A single-centre retrospective study of factors affecting steroid-free remission of immunoglobulin G4-related disease conducted in South Korea: A notable outcome after complete resection.

OBJECTIVES: Few studies have examined factors affecting steroid-free remission (SFR) in patients with immunoglobulin G4-related disease (IgG4-RD). The aim of this study was to investigate clinical factors affecting SFR in IgG4-RD. METHODS: The medical records of 68 patients who met the 2020 revised comprehensive diagnostic criteria for IgG4-RD were reviewed retrospectively. SFR was defined as remission maintained for at least 6 months without corticosteroids. Cox regression analysis was performed to examine the associations between SFR and various clinical factors. The relapse rate after SFR was examined using the log-rank test. RESULTS: After a median follow-up of 36 months, 30.9% (21/68) of patients with IgG4-RD achieved SFR. Multivariate Cox regression analysis revealed that IgG4-RD diagnosed by complete resection rather than by common diagnostic procedures was the only factor positively associated with SFR (hazard ratio, 7.41; 95% confidence interval, 2.23-24.60; P = .001). Furthermore, relapse after attainment of SFR was significantly less common in the group that underwent complete resection than in the group that did not undergo complete resection (log-rank P = .006). CONCLUSIONS: Patients with IgG4-RD diagnosed by complete resection had a higher likelihood of achieving SFR and a lower rate of relapse after attaining SFR.

Predictors for future development of systemic lupus erythematosus in Korean Sjögren's syndrome patients.

OBJECTIVE: This study determined the impact of demographic factors, clinical manifestations, disease activity, and serological tests at baseline on future SLE development in Sjögren's syndrome (SS) patients. METHODS: This retrospective study assessed 1,082 SS patients without other autoimmune diseases at baseline who visited our hospital between January 2012 and March 2021. We analyzed demographic features, extra-glandular manifestations (EGMs), clinical indices, and laboratory values at baseline between the two groups divided per future SLE development (SS/SLE group vs SS group). The probability and predictors of SLE development in SS patients were estimated using the Kaplan-Meier method and Cox proportional hazards models. RESULTS: The median follow-up duration was 1083.5 days. Forty-nine patients (4.5%) developed SLE that met the 2012 Systemic Lupus International Collaborating Clinics or 2019 EULAR/ACR classification criteria. The baseline EULAR SS disease activity index (ESSDAI) score was significantly higher in the SS/SLE group (p < .001). The SS/SLE group had more lymphadenopathy and renal involvement (p = .015 and p = .017, respectively). Shorter SS disease duration (<3 years) (hazard ratio [HR] = 2.12, p = .0328), high ESSDAI (HR = 8.24, p < .0001), leukopenia (HR = 4.17, p = .0005), thrombocytopenia (HR = 3.38, p = .0059), hypocomplementemia (HR = 29.06, p<.0001), and positive for anti-dsDNA (HR = 13.70, p < .0001), anti-ribonucleoprotein (RNP) (HR = 3.82, p = .0027), and anti-ribosomal P (HR = 6.70, p = .0002) at baseline were SLE development predictors in SS patients. CONCLUSION: Shorter disease duration and higher disease activity of SS at baseline may be risk factors for future SLE development. Serologic predictors of SLE development are hypocomplementemia, leukopenia, thrombocytopenia, and positivity for anti-dsDNA, anti-RNP, and anti-ribosomal P antibodies. If the above factors are observed, close monitoring will be necessary during the follow-up period, considering the possibility of future SLE development.

Safety and effectiveness of tofacitinib in Korean adult patients with rheumatoid arthritis: A post-marketing surveillance study.

OBJECTIVES: The aim of this article is to assess the safety and effectiveness of tofacitinib in patients with rheumatoid arthritis in routine clinical settings in Korea. METHODS: This is a prospective, multi-centre post-marketing surveillance study. Data were prospectively collected within 6 months after the start of tofacitinib therapy. Safety was evaluated based on the presence of adverse events (AEs) observed in patients who received at least one dose of tofacitinib. Effectiveness was assessed according to the proportion of patients who achieved low disease activity and remission, American College of Rheumatology 20 criteria (ACR20), European League Against Rheumatism (EULAR) response, and change of Disease Activity Score in 28 Joints (DAS28). RESULTS: The incidence rates [patients with events per 100 patient-years (PY)] of AEs and serious AEs were 56.92 and 10.69, respectively. Regarding AEs of special interest, the incidence rates were 4.33 per 100 PY for serious infections and infestations, 5.78 per 100 PY for herpes zoster, no event of tuberculosis, 0.29 per 100 PY for malignancy, 0.29 per 100 PY for venous thromboembolism (one event of deep vein thrombosis and no event of pulmonary embolism), 0.87 per 100 PY for major adverse cardiovascular event, and 0.58 per 100 PY for mortality. Moreover, ∼40.48% and 21.60% of patients achieved low disease activity and remission of DAS28-erythrocyte sedimentation rate. The EULAR response was classified as good responders with 39.12% in the DAS28-erythrocyte sedimentation rate. CONCLUSIONS: The benefit/risk profile of tofacitinib in adult patients with rheumatoid arthritis in routine clinical settings in Korea was similar to long-term clinical trial data.

Prognostic signature of interferon-γ and interleurkin-17A in early rheumatoid arthritis.

OBJECTIVES: CD4+ T cells are crucial for the pathogenesis of rheumatoid arthritis (RA). Here, we evaluated gene expression in CD4+ T cells in early RA, and main purpose of present study was to seek the changes in CD4+ T-cell-related cytokines according to RA progression. METHODS: Early RA was defined as methotrexate (MTX)-naïve patients. Established RA was defined as patients with more than 6 months of DMARDs. Patients with osteoarthritis were evaluated as controls. Microarray analysis was used to identify overexpressed genes in CD4+ T cells, and RT-qPCR was used to validate. Plasma cytokine were measured in patients with early and established RA, and correlations with disease activity were assessed in patients with early RA, whereas clinical prognosis was assessed in established patients with RA. RESULTS: Thirty-four genes showed overexpression in CD4+ T cells from patients with early RA compared with OA controls. Nineteen were related to interferon (IFN)-γ, and eight were related to interleukin (IL)-17A. Plasma levels of IL-17A, IL-6, IL-12, and TNF-α correlated with IFN-γ, and correlation coefficient was highest between DAS28-ESR and plasma IFN-γ levels in patients with early RA (Rho=0.553, p=0.0025). In established RA with low disease activity, drug reduction group showed lower plasma IFN-γ and IL-17A than drug maintenance/relapse group (13.61±5.75 vs. 29.89±18.72, p<0.001; and 10.91±3.92 vs. 21.04±12.81 pg/mL, p<0.001, respectively). CONCLUSIONS: The IFN-γ and IL-17 gene signature in CD4+ T cells was significantly increased in early RA. Patients with established RA with low levels of IFN-γ and IL-17A could be eligible for dose reduction.

Influence of proton pump inhibitor or rebamipide use on gut microbiota of rheumatoid arthritis patients.

OBJECTIVE: Patients with RA commonly use gastrointestinal (GI) protective drugs for treatment and prevention of drug-associated GI injuries. However, how these drugs affect the gut microbiota in RA patients remains unknown. The objective of this study was to examine the gut microbiota of RA patients according to use of GI protective drugs such as proton pump inhibitors (PPIs), histamine 2-receptor antagonists and rebamipide. METHODS: Faecal samples were obtained from 15 healthy controls and 32 RA patients who were receiving PPI, histamine 2-receptor antagonist or rebamipide. Bacterial DNA was extracted from the faecal samples and 16S rRNA sequencing was performed. Microbial composition and function were analysed using Quantitative Insights Into Microbial Ecology and Phylogenetic Investigation of Communities by Reconstruction of Unobserved States. RESULTS: RA patients exhibited reduced diversity and altered composition of the gut microbiota compared with healthy controls. The gut microbiota of RA patients receiving acid-suppressing drugs, particularly PPIs, was distinct from that of RA patients receiving rebamipide (PPI vs rebamipide, P = 0.005). Streptococcus was enriched in RA patients receiving PPI, while Clostridium bolteae was enriched in RA patients receiving rebamipide. The gut microbiota of PPI users was abundant with microbial functional pathway involved in the production of virulence factors. This featured microbial function was positively correlated with relative abundance of Streptococcus, the differentially abundant taxa of PPI users. CONCLUSION: The gut microbiota of RA patients receiving PPIs was distinguishable from that of those receiving rebamipide. The enriched virulent function in the gut microbiota of PPI users suggests that inappropriate PPI use may be harmful in RA patients.

A clinical comparison of an endothelin receptor antagonist and phosphodiesterase type 5 inhibitors for treating digital ulcers of systemic sclerosis.

OBJECTIVES: To assess the efficacy of an endothelin receptor antagonist (ERA) and phosphodiesterase type5 inhibitors (PDE5is) for treating SSc-related digital ulcers (DUs). METHODS: This prospective, multicentre, observational cohort study recruited patients with active SSc-related DUs from 13 medical centres in South Korea. The primary outcome was time to cardinal ulcer (CU) healing. A secondary outcome was time to new DU occurrence. Patients were followed up 4, 8, 12 and 24 weeks after treatment initiation. RESULTS: Sixty-three patients were analysed. Their mean age was 49.9 years (s.d. 11.4) and 49 were female. Twenty-eight had limited SSc. Forty-nine patients received ERA, 11 received a PDE5i (9 sildenafil, 1 udenafil and 1 tadalafil) and 3 received other medication. The hazard ratio (HR) for time to CU healing in the ERA group vs the PDE5i group was 0.75 (95% CI 0.35, 1.64; P = 0.47) in an unadjusted model and 0.80 (95% CI 0.36, 1.78; P = 0.59) in a model adjusted for age, sex, use of calcium channel blockers (CCBs), total DU number and initial CU area. The HR for new DU development in the ERA group vs the PDE5i group was 0.39 (95% CI 0.16, 0.93; P = 0.03) in an unadjusted model and 0.32 (95% CI 0.13, 0.81; P = 0.02) in an adjusted model. No patients receiving CCBs developed new DUs at 24 weeks. CONCLUSION: Time to CU healing is comparable for ERA and PDE5i. ERAs are more effective in reducing new DU occurrence than PDE5is. CCBs may be effective as a background medication.

Renal function deterioration is an independent mortality determinant in Koreans diagnosed with lupus nephritis.

OBJECTIVE: To evaluate the predictors of mortality, mortality rate, and causes of death in patients with lupus nephritis (LN) depending on final renal function. METHODS: The cohort included 401 Korean patients diagnosed with LN between 1985 and 2019. We retrospectively analyzed the clinical and laboratory indices, treatment response, and the final renal function. The final renal function was defined by the last stable level of eGFR measured in an out-patient department more than 3 times before death occurred and was categorized into five groups depending on CKD stage. RESULTS: The median follow-up time after the diagnosis of LN was 131 months. No difference in baseline demographic characteristics and laboratory findings was found except for the proportion of Hb less than 10 mg/dl and baseline eGFR (p = 0.011 and 0.037). We found no significant differences in therapeutic parameters, but all the response parameters including treatment response at 6 months (p = 0.004) and 12 months (p = 0.004), time to remission (p < 0.001), final renal response (p < 0.001), and the final renal function (p < 0.001) differed significantly between the two groups. In multivariate Cox proportional hazards analysis, the final renal function was an independent risk factor predicting mortality. The main causes of death were infection and SLE flare. Contrary to existing knowledge, SLE flare also triggered mortality in a few patients with LN progressed to end-stage renal disease (ESRD). Only two cases of mortality occurred in the kidney transplantation (KT) group (n = 25) with a median follow-up period of 224 months. The overall mortality rates calculated using the Kaplan-Meier method were 6.8%, 10.3%, 19.7%, and 28.0% at 5, 10, 20, and 30 years, respectively. CONCLUSION: Renal function deterioration was an independent determinant of mortality in Korean patients with LN. SLE flare also caused mortality in patients with LN who required maintenance dialysis, suggesting the benefit of KT on lupus activity and survival.

Impact of Posttranslational Modification in Pathogenesis of Rheumatoid Arthritis: Focusing on Citrullination, Carbamylation, and Acetylation.

Rheumatoid arthritis (RA) is caused by prolonged periodic interactions between genetic, environmental, and immunologic factors. Posttranslational modifications (PTMs) such as citrullination, carbamylation, and acetylation are correlated with the pathogenesis of RA. PTM and cell death mechanisms such as apoptosis, autophagy, NETosis, leukotoxic hypercitrullination (LTH), and necrosis are related to each other and induce autoantigenicity. Certain microbial infections, such as those caused by Porphyromonasgingivalis, Aggregatibacter actinomycetemcomitans, and Prevotella copri, can induce autoantigens in RA. Anti-modified protein antibodies (AMPA) containing anti-citrullinated protein/peptide antibodies (ACPAs), anti-carbamylated protein (anti-CarP) antibodies, and anti-acetylated protein antibodies (AAPAs) play a role in pathogenesis as well as in prediction, diagnosis, and prognosis. Interestingly, smoking is correlated with both PTMs and AMPAs in the development of RA. However, there is lack of evidence that smoking induces the generation of AMPAs.

Recent Updates of Diagnosis, Pathophysiology, and Treatment on Osteoarthritis of the Knee.

Osteoarthritis (OA) is a degenerative and chronic joint disease characterized by clinical symptoms and distortion of joint tissues. It primarily damages joint cartilage, causing pain, swelling, and stiffness around the joint. It is the major cause of disability and pain. The prevalence of OA is expected to increase gradually with the aging population and increasing prevalence of obesity. Many potential therapeutic advances have been made in recent years due to the improved understanding of the underlying mechanisms, diagnosis, and management of OA. Embryonic stem cells and induced pluripotent stem cells differentiate into chondrocytes or mesenchymal stem cells (MSCs) and can be used as a source of injectable treatments in the OA joint cavity. MSCs are known to be the most studied cell therapy products in cell-based OA therapy owing to their ability to differentiate into chondrocytes and their immunomodulatory properties. They have the potential to improve cartilage recovery and ultimately restore healthy joints. However, despite currently available therapies and advances in research, unfulfilled medical needs persist for OA treatment. In this review, we focused on the contents of non-cellular and cellular therapies for OA, and briefly summarized the results of clinical trials for cell-based OA therapy to lay a solid application basis for clinical research.

Increased Potential of Bone Formation with the Intravenous Injection of a Parathyroid Hormone-Related Protein Minicircle DNA Vector.

Osteoporosis is commonly treated via the long-term usage of anti-osteoporotic agents; however, poor drug compliance and undesirable side effects limit their treatment efficacy. The parathyroid hormone-related protein (PTHrP) is essential for normal bone formation and remodeling; thus, may be used as an anti-osteoporotic agent. Here, we developed a platform for the delivery of a single peptide composed of two regions of the PTHrP protein (1-34 and 107-139); mcPTHrP 1-34+107-139 using a minicircle vector. We also transfected mcPTHrP 1-34+107-139 into human mesenchymal stem cells (MSCs) and generated Thru 1-34+107-139-producing engineered MSCs (eMSCs) as an alternative delivery system. Osteoporosis was induced in 12-week-old C57BL/6 female mice via ovariectomy. The ovariectomized (OVX) mice were then treated with the two systems; (1) mcPTHrP 1-34+107-139 was intravenously administered three times (once per week); (2) eMSCs were intraperitoneally administered twice (on weeks four and six). Compared with the control OVX mice, the mcPTHrP 1-34+107-139-treated group showed better trabecular bone structure quality, increased bone formation, and decreased bone resorption. Similar results were observed in the eMSCs-treated OVX mice. Altogether, these results provide experimental evidence to support the potential of delivering PTHrP 1-34+107-139 using the minicircle technology for the treatment of osteoporosis.

Effects of birth months on rheumatic diseases in South Korea: a nationwide case-control study.

OBJECTIVES: Birth month/season impacts the development of certain diseases. However, the effect of birth month/season on the development of rheumatic diseases has not been thoroughly investigated. Thus, the objective of this study was to determine whether birth month/season might affect the development of rheumatic diseases. METHODS: Birth month patterns of patients with various rheumatic diseases were compared with those of the general population. The dataset included 17,247,458 individuals from the health insurance review and assessment service database of Korea. RESULTS: Among 24 rheumatic diseases, the development of Crohn's disease, ulcerative colitis (UC), rheumatoid arthritis, Sjögren's syndrome, polymyalgia rheumatica, ankylosing spondylitis (AS), gout, and fibromyalgia (FM) was significantly associated with birth month/season. UC and AS were more prevalent in individuals born in February/winter. On the contrary, those who were born in June or July/summer were at a higher risk of gout and FM. CONCLUSIONS: Seasonal variations in infectious agents, sun exposure, and food ingestion during gestation or early infancy seem to explain the association between birth month/season and development of rheumatic diseases.

The Role of Chondrocyte Hypertrophy and Senescence in Osteoarthritis Initiation and Progression.

Osteoarthritis (OA) is the most common joint disease that causes pain and disability in the adult population. OA is primarily caused by trauma induced by an external force or by age-related cartilage damage. Chondrocyte hypertrophy or chondrocyte senescence is thought to play a role in the initiation and progression of OA. Although chondrocyte hypertrophy and cell death are both crucial steps during the natural process of endochondral bone formation, the abnormal activation of these two processes after injury or during aging seems to accelerate the progression of OA. However, the exact mechanisms of OA progression and these two processes remain poorly understood. Chondrocyte senescence and hypertrophy during OA share various markers and processes. In this study, we reviewed the changes that occur during chondrocyte hypertrophy or senescence in OA and the attempts that were made to regulate them. Regulation of hypertrophic or senescent chondrocytes might be a potential therapeutic target to slow down or stop OA progression; thus, a better understanding of the processes is required for management.

Soluble siglec-5 is a novel salivary biomarker for primary Sjogren's syndrome.

Despite advances in the understanding of the pathogenesis, disease-specific biomarkers have not been included in the classification criteria for Primary Sjogren's syndrome (pSS). Based on a microarray of peripheral blood mononuclear cells (PBMCs) from patients with primary Sjogren's syndrome (pSS), we aimed to investigate whether soluble sialic acid-binding immunoglobulin-like lectin (siglec)-5 in saliva might be a biomarker for pSS. The concentration of siglec-5 in saliva and sera was determined by ELISA. Clinical parameters related with pSS were obtained from pSS registry and correlation with salivary siglec-5 level was evaluated. Receiver operating curve (ROC) analysis was performed to determine cut off value. A separate validation cohort consisted of subjects with suspicious pSS was evaluated to determine the performance. The level of salivary siglec-5 was significantly higher in pSS patients (n = 170) compared with HCs (n = 25), non SS sicca patients (n = 78) or patients with systemic lupus erythematosus (SLE) (n = 43) (1346.8 [202.8-4280.0] pg/mL, 6.08 [0-134.0] pg/mL, 195 [0-947.5] pg/mL, and 0 [0-238.7] pg/mL, median [interquartile range], P < 0.001). Salivary siglec-5 level negatively correlated with salivary flow rate (spearman's rho: -0.420, P < 0.001), and positively correlated with ocular surface score (rho: 0.331, P < 0.001) and serum immunoglobulin G level (rho = 0.202, P = 0.008). In ROC analysis, area under the curve was 0.774[0.724-0.826]. With a cut off value of 400 pg/mL, sensitivity and specificity was 0.69 and 0.70 respectively. In validation cohort (45 pSS patients and 45 non SS sicca patients), sensitivity and specificity of siglec-5 was 64.4% and 77.8%, respectively. In conclusion, the level of soluble siglec-5 is significantly higher in the saliva from pSS patients, which reflects the severity of hyposalivation and ocular surface damage. This novel salivary biomarker may provide benefits for pSS diagnosis.

A Novel Hepatic Anti-Fibrotic Strategy Utilizing the Secretome Released from Etanercept-Synthesizing Adipose-Derived Stem Cells.

Tumor necrosis factor-α (TNF-α)-driven inflammatory reaction plays a crucial role in the initiation of liver fibrosis. We herein attempted to design genetically engineered adipose-derived stem cells (ASCs) producing etanercept (a potent TNF-α inhibitor), and to determine the anti-fibrotic potential of the secretome released from the etanercept-synthesizing ASCs (etanercept-secretome). First, we generated the etanercept-synthesizing ASCs by transfecting the ASCs with mini-circle plasmids containing the gene insert encoding for etanercept. We subsequently collected the secretory material released from the etanercept-synthesizing ASCs and determined its anti-fibrotic effects both in vitro (in thioacetamide [TAA]-treated AML12 and LX2 cells) and in vivo (in TAA-treated mice) models of liver fibrosis. We observed that while etanercept-secretome increased the viability of the TAA-treated AML12 hepatocytes (p = 0.021), it significantly decreased the viability of the TAA-treated LX2 HSCs (p = 0.021). In the liver of mice with liver fibrosis, intravenous administration of the etanercept-secretome induced significant reduction in the expression of both fibrosis-related and inflammation-related markers compared to the control group (all Ps < 0.05). The etanercept-secretome group also showed significantly lower serum levels of liver enzymes as well as pro-inflammatory cytokines, such as TNF-α (p = 0.020) and IL-6 (p = 0.021). Histological examination of the liver showed the highest reduction in the degree of fibrosis in the entanercept-secretome group (p = 0.006). Our results suggest that the administration of etanercept-secretome improves liver fibrosis by inhibiting TNF-α-driven inflammation in the mice with liver fibrosis. Thus, blocking TNF-α-driven inflammation at the appropriate stage of liver fibrosis could be an efficient strategy to prevent fibrosis.

Inflammation on spinal magnetic resonance imaging is associated with poor bone quality in patients with ankylosing spondylitis.

Objective: To determine the association between inflammatory lesions on spinal magnetic resonance imaging (MRI) and trabecular bone score (TBS) in patients with ankylosing spondylitis (AS). Methods: Ninety-seven patients with AS underwent spine MRI and dual energy X-ray absorptiometry of the lumbar spine to measure TBS and bone mineral density (BMD). Bone marrow edema (BME) on MRI was considered an inflammatory lesion. The presence, depth (>1 cm), and intensity of BME on MRI were scored for the 1st-4th lumbar spine segments. Inflammatory markers and spinal structural damage scores at the time of MRI examination were recorded. The association between inflammatory activity score on MRI and TBS was evaluated. Results: Among the 97 patients, 52 had BME on spinal MRI (L1-L4). The mean TBS values were 1.38 ± 0.11 and 1.43 ± 0.11 for patients with and without BME, respectively (p = .022). Total inflammatory activity scores on spinal MRI correlated negatively with TBS, but not with BMD. Patients with a TBS value representing a high fracture risk had more deep BME (>1 cm) (p = .048) on MRI. After adjustment for age, symptom duration, and lumbar spinal structural damage, the TBS decreased as inflammation severity on MRI increased (p = .026). Discussion: In AS patients, inflammation on spinal MRI was negatively correlated with TBS. The severity of local bone inflammation in the spine was associated with poor bone quality. These findings suggest that the control of active bone inflammation may be effective for preventing osteoporosis in AS patients.

Performance of the 2016 ACR-EULAR classification criteria for primary Sjogren's syndrome in a Korean cohort.

This study compared the performance of the newly proposed 2016 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) criteria to the 2002 American-European Consensus Group (AECG) and 2012 ACR classification criteria for primary Sjogren's syndrome (pSS) in well-characterized Korean patients. Patients with pSS from 12 university-affiliated hospitals in Korea were enrolled from October 2013 to January 2017. Clinical and laboratory data were reviewed. For the validation set, patients who underwent evaluation tests to rule out pSS at Seoul St. Mary's hospital from November 2016 to December 2017 were analyzed. Baseline registry data were available in 458 patients, and 328 patients had sufficient data to determine the fulfillment of each criteria set. All three sets of criteria were met by 307 patients (93.6%). The newly proposed 2016 ACR/EULAR criteria were met by 325 patients (99.1%). The 2002 AECG and 2012 ACR criteria were met by 325 (99.1%) and 310 patients (94.5%), respectively. In a validation cohort consisting of 161 patients with pSS-related symptoms/signs, the sensitivity and specificity of the 2016 ACR/EULAR criteria were 100% [95% confidence interval (CI), 96.11-100.00] and 81.8% [95% CI, 76.15-94.26], respectively. Agreement between the 2016 criteria and 2012 or 2002 criteria was high (Cohen's kappa 0.736 and 0.769, respectively). The newly proposed 2016 ACR/EULAR criteria were met by most patients diagnosed with pSS according to previous criteria and showed higher sensitivity and lower specificity compared with both previous criteria sets.

Positive correlation between inflammation on sacroiliac joint MRI and serum C-terminal telopeptide of type-I collagen in ankylosing spondylitis but not in non-radiographic axial spondyloarthritis.

OBJECTIVES: To identify the clinical disease activity scores and laboratory markers that best reflect magnetic resonance imaging (MRI)-determined sacroiliac joint (SIJ) inflammation in ankylosing spondylitis (AS) and non-radiographic axial spondyloarthritis (nr-axSpA). METHODS: This cross-sectional study included all consecutive patients who presented with axial spondyloarthritis in 2013-2015. All underwent SIJ MRI. The bone marrow oedema in the inflammatory lesions on MRI was scored using the SPondyloArthritis Research Consortium of Canada (SPARCC) method. Bone-specific alkaline phosphatase (BALP), serum C-terminal telopeptide of type-I collagen (sCTX-I), and inflammatory markers were measured. Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Ankylosing Spondylitis Disease Activity Score (ASDAS) were assessed. The correlations between the MRI-determined SIJ inflammation scores and disease activity scores and laboratory variables were evaluated. RESULTS: Of the 81 patients with axSpA, 45 had AS and 36 had nr-axSpA. The AS and nr-axSpA groups did not differ in terms of disease activity scores, physical functional index, or MRI-determined SIJ inflammation. Erythrocyte sedimentation rate, C-reactive protein, and ASDAS correlated with MRI inflammatory scores in nr-axSpA but not in AS. sCTX-I correlated with MRI-determined SIJ inflammatory scores in AS only. BASDAI and BALP levels did not associate with MRI inflammatory scores in either group. Multivariate analysis showed that sCTX-I associated independently with MRI inflammatory score in AS (ß=17.047, p=0.038). CONCLUSIONS: Inflammatory markers and ASDAS correlated with active sacroiliitis on MRI in nr-axSpA only. In AS, only sCTX-I correlated with active inflammation on SIJ MRI. sCTX-I may be useful as a marker of objective inflammation in AS.

IL-12p40 Homodimer Ameliorates Experimental Autoimmune Arthritis.

IL-23 is the key cytokine that induces the expansion of Th17 cells. It is composed of p19 and p40 subunits of IL-12. The p40 subunit binds competitively to the receptor of IL-23 and blocks its activity. Our aim was to assess the preventive and therapeutic effect of the IL-12p40 homodimer (p40)2 subunit in autoimmune arthritis animal models. In the current study, using IL-1R antagonist-knockout mice and a collagen-induced arthritis model, we investigated the suppressive effect of (p40)2 on inflammatory arthritis. We demonstrated that the recombinant adenovirus-expressing mouse (p40)2 model prevented the development of arthritis when given before the onset of arthritis. It also decreased the arthritis index and joint erosions in the mouse model if transferred after arthritis was established. (p40)2 inhibited the production of inflammatory cytokines and Ag-specific T cell proliferation. It also induced CD4(+)CD25(+)Foxp3 regulatory T (Treg) cells in vitro and in vivo, whereas the generation of retinoic acid receptor-related organ receptor γt and Th17 cells was suppressed. The induction of Treg cells and the suppression of Th17 cells were mediated via activated STAT5 and suppressed STAT3. Our data suggest that (p40)2 suppressed inflammatory arthritis successfully. This could be a useful therapeutic approach in autoimmune arthritis to regulate the Th17/Treg balance and IL-23 signaling.

Monosodium urate crystal-induced triggering receptor expressed on myeloid cells 1 is associated with acute gouty inflammation.

OBJECTIVE: Triggering receptor expressed on myeloid cells 1 (TREM-1), which amplifies the inflammation elicited by the Toll-like receptor pathway, was originally implicated in sepsis and bacterial infection. However, it has been suggested that TREM-1 may also play an important role in non-infectious inflammation. The present study was conducted to investigate whether TREM-1 is involved in human acute gouty inflammation. METHODS: A total of 37 gout patients were recruited between March 2011 and January 2014 from Seoul St Mary's Hospital. The expression of TREM-1 on mononuclear cells was assessed using FACS analysis, immunostaining and real-time RT-PCR. To block the TREM-1 signal, soluble TREM-1 (sTREM-1) or the synthetic blocking peptide LP17 was used. The concentration of sTREM-1 was assessed by ELISA. RESULTS: FACS analysis and real-time RT-PCR demonstrated that TREM-1 expression was higher in the SF mononuclear cells of acute gouty arthritis patients than in peripheral blood mononuclear cells (PBMCs). Immunohistochemical staining of tophi tissues revealed TREM-1 expression, with confocal microscopy demonstrating TREM-1 expression on tophi tissue macrophages. We also demonstrated that MSU treatment induced TREM-1 expression on the PBMCs of acute gout patients in vitro. Although blockade of TREM-1 did not directly suppress MSU-induced IL-1ß production of PBMCs in vitro, the concentration of soluble TREM-1 was higher in the SF of gout vs OA patients and was positively correlated with serum CRP. CONCLUSION: TREM-1 is induced by MSU and is associated with the inflammation of human acute gouty arthritis.