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Infection of the lungs with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) via the angiotensin I converting enzyme 2 (ACE2) receptor induces a type of systemic inflammation known as a cytokine storm. However, the precise mechanisms involved in severe coronavirus disease 2019 (COVID-19) pneumonia are unknown. Here, we show that interleukin-10 (IL-10) changed normal alveolar macrophages into ACE2-expressing M2c-type macrophages that functioned as spreading vectors for SARS-CoV-2 infection. The depletion of alveolar macrophages and blockade of IL-10 attenuated SARS-CoV-2 pathogenicity. Furthermore, genome-wide association and quantitative trait locus analyses identified novel mRNA transcripts in human patients, COVID-19 infectivity enhancing dual receptor (CiDRE), which has unique synergistic effects within the IL-10-ACE2 system in M2c-type macrophages. Our results demonstrate that alveolar macrophages stimulated by IL-10 are key players in severe COVID-19. Collectively, CiDRE expression levels are potential risk factors that predict COVID-19 severity, and CiDRE inhibitors might be useful as COVID-19 therapies.Graphical abstract

SummaryAlternative splicing events are a major causal mechanism for complex traits, but they have been understudied due to the limitation of short-read sequencing. Here, we generated a comprehensive full-length isoform annotation of human immune cells, Immune Isoform Atlas, by long-read sequencing for 29 cell subsets. Our atlas contained a number of unannotated transcripts and isoforms such as a read-through transcript of TOMM40-APOE. We profiled functional characteristics of isoforms including encoded domains, inserted repetitive elements, and translational efficiency, and we showed that repetitive elements significantly explained the diversity of unannotated isoforms. Some of the isoforms are expressed in a cell-type specific manner, whose alternative 3’-UTRs usage contributed to their specificity. Further, we identified a number of disease-associated isoforms by isoform switch analysis and by integration of several quantitative trait loci analyses with genome-wide association study data. Our findings will promote the elucidation of the pathomechanism of diseases via alternative splicing.

To identify the predictive biomarkers for achieving remission with abatacept in patients with seropositive rheumatoid arthritis (RA).We enrolled patients with RA who were treated with abatacept. We compared the baseline laboratory results and longitudinal immune-phenotyping data between patients who achieved remission and those who did not achieve remission at 6 months according to the clinical disease activity index.One hundred and twenty RA patients were enrolled. In the seropositive patients with early RA (n = 24), high serum IgA levels, anti-citrullinated peptide (CCP) titers, and neutrophil counts before treatment were predictors of remission (area under the curve [AUC], 0.659, 0.741, and 0.704, respectively). Additionally, activated Th17 (aTh17) cells and activated Treg (aTreg) cells before treatment were found to be significantly higher in patients with remission compared to those without remission (2.9% vs 1.1%, P = 0.02; 34.3% vs 17%, P = 0.03, respectively). The measurement of longitudinal cell subpopulation revealed a decrease in the effector CD4 T cell population after abatacept treatment, which correlated with anti-CCP titers and neutrophil counts, and was associated with remission achievement. In seropositive patients with established RA (n = 79), high RF titers and low IFN-γ levels were associated with the good response to abatacept.Our study has shown that serum IgA levels, anti-CCP titer, and neutrophil counts are predictive biomarkers for predicting the response to abatacept in patients with seropositive and early RA and may reflect the inhibition of effector CD4 T cell subpopulations by abatacept. Key Points • Serum IgA levels and neutrophil counts are novel biomarkers for predicting the efficacy of abatacept. • Those may reflect the inhibition of effector CD4 T cell subpopulations by abatacept.

OBJECTIVE To identify immunologic factors in the lungs of patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD) and patients with idiopathic inflammatory myopathy-associated ILD (IIM-ILD) and to examine their pathologic mechanisms. METHODS Eleven patients with RA-ILD, 16 with IIM-ILD, 6 with drug-induced ILD (DI-ILD), and 8 healthy controls were enrolled. Peripheral blood (PB) and bronchoalveolar lavage (BAL) fluid were immunophenotyped by flow cytometry. Alveolar macrophages (AMs) were analyzed by coculture assay with PB naive CD4+ T cells from healthy individuals and RNA sequencing. RESULTS Several coinhibitory molecules were coexpressed on BAL fluid T cells (CTLA-4, programmed death 1 [PD-1], T cell immunoglobulin and mucin domain-containing protein 3 [TIM-3], and lymphocyte activation gene 3 protein, from most to least), whereas only PD-1 was expressed on PB T cells. CTLA-4+PD-1+CD4+ T cells were characteristic of RA-ILD, whereas CTLA-4+PD-1+TIM-3+CD8+ T cells were characteristic of IIM-ILD. BAL fluid PD-1+CD4+ T cells rarely expressed CXCR5, but their levels correlated with levels of plasmablasts and plasma cells (ρ = 0.57, P = 0.006), indicating that most of them would be considered peripheral helper T cells. In coculture experiments, AMs from patients with RA-ILD and IIM-ILD induced more PD-1 and TIM-3 on T cells (P < 0.05), suggesting that coinhibitory molecule expression on BAL fluid T cells was partly due to AMs. RNA sequencing showed significant down-regulation of PD ligand 1/2 genes in AMs from patients with RA-ILD compared to those with DI-ILD. CONCLUSION We have identified differences in coinhibitory molecule expression between patients with RA-ILD and those with IIM-ILD. PD-1 on T cells in RA-ILD and TIM-3 on CD8+ T cells in IIM-ILD might be key factors in the disease process. Evaluation of coinhibitory molecules on BAL fluid T cells could be clinically useful.

To investigate the relevance of RF in patients with EGPA, we reviewed consecutive patients who were newly diagnosed with EGPA from August 1998 to February 2019 in Keio University Hospital with RF titer at diagnosis available. We divided the patients according to the median level of RF titer of 75 IU/mL and compared clinical features between the two groups. Among 16 patients identified, 8 patients were in the RF high group and the other 8 patients were in the RF low group. All patients in the high RF group were negative for MPO-ANCA, whereas all in the low RF group was positive for MPO-ANCA with a mean titer of 103 IU/mL. The eosinophil count at diagnosis was significantly higher in the RF high group than the RF low group (20001/μL vs 5144/μL, p 0.01). Gastrointestinal lesion was significantly more frequent in the RF high group, and parenchymal organ lesions, such as heart and renal organ involvement, were frequent in the RF low group. With principal component analysis, RF high and low groups were clearly divided by the combination of eosinophil count, MPO-ANCA titer, gastrointestinal lesions, musculoskeletal symptoms, and disease activity score. Those results suggest EGPA can be divided into two groups in association with RF.Key Points• Our study showed that patients with EGPA can be separated into two groups according to RF titer.• The two subtypes reflect different underlying pathogenesis in EGPA, and the optimal treatment for them may be different.

A 38-year-old woman, who was diagnosed with systemic lupus erythematosus (SLE) and treated with tacrolimus and prednisolone, developed severe headache suddenly. Magnetic resonance imaging (MRI) and...

Introduction. While numerous disease-modifying anti-rheumatic drugs (DMARDs) have brought about a dramatic paradigm shift in the management of rheumatoid arthritis (RA), unmet needs remain, such as the small proportion of patients who achieve drug-free status. The aim of this study was to explore key molecules for remission at the T cell level, which are known to be deeply involved in RA pathogenesis, and investigate the disease course of patients who achieved molecular remission (MR). Methods. We enrolled a total of 46 patients with RA and 10 healthy controls (HCs). We performed gene expression profiling and selected remission signature genes in CD4+ T cells and CD8+ T cells from patients with RA using machine learning methods. In addition, we investigated the benefits of achieving MR on disease control. Results. We identified 9 and 23 genes that were associated with clinical remission in CD4+ and CD8+ T cells, respectively. Principal component analysis (PCA) demonstrated that their expression profiling was similar to those in HCs. For the remission signature genes in CD4+ T cells, the PCA result was reproduced using a validation cohort, indicating the robustness of these genes. A trend toward better disease control was observed during 12 months of follow-up in patients treated with tocilizumab in deep MR compared with those in non-deep MR, although the difference was not significant. Conclusion. We identified robust genes that represent remission status in CD4+ T cells using machine learning techniques. The current study will promote our understanding of the molecular mechanisms necessary to achieve deep remission during the management of RA. Trial registration: Not required.

Background. While numerous disease-modifying anti-rheumatic drugs (DMARDs) has brought about a dramatic paradigm shift in the management of rheumatoid arthritis (RA), unmet needs remain such as small proportion of achievement drug-free patients. The aim of this study is to explore key molecules for remission at T cell level, which is known to involve the pathogenesis of RA deeply, and investigate disease course of patients who achieved molecular remission (MR).Methods. We enrolled a total of 46 patients with RA and 10 healthy controls (HCs). We performed gene expression profiling and selected remission signature genes in CD4+ T cells and CD8+ T cells of patients with RA using machine learning methods. In addition, we investigated the benefit of achieving MR on disease control thereafter.Results. We identified 9 and 23 genes that were associated with clinical remission in CD4+ and CD8+ T cells. Principal component analysis (PCA) demonstrated expression profiling of them was similar with HCs. As to remission signature genes in CD4+ T cells, PCA result was reproduced using validation cohort, indicating their robustness. There was a trend towards better disease control during 12 months follow-up in patients treated with tocilizumab in deep MR than those in non-deep MR, although it was not significant.Conclusion. We identified robust genes which represented remission status in CD4+ T cells using machine learning techniques. The current study will promote our understandings about molecular mechanism to achieve deep remission in the management of RA.Trial registration: Not required.

Background The aim of this study was to identify the molecular mechanism of dysregulation of B cell subpopulations of primary Sjögren’s syndrome (pSS) at the transcriptome level. Methods We enrolled patients with pSS (n = 6) and healthy controls (HCs) (n = 6) in the discovery cohort using microarray and pSS (n = 14) and HCs (n = 12) in the validation cohort using quantitative PCR (qPCR). Peripheral B cells acquired from these subjects were separated by cell sorting into four subsets: CD38−IgD+ (Bm1), CD38+IgD+ (naive B cells), CD38highIgD+ (pre-germinal centre B cells) and CD38±IgD− (memory B cells). We performed differentially expressed gene (DEG) analysis and weighted gene co-expression network analysis (WGCNA). Results Expression of the long non-coding RNA LINC00487 was significantly upregulated in all B cell subsets, as was that of HLA and interferon (IFN) signature genes. Moreover, the normalized intensity value of LINC00487 significantly correlated with the disease activity score of all pSS B cell subsets. Studies of human B cell lines revealed that the expression of LINC00487 was strongly induced by IFNα. WGCNA revealed six gene clusters associated with the B cell subpopulation of pSS. Further, SOX4 was identified as an inter-module hub gene. Conclusion Our transcriptome analysis revealed key genes involved in the dysregulation of B cell subpopulations associated with pSS. Trial registration Not required.

ObjectiveThe aim of this study was to investigate relevance between type of autoantibody and gene expression profile in skin lesion of systemic sclerosis (SSc), and identify specifically dysregulated pathways.MethodsSixty-one patients with SSc from the Genetics versus Environment in Scleroderma Outcome Study cohort and thirty-six healthy controls (HC) are included. Differentially expressed genes (DEGs) were extracted and functional enrichment and pathways analysis were conducted.ResultsCompared with HC, lists consisting of 2, 71, 10, 144 and 78 DEGs were created for patients without specific autoantibody, anti-centromere (ACA), anti-U1 RNP (RNP), anti-RNA polymerase III (RNAP) and anti-topoisomerase I (ATA) antibody, respectively. While part of enriched pathways overlapped, distinct pathways were identified except those without specific autoantibody: keratinocyte differentiation in ACA, NF-kB signaling and cellular response to transforming growth factor beta stimulus in RNAP, interferon alpha/beta signaling of RNP and cellular response to stress in ATA.ConclusionPathogenic pathways were identified according to type of autoantibodies by leveraging gene expression data of patients and controls from multi-center cohort. The current study will promote to explore new therapeutic target for SSc.Key messageDistinct pathways are associated with type of autoantibody in skin lesion of systemic sclerosis.

Objectives The aims of this study were to investigate the relationship between the type of autoantibody and gene expression profile in skin lesions from patients with SSc, and to identify specific dysregulated pathways in SSc patients compared with healthy controls. Methods Sixty-one patients with SSc from the Genetics vs Environment in Scleroderma Outcome Study cohort and 36 healthy controls were included in this study. Differentially expressed genes were extracted and functional enrichment and pathway analysis were conducted. Results Compared with healthy controls, lists containing 2, 71, 10, 144 and 78 differentially expressed genes were created for patients without specific autoantibody, ACA, anti-U1 RNP antibody (RNP), anti-RNA polymerase III antibody (RNAP) and anti-topoisomerase I antibody (ATA), respectively. While part of the enriched pathways overlapped, distinct pathways were identified except in those patients lacking specific autoantibody. The distinct enriched pathways included ‘keratinocyte differentiation’ for ACA, ‘nuclear factor κB signalling’ and ‘cellular response to TGF-β stimulus’ for RNAP, ‘interferon α/β signalling’ for RNP, and ‘cellular response to stress’ for ATA. Cell type signature score analysis revealed that macrophages/monocytes, endothelial cells and fibroblasts were associated with ACA, RNAP, ATA and the severity of the SSc skin lesions. Conclusion Pathogenic pathways were identified according to the type of autoantibody by leveraging gene expression data of patients and controls from a multicentre cohort. The current study may promote the search for new therapeutic targets for SSc.

Background To identify the predictive biomarkers for achieving remission with abatacept in patients with seropositive rheumatoid arthritis (RA). Methods We enrolled patients with RA who were treated with abatacept. We compared the baseline laboratory results and longitudinal immune-phenotyping data between patients who achieved remission and those who did not achieve remission at 6 months according to the clinical disease activity index. Results One hundred and twenty RA patients were enrolled. In the seropositive patients with early RA, high serum IgA levels, anti-CCP titers and neutrophil counts before treatment were predictors of remission (area under the curve [AUC], 0.659, 0.741, and 0.704, respectively). Additionally, activated Th17 (aTh17) cells and activated Treg (aTreg) cells before treatment were found to be significantly higher in patients with remission compared to those without remission (2.9% vs 1.1%, P = 0.02; 34.3% vs 17%, P = 0.03, respectively). The measurement of longitudinal cell subpopulation revealed a decrease in the effector CD4 T cell population after abatacept treatment, which correlated with anti-CCP titers and neutrophil counts, and was associated with remission achievement. In seropositive patients with established RA, high RF titers and low IFN-γ levels may be possible biomarkers for remission. Conclusion Our study has shown that serum IgA levels, anti-CCP titer and neutrophil counts are predictive biomarkers for evaluating the response to abatacept in patients with seropositive and early RA, and may reflect the inhibition of effector CD4 T cell subpopulations by abatacept.

Background: Primary Sjogren’s syndrome (pSS) is a systemic autoimmune disease characterized by interferon signature [1] and exocrine gland dysfunction which leads to dryness of the eyes and mouth [2]. B cells are considered to play an important role in the pathogenesis of pSS. Dysregulation of B cells can lead to production of anti-Sjogren’s syndrome-related antigen A (anti-SSA) autoantibodies. Objectives: We investigated the differential gene expression of peripheral B cell subsets to reveal the precise role of B cells in the pathogenesis of pSS. Methods: We enrolled pSS patients (n=6) and healthy controls (HC) (n=6), with matching for age and sex. Peripheral B cells acquired from the participants were separated by cell sorting into 4 subsets: CD38-IgD+, CD38+IgD+, CD38highIgD+ and CD38±IgD-. Total RNA was extracted and gene expression was measured using the Human Genome U133 Plus 2.0 Array (Affymetrix). The data were bioinformatically analyzed with reference to the corresponding clinical information. Results: Using principal component and clustering analyses, we found that transcript expression patterns depended on cell type rather than clinical condition (pSS or HC). Interferon signaling was the most upregulated pathway in many of B cell subsets of pSS patients. As well as HLA and interferon signature genes, LINC00487 was upregulated significantly in all B cell subsets. Its fold changes in CD38-IgD+, CD38+IgD+, CD38highIgD+ and CD38±IgD- were 8.4 (p=0.038), 11.3 (p=0.014), 8.5 (p=0.089) and 6.37 (p=0.078), respectively. In addition, the normalized intensity value of LINC00487 was significantly correlated with disease activity score in all pSS B cell subsets, namely CD38-IgD+(Figure A, r=0.96, p=0.002), CD38+IgD+(Figure B, r=0.90, p=0.015), CD38highIgD+ (Figure C, r=0.81, p=0.049) and CD38±IgD- (Figure D, r=0.96, p=0.003). The expression of LINC00487 in B cell lines was regulated by IFNα. Conclusion: Compared to HC, patients with pSS showed upregulation of the interferon signaling pathway and LINC00487 gene in all B cell subsets. This upregulation correlated with disease activity and regulated by IFNα in B cell lines. These results may suggest that long non-coding RNA contributes to B cell dysregulation in patients with pSS and the precise role of LINC00487 in B cell and pathogenesis of pSS requires further study. References [1] Muskardin TLW, et al. Nat Rev Rheumatol2018;14:214-228. [2] Qin, B. et al. Ann Rheum Dis. 2015;74:1983-1989. ESSDAI; EULAR Sjogren’s Syndrome Disease Activity Index Disclosure of Interests: Jun Inamo: None declared, Katsuya Suzuki: None declared, Masaru Takeshita Grant/research support from: Novartis, Yoshiaki Kasai Employee of: Takeda Pharmaceutical Company Limited, Rina Kurisu Employee of: Takeda Pharmaceutical Company Limited, Maiko Takiguchi Employee of: Takeda Pharmaceutical Company Limited, Yuumi Okuzono Employee of: Takeda Pharmaceutical Company Limited, Shinya Tasaki Employee of: Takeda Pharmaceutical Company Limited, Tsutomu Takeuchi Grant/research support from: Astellas Pharma Inc, Chugai Pharmaceutical Co, Ltd., Daiichi Sankyo Co., Ltd., Takeda Pharmaceutical Co., Ltd., AbbVie GK, Asahikasei Pharma Corp., Mitsubishi Tanabe Pharma Co., Pfizer Japan Inc., Eisai Co., Ltd., AYUMI Pharmaceutical Corporation, Nipponkayaku Co. Ltd., Novartis Pharma K.K., Grant/research support from: AbbVie, Asahi Kasei, Astellas, AstraZeneca, AYUMI, Bristol-Myers Squibb, Chugai, Daiichi Sankyo, Eisai, Eli Lilly Japan, Janssen, Mitsubishi Tanabe, Nippon Kayaku, Novartis, Pfizer Japan Inc, Taiho, Taisho Toyama, Takeda, Teijin, Grant/research support from: Astellas Pharma Inc., Bristol Myers Squibb, Chugai Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Co., Pfizer Japan Inc., Santen Pharmaceutical Co., Ltd., Takeda Pharmaceutical Co., Ltd., Teijin Pharma Ltd., AbbVie GK, Asahi Kasei Pharma Corp., Taisho Toyama Pharmaceutical Co., Ltd., SymBio Pharmaceuticals Ltd., Janssen Pharmaceutical K.K., Celltrion Inc., Nipponkayaku Co. Ltd., and UCB Japan, Consultant for: Astra Zeneca K.K., Eli Lilly Japan K.K., Novartis Pharma K.K., Mitsubishi Tanabe Pharma Co., Abbivie GK, Nipponkayaku Co.Ltd, Janssen Pharmaceutical K.K., Astellas Pharma Inc., Taiho Pharmaceutical Co. Ltd., Chugai Pharmaceutical Co. Ltd., Taisho Toyama Pharmaceutical Co. Ltd., GlaxoSmithKline K.K., UCB Japan Co. Ltd., Consultant for: AbbVie, Asahi Kasei, Astellas, AstraZeneca, AYUMI, Bristol-Myers Squibb, Chugai, Daiichi Sankyo, Eisai, Eli Lilly Japan, Janssen, Mitsubishi Tanabe, Nippon Kayaku, Novartis, Pfizer Japan Inc, Taiho, Taisho Toyama, Takeda, Teijin, Consultant for: Astra Zeneca K.K., Eli Lilly Japan K.K., Novartis Pharma K.K., Mitsubishi Tanabe Pharma Co., Asahi Kasei Medical K.K., AbbVie GK, Daiichi Sankyo Co., Ltd., Bristol Myers Squibb, and Nipponkayaku Co. Ltd., Speakers bureau: Astellas Pharma Inc., Bristol Myers Squibb, Chugai Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Co., Pfizer Japan Inc., Santen Pharmaceutical Co., Ltd., Takeda Pharmaceutical Co., Ltd., Teijin Pharma Ltd., AbbVie GK, Asahi Kasei Pharma Corp., Taisho Toyama Pharmaceutical Co., Ltd., SymBio Pharmaceuticals Ltd., Janssen Pharmaceutical K.K., Celltrion Inc., Nipponkayaku Co. Ltd., and UCB Japan, Speakers bureau: AbbVie, Asahi Kasei, Astellas, AstraZeneca, AYUMI, Bristol-Myers Squibb, Chugai, Daiichi Sankyo, Eisai, Eli Lilly Japan, Janssen, Mitsubishi Tanabe, Nippon Kayaku, Novartis, Pfizer Japan Inc, Taiho, Taisho Toyama, Takeda, Teijin, Speakers bureau: AbbVie GK., Bristol–Myers K.K., Chugai Pharmaceutical Co. Ltd., Mitsubishi Tanabe Pharma Co., Pfizer Japan Inc., Astellas Pharma Inc, Diaichi Sankyo Co. Ltd., Eisai Co. Ltd., Sanofi K.K., Teijin Pharma Ltd., Takeda Pharmaceutical Co. Ltd., Novartis Pharma K.K.

Background Biological disease modifying antirheumatic drugs (bDMARDs) now play an important role of clinical practice for patients with rheumatoid arthritis (RA). Abatacept (ABT) has a biologic agent that has an unique mechanism of action suppressing T lymphocyte activation. Although many prediction studies about therapeutic responses to bDMARDs for RA have been conducted to date [1], few studies has focused on ABT. Objectives The aim of this study was to identify predictive clinical biomarkers for remission achievement with ABT in RA patients. Methods We retrospectively reviewed consecutive patients with RA who started ABT from 2010 through 2018 in Keio University Hospital. We defined early ABT use as the initiation of ABT within two years from diagnosis without radiographic progression in hand X rays, and stratified the patients into the early ABT users and the late ABT users. Baseline characteristics were compared between patients who achieved CDAI remission achievement at 6 months and those who did not in both groups. Results One hundred and seven RA patients who were treated with ABT with baseline information available were enrolled in the study. Among them, 15 patients were classified into the early ABT users and 92 were the late ABT users, and the remission rates at 6 months were 40% and 24%, respectively. In the early ABT users, patients who achieved CDAI remission at 6 months showed significantly higher IgA levels than those who did not achieve remission (390 mg/dL vs 279 mg/dL, P=0.04, respectively). The difference in IgA disappeared in the late ABT users (332 mg/dL vs 313 mg/dL, P=0.60, respectively). Principal component analysis revealed that in the early ABT users, patients who achieved remission and those who did not could be clearly separated by the levels of IgA, IgG, rheumatoid factor, and albumin (Figure), whereas those baseline characteristics were mostly overlapped in the late ABT users (cut-off value for predicting remission with sensitivity and specificity in the early ABT users; IgA 342 mg/dL with 83% and 100%, IgG 1880 mg/dL with 50% and 100%, rheumatoid factor 152 IU/mL with 50% and 100%, albumin 3.7 g/dL with 88% and 67%, respectively). The area under the curves of receiver operating characteristic curves to predict remission were 0.833 of IgA and 0.778 of rheumatoid factor titer. Conclusion We identified serum IgA titer was the novel predictive factor for response of ABT. Reference [1] Wijbrandts CA, Tak PP. Prediction of Response to Targeted Treatment in Rheumatoid Arthritis. Mayo Clin Proc. 2017;92:1129-1143. Disclosure of Interests Jun Inamo: None declared, Yuko Kaneko Grant/research support from: Abbvie, Eisai, Speakers bureau: AbbVie, Astellas, Ayumi, Bristol-Myers Squibb, Chugai, Eisai, Eli Lilly, Jansen, Kissei, Pfizer, Sanofi, Takeda, Tanabe-Mitsubishi, UCB, Jun Kikuchi: None declared, Tsutomu Takeuchi Grant/research support from: Astellas Pharma Inc, Chugai Pharmaceutical Co, Ltd., Daiichi Sankyo Co., Ltd., Takeda Pharmaceutical Co., Ltd., AbbVie GK, Asahikasei Pharma Corp., Mitsubishi Tanabe Pharma Co., Pfizer Japan Inc., Eisai Co., Ltd., AYUMI Pharmaceutical Corporation, Nipponkayaku Co. Ltd., Novartis Pharma K.K., Grant/research support from: AbbVie, Asahi Kasei, Astellas, AstraZeneca, AYUMI, Bristol-Myers Squibb, Chugai, Daiichi Sankyo, Eisai, Eli Lilly Japan, Janssen, Mitsubishi Tanabe, Nippon Kayaku, Novartis, Pfizer Japan Inc, Taiho, Taisho Toyama, Takeda, Teijin, Grant/research support from: Astellas Pharma Inc., Bristol Myers Squibb, Chugai Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Co., Pfizer Japan Inc., Santen Pharmaceutical Co., Ltd., Takeda Pharmaceutical Co., Ltd., Teijin Pharma Ltd., AbbVie GK, Asahi Kasei Pharma Corp., Taisho Toyama Pharmaceutical Co., Ltd., SymBio Pharmaceuticals Ltd., Janssen Pharmaceutical K.K., Celltrion Inc., Nipponkayaku Co. Ltd., and UCB Japan, Consultant for: Astra Zeneca K.K., Eli Lilly Japan K.K., Novartis Pharma K.K., Mitsubishi Tanabe Pharma Co., Abbivie GK, Nipponkayaku Co.Ltd, Janssen Pharmaceutical K.K., Astellas Pharma Inc., Taiho Pharmaceutical Co. Ltd., Chugai Pharmaceutical Co. Ltd., Taisho Toyama Pharmaceutical Co. Ltd., GlaxoSmithKline K.K., UCB Japan Co. Ltd., Consultant for: AbbVie, Asahi Kasei, Astellas, AstraZeneca, AYUMI, Bristol-Myers Squibb, Chugai, Daiichi Sankyo, Eisai, Eli Lilly Japan, Janssen, Mitsubishi Tanabe, Nippon Kayaku, Novartis, Pfizer Japan Inc, Taiho, Taisho Toyama, Takeda, Teijin, Consultant for: Astra Zeneca K.K., Eli Lilly Japan K.K., Novartis Pharma K.K., Mitsubishi Tanabe Pharma Co., Asahi Kasei Medical K.K., AbbVie GK, Daiichi Sankyo Co., Ltd., Bristol Myers Squibb, and Nipponkayaku Co. Ltd., Speakers bureau: Astellas Pharma Inc., Bristol Myers Squibb, Chugai Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Co., Pfizer Japan Inc., Santen Pharmaceutical Co., Ltd., Takeda Pharmaceutical Co., Ltd., Teijin Pharma Ltd., AbbVie GK, Asahi Kasei Pharma Corp., Taisho Toyama Pharmaceutical Co., Ltd., SymBio Pharmaceuticals Ltd., Janssen Pharmaceutical K.K., Celltrion Inc., Nipponkayaku Co. Ltd., and UCB Japan, Speakers bureau: AbbVie, Asahi Kasei, Astellas, AstraZeneca, AYUMI, Bristol-Myers Squibb, Chugai, Daiichi Sankyo, Eisai, Eli Lilly Japan, Janssen, Mitsubishi Tanabe, Nippon Kayaku, Novartis, Pfizer Japan Inc, Taiho, Taisho Toyama, Takeda, Teijin, Speakers bureau: AbbVie GK., Bristol–Myers K.K., Chugai Pharmaceutical Co. Ltd., Mitsubishi Tanabe Pharma Co., Pfizer Japan Inc., Astellas Pharma Inc, Diaichi Sankyo Co. Ltd., Eisai Co. Ltd., Sanofi K.K., Teijin Pharma Ltd., Takeda Pharmaceutical Co. Ltd., Novartis Pharma K.K.

Background: Artificial intelligence (AI) techniques including deep learning have been rapidly evolving and have yielded appreciable benefits in many fields in recent years. In rheumatology field, however, these techniques have not been used often. Objectives: In an early phase of development of an AI-based automatic radiographic evaluating system for bone destruction, we aimed to develop learning-based models to automatically detect hand joint region, ankylosis and subluxation in radiographic images. Methods: A total of 130 radiographic image sets of both hands were randomly obtained from rheumatoid arthritis patients who had visited our division at Keio University Hospital in 2015. Well-trained rheumatologists determined the boundaries of regions of MP and PIP/IP joints and evaluated the presence of ankylosis and subluxation of each joint in radiographs. These evaluations of hand joints were performed using our developed annotation software tool [1]. In learning phase, joint images were randomly divided into five sets for 5-fold cross validation. As deep learning models, we utilized Single Shot Multibox Detector (SSD) method [2] with ensemble learning for detecting ankylosis and subluxation of MP and PIP/IP joint regions. Results: Our model showed 100% detection rate of MP and PIP/IP joint regions. As a performance of detecting hand joint ankylosis and subluxation, our model presented precision values of 0.85 and 0.73, recall values of 0.94 and 0.79, and F-measure values of 0.90 and 0.76, respectively. Conclusion: Deep learning-based models to automatically detect hand joint region, ankylosis and subluxation in radiographic images were developed with relatively small samples, which suggests that the predictive performance may increase by collecting more training dataset. Next, we are elaborating a plan for a deep learning-based evaluating system for erosion and joint space narrowing. References [1] Izumi K, Hashimoto M, Suzuki K, Endoh T, Doi K, Iwai Y, Jinzaki M, Ko S, Takeuchi T. Detecting Hand Joint Ankylosis in Radiographic Images Using Deep Learning: A Step in Developing Automatic Radiographic Scoring System for Bone Destruction. Arthritis Rheumatol 2018;70(suppl 10). [2] Liu W, Anguelov D, Erhan D, Szegedy C, Reed S, Fu CY, Berg AC. SSD: single shot multibox detector. European Conference on Computer Vision (ECCV) 2016. Acknowledgement: Keisuke Izumi and Kanata Suzuki are contributed equally. Disclosure of Interests: Keisuke Izumi Grant/research support from: Asahi Kasei Pharma, Speakers bureau: Asahi Kasei Pharma Corp, Astellas Pharma Inc., Bristol Myers Squibb, Chugai Pharmaceutical Co., Ltd., Eli Lilly Japan K.K., Mitsubishi Tanabe Pharma Co., Kanata Suzuki Employee of: Fujitsu Laboratories Ltd., Masahiro Hashimoto: None declared, Toshio Endoh Employee of: Fujitsu Laboratories Ltd., Kentaro Doi Employee of: Fujitsu Ltd., Yuki Iwai Employee of: Fujitsu Ltd., Jun Inamo: None declared, Yuichiro Ota: None declared, Nobuhiko Kajio: None declared, Jun Kikuchi: None declared, Komei Sakata: None declared, Satoshi Takanashi: None declared, Chihiro Takahashi: None declared, Hiroshi Takei: None declared, Hiroya Tamai: None declared, Kazuoto Hiramoto: None declared, Yuko Kaneko Speakers bureau: AbbVie, Eisai Pharmaceutical, Chugai Pharmaceutical Co., Ltd., Bristol Myers Squibb, Astellas Pharma Inc., Mitsubishi Tanabe Pharma Co., Pfizer Japan Inc., Janssen Pharmaceutical K.K., Eli Lilly Japan K.K., Santen Pharmaceutical Co., Ltd., Kyowa Hakko Kirin Co. Ltd. and UCB Japan Co. Ltd., Masahiro Jinzaki: None declared, Shigeru Ko Grant/research support from: Fujitsu Ltd., Tsutomu Takeuchi Grant/research support from: Astellas Pharma Inc, Chugai Pharmaceutical Co, Ltd., Daiichi Sankyo Co., Ltd., Takeda Pharmaceutical Co., Ltd., AbbVie GK, Asahikasei Pharma Corp., Mitsubishi Tanabe Pharma Co., Pfizer Japan Inc., Eisai Co., Ltd., AYUMI Pharmaceutical Corporation, Nipponkayaku Co. Ltd., Novartis Pharma K.K., Grant/research support from: AbbVie, Asahi Kasei, Astellas, AstraZeneca, AYUMI, Bristol-Myers Squibb, Chugai, Daiichi Sankyo, Eisai, Eli Lilly Japan, Janssen, Mitsubishi Tanabe, Nippon Kayaku, Novartis, Pfizer Japan Inc, Taiho, Taisho Toyama, Takeda, Teijin, Grant/research support from: Astellas Pharma Inc., Bristol Myers Squibb, Chugai Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Co., Pfizer Japan Inc., Santen Pharmaceutical Co., Ltd., Takeda Pharmaceutical Co., Ltd., Teijin Pharma Ltd., AbbVie GK, Asahi Kasei Pharma Corp., Taisho Toyama Pharmaceutical Co., Ltd., SymBio Pharmaceuticals Ltd., Janssen Pharmaceutical K.K., Celltrion Inc., Nipponkayaku Co. Ltd., and UCB Japan, Consultant for: Astra Zeneca K.K., Eli Lilly Japan K.K., Novartis Pharma K.K., Mitsubishi Tanabe Pharma Co., Abbivie GK, Nipponkayaku Co.Ltd, Janssen Pharmaceutical K.K., Astellas Pharma Inc., Taiho Pharmaceutical Co. Ltd., Chugai Pharmaceutical Co. Ltd., Taisho Toyama Pharmaceutical Co. Ltd., GlaxoSmithKline K.K., UCB Japan Co. Ltd., Consultant for: AbbVie, Asahi Kasei, Astellas, AstraZeneca, AYUMI, Bristol-Myers Squibb, Chugai, Daiichi Sankyo, Eisai, Eli Lilly Japan, Janssen, Mitsubishi Tanabe, Nippon Kayaku, Novartis, Pfizer Japan Inc, Taiho, Taisho Toyama, Takeda, Teijin, Consultant for: Astra Zeneca K.K., Eli Lilly Japan K.K., Novartis Pharma K.K., Mitsubishi Tanabe Pharma Co., Asahi Kasei Medical K.K., AbbVie GK, Daiichi Sankyo Co., Ltd., Bristol Myers Squibb, and Nipponkayaku Co. Ltd., Speakers bureau: Astellas Pharma Inc., Bristol Myers Squibb, Chugai Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Co., Pfizer Japan Inc., Santen Pharmaceutical Co., Ltd., Takeda Pharmaceutical Co., Ltd., Teijin Pharma Ltd., AbbVie GK, Asahi Kasei Pharma Corp., Taisho Toyama Pharmaceutical Co., Ltd., SymBio Pharmaceuticals Ltd., Janssen Pharmaceutical K.K., Celltrion Inc., Nipponkayaku Co. Ltd., and UCB Japan, Speakers bureau: AbbVie, Asahi Kasei, Astellas, AstraZeneca, AYUMI, Bristol-Myers Squibb, Chugai, Daiichi Sankyo, Eisai, Eli Lilly Japan, Janssen, Mitsubishi Tanabe, Nippon Kayaku, Novartis, Pfizer Japan Inc, Taiho, Taisho Toyama, Takeda, Teijin, Speakers bureau: AbbVie GK., Bristol–Myers K.K., Chugai Pharmaceutical Co. Ltd., Mitsubishi Tanabe Pharma Co., Pfizer Japan Inc., Astellas Pharma Inc, Diaichi Sankyo Co. Ltd., Eisai Co. Ltd., Sanofi K.K., Teijin Pharma Ltd., Takeda Pharmaceutical Co. Ltd., Novartis Pharma K.K.

Background:Interstitial lung disease (ILD) is a common extra-articular manifestation of rheumatoid arthritis (RA) and also the most common non-musculoskeletal manifestation of idiopathic inflammatory myopathies (IIM), including polymyositis, dermatomyositis and clinically amyopathic dermatomyositis. Previous studies have suggested that alveolar macrophages (AMs) and T cells are associated with the pathogenesis of ILD. Recently, it is reported that coinhibitory molecules are expressed at the site of inflammation such as RA synovium; however, detailed lung immunophenotyping has not been reported.Objectives:To identify immunologic factors in the lungs of patients with RA-associated ILD (RA-ILD) and IIM-associated ILD (IIM-ILD) and to examine their pathological mechanisms.Methods:A total of 11 patients with RA-ILD, 16 with IIM-ILD, and 6 with drug-induced ILD (DI-ILD) and 8 healthy controls were enrolled. Peripheral blood and bronchoalveolar lavage fluid (BALF) were immunophenotyped by flow cytometry. AMs were analyzed by RNA-sequence and coculture assay with peripheral naïve CD4+ T cells of healthy individuals.Results:Several coinhibitory molecules were coexpressed on BALF T cells in the order of CTLA-4, PD-1, Tim-3, and LAG-3 from most to least, whereas only PD-1 was expressed on peripheral T cells among them. In RA-ILD, PD-1+ and Tim-3+ CD4+ T cells in the BALF were increased. PD-1+CD4+ T cells populations correlated differentiated B cells and Tim-3+CD4+ T cells populations correlated with ILD severity and RF titer. In contrast, in IIM-ILD, activated CD8+ T cells were increased and they coexpressed CTLA-4, PD-1 and Tim-3. BALF PD-1+CD4+ T cells rarely expressed CXCR5, and they positively correlated with plasmablasts and plasma cells, indicating most of them are considered Tph cells. In the coculture experiments, AMs of RA-ILD and IIM-ILD induced more PD-1 and Tim-3 on CD4+ T cells, suggesting that coinhibitory molecule expression on BALF T cells was partly due to AMs. In RNA-sequence, PD-ligand (PD-L) 1 and PD-L2 genes were significantly downregulated in AMs from RA-lLD compared with DI-ILD.Conclusion:We identified T cell subsets that play a central role in the pathogenesis of RA-ILD and IIM-ILD; PD-1 on T cells in RA-ILD and Tim-3 on CD8+ T cells in IIM-ILD might be key factors in the disease process. The evaluation of coinhibitory molecules on BALF T cells could be clinically useful.Disclosure of Interests:Maho Nakazawa: None declared, Katsuya Suzuki: None declared, Masaru Takeshita: None declared, Jun Inamo: None declared, Hirofumi Kamata: None declared, Makoto Ishii: None declared, Yoshitaka Oyamada: None declared, Hisaji Oshima: None declared, Tsutomu Takeuchi Grant/research support from: Eisai Co., Ltd, Astellas Pharma Inc., AbbVie GK, Asahi Kasei Pharma Corporation, Nippon Kayaku Co., Ltd, Takeda Pharmaceutical Company Ltd, UCB Pharma, Shionogi & Co., Ltd., Mitsubishi-Tanabe Pharma Corp., Daiichi Sankyo Co., Ltd., Chugai Pharmaceutical Co. Ltd., Consultant of: Chugai Pharmaceutical Co Ltd, Astellas Pharma Inc., Eli Lilly Japan KK, Speakers bureau: AbbVie GK, Eisai Co., Ltd, Mitsubishi-Tanabe Pharma Corporation, Chugai Pharmaceutical Co Ltd, Bristol-Myers Squibb Company, AYUMI Pharmaceutical Corp., Eisai Co., Ltd, Daiichi Sankyo Co., Ltd., Gilead Sciences, Inc., Novartis Pharma K.K., Pfizer Japan Inc., Sanofi K.K., Dainippon Sumitomo Co., Ltd.

Background:Residual synovitis can be detected by sensitive modalities such as ultrasonography in patients with rheumatoid arthritis in clinical remission. On the other hand, a previous study has shown that ultrasound-guided treatment provides modest benefit compared to a conventional strategy aiming clinical remission in early patients. It is still unclear how discordant clinical remission is from imaging remission by ultrasonography in patients treated with biologic agentsObjectives:To clarify the discordance between clinical remission and imaging remission in patients with rheumatoid arthritis treated with biologic agents.Methods:Patients with rheumatoid arthritis who were treated with biologic agents and in clinical remission defined as disease activity score for 28 joints (DAS28)Results:A total of 41 patients were enrolled with 22 patients treated with tumor necrosis factor (TNF)-α inhibitors and 19 with interleukin (IL)-6 inhibitors. The mean age, female ratio, the mean disease duration, and the mean duration of clinical remission were 60 years old, 87%, 5.1 years and 11.5 years. The imaging remission by ultrasonography was observed only in 51.2 %. When patients were divided according to biologic agents, baseline characteristics including median age, disease duration and clinically remission duration were comparable between both groups, while the rates of seropositivity and the stage of radiological progression was higher in IL-6 group (seropositivity, p=0.04; radiological progression, p=0.02). The mean DAS28 was 1.93 in the TNFα group and 1.02 in the IL-6 group. The discordance of clinical remission and imaging remission was observed in 28.6% of the TNFα group and 71.4% of the IL-6 group (p=0.03). The residual synovitis scores of GS and PD in 44 joints were significantly lower in the TNFα than the IL-6 group (GS, 1.1±1.8 vs 4.7 ± 4.6, pConclusion:Our results showed that there was substantial discordance between clinical remission and imaging remission, especially in the patients treated with IL-6 inhibitors. In patients treated with biologic agents, clinical remission should be assessed more stringently than the usual 2.6, and ulltrasound-guided management may be useful.References:[1]Smolen JS, et al. Ann Rheum Dis 2020;0:1–15.[2]Iwamoto T, et al. Arthritis Care Res (Hoboken). 2014;66(10):1576-81[3]Tanaka Y. Ann Rheum Dis 2010;69:1286 –91[4]Kaneko Y, et al. Ann Rheum Dis 2018;77:1268–1275[5]Brown AK, et al. Arthritis Rheum 2008;58: 2958 – 67.Acknowledgments:We would like to thank Harumi Kondo for their assistance.Disclosure of Interests:Yasushi Kondo: None declared, Yuko Kaneko Speakers bureau: Dr. Kaneko reports personal fees from AbbVie, personal fees from Astellas, personal fees from Ayumi, personal fees from Bristol-Myers Squibb, personal fees from Chugai, personal fees from Eisai, personal fees from Eli Lilly, personal fees from Hisamitsu, personal fees from Jansen, personal fees from Kissei, personal fees from Pfizer, personal fees from Sanofi, personal fees from Takeda, personal fees from Tanabe-Mitsubishi, personal fees from UCB, Shuntaro Saito: None declared, Yuichiro Ohta: None declared, Komei Sakata: None declared, Yumiko Inoue: None declared, Chihiro Takahashi: None declared, Kazuoto Hiramoto: None declared, Jun Inamo: None declared, Tsutomu Takeuchi Grant/research support from: Eisai Co., Ltd, Astellas Pharma Inc., AbbVie GK, Asahi Kasei Pharma Corporation, Nippon Kayaku Co., Ltd, Takeda Pharmaceutical Company Ltd, UCB Pharma, Shionogi & Co., Ltd., Mitsubishi-Tanabe Pharma Corp., Daiichi Sankyo Co., Ltd., Chugai Pharmaceutical Co. Ltd., Consultant of: Chugai Pharmaceutical Co Ltd, Astellas Pharma Inc., Eli Lilly Japan KK, Speakers bureau: AbbVie GK, Eisai Co., Ltd, Mitsubishi-Tanabe Pharma Corporation, Chugai Pharmaceutical Co Ltd, Bristol-Myers Squibb Company, AYUMI Pharmaceutical Corp., Eisai Co., Ltd, Daiichi Sankyo Co., Ltd., Gilead Sciences, Inc., Novartis Pharma K.K., Pfizer Japan Inc., Sanofi K.K., Dainippon Sumitomo Co., Ltd.

Background Twenty eight joints that are usually evaluated for disease activity score of rheumatoid arthritis (RA) do not include ankles and metatarsophalangeal joints. Although foot synovitis of patients in remission is clinically important in that it associates to relapse and worse physical function,1 composite markers without an assessment of foot have demonstrated poor performance in detecting foot synovitis.2 Objectives The aim of this study was to investigate the frequency and impact of residual synovitis in ankles and feet in patients with RA. Methods Patients with RA who underwent both physical examination and ultrasonography (US) on 44 joints including hands, fingers, ankles, and metatarsophalangeal joints between April 2016 and January 2018 in Keio University Hospital were enrolled. We compared patients with swollen joints of feet and ankles and those without, and then analysed those who did not have swollen joints by physical examination but were detected to have synovitis by US. Results Sixty one patients were enrolled in the study. The mean age was 58.5 years old, the disease duration was 7.1 years, and 85% were female. Among them, 21 patients had joint swelling in feet and ankles and 40 patients did not by physical examination. The patients in the former group showed significantly higher disease activity (DAS28 4.0 vs 2.4, p Conclusions The residual synovitis in ankles and feet did not reflect in remission criteria by DAS28 but did by Boolean criteria. It caused a discordance in global assessments between patient and estimator. References [1] Wechalekar MD, Lester S, Hill CL, Lee A, Rischmueller M, Smith MD, Walker JG, Proudman SM. Active Foot Synovitis in Patients With Rheumatoid Arthritis: Unstable Remission Status, Radiographic Progression, and Worse Functional Outcomes in Patients With Foot Synovitis in Apparent Remission. Arthritis Care Res (Hoboken)2016;68(11):1616–1623. [2] Wechalekar MD1, Lester S, Proudman SM, Cleland LG, Whittle SL, Rischmueller M, Hill CL. Active foot synovitis in patients with rheumatoid arthritis: applying clinical criteria for disease activity and remission may result in underestimation of foot joint involvement. Arthritis Rheum2012;64(5):1316–22. Disclosure of Interest None declared

Background Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), which is characterised by vasculitis with allergic features such as asthma and eosinophilia. Although rheumatoid factor (RF) positivity is known to be as high as 37%–50% in AAV patients1 the clinical significance of RF-positivity remains unknown. Objectives To investigate clinical features in patients with RF in EGPA. Methods Consecutive patients who were diagnosed with EGPA between January 2008 and January 2018 in Keio University Hospital were enrolled. Clinical information were collected from medical records retrospectively. We divided patients into 2 groups according to RF positivity, and compared clinical features. Results Seventeen patients were enrolled in the study. The mean age was 57.4 years old, and 82% were female. Among them, 11 patients were RF positive (RF positive group) and 6 patients were negative (RF negative group). The female rate tended to be higher in the RF positive group than the negative group (82% vs 50%, p=0.087). While the Birmingham Vasculitis Activity Score was comparable between the two groups (21.5 vs 17.3, p=0.329), general symptoms (fever and weight loss) and gastrointestinal lesions were more frequent in the RF positive group (55% vs 17%, p=0.072; 45% vs 17%, p=0.137) and central nervous involvement was less frequent (18% vs 67%, p=0.024). No patient with negative RF presented with arthralgia/arthritis. The count of eosinophil and IgA levels at diagnosis were significantly higher in the RF positive group than the RF negative group (15704/μl vs 4751/μl, p=0.009; 238 mg/dL vs 162 mg/dL, p=0.048). Interestingly, ANCA positivity was negatively correlated with RF positivity. MPO-ANCA was positive in 27% of the RF positive group and in 66% of the RF negative group, and PR3-ANCA was positive in none of the RF positive group and 17% of the RF negative group. Double negative was more frequent in RF positive group (73% vs 33%, p=0.060). Conclusions RF positivity was associated with clinical and serological characteristics in patients with EGPA, suggesting different pathogenesis or immunological disturbances is related. Reference [1] Pagnoux C, Seror R, Berezne A, Rouabhia S, Goulvestre C, Guillevin L. Remittent non-destructive polysynovitis in P-ANCA-positive vasculitis patients with anti-CCP antibodies. Joint Bone Spine. 2010;77(6):604–7. Disclosure of Interest None declared

Reports about immune-related adverse events (IrAEs) induced by immune checkpoint inhibitors (ICIs) have been increasing. Although the importance of understanding joint involvement and myalgia as an IrAE has grown, little is known about its characteristics. The aim of this study was to investigate the incidence and clinical characteristics of articular IrAEs. We reviewed 133 patients who were treated with ICIs in our institution and referred to our rheumatologic. Among them, 2 (1.5%) developed arthritis during the use of anti-PD-1 inhibitor, and there was one patient with joint pain after anti-PD-L1 inhibitor who was referred to our department from another institution. No patients had antecedent inflammatory arthritis or any relevant medical history. All 3 patients were negative for anti-nuclear antibody, rheumatoid factor, and anti-cyclic citrullinated peptide antibody. The ultrasonography showed tenosynovitis and enthesitis in both small and large joints with no or insignificant synovitis. Joint pain improved gradually within 6 months with only NSAIDs in 2 patients, and disappeared quickly in the other patient 2 weeks after 20 mg/day of predonisolone. Our report suggested diverse phenotypes of joint involvement and highlighted the importance of accumulating such patients.

I am grateful to Dr Young Ho Lee1 for response to my article.2 Although my study demonstrated non-causal association between gut microbiome and the risk of rheumatoid arthritis (RA), the author demonstrated significant association between them. First, the reason why different conclusions were drawn from two studies is that I extracted only ‘Gut microbiota (bacterial taxa) (unit decrease)’ from variables of exposures in harmonised dataset before conducting Mendelian randomisation (MR) (R script is …

I read with great interest the article by Alpizar-Rodriguez et al regarding the risk of intestinal dysbiosis, particularly Prevotella spp enrichment, in preclinical rheumatoid arthritis (RA).1 Immune response in gut is assumed to be one of the triggers of development of RA.2 However, it is hard to assess causal association by case–control study due to limitations such as latent confounding factors; dysbiosis first or RA first . Therefore, to investigate causal effect of gut microbiome on the development of RA, I conducted Mendelian randomisation (MR) analysis.3 MR is useful to investigate causal association among phenotypes and/or biomarkers because it is based on genetic variation to mimic the design of randomised controlled trials. In MR, single nucleotide polymorphisms (SNP) are expected to be random and causally upstream of the exposure; thus, SNP are used as instrumental variables (IVs) in MR. I used the publicly available two data sets of genome-wide association studies (GWASs) for gut microbiome (totally 3326 individuals) of European ancestry as the exposure4 5 and one data set …