characteristics of patient cohort with RA taking ADL (n=283)

CharacteristicnMissing (%)Age at baseline, median years (IQR)58 (51, 64)0Disease duration, median years (IQR)7 (3, 16)0Female Sex, n (%)206 (73)0BMI, median (IQR)27.4 (23.7, 31.9)0Smoking Status132 (46)Current, n (%)57 (38)-Ex, n (%)32 (21)-Non, n (%)62 (41)-On concurrent DMARD(s)1 (0.4)No, n (%)34 (12)-Yes, n (%)248 (88)-Baseline DAS Score, median (IQR)5.61 (5.18, 6.14)On MTX at baseline38 (13)No, n (%)44 (18)Yes, n (%)201 (82)

In 93 fully adherent RA patients taking ADL at 3 months, good EULAR responders had significantly higher SDLs compared to non/moderate EULAR responders (p=0.0234). In 47/93 (50.5%) fully adherent good responders median SDL at 3 months was 10.94mg/L (IQR 7.75 to 12.0), whereas in 46/93 (49.5%) non/moderate responders, median SDL at 3 months was 9.014 (IQR 6.96 to 11.1).

ROC analysis (see Figure 1) reported a 3-month non-trough ADL SDL cut-off of 7.5mg/L in fully adherent RA patients which discriminated Good EULAR responders compared to non/moderate responders with an AUC of 0.63 (95% CI 0.52 – 0.75), 39.1% specificity, and 80.9% sensitivity.

Figure 1.

ROC curve analysis: EULAR non/moderate vs good responders with 3 month ADL SDLs.

Conclusion

In keeping with previous work, SDLs were higher in adherent compared with non-adherent patients, but this is the first study to demonstrate that SDLs are higher in fully adherent good EULAR responders compared with non/moderate responders. Based on our methods, cut-offs of 7.5mg/L for ADL may be useful targets in clinical practice to achieve good EULAR response.

References

[1]Jani M, Chinoy H, Warren RB, Griffiths CEM, Plant D, Fu B, et al. Clinical Utility of Random Anti–Tumor Necrosis Factor Drug–Level Testing and Measurement of Antidrug Antibodies on the Long-Term Treatment Response in Rheumatoid Arthritis. Arthritis & Rheumatology. 2015;67(8):2011-9.

[2]Pouw MF, Krieckaert CL, Nurmohamed MT, van der Kleij D, Aarden L, Rispens T, et al. Key findings towards optimising adalimumab treatment: the concentration-effect curve. Ann Rheum Dis. 2015;74(3):513-8.

Disclosure of Interests

None declared

POS0509 DEVELOPMENT OF A MULITNOMIAL PREDICTION MODEL OF TREATMENT RESPONSE TO ETANERCEPT IN A MULTI-CENTRE COHORT OF PATIENTS WITH ESTABLISHED RA

Background

Treatment response in rheumatoid arthritis (RA) is assessed through EULAR response groups of good, moderate, and poor response. Clinical prediction models from the literature typically frame this as a binary model, to differentiate poor from good and moderate responders. Here, we develop a multinomial model, to predict each group separately, after 3 months on the anti-TNF drug Etanercept (ETN).

Objectives

Develop and validate a multinomial prediction model of treatment response to ETN in RA, based on baseline clinical covariates.

Methods

We identified patients treated with ETN or biosimilars (N = 778) from the Biologics in RA Genetics and Genomics Study Syndicate (BRAGGSS). Response groups were derived from the CRP based 4C-DAS28 at baseline and 3 month follow up, yielding 310 good, 320 moderate, and 148 poor responders. A multinomial logistic regression model was fitted, using good responders as reference category. Multiple imputation by chained equations was used to impute missing data, and models were internally validated via bootstrapping. We report model accuracy, as well as calibration, and compare effect sizes across response groups. Table 1shows the baseline statistics, and odds ratios for the included covariates.

Table 1.

Baseline covariate statistics and odds ratios (in bold: significant at p < 0.05); HADS: Hospital Anxiety and Depression Scale

VariableMean (± SD)ORModerate [95% CI]pORPoor [95% CI]por % YesSwollen Joint8.84450.980.350.948e-3Count (SJC)(± 5.20)[0.95 1.02][0.89 0.98]Tender Joint14.68771.076e-61.050.01Count (TJC)(± 6.74)[1.04 1.10][1.01 1.08]General Health74.74291.000.60.981e-3Visual Analog Scale (GHVAS)(±17.79)[0.99 1.01][0.97 0.99]CRP19.07391.000.220.990.26(±25.07)[1.00 1.01][0.98 1.00]BMI30.30351.000.481.000.41(±23.28)[0.99 1.01][0.99 1.01]Age of47.33301.010.121.020.06onset(±13.86)[1.00 1.03][1.00 1.04]Disease9.94011.000.840.990.45duration(±10.35)[0.98 1.02][0.96 1.02]HAQ1.60851.480.022.951e-6(± 0.65)[1.06 2.08][1.91 4.54]HADS-Anxiety8.08681.040.191.060.12(± 4.54)[0.98 1.10][0.99 1.13]HADS-Depression7.38411.060.120.970.55(± 4.02)[0.99 1.13][0.89 1.06]Concurrent81.49%0.412e-40.520.03DMARD[0.26 0.66][0.28 0.94]Female78.66%1.390.121.110.71[0.92 2.10][0.65 1.87]Seropositive77.89%0.540.020.470.01[0.33 0.89][0.26 0.86]1st Biologic90.62%1.060.860.480.03[0.55 2.06][0.24 0.94]

Results

Adjusted for optimism, the multinomial model achieves an accuracy of 50.7% (IQR: 50 – 51.3%), with calibration slopes of 0.574 (IQR: 0.569 - 0.579) and 0.534 (IQR: 0.525 - 0.544) for moderate and poor response, respectively. Figure 1 shows a comparison of odds ratios (OR) for the different outcome groups. The Health Assessment Questionnaire (HAQ) score is the biggest driver of both moderate and poor response. Previous biologic treatment also predicts poor but not moderate response. Compared to the multinomial model, a binary model, that discriminates poor from moderate and good responders, underestimates the effect size of HAQ.

Figure 1.

Odds ratios of FIRSTBIO and HAQ for moderate and poor response. Size of crosses indicate 95% confidence intervals.

Conclusion

The model predicts EULAR response groups moderately well but is poorly calibrated, which can partly be explained by the generally higher sample size requirement of multinomial modelling. In the multinomial model, moderate and poor response is largely driven by the same covariates, which leads to blurred boundaries between good and poor responders, when response groups are merged to create a binary problem. Future research should consider the most appropriate model choice to describe data, including the use of multinomial instead of binomial models. More research and bigger sample sizes are required to improve on this multinomial model.

Disclosure of Interests

Michael Stadler: None declared, Stephanie Ling: None declared, Nisha Nair: None declared, John Isaacs Speakers bureau: Abbvie, Gilead, Roche, UCB, Grant/research support from: GSK, Janssen, Pfizer, Kimme Hyrich Speakers bureau: Abbvie, Grant/research support from: Pfizer and BMS, Ann Morgan Speakers bureau: Roche/ Chuga, Consultant of: GSK, Roche, Chugai, AstraZeneka, Regeneron, Sanofi, Vifor, Grant/research support from: Roche, Kiniksa Pharmaceuticals, Anthony G Wilson: None declared, Darren Plant: None declared, John Bowes: None declared, Anne Barton Grant/research support from: Pfizer, Galapagos, Scipher Medicine, and Bristol Myers Squibb.

Strategic placement of automated external defibrillators (AEDs) for cardiac arrests in public locations and private residences

•

We ranked businesses for their ability to fill gaps in the AED landscape.

•

23% of OHCAs in public, and 4% in homes, were within 100 m of an existing AED.

•

Many businesses can simultaneously improve coverage of arrests in public and homes.

•

Rankings were largely robust to the coverage radius used (100 m, 200 m, and 500 m).

•

Even if all 5006 business locations hosted AEDs, large gaps in OHCA coverage remain.

Aim

Methods

Results

Conclusion

AB0337 BASELINE C-REACTIVE PROTEIN PREDICTS ADHERENCE TO ADALIMUMAB THERAPY AT 3 MONTHS IN AN OBSERVATIONAL COHORT OF PATIENTS WITH RHEUMATOID ARTHRITIS

Background

Adherence to biologic treatment in rheumatoid arthritis (RA) is often self-reported and little is known about the predictors of adherence to biologic medications. Many studies have reported the predictors of adherence to be linked to psychological factors. A systematic review [1] identified several predictors of adherence to methotrexate in RA patients with the strongest predictors related to psychological factors including beliefs in medication necessity and absence of low mood. Mild disease activity was also found to be a significant predictor of adherence from this study. It is unknown whether similar factors will predict adherence in an established cohort of patients with RA starting biologic therapy.

Objectives

To investigate levels of self-reported adherence to adalimumab treatment and identify the contribution of demographic, physical and psychological factors to medication adherence in an RA cohort.

Methods

Patients with RA who were commencing on adalimumab were recruited through the Biologics in Rheumatoid Arthritis Genetics and Genomics Study Syndicate (BRAGGSS), a large UK multicentre prospective observational cohort study. Demographics, baseline clinical and psychological measures including illness and medication beliefs were collected. Self-reported adherence, defined as the patient has never stopped, altered, missed, forgot to take, or took a lower dose than prescribed of adalimumab, were recorded at 3 months. Potential baseline predictors of adherence to adalimumab therapy were determined using logistic regression analyses.

Results

202 patients were included; 76% female, median (IQR): age 59 (52-67) years, pre-treatment DAS28-CRP score 5.6 (5.1-6.1) and disease duration 5 (2-15) years. During the first 3 months following commencement of adalimumab, 176 (87%) patients reported full adherence. Univariable analyses found that high baseline C-reactive protein (CRP) [odds ratio (OR) 1.04 per mg/L, 95% CI 1.01, 1.09] was associated with adherence to adalimumab at 3 months. However, there were no associations identified from the psychological variables and this includes perceived necessity towards medication [OR 0.92, 95% CI 0.79, 1.05], hospital depression score [OR 0.94, 95% CI 0.84, 1.06] and hospital anxiety score [OR 0.97, 95% CI 0.88, 1.08].

Conclusion

These findings suggest that the psychological measures were less able to predict adherence to adalimumab therapy. The high percentage of adherence during the first three months of therapy may limit power to detect small effects in this cohort. Further research to investigate whether psychological variables correlate with drug levels as an alternative surrogate for adherence and to consider including other biological agents with a longer follow-up timeline are needed.

High baseline CRP levels were associated with adherence. This finding suggests active disease with higher levels of inflammation in RA may be a factor for adherence in patients who are commencing biologic therapy.

References

[1]Hope, H. F., Bluett, J., Barton, A., Hyrich, K. L., Cordingley, L., & Verstappen, S. M. M. (2016). Psychological factors predict adherence to methotrexate in rheumatoid arthritis; findings from a systematic review of rates, predictors and associations with patient-reported and clinical outcomes. RMD Open, 2(1), e000171. https://doi.org/10.1136/rmdopen-2015-000171

Disclosure of Interests

Adlan Wafi Ramli: None declared, Nisha Nair: None declared, Kimme Hyrich Consultant of: AbbVie, Grant/research support from: Pfizer, BMS, John Isaacs Speakers bureau: Abbvie, Gilead, Roche, UCB, Grant/research support from: GSK, Janssen, Pfizer, Ann Morgan Speakers bureau: Roche/Chugai, Consultant of: GSK, Roche, Chugai, AstraZeneca, Regeneron, Sanofi, Vifor, Grant/research support from: Roche, Kiniksa Pharmaceuticals, Darren Plant: None declared, Anthony G Wilson: None declared, Anne Barton Grant/research support from: I have received grant funding from Pfizer, Galapagos, Scipher Medicine and Bristol Myers Squibb.

OP0190 COMPREHENSIVE GENETIC AND FUNCTIONAL ANALYSES OF Fc GAMMA RECEPTORS EXPLAIN RESPONSE TO RITUXIMAB THERAPY FOR AUTOIMMUNE RHEUMATIC DISEASES

Background

Rituximab is widely used to treat rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) but clinical response varies. Efficacy is determined by the efficiency of depletion, which may depend on a variety of Fc gamma receptor (FcγR)-dependent mechanisms. Previous research was limited by complexity of the FCGR locus, not integrating copy number variation with functional SNP, and small sample size.

Objectives

The study objectives were to assess the effect of the full range of FcγRs variants on depletion, clinical response and functional effect on NK-cell-mediated killing in two rheumatic diseases with a view to personalised B-cell depleting therapies.

Methods

A prospective longitudinal cohort study was conducted in 873 patients [RA=611; SLE=262] from four cohorts (BSRBR-RA and BILAG-BR registries, Leeds RA and Leeds SLE Biologics). For RA, the outcome measures were 3C-DAS28CRP and 2C-DAS28CRP at 6 (+/-3) months post-rituximab (adjusted for baseline DAS28). For SLE, major clinical response (MCR) was defined as improvement of active BILAG-2004 domains to grade C/better at 6 months. B-cell depletion was evaluated by highly-sensitive flow cytometry. Qualitative and quantitative polymorphisms for five major FcγRs were measured using a commercial multiplex ligation-dependent probe amplification. Median NK cell FcγRIIIa expression (CD3-CD56+CD16+) and NK-cell degranulation (CD107a) in the presence of rituximab-coated Daudi/Raji B-cell lines were assessed using flow cytometry.

Results

In RA, for FCGR3A, carriage of V allele (coefficient -0.25 (SE 0.11); p=0.02) and increased copies of V allele (-0.20 (0.09); p=0.02) were associated with greater 2C-DAS28 response. Irrespective of FCGR3A genotype, increased gene copies were associated with a better response. In SLE, 177/262 (67.6%) achieved BILAG response [MCR=34.4%; Partial=33.2%]. MCR was associated with increased copies of FCGR3A-158V allele, OR 1.64 (95% CI 1.12-2.41) and FCGR2C-ORF allele 1.93 (1.09-3.40). Of patients with B-cells data in the combined cohort, 236/413 (57%) achieved complete depletion post-rituximab. Only homozygosity for FCGR3A-158V and increased FCGR3A-158V copy number were associated with increased odds of complete depletion. Patients with complete depletion had higher NK cell FcγRIIIa expression at rituximab initiation than those with incomplete depletion (p=0.04) and this higher expression was associated with improved EULAR response in RA. Moreover, for FCGR3A, degranulation activity was increased in V allele carriers vs FF genotype in the combined cohort; p=0.02.

Conclusion

FcγRIIIa is the major low affinity FcγR and increased copies of the FCGR3A-158V allele, encoding the allotype with a higher affinity for IgG1, was associated with clinical and biological responses to rituximab in two autoimmune diseases. This was supported by functional data on NK cell-mediated cytotoxicity. In SLE, increased copies of the FCGR2C-ORF allele was also associated with improved response. Our findings indicate that enhancing FcγR-effector functions could improve the next generation of CD20-depleting therapies and genotyping could stratify patients for optimal treatment protocols.

References

None

Acknowledgements

This research was funded/supported by the joint funding from the Medical Research Council (MRC) and Versus Arthritis of MATURA (grant codes 36661 and MR/K015346/1). MASTERPLANS was funded by the MRC (grant code MR/M01665X/1). The Leeds Biologics Cohort was part funded by programme grants from Versus Arthritis (grant codes 18475 and 18387), the National Institute for Health Research (NIHR) Leeds Biomedical Research Centre (BRC) and Diagnostic Evaluation Co-operative and the Ann Wilks Charitable Foundation. The BILAG-BR has received funding support from Lupus UK, and unrestricted grants from Roche and GSK.

The functional studies were in part supported through a NIHR/HEFCE Clinical Senior Lectureship and a Versus Arthritis Foundation Fellowship (grant code 19764) to AWM, the Wellcome Trust Institutional Strategic Support Fund to JIR and MYMY (204825/Z/16/Z), NIHR Doctoral Research Fellowship to MYMY (DRF-2014-07-155) and NIHR Clinician Scientist to EMV (CS-2013-13-032). . AWM, INB, JDI and PE were supported by NIHR Senior Investigator awards. Work in JDI’s laboratory is supported by the NIHR Newcastle BRC, the Research Into Inflammatory Arthritis Centre Versus Arthritis, and Rheuma Tolerance for Cure (European Union Innovative Medicines Initiative 2, grant number 777357). INB is funded by the NIHR Manchester BRC.

This article/paper/report presents independent research funded/supported by the NIHR Leeds BRC and the NIHR Guy’s and St Thomas’ BRC. The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care.

Disclosure of Interests

Md Yuzaiful Md Yusof: None declared, James Robinson: None declared, Vinny Davies: None declared, Dawn Wild: None declared, Michael Morgan: None declared, John Taylor: None declared, Yasser El-Sherbiny: None declared, David Morris: None declared, Lu Liu: None declared, Andrew Rawstron: None declared, Maya H Buch: None declared, Darren Plant: None declared, Heather Cordell: None declared, John Isaacs: None declared, Ian N. Bruce: None declared, Paul Emery Speakers bureau: Roche, Consultant of: Roche, Grant/research support from: Roche, Anne Barton: None declared, Timothy Vyse: None declared, Jennifer Barrett: None declared, Edward Vital Consultant of: Roche, Grant/research support from: Roche, Ann Morgan Speakers bureau: Roche/Chugai, Consultant of: GSK, Roche, Chugai, AstraZeneka, Regeneron, Sanofi, Vifor, Grant/research support from: Roche, Kiniksa Pharmaceuticals

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

POS0357 MiRNAs CORRELATE WITH IMPROVEMENT IN DISEASE ACTIVITY IN PATIENTS WITH RHEUMATOID ARTHRITIS ON TUMOUR NECROSIS FACTOR INHIBITORS

Background:

Tumour necrosis factor inhibitors (TNFi) although effective in the treatment of rheumatoid arthritis (RA), show a variable response rate. Therefore, there is a need to identify treatment response predictors to inform therapy selection in order to practise precision medicine. MicroRNAs (miRNAs) are endogenous, single-stranded, non-coding RNAs that can alter gene expression by regulating messenger RNA translation. There is evidence for miRNA involvement in RA pathogenesis and they may serve as a useful biomarker of treatment response.

Objectives:

To identify miRNAs associated with response to TNFi in RA.

Methods:

Biologic naïve patients were selected from the Biologics in Rheumatoid Arthritis Genetics and Genomics Study Syndicate (BRAGGSS), a prospective multi-center UK study investigating treatment response biomarkers to TNFi with a primary outcome measure of change in DAS28 scores. Patients were stratified into European League Against Rheumatism (EULAR) good or non-responders based on their 3 or 6-month DAS28-CRP score.

Pre-treatment and 3-month post-treatment serum samples were substrates for miRNA profiling, which was conducted by FIRALIS using the HTG EdgeSeq miRNA whole transcriptome V2 targeted sequencing assay. Linear modelling using R package limma compared miRNA expression at (i) pre-treatment and at three-months, in EULAR good-responders and non-responders (ii) longitudinal change in expression from pre-treatment to three-months in EULAR good and non-responders.

A literature search was conducted to identify miRNAs associated with RA as a diagnostic and/or treatment response predictor. Data on these miRNAs were extracted from the miRNAs identified in the serum samples. A correction for multiple testing was applied to statistical tests.

Results:

A total of 54 patients were analysed; of these, 35 (65%) were female, median disease duration [inter-quartile range] was 6 years [2 – 14] (n=51), and 44/51 (86%) patients were on a concomitant disease modifying anti-rheumatic drug. Of the 54 patients, 39 (72%) were classified as EULAR good-responders and 15 (28%) as non-responders. 1880 miRNAs were detected in the serum samples. 64 miRNAs were identified to be associated with RA from the literature, of which, 26 were identified in the serum samples tested.

No difference in pre-treatment or three-month miRNA levels was seen comparing EULAR good-responders and non-responders (FDR p<0.05). There was a significant differential expression of four miRNAs at 3-months in good-responders compared with pre-treatment levels; miR-125a-3p (downregulated, p-value 0.002), miR-149-3p (upregulated, p-value 0.004), miR-766-3p (downregulated, p-value 0.008), miR-146b-5p (upregulated, p-value 0.006). No significant differences were observed between 3-months and baseline in non-responders.

Conclusion:

Although no pre-treatment miRNAs were associated with TNFi response, changes in the levels of four miRNAs were detected at 3-months compared to baseline in EULAR good-responders. Future work involves validation of these samples in a larger patient cohort and analysing miRNA levels at 6 and 12 months. Replication and validation of these results in larger studies are required to analyse the role of miRNAs in stratifying EULAR good-responders from non-responders at three-months, and as treatment response predictors to TNFi in RA.

Acknowledgements:

Joint last-author: Dr. Darren Plant

Disclosure of Interests:

Trixy David: None declared, Nisha Nair: None declared, James Oliver: None declared, Eric Schordan: None declared, Hüseyin Firat: None declared, Kimme Hyrich Consultant of: consultancy/honoraria from AbbVie, Grant/research support from: Pfizer, UCB, BMS, Ann Morgan: None declared, Anthony G Wilson: None declared, John D Isaacs Speakers bureau: consultancy/speaker fees from AbbVie, Gilead, Roche, UCB, Consultant of: consultancy/speaker fees from AbbVie, Gilead, Roche, UCB, Grant/research support from: Pfizer, Darren Plant: None declared, Anne Barton: None declared

Adult North Star Network (ANSN): Consensus Guideline For The Standard Of Care Of Adults With Duchenne Muscular Dystrophy

There are growing numbers of adults with Duchenne Muscular Dystrophy living well into their fourth decade. These patients have complex medical needs that to date have not been addressed in the International standards of care. We sought to create a consensus based standard of care through a series of multi-disciplinary workshops with specialists from a wide range of clinical areas: Neurology, Cardiology, Respiratory Medicine, Gastroenterology, Endocrinology, Palliative Care Medicine, Rehabilitation, Renal, Anaesthetics and Clinical Psychology. Detailed reports of evidence reviewed and the consensus building process were produced following each workshop and condensed into this final document which was approved by all members of the Adult North Star Network including service users. The aim of this document is to provide a framework to improve clinical services and multi-disciplinary care for adults living with Duchenne Muscular Dystrophy.

Right atrium to pulmonary capillary wedge pressure ratio is associated with right ventricular failure and mortality after left ventricular assist device surgery

Introduction

Right ventricular failure (RVF) is a major cause of morbidity and mortality after left ventricular assist device (LVAD) implantation. We investigated the role of right atrium to pulmonary capillary wedge pressure (RA/PCWP) ratio as a preoperative predictor of postoperative RVF after LVAD surgery.

Methods

A retrospective analysis of all consecutive patients who received continuous-flow LVADs (HeartMate 2, 3, and HVAD) between August 2012 and May 2018 in a single tertiary center. INTERMACS profile 1 patients were excluded. RA/PCWP ratio was calculated for the entire cohort and divided into quartiles (Q). Patients were stratified into high (Q4) vs. low (Q1–3) RA/PCWP ratio. The primary end point was the composite of in hospital mortality and RVF (defined as the need for a right ventricular assist device or inotrope dependence for &gt;7 days). The secondary endpoint was readmission within 14 days after discharge.

Results

The study cohort consisted of 59 patients (15 patients in the high RA/PCWP group and 44 patients in the low RA/PCWP group) with a median follow-up of 21 months (Interquartile range 14–31). The mean age was 56±11 years and the majority of patients were male (88%). Patients were classified as INTERMACS profile 2 (34%), 3 (19%) or 4 (47%).

Preoperative clinical, laboratory, and echocardiographic parameters were similar in both groups except for a larger proportion of patients with a dilated right ventricle and above moderate tricuspid regurgitation in the high compared to the low RA/PCWP group (73% vs. 29%; P=0.006 and 40% vs. 2%; P=0.001, respectively). Overall, 7 patients (12%) developed the primary end-point and 9 patients (15%) developed the secondary end-point.

Univariate analysis demonstrated that high RA/PCWP is associated with both primary and secondary end-points (odds ratio [OR], 7.6; 95% confidence interval [CI] 1.2–47.2, P=0.029 and OR, 6.25; 95% CI 1.3–28.5, P=0.018, respectively). On multivariable analysis, the association remained significant after adjustment for INTERMACS score (OR, 10.6; 95% CI 1.4–80.9, P=0.022 and OR, 7.9; 95% CI 1.5–42.2, P=0.015, respectively).

Using receiver operating characteristic curve (ROC) derived cut-points, RA/PCWP &gt;0.57 provided 67% sensitivity and 79% specificity (C-statistic = 0.73) for the prediction of in hospital mortality and RVF and 56% sensitivity and 84% specificity (C-statistic = 0.69) for the prediction of readmissions within 14 days after discharge. In comparison, in our cohort using ROC-derived cut points, pulmonary artery pulsatility index, an established RVF predictor, of less than 1.84 provided 40% sensitivity and 20% specificity (C-statistic = 0.3) for the prediction of inhospital death and RVF.

Conclusion

RA/PCWP ratio may help to identify patients at high risk of developing adverse clinical outcomes, including RVF and mortality, after LVAD surgery.

Funding Acknowledgement

Type of funding source: None