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Background Rotator cuff tear (RCT) and hand osteroarthritis (HOA) are commonly accompanied because they share a similar pathogenesis. However, there was no previous study investigating the relationship between RCT and HOA. Objectives To estimate the prevalence and associated factors of RCT in patients with HOA. Methods In this study, we enrolled 1150 farmers who lived in Gyeongnam province in Korea from June 2013 to December 2015. Physical examinations were performed by rheumatologists and orthopedists. Plain radiography of hands and magnetic resonance imaging (MRI) of shoulders were performed in all participants. Serum levels of high sensitive C-reactive protein (hsCRP) and high density lipoprotein (HDL) were checked. RCT was diagnosed by clinical examination and MRI findings. Diagnosis of HOA was made by the 1990 American College of Rheumatology classification criteria. Severity of HOA was defined as Kellgren–Lawrence (KL) grade ≥3 on plain radiographs. Erosive HOA was defined as having eroded 9E9 or remodelled 9R9 phase of the Verbruggen. Results The prevalence of RCT was higher in patients with HOA group (192/307, 62.5%) than those without HOA (410/827, 49.5%, p Conclusions The prevalence of RCT is high and age and serum levels of hsCRP and HDL have predictive roles in the development of RCT in HOA patients. References Jin X, Beguerie JR, Zhang W, Blizzard L, Otahal P, Jones G, Ding C. Extended report: Circulating C reactive protein in osteoarthritis: a systematic review and meta-analysis. Ann Rheum Dis 2015;74(4):703–10. Acknowledgement This study was supported by a grant of the Center for Farmer9s Safety and Health, Ministry of Agriculture, Food and Rural Affairs, Republic of Korea. Disclosure of Interest None declared

Background Various upper extremity musculoskeletal diseases (MSDs) can affect pain and disability in patients with hand osteoarthritis (HOA). However, there was no previous study investigating the relationship between upper extremity MSDs and HOA. Objectives To explore the influence of major upper extremity MSDs on pain severity and functional status of patients with HOA. Methods In this study, we enrolled 1150 farmers who lived in Gyeongnam province in Korea from June 2013 to December 2015. Physical examinations were performed by rheumatologists, orthopedists, and rehabilitation specialists. Grip powers of both hands also were evaluated. Plain radiography, a nerve conduction velocity (NCV) examination, and magnetic resonance imaging (MRI) of shoulders were performed. The Australian/Canadian Osteoarthritis Hand Index (AUSCAN) was used to assess pain severity and functional status of hand joints. The diagnosis of HOA was made by the 1990 American College of Rheumatology classification criteria. Carpal tunnel syndrome (CTS) was confirmed by NCV findings, and rotator cuff tear (RCT) was diagnosed by MRI findings. Myofascial pain syndrome (MPS) was diagnosed by palpations of myofascial trigger points. Results Of 1150 participants, 307 were diagnosed with HOA. Among HOA patients, 151 (49.7%), 192 (62.5%), and 249 (80.1%) patients had CTS, RCTs, and MPS, respectively. HOA patients with MPS showed significantly higher AUSCAN scores (350.4±285.0 vs 200.4±201.8, p Conclusions MPS has a significant impact on pain and functional status in patients with HOA. Therefore, management of coexisting MPS is the better way to improve pain and function of hand joints in patients with HOA. Acknowledgement This study was supported by a grant of the Center for Farmer9s Safety and Health, Ministry of Agriculture, Food and Rural Affairs, Republic of Korea. Disclosure of Interest None declared

Background Farming activity is burdened work with excessive use of hands. Thus, farmers are expected to have high prevalence of hand osteoarthritis (HOA). However, there is a lack of studies investigating prevalence and characteristics of HOA in Korean farmers. Objectives To estimate the prevalence of HOA among farmers in rural areas of Korea and assess whether HOA is related to farming activity. Methods The study was carried out from June 2013 to Dec 2014 with 700 farmers in Gyeong-nam Province of Korea. Clinical evaluation for hand joints was performed by rheumatologists and the plain radiographs of both hands were taken. The Australian/Canadian Osteoarthritis Hand Index (AUSCAN) was used to assess symptoms and function of hand joints. Radiographic HOA was defined as Kellgren–Lawrence (KL) grade≥2 on plain radiographs and symptomatic HOA as KL grade≥2 with pain/aching/stiffness at the same joints. Severe HOA was defined KL grade≥3. Presence of HOA at individual level was defined as ≥1 affected joint. Results Participants comprised of 53% female and 47% male with mean age of 59.7±8.6 years. As divided types of growing crops, persimmon growers, strawberry growers, rice growers, and persimmon plus rice growers were 28.6%, 27.0%, 11.7%, 23.0%, respectively. The prevalence of radiographic, symptomatic, and severe HOA was 59.1%, 13.9%, and 24.4%, respectively. Finger joints were affected in 51.4% and thumb joints in 34.1%. Interestingly, male farmers showed high prevalence of radiographic HOA (55.9%) and symptomatic HOA (13.0%). The prevalence of HOA was similar in both hands and increased with longer duration of farming. Multiple logistic regression analysis showed a significant association of age, female sex, and body mass index with radiographic HOA. As adjusted for determinants above, rice growers were associated with an increased risk of HOA (odds ratio 3.5; 95% confidence interval 1.71 to 7.21). AUSCAN score was high in female and increased according to the severity of HOA. Conclusions The prevalence of HOA in male is high, and related to types of growing crops. Therefore, this study suggests that development of HOA is associated with farming activity. References Zhang Y, Niu J, Kelly-Hayes M, Chaisson CE, Aliabadi P, Felson DT. Prevalence of symptomatic hand osteoarthritis and its impact on functional status among the elderly: The Framingham Study. Am J Epidemiol. 2002;156(11):1021-7. Cho NH, Kim SH, Kim HA, Seo YI. The Prevalence and Risk Factors of Knee and Hand Osteoarthritis in Korea. Journal of Rheumatic Diseases. 2007;14(4):354-362. Acknowledgements This study was supported by a grant of the Center for Farmer9s Safety and Health, Ministry of Agriculture, Food and Rural Affairs, Republic of Korea. Disclosure of Interest None declared

Background Orchardists are expected to show high prevalence of upper limb musculoskeletal disorders (MSDs) due to their heavy works and working postures. However, there are no systematic studies relating upper limb MSDs in Korean orchardists. Objectives To evaluate the prevalence and characteristics of upper limb MSDs among orchardists in rural areas of Korea. Methods The study was carried out from June 2013 to May 2014 in a tertiary medical center. The physical examinations of upper extremities were performed by rheumatologists, orthopedists, and rehabilitation medicine specialists. The plain radiographs of shoulder, elbow, and hand, nerve conduction examination of upper extremities, and MRI of both shoulder were taken. The Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire was used to assess symptoms and function of upper extremities. Results Five hundred and fifty orchardists were included. Participants comprised of 49.5% female and 50.5% male with mean age of 59.5±8.1 years. The mean farming duration was 31.3±13.2 years. A total of 34 different types of upper limb MSDs were detected. The most frequent disorder was myofascial pain syndrome (80.5%) followed by rotator cuff syndrome (58.9%), hand osteoarthritis (58.0%), carpal tunnel syndrome (42.9%), and lateral epicondylitis (39.5%). Prevalence of any form of MSD was 98.5% and of three and more of MSDs was 77.3%. Participants with longer duration of farming had higher numbers of MSDs. Almost part of pruning and harvesting postures in orchard farming were loaded works for musculoskeletal systems. Total DASH score was relatively high (14.9±14.4). Conclusions Almost orchardists have upper limb MSDs. Our results suggest the need to implement interventions in orchardists to prevent MSDs. References Gomez MI, Hwang S, Stark AD, May JJ, Hallman EM, Pantea CI. An analysis of self-reported joint pain among New York farmers. J Agric Saf Health. 2003;9:143–157. Holmberg S, Stiernstrom EL, Thelin A, Svardsudd K. Musculoskeletal symptoms among farmers and non-farmers: A population based study. Int J Occup Environ Health. 2002;8:339–345. Osborne A, Blake C, Fullen BM, Meredith D, Phelan J, McNamara J, Cunningham C. Prevalence of musculoskeletal disorders among farmers: A systematic review. Am J Ind Med. 2012;55(2):143-58. Acknowledgements This study was supported by a grant of the Center for Farmer9s Safety and Health, Ministry of Agriculture, Food and Rural Affairs, Republic of Korea. Disclosure of Interest None declared

Objectives The type III histone deacetylase SIRT1 is a critical molecule in the modulation of immune and inflammatory response through the deacetylation of various histones and non-histone proteins. However, there are limited and controversial data regarding the roles of SIRT1 in rheumatoid arthritis (RA) and its role in dendritic cells (DCs) remains unknown. Thus, this study sought to assess the role of SIRT1 in collagen-induced arthritis (CIA) using a myeloid cell-specific SIRT1 knockout (mSIRT1 KO) mouse. Methods mSIRT1 KO mice were generated using the loxP/Cre recombinase system. CIA was induced in mSIRT1 KO mice and age-matched littermate loxP control mice. Arthritis severity was assessed by clinical, radiological, and pathological scoring. The levels of various cytokines in the joints, serum, lymph nodes were determined by quantitative polymerase chain reaction and ELISA. T cells and DCs were quantified using flow-cytometry and in vitro T cell cytokines and DCs markers were also measured. Results The mSIRT1 KO mice showed significantly lower arthritis severity and joint destruction compared with control mice. The expression of inflammatory cytokines, MMPs, and ROR-γT was also reduced in mSIRT1 KO mice. These effects were paralleled by reduction of Th1, Th17, CD69-positive T cells, CD80, and CD86 positive DCs in mSIRT1 KO mice. In addition, in vitro studies showed that interferon-γ and IL-17 production by T cells and the maturation of DCs were significantly decreased in mSIRT1 KO mice. Conclusions Unlike passive K/BxN serum transfer arthritis, myeloid cell-specific deletion of SIRT1 was associated with lower arthritis severity in CIA by modulating DCs maturation and Th1 and Th17 responses. The data suggest that SIRT1 plays a complex role in RA and careful investigation of cell-specific effects is necessary to delineate possible therapeutic uses of agents targeting SIRT1. Disclosure of Interest : None declared DOI 10.1136/annrheumdis-2014-eular.4188

Background Systemic lupus erythematosus (SLE) is an autoimmune disease in which various organs and tissues are damaged through abnormal immune responses mediated by tissue-binding autoantibodies and immune complex deposition. As the majority of SLE patients are women of child-bearing age, estrogen has been suggested to play an important role in the pathogenesis of SLE. One of the proposed roles of estrogen is to increase autoantibody production. IL-21, a common-γ chain cytokine, has been shown to be crucial in the differentiation of activated B cells into plasma cells. Objectives Based on these concepts, we investigated the effect of estrogen on the production of IL-21 by T cells and subsequent B cell activation in SLE patients. Methods Peripheral blood mononuclear cells (PBMCs) were obtained from peripheral blood of 23 SLE patients and 16 healthy controls. CD4+ T cells, non CD4+ T cells and B cells were isolated using microbeads. Isolated cells were treated with 17-β estradiol at various concentrations for 48hrs. The expression of IL-21 and its receptor was assessed by measuring the level of protein and mRNA using ELISA and RT-PCR, respectively. The level of immunoglobulin G was measured with specific ELISA. Results The expression of IL-21 and its receptor in serum, PBMCs, and CD4+ T cells were higher in the patients with SLE compared to healthy controls. Exposure of CD4+ T cells from SLE patients to 17-β estradiol leads to a dose-and time-dependent increase in the IL-21 expression. The increase was abolished in the presence of MAP kinase (MEK, p38, JNK) inhibitors. B cells of healthy controls showed an increased antibody production when they were co-cultured with estrogen treated CD4+ T cells of patients with SLE. Treatment with anti-IL-21 antibody abrogated the increased antibody production of the co-culture systems, suggesting the increase was mediated by IL-21 dependent manner. Conclusions Estrogen upregulates IL-21 expression of CD4+ T cells via MAPK dependent pathways in SLE patients, which in turn induces increased antibody production by B cells. Disclosure of Interest : None declared DOI 10.1136/annrheumdis-2014-eular.3160

Background Leg muscle mass is related to development and progression of knee OA, and some studies suggested low leg muscle mass quantified by cross-sectional images of CT or MRI was related to knee symptoms [1,2]. However, this direct method of quantification is hard to apply to clinical practices, and it can be affected by total body mass which can confound the relationship of leg muscle mass and knee symptoms. Objectives We sought to examine if the ratio of leg to whole body muscle or fat mass by DXA relates to knee symptoms in radiographic knee OA. Methods We performed a cross-sectional study using data from the Fifth Korean National Health and Nutrition Examination Survey. We included subjects with radiographic knee OA (Kellgren-Lawrence grade≥2) and obtained degree of symptoms, body composition of both legs and the whole body using DXA and calculated the ratios of leg to whole body for muscle and fat mass. Analysis of covariance and multivariable logistic regression models were used to examine the associations of leg to whole body mass with knee symptoms adjusting for possible confounders. Results 1664 subjects were eligible for analysis. The ratio of leg to whole body muscle mass (LTWBM) was significantly lower in the group with knee pain or stiffness (30.27±0.10 vs. 30.92±0.08, p Conclusions Symptomatic knee OA was associated with reduced leg muscle mass. Local sarcopenia indicated by low leg to whole body muscle mass could be an important and useful clinical marker for symptomatic knee OA. Strategies to increase leg muscle mass might counteract having symptomatic knee OA. References Sattler, M., et al., Side differences of thigh muscle cross-sectional areas and maximal isometric muscle force in bilateral knees with the same radiographic disease stage, but unilateral frequent pain - data from the osteoarthritis initiative. Osteoarthritis Cartilage, 2012. 20(6): p. 532-40. Wang, Y., et al., Increase in vastus medialis cross-sectional area is associated with reduced pain, cartilage loss, and joint replacement risk in knee osteoarthritis. Arthritis Rheum, 2012. 64(12): p. 3917-25. Disclosure of Interest : None declared DOI 10.1136/annrheumdis-2014-eular.2422

Background Ursolic acid (UA) is a pentacytclic triterpenoid compound which is ubiquitously present in plants. Objectives Based on its known anti-inflammatory and anti-oxidative effect, this study was undertaken to investigate the effect of UA on collagen-induced arthritis (CIA) and to delineate the underlying mechanism. Methods UA (150mg/kg) or 10% dimethyl sulfoxide was injected intraperitoneally three times a week to mice with CIA from the day 14 after immunization. The expressions of proinflammatory cytokines and molecules associated with oxidative stress in arthritic joints were measured by immunohistochemical staining. The number of CD4+IL-17+ cells or CD4+CD25+Foxp3+ cells or phosphorylated (p) STAT3 + cells was determined by confocal immunostaining of the spleen or flow cytometry analysis of splenocytes. The level of mRNA expression and immunoglobulin was analyzed by real time RT-PCR and ELISA, respectively. Results UA injection prevented clinical arthritis incidence and joint inflammation in mice with CIA. A significant reduction in pSTAT3 and resultant decrease in the number of Th17 was observed with UA treatment. Consistently, the expression of IL-17 and retinoic acid orphan receptor (ROR)γt was markedly reduced with UA. Although the expression of Foxp3 was unaffected, the number of Treg cells was increased with UA treatment. There was a marked reduction in type II collagen-specific immunoglobulin G production. When IL-21-or LPS-stimulated CD19+ B cells were cultured in the presence or absence of UA, the mRNA expression of markers associated with B cell activation (Bcl-6), plasma cell differentiation (Blimp-1) and isotype switching (activation-induced deaminase) was markedly reduced with UA treatment. Conclusions Our findings suggest that UA can regulate Th17 and reciprocally promote Treg cells by inhibiting expression of ROR γt and pSTAT3. UA also inhibits plasma cell differentiation, resulting in a reduction of immunoglobulin production. By targeting pathogenic Th17 and immunoglobulin production, UA may be a novel therapeutic for treatment of autoimmune arthritis and other Th17-related diseases. Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.3181

Background Since the concept of reprogramming mature somatic cells to generate induced pluripotent stem cells (iPSCs) was demonstrated in 2006, iPSCs have become a potential substitute for embryonic stem cells (ESCs) given their pluripotency and “stemness” characteristics, which resemble those of ESCs. Objectives We investigated to reprogram fibroblast-like synoviocytes (FLSs) from patients with rheumatoid arthritis (RA) and osteoarthritis (OA) to generate iPSCs using a 4-in-1 lentiviral vector system. Methods A 4-in-1 lentiviral vector containing Oct4, Sox2, Klf4, and c-Myc was transduced into RA and OA FLSs isolated from the synovia of two RA patients and two OA patients. Immunohistochemical staining and real-time PCR studies were performed to demonstrate the pluripotency of iPSCs. Chromosomal abnormalities were determined based on the karyotype. SCID-biege mice were injected with iPSCs and sacrificed to test for teratoma formation. Results After 14 days of transduction using the 4-in-1 lentiviral vector, RA FLSs and OA FLSs were transformed into spherical shapes that resembled embryonic stem cell colonies. Colonies were picked and cultivated on matrigel plates to produce iPSC lines. Real-time PCR of RA and OA iPSCs detected positive markers of pluripotency. Immunohistochemical staining tests with Nanog, Oct4, Sox2, Tra-1-80, Tra-1-60, and SSEA-4 were also positive. Teratomas that comprised three compartments of ectoderm, mesoderm, and endoderm were formed at the injection sites of iPSCs. Established iPSCs were shown to be compatible by karyotyping. Finally, we confirmed that the patient-derived iPSCs were able to differentiate into osteoblast, which was shown by an osteoimage mineralization assay. Conclusions FLSs derived from RA and OA could be cell resources for iPSC reprogramming. Disease- and patient-specific iPSCs have the potential to be applied in clinical settings as source materials for molecular diagnosis and regenerative therapy. References Takahashi K, Yamanaka S: Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors. Cell 2006, 126:663-76. Tiscornia G, Vivas EL, Izpisua Belmonte JC: Diseases in a dish: modeling human genetic disorders using induced pluripotent cells. Nat Med 2011, 17:1570-6. Grskovic M, Javaherian A, Strulovici B, Daley GQ: Induced pluripotent stem cells–opportunities for disease modelling and drug discovery. Nat Rev Drug Discov 2011, 10:915-29. Acknowledgements This work was supported by a grant from the Korea Healthcare Technology R&D Project, Ministry for Health, Welfare & Family Affairs, Republic of Korea (A092258). Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.4862

Background Gout is a chronic inflammatory disease of which the development is associated with metabolic abnormality caused by obesity. However, there are a substantial number of non-obese patients (body mass index (BMI) 100cm2 was defined as visceral fat obesity (VFO). The frequency of VFO was compared in patients and control groups. The frequency of metabolic syndrome as well as its components was investigated. Results The prevalence of metabolic syndrome in patients with gout was 31.7% (33/104) according to modified ATP III criteria. BMI (26.3±3.8 vs. 23.4±2.4 kg/m2, P

Background Anti-TNF therapy was known to increase the risk of certain infection. There are no sufficient data about the reactivation of hepatitis B virus (HBV) after anti-TNF therapy. Objectives The study was aimed to investigate the clinical course of hepatitis B in patients with rheumatoid arthritis (RA) and ankylosing spondylitis (AS) after the introduction of anti-TNF therapy. Methods We retrospectively reviewed to identify patients infected with HBV treated with TNF inhibitors between October, 2004 and September, 2013. For patients with HBV infection, the liver enzyme and the viral status were monitored. The HBV reactivation was defined according to the Korean guideline by hepatology. Results Of 983 patients (RA, n=536; AS, n=447) who were treated with TNF inhibitors, 23 patients (RA, n=17; AS, n=6) had comorbidities of HBV infection. Eighteen patients were treated with etanercept, three with adalimumab, and two with infliximab. Seven patients received pre-emptive antiviral prophylaxis before anti-TNF therapy: 4 with entecavir, 1 with telbivudine, 1 with tenofovir, and 1 with lamivudine. Among 23 patients with HBV infection, 4 (17.4%) patients experienced the reactivation of HBV, which occurred in 3 patients without prophylaxis and 1 patient with lamivudine prophylaxis. In the latter case, YMDD mutation was identified and addition of adefovir resulted in virological response. The other three patients were treated successfully with entecavir or tenofovir. There was no subsequent events associated with HBV infection. Conclusions This study indicates the risk of HBV reactivation after anti-TNF therapy. Careful management is mandatory for patients who planned to be treated with TNF inhibitors. References Vassilopoulos D, Calabrese LH. Management of rheumatic disease with comorbid HBV or HCV infection. Nature reviews Rheumatology. 2012 Jun;8(6):348-57 Oketani M, Ido A, Uto H, Tsubouchi H. Prevention of hepatitis B virus reactivation in patients receiving immunosuppressive therapy or chemotherapy. Hepatology research: the official journal of the Japan Society of Hepatology. 2012 Jul;42(7):627-36 Korean Association for the Study of the L. KASL Clinical Practice Guidelines: Management of chronic hepatitis B. Clinical and molecular hepatology. 2012 Jun;18(2):109-62 Acknowledgements This study was supported by a grant from the Korea Healthcare Technology R&D Project, Ministry of Health and Welfare, Republic of Korea (HI10C2020). Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.5251

Background Periostin is a matricellular protein that expressed in bone, periodontal ligament, heart valve, tendon and skin. Previous study indicated that periostinis linked with several inflammatory diseases such as airway hypersensitivity, periodontal inflammation, and pulmonary fibrosis. However, there is no study to investigate the role of periostin in rheumatoid arthritis (RA). Objectives This study was performed to assess the function of periostin in K/BxN serum transfer arthritic mice. Methods Synovial tissues, serum, joint fluid, and fibroblast-like synoviocyte (FLS) were obtained from patients with RA and osteoarthritis (OA). The expression of periostin in synovial tissues was assessed by immunohistochemistry. The levels of periostin were checked by Western blot and enzyme-linked immunosorbent assay (ELISA). K/BxN serum transfer arthritis was induced in periostin knockout (KO) and age-matched wild type (WT) mice. Arthritis severity was assessed by clinical and histopathologic scoring. The levels of inflammatory cytokines in ankles and serum were measured by quantitative PCR and ELISA. The osteoclastogenesis was assessed by using bone marrow monocytes (BMM) from periostin KO or WT mice. Results Periostin was highly expressed in the synovium of RA patient than OA. The periostin levels were increased in the presence of IL-1β and TNF-α in RA-FLS. The periostin KO mice showed more severe arthritis from day 4 to day 10. The peak clinical scores were: 5.0±0.6 in WT, 7.36±0.5 in periostin KO mice; p Conclusions This study suggests that regulation of periostin contributes to pathogenesis of RA and periostin has a potential protective role in RA. Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.4201

Background IL-33 and its receptor, ST2, are associated with many inflammatory disorders. However, the data on IL-33/ST2 in Sjogren9s syndrome (SS) is very limited. Objectives To evaluate the expression of IL-33 and its receptor in sera and salivary tissues obtained from patients with primary Sjogren9s syndrome (pSS) and to investigate the possible relationship with clinical profiles. Methods Serum IL-33 and soluble ST2 (sST2) of 55 patients with pSS and 48 controls were determined using ELISA, and assessed for correlation with clinical profiles. The expression of IL-33/ST2 in salivary tissues was investigated by immunohistochemical (IHC) staining, and was further characterized by confocal microscopy. We also measured ST2 expression in peripheral blood mononuclear cells (PBMCs) of pSS patients, and IL-33 production in salivary glandular epithelial cell by pro-inflammatory stimuli. Results The serum levels of IL-33 and sST2 were higher in pSS patients compared to healthy controls ( P =0.018 and P P =0.029) and duration of disease ( p =0.013). Contrary to sST2, ST2 was downregulated in PBMCs obtained from pSS patients. The expression of IL-33 and ST2 was elevated in salivary gland of pSS patients with grade 2 inflammation, and decreased as inflammation progresses. In pSS patients, IL-33 was mainly observed in epithelial cells and endothelial cells of gland tissue. The production of IL-33 mRNA by salivary gland epithelial cell line was increased under stimulation with interferon-γ. Conclusions IL-33 and sST2 concentrations were elevated in sera of pSS patients, whereas ST2 in salivary gland and PBMC of pSS patients showed downregulated expression. This result suggests that IL-33/ST2 axis might have a role in the pathogenesis of pSS. References Schmitz, J., et al., IL-33, an interleukin-1-like cytokine that signals via the IL-1 receptor-related protein ST2 and induces T helper type 2-associated cytokines. Immunity, 2005. 23(5): p. 479-90. Palmer, G. and C. Gabay, Interleukin-33 biology with potential insights into human diseases. Nat Rev Rheumatol, 2011. 7(6): p. 321-9. Moussion, C., N. Ortega, and J.P. Girard, The IL-1-like cytokine IL-33 is constitutively expressed in the nucleus of endothelial cells and epithelial cells in vivo: a novel `9alarmin”? PLoS One, 2008. 3(10): p. e3331. Acknowledgements This study was supported by a grant from the Korea Healthcare Technology R&D Project, Ministry of Health and Welfare, Republic of Korea (HI13C0016). Disclosure of Interest : None declared DOI 10.1136/annrheumdis-2014-eular.4921

Background Gout is caused by hyperuricemia related to altered purine metabolism characterized by monosodium urate (MSU) crystals deposition into the joints, particularly the first metartarsophalangeal joint (1st MTPJ). Chronic gout is characterized by the presence of tophi, chronic granulomatous synovitis and bone erosion. As well known, bone erosion is a strong predictor of musculoskeletal disability and is strongly associated with the presence of gout tophi. The size of gout tophi can be decreased when serum urate level is maintained below 6mg/dl. Therefore tophi measurement may reflect outcome after urate-lowering therapy in chronic gout. Plain radiography remains the most widely used imaging modality in the clinical practice. In our knowledge, however, there have been no grading system for tophi on plain radiography. Objectives The aim of our study is to investigate the usefulness of new grading system for gout tophi by plain radiography. Methods 334 patients who fulfilled ACR diagnostic criteria of gout and had anteroposterior plain radiography of both 1st MTPJs included retrospectively in our study. Two rheumatologist evaluated gout tophi, soft tissue swelling, bone erosion (BE) and joint space narrowing (JSN) on plain radiography, independently. The agreement between two observer were good (k>0.08). Gout tophi were defined as increased densities which are distinct from adjacent soft tissues. They were graded by measuring maximum diameters vertically and horizontally, and scored by adding up the scores of grades. The vertical diameter of tophi was measured at both sides of proximal phalanges (PPs). The horizontal diameter was measured at lateral side of PP. The measurement of maximum vertical diameter of tophi were graded as follows: grade 0, no tophi; grade 1, the presence of tophi is suspicious; grade 2, less than half of maximum vertical diameter of PP; grade 3, half or more of and less than the maximum vertical diameter of PP; grade 4, more than the maximum vertical diameter of PP. The maximum horizontal diameter of tophi was measured including the adjacent swollen soft tissues, and graded as follows: grade 0, no tophi; grade 1, less than half of maximum horizontal diameter of PP; grade 2, half or more of and less than the maximum horizontal diameter of PP; grade 3, more than the maximum horizontal diameter of PP (Figure 1). Results 111 (33.3%) of 334 patients had abnormal findings (gout tophi; 26.9%, BE; 22.2% and JSN; 7.8%) at initial plain radiography. 43 patients showed tophi and/or soft tissue swelling on plain radiographs. 31 of 43 patients showed improvement of tophi on follow-up plain radiographs. 23 of 31 patients had less than 6 mg/dL of serum urate level after treatment. Points by new grading methods differed significantly between the patient group having 6 mg/dL or more and the patient group having less than 6 mg/dL of serum urate level after hypouricemic treatment ( p =0.05). Conclusions New grading system for gout tophi on plain radiography is useful for evaluating changes of gout tophi after hypouricemic therapy. Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.4164

Background Recent studies demonstrated that sodium chloride (NaCl) can be a risk factor for autoimmune disease through the induction of pathogenic IL-17 producing T helper (Th17) cells. Objectives This study was aimed to evaluate the potential effect of NaCl on Th17 differentiation in patients with rheumatoid arthritis (RA) and on the inflammation in collagen induced arthritis (CIA) model. Methods Peripheral blood mononuclear cells (PBMC) obtained from RA patients were cultured under high salt condition, and analyzed using flowcytometry to determine Th17 population. For evaluation of in vivo effect, CIA mice were fed with normal diet (control group) or high salt diet ad libitum (high salt group). Clinical assessment was performed daily based on visual scoring of paw swelling. The arthrogenic differentiation of mouse bone marrow derived cells and mouse splenocytes were evaluated with tartrate-resistant acid phosphatase (TRAP) staining and flowcytometry, respectively. Results NaCl promoted the induction of Th17 cells from PBMC in RA patients. Th17 differentiation was progressively upregulated as NaCl concentration increased upto 60 mM. Correspondingly, high salt diet exacerbated the arthritis of CIA mice. The arthritis score was considerably elevated in high salt group compared with control group. In high salt group, osteoclast differentiation represented by TRAP activity was more prominent. We also observed the increased expression of CD4+ RORrt+ cells in spleen of high salt fed mice. Conclusions This study suggests that NaCl can aggravate arthritis via Th17 differentiation. High salt condition can contribute to the development and progression of RA. References Kleinewietfeld, M., et al., Sodium chloride drives autoimmune disease by the induction of pathogenic T17 cells. Nature, 2013. Wu, C., et al., Induction of pathogenic TH17 cells by inducible salt-sensing kinase SGK1. Nature, 2013. 496(7446): p. 513-7. Acknowledgements This work was supported by a grant from the Korea Healthcare Technology R&D Project, Ministry for Health, Welfare & Family Affairs, Republic of Korea (A092258). Disclosure of Interest None declared DOI 10.1136/annrheumdis-2014-eular.5138