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ObjectiveGout is characterised by severe interleukin (IL)-1-mediated joint inflammation induced by monosodium urate crystals. Since IL-37 is a pivotal anti-inflammatory cytokine suppressing the activity of IL-1, we conducted genetic and functional studies aimed at elucidating the role of IL-37 in the pathogenesis and treatment of gout.MethodsVariant identification was performed by DNA sequencing of all coding bases of IL37 using molecular inversion probe-based resequencing (discovery cohort: gout n=675, controls n=520) and TaqMan genotyping (validation cohort: gout n=2202, controls n=2295). Predictive modelling of the effects of rare variants on protein structure was followed by in vitro experiments evaluating the impact on protein function. Treatment with recombinant IL-37 was evaluated in vitro and in vivo in a mouse model of gout.ResultsWe identified four rare variants in IL37 in six of the discovery gout patients; p.(A144P), p.(G174Dfs*16), p.(C181*) and p.(N182S), whereas none emerged in healthy controls (Fisher’s exact p-value=0.043). All variants clustered in the functional domain of IL-37 in exon 5 (p-value=5.71×10−5). Predictive modelling and functional studies confirmed loss of anti-inflammatory functions and we substantiated the therapeutic potential of recombinant IL-37 in the treatment of gouty inflammation. Furthermore, the carrier status of p.(N182S)(rs752113534) was associated with increased risk (OR=1.81, p-value=0.031) of developing gout in hyperuricaemic individuals of Polynesian ancestry.ConclusionHere, we provide genetic as well as mechanistic evidence for the role of IL-37 in the pathogenesis of gout, and highlight the therapeutic potential of recombinant IL-37 for the treatment of gouty arthritis.

IntroductionRheumatoid arthritis (RA) affects approximately 0.5%–1% of the general population. Clinically significant interstitial lung diseases (ILD) develops in just under 10% of people with RA, and subclinical disease is more common. Little is known about RA-ILD in New Zealand (NZ), or the number of persons with RA in Canterbury, NZ. This study aims to determine: (1) incidence and prevalence of RA, (2) incidence and prevalence of RA-ILD, (3) clinical characteristics and risk factors for the development of RA-ILD, (4) long-term outcomes of RA-ILD, in the population resident within the Canterbury District Health Board (CDHB) catchment area.Methods and analysisPersons aged 18 years of age and older, and resident in the region covered by the CDHB with RA as well as RA-ILD will be identified by retrospective review of medical records. Prevalent as well as incident cases of RA between 1 January 2006 and 31 December 2008 and between 1 January 2011 and 31 December 2013 will be identified, and followed until 30 June 2019. Existing as well as incident cases of RA-ILD during this time will be identified. The association between the development of ILD and clinical characteristics and environmental exposures will be examined using Cox-proportional hazard models. Kaplan-Meier methods will be used to estimate survival rates for patients with RA-ILD. Mortality for people with RA and RA-ILD will also be compared with the general population of the CDHB.Ethics and disseminationData will be obtained by retrospective review of medical records. Deidentified patient data will be stored in a secure online database. Data on individual patients will not be released, and all results will only be published in aggregate. Ethical approval has been obtained from the University of Otago Human Research Ethics Committee (REF HD18/079). Results will be published in peer-reviewed medical journals and presented at conferences.Trial registration numberACTRN12619001310156; Pre-results.

ObjectiveMitochondria have an important role in the induction of the NLRP3 inflammasome response central in gout. The objective was to test whether mitochondrial genetic variation and copy number in New Zealand Māori and Pacific (Polynesian) people in Aotearoa New Zealand associate with susceptibility to gout.Methods437 whole mitochondrial genomes from Māori and Pacific people (predominantly men) from Aotearoa New Zealand (327 people with gout, 110 without gout) were sequenced. Mitochondrial DNA copy number variation was determined by assessing relative read depth using data produced from whole genome sequencing (32 cases, 43 controls) and targeted resequencing of urate loci (151 cases, 222 controls). Quantitative PCR was undertaken for replication of copy number findings in an extended sample set of 1159 Māori and Pacific men and women (612 cases, 547 controls).ResultsThere was relatively little mitochondrial genetic diversity, with around 96% of those sequenced in this study belonging to the B4a1a and derived sublineages. A B haplogroup heteroplasmy in hypervariable region I was found to associate with a higher risk of gout among the mitochondrial sequenced sample set (position 16181: OR=1.57, P=0.001). Increased copies of mitochondrial DNA were found to protect against gout risk with the effect being consistent when using hyperuricaemic controls across each of the three independent sample sets (OR=0.89, P=0.007; OR=0.90, P=0.002; OR=0.76, P=0.03). Paradoxically, an increase of mitochondrial DNA also associated with an increase in gout flare frequency in people with gout in the two larger sample sets used for the copy number analysis (β=0.003, P=7.1×10–7; β=0.08, P=1.2×10–4).ConclusionAssociation of reduced copy number with gout in hyperuricaemia was replicated over three Polynesian sample sets. Our data are consistent with emerging research showing that mitochondria are important for the colocalisation of the NLRP3 and ASC inflammasome subunits, a process essential for the generation of interleukin-1β in gout.

Background:Classification criteria for calcium pyrophosphate deposition disease (CPPD) will facilitate clinical research on this common crystalline arthritis. ACR/EULAR are jointly sponsoring development of CPPD classification criteria using a multi-phase process.Objectives:To report preliminary results from the first two phases of a four-phase process for developing CPPD classification criteria.Methods:CPPD classification criteria development is overseen by a 12-member Steering Committee. Item generation (Phase I) included a scoping literature review of five literature databases and contributions from a 35-member Combined Expert Committee and two Patient Research Partners. Item reduction and refinement (Phase II) involved a Combined Expert Committee meeting, discussions among Clinical, Imaging, and Laboratory Advisory Groups, and an item rating exercise to assess the influence of individual items toward classification. The Steering Committee reviewed the modal rating score for each item (range -3 [strongly pushes away from CPPD] to +3 [strongly pushes toward CPPD]) to determine items to retain for future phases of criteria development.Results:Item generation yielded 420 items (312 from the literature, 108 from experts/patients). The Advisory Groups eliminated items they agreed were unlikely to distinguish between CPPD and other forms of arthritis, yielding 127 items for the item rating exercise. Fifty-six items, most of which had a modal rating of +/- 2 or 3, were retained for future phases (see Table 1). As numerous imaging items were rated +3, the Steering Committee recommended focusing on imaging of the knee, wrist, and one additional affected joint for calcification suggestive of CPP crystal deposition.Conclusion:The ACR/EULAR CPPD classification criteria working group has adopted both data- and expert-driven approaches, leading to 56 candidate items broadly categorized as clinical, imaging, and laboratory features. Remaining steps for criteria development include domain establishment, item weighting through a multi-criteria decision analysis exercise, threshold score determination, and criteria validation.Table 1.Categories of items retained for future phases of classification criteria developmentAge in decade at symptom onsetAcute inflammatory arthritis (e.g. knee, wrist, 1st MTP joint*)Recurrence and pattern of joint involvement (e.g. 1 self-limited episode, >1 self-limited episode)Physical findings (e.g. palpable subcutaneous tophus*, psoriasis*)Co-morbidities and family history (e.g. Gitelman disease, hemochromatosis, familial CPPD)Osteoarthritis location and features (e.g. 2nd or 3rd MCP joint, wrist)Synovial fluid findings (e.g. CPP crystals present, CPP crystals absent on 1 occasion* or 2 occasions*, monosodium urate crystals present*)Laboratory findings (e.g. hypomagnesemia, hyperparathyroidism, rheumatoid factor*, anti-CCP*)Plain radiograph: calcification in regions of fibro- or hyaline cartilage+Plain radiograph: calcification of the synovial membrane/capsule/tendon+Conventional CT: calcification in regions of fibro- or hyaline cartilage+Conventional CT: calcification of the synovial membrane/capsule/tendon+Ultrasound: CPP crystal deposition in fibro- or hyaline cartilage+Ultrasound: CPP crystal deposition in synovial membrane/capsule/tendons+Dual-energy CT: CPP crystal deposition in fibro- or hyaline cartilage+Dual-energy CT: CPP crystal deposition in synovial membrane/capsule/tendon+*Potential negative predictor +Assessed in the knee, wrist, and/or 1 additional affected jointDisclosure of Interests:Sara Tedeschi Consultant of: NGM Biopharmaceuticals, Tristan Pascart: None declared, Augustin Latourte Consultant of: Novartis, Cattleya Godsave: None declared, Burak Kundaki: None declared, Raymond Naden: None declared, William Taylor: None declared, Nicola Dalbeth Speakers bureau: Abbvie and Janssen, Consultant of: AstraZeneca, Dyve, Selecta, Horizon, Arthrosi, and Cello Health, Tuhina Neogi: None declared, Fernando Perez-Ruiz: None declared, Ann Rosenthal: None declared, Fabio Becce Consultant of: Horizon Therapeutics, Grant/research support from: Siemens Healthineers, Eliseo Pascual: None declared, Mariano Andrés: None declared, Thomas Bardin: None declared, Michael Doherty: None declared, Hang Korng Ea: None declared, Georgios Filippou: None declared, John FitzGerald: None declared, Marwin Gutierrez: None declared, Annamaria Iagnocco: None declared, Tim Jansen Speakers bureau: Abbvie, Amgen, BMS, Grunenthal, Olatec, Sanofi Genzyme, Consultant of: Abbvie, Amgen, BMS, Grunenthal, Olatec, Sanofi Genzyme, Minna Kohler Speakers bureau: Lilly, Consultant of: Novartis, Frederic Lioté: None declared, Mark Matza: None declared, Geraldine McCarthy Consultant of: PK Med, Roberta Ramonda: None declared, Anthony Reginato: None declared, Pascal Richette: None declared, Jasvinder Singh Speakers bureau: Simply Speaking, Consultant of: Crealta/Horizon, Medisys, Fidia, UBM LLC, Trio health, Medscape, WebMD, Adept Field Solutions, Clinical Care options, Clearview healthcare partners, Putnam associates, Focus forward, Navigant consulting, Spherix, Practice Point communications, Francisca Sivera: None declared, Alexander So: None declared, Lisa Stamp: None declared, Janeth Yinh: None declared, Chio Yokose: None declared, Robert Terkeltaub Consultant of: Sobi, Horizon Therapeutics, Astra-Zeneca, Selecta, Grant/research support from: Astra-Zeneca, Hyon Choi: None declared, Abhishek Abhishek Consultant of: NGM Biopharmaceuticals.

ObjectivesTo determine the efficacy and safety of allopurinol dose escalation using a treat-to-target serum urate (SU) approach.MethodsA randomised, controlled, parallel-group, comparative clinical trial was undertaken. People with gout receiving at least creatinine clearance (CrCL)-based allopurinol dose for ≥1 month and SU ≥6 mg/dL were recruited. Participants were randomised to continue current dose (control) or allopurinol dose escalation for 12 months. In the dose escalation group, allopurinol was increased monthly until SU was Results183 participants (93 control, 90 dose escalation) were recruited. At baseline, mean (SD) urate was 7.15 (1.6) mg/dL and allopurinol dose 269 mg/day. 52% had CrCLConclusionsHigher than CrCL-based doses of allopurinol can effectively lower SU to treatment target in most people with gout. Allopurinol dose escalation is well tolerated.Trial registration number:ANZCTR12611000845932; Results.

Background:There is a strong association between gout and obesity. Lowering urate is the cornerstone of gout management [1] and urate levels correlate strongly with central obesity. Previous studies suggest that weight loss has a positive effect on serum urate, however, the studies are sparse and small [2].Objectives:To assess the impact of an initial low-calorie diet-induced weight loss and subsequent randomisation to the body weight-lowering drug liraglutide (a glucagon-like peptide 1 receptor agonist) or placebo on serum urate levels.Methods:In the LOSE-IT trial (NCT02905864), a randomised, double-blinded, placebo-controlled, parallel group, single-centre trial [3], 156 obese individuals with knee osteoarthritis, but without gout, were offered an initial 8-week intensive diet intervention (week -8 to 0) on Cambridge Weight Plan (800-1000 kcal/day) followed by a weight loss maintenance period in which participants were randomised to either liraglutide 3 mg/day or placebo for 52 weeks. We conducted a secondary analysis of blood samples collected at week -8, 0 and 52. The primary outcome measure was change in serum urate. We used paired t-test for the change from week -8 to 0, and for change from week 0 to 52 we used an ANCOVA model adjusted for stratification factors (sex, age category and obesity class), and the level of the outcome at baseline. Data were analysed as observed (i.e. no imputation of missing data).Results:156 individuals were randomised and 155 had blood samples taken at baseline. In the initial intensive diet intervention period (week -8 to 0) they lost a mean of 12.5 kg (95% CI -13.1 to -11.9, n 156). In the following 52 weeks, the liraglutide group lost an additional 4.1 kg (SE 1.2, n 71) whereas the control group was almost unchanged with a weight loss of 0.2 kg (SE 1.2, n 66). Looking at the main outcome of serum urate levels change, the initial intensive diet resulted in a mean decrease of 0.21 mg/dL (95% CI 0.35 to 0.07, n 155) for the entire cohort. In the following year (week 0 to 52) the liraglutide group exhibited a further mean decrease in serum urate of 0.48 mg/dL (SE 0.11, n 69), whereas the placebo group exhibited a slight decrease in mean serum urate of 0.07 mg/dL (SE 0.12, n 65) resulting in a significant between-group difference of -0.40 mg/dL (95% CI -0.69 to -0.12, n 134) – see Figure 1. Four participants in each group experienced serious adverse events; no deaths were observed.Conclusion:This secondary analysis of the LOSE-IT trial suggests that liraglutide provides a potential novel serum urate lowering drug mechanism in obese patient populations, with potential implication for gout treatment.References:[1]Richette P et al. 2016.Ann Rheum Dis2017;76:29–42.[2]Nielsen SM et al.Ann Rheum Dis2017 76(11):1870-1882.[3]Gudbergsen H et al.BMJ2019. 71–2.Disclosure of Interests:Kristian Zobbe: None declared, Sabrina Mai Nielsen: None declared, Robin Christensen: None declared, Anders Overgaard: None declared, henrik gudbergsen Speakers bureau: Pfizer 2016, Marius Henriksen: None declared, Henning Bliddal Grant/research support from: received research grant fra NOVO Nordic, Consultant of: consultant fee fra NOVO Nordic, Lene Dreyer: None declared, Lisa Stamp: None declared, Filip Krag Knop Shareholder of: Minority shareholder in Antag Therapeutics Aps, Grant/research support from: AstraZeneca, Gubra, Novo Nordisk, Sanofi and Zealand Pharma, Consultant of: Amgen, AstraZeneca, Boehringer Ingelheim, Carmot Therapeutics, Eli Lilly, MSD/Merck, Mundipharma, Novo Nordisk, Sanofi and Zealand Pharma., Speakers bureau: AstraZeneca, Bayer, Boehringer Ingelheim, Eli Lilly, MedImmune, MSD/Merck, Mundipharma, Norgine, Novo Nordisk, Sanofi and Zealand Pharma., Lars Erik Kristensen Consultant of: UCB Pharma (Advisory Board), Sannofi (Advisory Board), Abbvie (Advisory Board), Biogen (Advisory Board), Speakers bureau: AbbVie, Amgen, Biogen, Bristol-Myers Squibb, Celgene, Eli Lilly, Gilead, Forward Pharma, Janssen Pharmaceuticals, MSD, Novartis, Pfizer, and UCB Pharma

To investigate the contributions towards hyperuricaemia of known risk factors, focusing on fractional (renal) clearance of urate (FCU) and variation in the ATP-binding cassette transporter, sub-family G 2 (ABCG2) gene.The contributions of age, sex, ancestry, Q141K genotype for ABCG2, FCU, sugar-sweetened beverage and alcohol consumption, metabolic syndrome disorders and measures of renal function to the risk of hyperuricaemia were evaluated by comparing hyperuricaemic (serum urate≥0.42 mmol/L, n=448) with normouricaemic (serum urate0.42 mmol/L, n=344) participants using stepwise logistic regression. Model performance was evaluated using the area under the receiver operator characteristic curve (AUROC).ABCG2 genotype, FCU, male sex, body mass index, serum triglyceride concentrations, estimated glomerular filtration rate and consumption of alcohol were the best predictors of hyperuricaemia (AUROC 0.90, 81% accuracy). Homozygosity in the 141K variant for ABCG2 conferred an adjusted OR of 10.5 for hyperuricaemia (95% CI 2.4 to 46.2). For each 1% decrease of FCU, the adjusted OR increased by 51% (OR 1.51, 95% CI 1.37 to 1.66). There was no association between ABCG2 genotype and FCU (r=0.02, p=0.83).The ABCG2 141K variant and the FCU contribute strongly but independently to hyperuricaemia. These findings provide further evidence for a significant contribution of ABCG2 to extra-renal (gut) clearance of urate.

BackgroundTophus burden is currently measured using physical examination and imaging methods. The aim of this study was to develop a patient-reported outcome (PRO) tool to assess tophus burden in people with gout.MethodsThe responses from interviews with 25 people with tophaceous gout were used to generate items for a preliminary PRO tool. Following cognitive testing of each item, a preliminary 34-item questionnaire was administered to 103 people with tophaceous gout. Rasch analysis generated a 20-item Tophus Impact Questionnaire (TIQ-20). Test-retest reproducibility and construct validity of the TIQ-20 were assessed.ResultsThe TIQ-20 responses fit the Rasch model and demonstrated unidimensionality, adequate precision, absence of differential item functioning and adequate person separation index. The TIQ-20 included items related to pain, activity limitation, footwear modification, participation, psychological impact and healthcare use due to tophi. In the 103 patients with tophaceous gout, floor effects were observed in 4.9% and ceiling effects in 1%. The TIQ-20 test-retest intraclass correlation coefficient was 0.76 (95% CI 0.61 to 0.85). All predicted correlations for construct validity testing were observed, including weak correlation with serum urate concentrations (r0.50).ConclusionsWe have developed a tophus-specific PRO in patients with tophaceous gout. The TIQ-20 demonstrates acceptable psychometric properties. Initial results show internal, face and construct validity, reproducibility and feasibility. Further research is required to determine responsiveness to change.

Objective Consumption of high fructose corn syrup (HFCS)-sweetened beverages increases serum urate and risk of incident gout. Genetic variants in SLC2A9, that exchanges uric acid for glucose and fructose, associate with gout. We tested association between sugar (sucrose)-sweetened beverage (SSB) consumption and prevalent gout. We also tested the hypothesis that SLC2A9 genotype and SSB consumption interact to determine gout risk. Methods Participants were 1634 New Zealand (NZ) European Caucasian, Ma¯ori and Pacific Island people and 7075 European Caucasians from the Atherosclerosis Risk in Communities (ARIC) study. NZ samples were genotyped for rs11942223 and ARIC for rs6449173. Effect estimates were multivariate adjusted. Results SSB consumption increased gout risk. The OR for four drinks/day relative to zero was 6.89 (p=0.045), 5.19 (p=0.010) and 2.84 (p=0.043) for European Caucasian, Ma¯ori and Pacific Islanders, respectively. With each extra daily SSB serving, carriage of the gout-protective allele of SLC2A9 associated with a 15% increase in risk (p=0.078), compared with a 12% increase in non-carriers (p=0.002). The interaction term was significant in pooled (pInteraction=0.01) but not meta-analysed (pInteraction=0.99) data. In ARIC, with each extra daily serving, a greater increase in serum urate protective allele carriers (0.005 (p=8.7×10(-5)) compared with 0.002 (p=0.016) mmol/L) supported the gout data (pInteraction=0.062). Conclusions Association of SSB consumption with prevalent gout supports reduction of SSB in management. The interaction data suggest that SLC2A9-mediated renal uric acid excretion is physiologically influenced by intake of simple sugars derived from SSB, with SSB exposure negating the gout risk discrimination of SLC2A9.

The current widely used clinical staging system for hyperuricaemia and gout describes the symptomatology of gout, but does not capture key aspects of the pathological basis of the disease. We propose a new clinical staging system. Stage A: hyperuricaemia, but without evidence of monosodium urate (MSU) crystal deposition or symptoms of gout. Stage B: MSU crystal deposition by microscopy or advanced imaging, but without signs or symptoms of gout. Stage C: MSU crystal deposition with prior or current symptoms of acute gout flares. Stage D: advanced gout requiring specialist interventions. This proposed new staging system provides a clear focus on gout as a chronic disease of MSU crystal deposition, and provides a rational framework to test the role of screening and treatment of asymptomatic disease.

Objectives Genetic variation in the renal urate transporters SLC2A9 (GLUT9) and SLC22A11 (OAT4) has been reported to interact with diuretics to increase the risk of developing gout. The aim of this study was to determine whether variation in SLC2A9 or SLC22A11 influences acute renal handling of uric acid in response to frusemide. Methods Following an overnight fast, healthy participants (n=100) attended a study visit with oral intake of 40 mg frusemide. Blood and urine samples were obtained at baseline and 30, 60, 120 and 180 min after frusemide intake. The primary end point was change in fractional excretion of uric acid (FEUA). Results Following intake of frusemide, FEUA initially increased (mean (SD) change from baseline +1.9% (3.0%) at 60 min, p

We commend the authors of the ‘2016 updated EULAR evidence-based recommendations for the management of gout’ for advocating starting allopurinol at a lower dose in patients with normal renal function.1 Specifically, this recognises an approach to potentially decrease the risk of precipitating flares of gout early in the course of urate lowering, and also to possibly decrease the risk of severe cutaneous reactions (SCARs) compared with higher starting doses of allopurinol.2 However, we note that the authors do not provide a recommendation on starting dose for patients with renal impairment , the patient group most likely to benefit from starting at a much lower dose of allopurinol.2 Furthermore, recommendation #9,i which advocates limiting the maximal dose of allopurinol based on creatinine clearance (CrCL), is concerning. It is well-documented that such practice results in suboptimal management of hyperuricaemia in the majority of …

Background Colonoscopic, endoscopic, and histological studies have demonstrated that intestinal inflammation, similar to the ileo-colitis seen in Crohn9s disease (CD), is a common feature of ankylosing spondylitis (AS). More recently, the existence of a shared genetic basis to CD and AS has been demonstrated [1,2]. Objectives To test whether the association of known CD risk loci with AS is primarily due to the presence of bowel inflammation in AS patients. Methods 286 Caucasian patients fulfilling the modified New York criteria for AS and with no history of inflammatory bowel disease were assessed non-invasively for bowel inflammation using faecal calprotectin and the Dudley Inflammatory Bowel Symptom Questionnaire (DISQ) [3]. All patients and 568 matched healthy controls were genotyped with TaqMan® SNP genotyping assays for the confirmed CD risk loci [2], 1q32 (rs11584383), JAK2 (rs10758669), CDKAL1 (rs6908425), IL12B (rs100454310), ZPBP2 (rs2872507), MUC19/LRRK2 (rs11175593), STAT3 (rs744166), and IL23R (rs1343151, rs10489630, rs11209026). Chi square testing was used to test for association. Results Minor alleles of 1q32 SNP rs11584383 (p=0.002, OR=0.69, 95% CI 0.55–0.87), and IL23R SNPs rs11209026 (p=0.011, OR=0.53, 95% CI 0.32–0.87) and rs1343151 (p=0.027, OR=0.77, 95% CI 0.61–0.97) all conferred protection against AS. However, only the association of 1q32 SNP rs11584383 remained significant after Bonferroni correction for multiple testing (p=0.02). The Cochran9s Q test found no significant difference between ORs after stratification of AS patients by DISQ score and faecal calprotectin (P difference >0.09). Conclusions Previously, the association of CD risk loci with susceptibility to AS has been attributed to the co-occurrence of asymptomatic intestinal inflammation which is well recognised and supports the concept that CD and AS are two extremes of a related genetic and phenotypic disease spectrum. However, our study provides preliminary evidence that the association of the confirmed CD risk locus 1q32 SNP rs11584383 with AS is independent of bowel inflammation. References Parkes M, et al. 2013. Nature reviews Genetics. 14(9):661–673. Danoy P et al. 2010. PLoS genetics. 6(12):e1001195. Stebbings S et al. 2012. Rheumatology. 51(5):858–865. Disclosure of Interest None declared

Background Genetic variants in uric acid transporters that control serum urate levels have been identified in Europeans by genome-wide association studies [1]. However there is no evidence for association with serum urate (or gout) with the organic anion transporters (OAT) 1–3 (SLC22A6, SLC22A7 and SLC22A8) and multi-drug resistance protein 4 (MRP4) encoded by ABCC4; all four transporters have been implicated in uric acid secretion [2]. The Māori and Pacific (Polynesian) population of New Zealand (NZ) has the highest prevalence of gout worldwide and exhibits lower fractional excretion of uric acid (FEUA) than Europeans. Objectives To identify any Polynesian population-specific genetic variants in the SLC22A6–8 and ABCC4 genes associated with gout. Methods All participants had ≥3 self-reported Māori and/or Pacific grandparents. From the total sample set of 1808 individuals, 191 hyperuricaemic (highest urate levels) and 202 normouricaemic (lowest urate levels) individuals were selected and resequenced over a total of 24.3 kb of promoter, exon and 39 and 59 untranslated region DNA within the four genes. Replication genotyping for rs4148500 was done using Taqman over the remaining 1415 individuals. Logistic regression association analysis with gout or hyperuricaemia (≥0.36 mmol/L in women, ≥0.42 mmol/L in men) as outcome, or linear regression with FEUA or serum urate as outcome, was performed adjusting by age, sex and Polynesian ancestry. Results A total of 39 common variants were detected with one in ABCC4 (rs4148500) significantly associated with hyperuricaemia and gout. There were substantial differences in allele frequency between Western (Samoan, Tongan, Niuean, Tokelaun) and Eastern (NZ and Cook Island Māori) Polynesian samples – adjusting for ancestry revealed evidence for association with gout in the resequenced samples (OR=1.62, P=0.012 for rs4148500). The association of rs4148500 with gout was replicated (OR=1.25, P=0.033) and was restricted to males (ORMales=1.43, P=0.001; ORFemales=0.98, P=0.89). The gout risk allele was associated with FEUA in males (b=-0.570, P=0.01) and there was a trend towards association with serum urate in the male controls (b=0.013, P=0.07). The Ensembl database revealed that the variant was monomorphic (for the protective major allele) in Europeans. Conclusions This is the first report of a genetic factor specifically contributing to the increased risk of gout in men of Māori and Pacific ancestry in NZ. Association of ABCC4 with gout and FEUA is consistent with the established role of MRP4 as a unidirectional urinary uric acid efflux pump of uric acid [3]. References Kottgen et al. Nat Genet 2013;45:145 Mandal and Mount. Ann Rev Physiol 2015;77:323 Van Aubel et al. Am J Physiol 2005;288:F327 Acknowledgement The New Zealand Health Research Council, Lottery Health New Zealand, Arthritis New Zealand and the National Institute of Health (United States) are thanked for funding this study. Disclosure of Interest T. Merriman Grant/research support from: ArdeaBio, J. Boocock: None declared, E. Stahl: None declared, M. Cadzow: None declared, A. Phipps-Green: None declared, R. Topless: None declared, J. Harre Hindmarsh: None declared, D. Mount: None declared, L. Stamp: None declared, N. Dalbeth Grant/research support from: Fonterra, ArdeaBio, AstraZeneca, Consultant for: Takeda, Menarini, Teijin, Pfizer, Crealta, Cymabay, H. Choi: None declared, C. Tanner: None declared

Background Mitochondria appear to play a central role in the induction of an NLRP3 inflammatory response, an immune response critical for the development of gouty pathology. Mitochondria are in part self-encoding, possessing a 16.5 kB circular genome which encodes 36 genes. Therefore mitochondrial genetic variation may contribute to susceptibility to gout. Objectives The objective of this study was to test whether mitochondrial genetic variation and copy number among New Zealand Polynesians may be contributing to susceptibility to gout. The Māori and Pacific (Polynesian) populations of New Zealand exhibit a high prevalence of gout (6 and 8%, respectively). Methods 439 whole mitochondrial genomes belonging to Māori and Pacific men from New Zealand (327 cases, 112 controls) were sequenced to explore whether mitochondrial DNA (mtDNA) variation may contribute risk to gout. mtDNA copy number variation was also investigated by looking at relative read depth using Next Generation Sequencing data produced from whole genome sequencing and resequencing of urate loci. Quantitative PCR was undertaken for replication in an extended sample set of 540 Polynesian male and female cases and 530 controls. Results Within Polynesia, there is relatively little mitochondrial genetic diversity, with around 96% of those sequenced in this study belonging to the B4a1a and derived sub-lineages. A lineage-specific heteroplasmy in hypervariable region I was found to associate with a greater than three-fold higher risk of gout among the mitochondrial sequenced sample set (e.g. heteroplasmy at position 16179: OR 3.28, P =0.009; heteroplasmy at position 16181: 3.86, P =9x10 –5 ; heteroplasmy at position 16182: 3.43, P =0.005). Quantitative PCR of mtDNA from the 1070 Polynesian gout cases and controls showed that individuals with gout possess less mtDNA, on average than healthy controls. With each unit increase in ΔCt (which reflects a decrease in mtDNA content), there was a 33% increase in gout risk (OR 1.33, P =0.003). The effect was stronger when looking at those participants who possessed urate levels exceeding 0.40 mmol L –1 (n=422, OR 1.69, P =0.0005). References It is unclear whether the reduced mtDNA copy number in gout is a result of the gouty pathology directly (i.e. the reduced mtDNA copy number is caused by the inflammatory processes underlying gout) or whether the reduced mtDNA copy number contributes to the risk of gout. The latter possibility is supported by the increase in risk using hyperuricemic controls suggesting that reduced mtDNA copy number plays a role in inflammation. Given emerging research is showing that mitochondria play a central role in the induction of the NLRP3 inflammasome, in particular with the co-localisation of the NLRP3 and ASC sub-units, a process essential for the generation of IL-1β, these observations may be significant. Exploring mitochondrial genetic variation may further elucidate the inflammatory processes underlying gout. Acknowledgement The New Zealand Health Research Council, Lottery Health New Zealand, Arthritis New Zealand and the National Institute of Health (United States) are thanked for funding this study. Disclosure of Interest T. Merriman Grant/research support from: ArdeaBio, A. Gosling: None declared, J. Boocock: None declared, N. Dalbeth Grant/research support from: AstraZeneca, Fonterra, ArdeaBio, Consultant for: Menarini, Takeda, Teijin, Pfizer, Crealta, Cymabay, L. Stamp: None declared, E. Stahl: None declared, H. Choi: None declared, L. Matisoo-Smith: None declared

Background Gout results from innate immune response to monosodium urate (MSU) crystals that form when serum urate is elevated. Identification of genetic risk factors for hyperuricemia and the MSU immune response is therefore important for insight into the etiology of gout. Whilst genome-wide association studies have provided significant insights into the causes of hyperuricemia there are no confirmed loci for non-serum urate pathways in gout. Recently association of the rs2149356 variant in the TLR4 locus with gout was reported in a Chinese sample set (odds ratio TT genotype =1.88, P =8x10–5)1. TLR4 triggers innate immune response to endogenous ligands, including MSU crystals2. Objectives To test rs2149356 for association in European and New Zealand (NZ) Polynesian gout case-control sample sets. Methods All gout cases were clinically ascertained according to the American Rheumatism Association criteria. European cases (n=1606) were recruited from New Zealand (n=599), by the Eurogout consortium within the European Crystal Network (n=784) and by the Arthritis Genomics Recruitment Initiative in Australasia (AGRIA; n=223). European non-gouty controls (n=8066) were recruited from NZ (n=875) and sourced from the Atherosclerosis Risk in Communities (n=4144) and Framingham Heart (n=3047) studies. There were 872 New Zealand Maori and Pacific Island (Polynesian) cases and 1088 controls. Genotyping was done by Taqman and statistical analysis by STATA. Results Using unstratified controls the T allele, but not the TT genotype, was associated with gout in Europeans (ORTallele=1.09, P =0.05; ORTTgenotype=1.15, P =0.13). There was no evidence for association in Polynesians (ORTallele=0.90, P =0.12; ORTTgenotype=0.88, P =0.31). However, comparison of cases to hyperuricemic controls strengthened evidence for association with gout in Europeans (ORTallele=1.18, P =0.004; ORTTgenotype=1.38, P =0.017), but made no difference in Polynesians (ORTallele=, P =0.30; ORTTgenotype=0.87, P =0.47). ![Figure][1] Conclusions The previous report of association of TLR4 with gout in Chinese was replicated in Europeans but not Polynesians. Strengthening of association using hyperuricemic controls is consistent with a role for this locus in gouty inflammation in the presence of hyperuricemia. Subject to further replication, TLR4 represents the first non-serum urate genetic risk locus identified in gout, and provides support for a role of TLR4 in etiology. References 1. Qing et al. PLoS One 2013;5:e64845. 2. Liu-Bryan et al. Arthritis Rheum 2005;52:2936 Disclosure of Interest : None declared DOI 10.1136/annrheumdis-2014-eular.4781 [1]: pending:yes

Background Elevated serum urate levels are causal for gout. The first genome-wide association studies associated common genetic variation in 10 loci of stronger effect with serum urate. Predictably, the majority of these loci (e.g. SLC2A9 and ABCG2 ) are dominated by uric acid transporters involved in renal and gut excretion of uric acid, and have been associated with gout in multiple ancestral groups. However, despite very strong evidence for association with serum urate levels, PDZK1 is unequivocally not associated with gout (OR=1.03) in a large European sample set 1 . Therefore, it is important to test serum urate loci for association with gout. Lack of association could indicate pleiotropic effects (e.g. PDKZ1 ), and understanding the reasons for lack of association should yield insights into the etiology of gout. Recently, a further 18 serum urate loci have been identified by meta-analysis of individual GWAS, of which 9 were nominally associated with gout in >3,000 cases 1 . These loci include genes involved in glycolysis, but no known uric acid transporters. Objectives To test the 18 recently discovered loci for association with gout in New Zealand European and Polynesian (Maori and Pacific Island) case-control sample sets. Methods All gout cases were ascertained by clinical examination according to the American Rheumatology Association criteria and comprised 648 European and 888 Polynesian cases. The 1550 European and 1095 Polynesian controls self-reported no gout. The 18 genetic variants were genotyped by Sequenom multiplex technology or Taqman SNP genotyping. Association analysis was performed using STATA. Age and sex were adjusted for in both sample sets, with European admixture adjusted for in Polynesian. Results There was evidence for association with gout at six of the loci in the European sample set ( TRIM46, SFMBT1, PRKAG2, A1CF, INHBB, IGF1GR ). In all instances, the same allele associated with increased serum urate was also associated with gout. Two of the loci were associated in the Polynesian samples ( SFMBT1, VEGFA ) with the same allele associated with gout as associated with increased serum urate in Europeans. Analysis of participants with higher Polynesian ancestry revealed association at SFMBT1, VEGFA, PRKAG2 and HLF . For PRKAG2 and HLF , the allele associated with decreased serum urate in European was associated with increased risk of gout in Polynesian. Meta-analysing the NZ European and Polynesian data sets revealed association at MAF. Conclusions Nine of the 18 loci had previously been associated with gout by Kottgen et al. ( TRIM46, SFMBT1, TMEM171, VEGFA, BAZ1B, PRKAG2, STC1, A1CF, NFAT5 ). We replicated four of these loci ( TRIM46, SFMBT1, PRKAG2, A1CF ) and associated a further four loci with gout ( INHBB, IGF1R, MAF, HLF ). Our results also suggest alleles with opposing effects between European and Polynesian at PRKAG2 and HLF . This may indicate recombinant haplotypes, which can be exploited in fine-mapping the etiological variants. References Kottgen et al. Nat Genet. 2013;45:145 Disclosure of Interest : None declared DOI 10.1136/annrheumdis-2014-eular.4679

Pharmacogenetic studies examining methotrexate (MTX) response/toxicity have focused on enzymes involved in MTX transport and folate metabolism.1 However, recently it has been reported that patients with rheumatoid arthritis (RA) with the HLA-G −/−14 bp genotype are more likely to respond to MTX.2 3 Human leukocyte antigen (HLA)-G molecules are non-classical major histocompatability complex (MHC) class I antigens that play a role in the immune system.4 We investigated whether an association exists between the HLA-G −/−14 bp polymorphism and response to MTX in a cross-sectional study of patients with RA. Of the 130 patients recruited, 75.4% were female, 81% were rheumatoid factor (RF) positive and 67% …