Granzyme K- and amphiregulin-expressing cytotoxic T cells and activated extrafollicular B cells are potential drivers of IgG4-related disease.

BACKGROUND: IgG4-related disease (IgG4-RD), an example of a type I immune disease, is an immune-mediated fibrotic disorder characterized by dysregulated resolution of severe inflammation and wound healing. However, truly dominant or pathognomonic autoantibodies related to IgG4-RD are not identified. OBJECTIVE: We sought to perform single-cell RNA sequencing and T-cell receptor and B-cell receptor sequencing to obtain a comprehensive, unbiased view of tissue-infiltrating T and B cells. METHODS: We performed unbiased single-cell RNA-sequencing analysis for the transcriptome and T-cell receptor sequencing and B-cell receptor sequencing on sorted CD3+ T or CD19+ B cells from affected tissues of patients with IgG4-RD. We also conducted quantitative analyses of CD3+ T-cell and CD19+ B-cell subsets in 68 patients with IgG4-RD and 30 patients with Sjögren syndrome. RESULTS: Almost all clonally expanded T cells in these lesions were either Granzyme K (GZMK)-expressing CD4+ cytotoxic T cells or GZMK+CD8+ T cells. These GZMK-expressing cytotoxic T cells also expressed amphiregulin and TGF-ß but did not express immune checkpoints, and the tissue-infiltrating CD8+ T cells were phenotypically heterogeneous. MKI67+ B cells and IgD-CD27-CD11c-CXCR5- double-negative 3 B cells were clonally expanded and infiltrated affected tissue lesions. GZMK+CD4+ cytotoxic T cells colocalized with MKI67+ B cells in the extrafollicular area from affected tissue sites. CONCLUSIONS: The above-mentioned cells likely participate in T-B collaborative events, suggesting possible avenues for targeted therapies. Our findings were validated using orthogonal approaches, including multicolor immunofluorescence and the use of comparator disease groups, to support the central role of cytotoxic CD4+ and CD8+ T cells expressing GZMK, amphiregulin, and TGF-ß in the pathogenesis of inflammatory fibrotic disorders.

Novel susceptibility loci for steroid-associated osteonecrosis of the femoral head in systemic lupus erythematosus.

Osteonecrosis of the femoral head (ONFH) involves necrosis of bone and bone marrow of the femoral head caused by ischemia with unknown etiology. Previous genetic studies on ONFH failed to produce consistent results, presumably because ONFH has various causes with different genetic backgrounds and the underlying diseases confounded the associations. Steroid-associated ONFH (S-ONFH) accounts for one-half of all ONFH, and systemic lupus erythematosus (SLE) is a representative disease underlying S-ONFH. We performed a genome-wide association study (GWAS) to identify genetic risk factors for S-ONFH in patients with SLE. We conducted a two-staged GWAS on 636 SLE patients with S-ONFH and 95 588 non-SLE controls. Among the novel loci identified, we determined S-ONFH-specific loci by comparing allele frequencies between SLE patients without S-ONFH and non-SLE controls. We also used Korean datasets comprising 148 S-ONFH cases and 37 015 controls to assess overall significance. We evaluated the functional annotations of significant variants by in silico analyses. The Japanese GWAS identified 4 significant loci together with 12 known SLE susceptibility loci. The four significant variants showed comparable effect sizes on S-ONFH compared with SLE controls and non-SLE controls. Three of the four loci, MIR4293/MIR1265 [odds ratio (OR) = 1.99, P-value = 1.1 × 10-9)], TRIM49/NAALAD2 (OR = 1.65, P-value = 4.8 × 10-8) and MYO16 (OR = 3.91, P-value = 4.9 × 10-10), showed significant associations in the meta-analysis with Korean datasets. Bioinformatics analyses identified MIR4293, NAALAD2 and MYO16 as candidate causal genes. MIR4293 regulates a PPARG-related adipogenesis pathway relevant to S-ONFH. We identified three novel susceptibility loci for S-ONFH in SLE.

Immunosuppressive therapy and humoral response to third mRNA COVID-19 vaccination with a six-month interval in rheumatic disease patients.

OBJECTIVES: To evaluate the long-term impact of immunosuppressive therapeutic agents on antibody response to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) mRNA vaccination in patients with autoimmune rheumatic diseases (AIRD) in order to propose a strategy for annual vaccination. METHODS: This prospective multicentre cohort study evaluated the humoral response to second and third BNT162b2 and/or mRNA-1273 vaccines in 382 Japanese AIRD patients classified into 12 different medication groups and in 326 healthy controls (HCs). The third vaccination was administered six months after the second vaccination. Antibody titres were measured using the Elecsys Anti-SARS-CoV-2 S assay. RESULTS: The seroconversion rate and antibody titres were lower in AIRD patients than in HCs 3-6 weeks after the second vaccination and 3-6 weeks after the third vaccination. Seroconversion rates were <90% after the third vaccination in patients receiving mycophenolate mofetil and rituximab. Antibody levels after the third vaccination were significantly lower in the groups prescribed TNF inhibitor with or without methotrexate, abatacept and rituximab or cyclophosphamide than those of HCs in a multivariate analysis adjusting for age, sex, and glucocorticoid dosage. The third vaccination induced an adequate humoral response in patients treated with sulfasalazine, bucillamine, methotrexate monotherapy, iguratimod, interleukin-6 inhibitors or calcineurin inhibitors including tacrolimus. CONCLUSIONS: Repeated vaccinations in many immunosuppressed patients produced antibody responses similar to those observed in HCs. In contrast, annual vaccination in patients receiving TNF inhibitors, abatacept, mycophenolate mofetil and rituximab may require caution.

TNFR2 Signaling Enhances Suppressive Abilities of Human Circulating T Follicular Regulatory Cells.

T follicular regulatory (Tfr) cells are a subset of CD4+ T cells that express CXCR5 and migrate into germinal centers (GCs). They regulate GC reactions by communicating with T follicular helper (Tfh) and B cells. TNF inhibitors are used in inflammatory diseases; however, the generation of autoantibodies or anti-drug Abs sometimes causes problems. Because TNFR2 signaling is important for suppressive functions of regulatory T cells, we investigated the role of TNFR2 on human Tfr cells. Tfr cells stimulated with MR2-1 (an anti-TNFR2 agonistic Ab) were analyzed for cell proliferation, Foxp3 expression, and surface molecules. Tfh/B cell proliferation, IgM production, and differentiation in cocultures with MR2-1-stimulated Tfr cells were examined. Tfr cells express a high level of TNFR2. MR2-1 stimulation altered the gene expression profile of Tfr cells. Cell proliferation and Foxp3 expression of Tfr cells were enhanced by MR2-1. MR2-1-stimulated Tfr cells expressed ICOS and Programmed cell death protein 1 and significantly suppressed Tfh/B cell proliferation, IgM production, and B cell differentiation. TNFR2-stimulated Tfr cells retained the migration function according to the CXCL13 gradient. In conclusion, we showed that TNFR2-stiumulated Tfr cells can regulate Tfh and B cells. Aberrant antibody production during TNF inhibitor treatment might be, at least in part, associated with TNFR2 signaling inhibition in Tfr cells. In addition, expansion and maturation of Tfr cells via TNFR2 stimulation in vitro may be useful for a cell-based therapy in inflammatory and autoimmune diseases to control GC reactions.

No clear influence of treatment escalation on flare prevention in serologically active clinically quiescent patients with systemic lupus erythematosus: a retrospective cohort study.

This study aimed to clarify the efficacy and safety of treatment escalation by initiating therapeutic agents in serologically active clinically quiescent (SACQ) patients with systemic lupus erythematosus (SLE). We retrospectively evaluated SACQ patients with SLE for ≥ 180 days, with the introduction of a therapeutic agent for SLE defined as exposure. The efficacy endpoints included the time to flare and time to remission, whereas the safety endpoint was the incidence of adverse events. The efficacy endpoints were assessed via Cox proportional hazards model with time-dependent covariates, which included exposure, serological activity, and prednisolone dose. Among 109 SACQ patients, 24 were initiated on the following therapeutic agents for SLE: hydroxychloroquine (10 patients), belimumab (6 patients), and immunosuppressive agents (8 patients). A total of 37 patients experienced a flare (8 and 29 patients during exposure and nonexposure periods, respectively). The time to flare was comparable between the exposure and control groups. Among 68 patients who were not in remission at the start of observation, 27 patients achieved remission (5 and 22 patients during exposure and nonexposure periods, respectively). Although both groups had a similar time to remission, the exposure group treated with belimumab had a significantly higher rate of remission than the control group. The adverse events were more frequent during the exposure period than during the nonexposure period. Thus, this study did not reveal a clear influence of treatment escalation on flare prevention and remission achievement.

Relationships between Type 1 interferon signatures and clinical features of the new-onset lupus patients in Japan.

OBJECTIVES: The objective of the study is to investigate the relationships between Type 1 interferon (T1-IFN) signatures and clinical characteristics of lupus patients. METHODS: We examined 49 new-onset lupus patients who were diagnosed between 1999 and 2017. The patients treated with >10 mg of prednisolone or hydroxychloroquine were excluded from this study. Serum T1-IFN signatures were revealed by a functional reporter assay and standardized by recombinant IFN-α. Patient backgrounds, clinical findings, and treatments were retrospectively extracted from their electrical medical records. Clinical data were also available, including SLE Disease Activity Index of SLE patients on admission. RESULTS: T1-IFN signatures of lupus patients closely correlated with lupus disease activities, such as SLE Disease Activity Index-2K, white blood cell, C3 levels, and the titre of double-strand DNA antibody. We found fever and acute lupus dermatitis closely associated with T1-IFN signature. CONCLUSIONS: In lupus patients, fever and acute lupus dermatitis are good indicators of a strong T1-IFN signature.

Establishing clinical remission criteria for giant cell arteritis: Results of a Delphi exercise carried out by an expert panel of the Japan Research Committee of the Ministry of Health, Labour, and Welfare for Intractable Vasculitis.

OBJECTIVE: To develop a proposal for giant cell arteritis remission criteria in order to implement a treat-to-target algorithm. METHODS: A task force consisting of 10 rheumatologists, 3 cardiologists, 1 nephrologist, and 1 cardiac surgeon was established in the Large-vessel Vasculitis Group of the Japanese Research Committee of the Ministry of Health, Labour and Welfare for Intractable Vasculitis to conduct a Delphi survey of remission criteria for giant cell arteritis. The survey was circulated among the members over four reiterations with four face-to-face meetings. Items with a mean score of ≥4 were extracted as items for defining remission criteria. RESULTS: An initial literature review yielded a total of 117 candidate items for disease activity domains and treatment/comorbidity domains of remission criteria, of which 35 were extracted as disease activity domains (systematic symptoms, signs and symptoms of cranial and large-vessel area, inflammatory markers, and imaging findings). For the treatment/comorbidity domain, ≤5 mg/day of prednisolone 1 year after starting glucocorticoids was extracted. The definition of achievement of remission was the disappearance of active disease in the disease activity domain, normalization of inflammatory markers, and ≤5 mg/day of prednisolone. CONCLUSION: We developed proposals for remission criteria to guide the implementation of a treat-to-target algorithm for giant cell arteritis.

Anti-dsDNA IgE induces IL-4 production from basophils, potentially involved in B-cell differentiation in systemic lupus erythematosus.

OBJECTIVES: Recently, the involvement of basophils and IgE-type autoantibodies in the pathogenesis of SLE has been elucidated using mouse models; however, few studies have been conducted in humans. In this study, the role of basophils and anti-double-stranded DNA (dsDNA) IgE in SLE was examined using human samples. METHODS: The correlation between disease activity and serum levels of anti-dsDNA IgE in SLE was evaluated using enzyme-linked immunosorbent assay. Cytokines produced by IgE-stimulated basophils from healthy subjects were assessed using RNA sequences. The interaction of basophils and B cells to promote B cell differentiation was investigated using a co-culture system. The ability of basophils from patients with SLE with anti-dsDNA IgE to create cytokines that may be involved in B cell differentiation in response to dsDNA was examined using real-time PCR. RESULTS: Anti-dsDNA IgE levels in the serum of patients with SLE correlated with disease activity. Healthy donor basophils produced IL-3, IL-4 and TGF-ß1 after anti-IgE stimulation. Co-culture of B cells with anti-IgE-stimulated basophils increased plasmablasts which were cancelled by neutralizing IL-4. After encountering the antigen, basophils released IL-4 more quickly than follicular helper T cells. Basophils isolated from patients with anti-dsDNA IgE promoted IL-4 expression by adding dsDNA. CONCLUSIONS: These results suggest that basophils contribute to the pathogenesis of SLE by promoting B cell differentiation via dsDNA-specific IgE in patients similar to the process described in mouse models.

Safety and efficacy of switching immunosuppressive drugs for maintenance treatment in patients with systemic lupus erythematosus: A retrospective cohort study.

OBJECTIVES: We aim to clarify the efficacy and safety of switching immunosuppressive drugs and to identify the predictive factors for treatment failure after switching in patients with systemic lupus erythematosus (SLE). METHODS: We retrospectively evaluated patients with SLE who switched immunosuppressive drugs for any reason in our hospital between 2015 and 2020. The efficacy endpoints were the change in SLE Disease Activity Index 2000 score, prednisolone dose, and disease status over 12 months, as well as treatment continuation rates. The safety endpoint was the frequency of adverse events over 1 year before and after switching. Cox hazard regression analyses were used to identify the predictive factors for treatment failure. RESULTS: Thirty-nine patients (age, 41.5 ± 12.6 years; 35 women and 4 men) were analysed. The SLE Disease Activity Index score and prednisolone dose were significantly reduced after switching, with few disease exacerbations over 12 months. The 1- and 2-year continuation rates were 71.4% and 62.3%, respectively. The frequency of adverse events was similar in the year before and after switching the drug. Drug switching due to inadequate efficacy was a predictive factor of less likely treatment failure. CONCLUSIONS: Immunosuppressive drug switching led to reduced disease activity and decreased glucocorticoid dose without disease exacerbations and severe adverse events.

Antibody response to SARS-CoV-2 mRNA vaccines in patients with rheumatic diseases in Japan: Interim analysis of a multicentre cohort study.

OBJECTIVES: To evaluate the impact of medication on antibody response to severe acute respiratory syndrome coronavirus-2 mRNA vaccines in Japanese patients with rheumatic diseases. METHODS: This prospective multicentre cohort study evaluated the humoral response in 12 different medication groups. Antibody levels before the first vaccination and 3-6 weeks after the second vaccination were measured using the Elecsys Anti-SARS-CoV-2 S assay. Statistical analysis included comparing antibody titres among the different medication groups using the Kruskal-Wallis test followed by the Bonferroni-Dunn test and multiple linear regression analysis. RESULTS: 295 patients were analysed. The seroconversion rate was 92.2% and the median antibody titre was 255 U/ml (interquartile range, 34.1-685) after the second mRNA vaccination. Antibody levels were significantly lower in the groups treated with Tumour necrosis factor inhibitor with methotrexate, abatacept, mycophenolate mofetil (MMF), MMF or mizoribine combined with calcineurin inhibitor, and rituximab or cyclophosphamide compared with those treated with sulfasalazine and/or bucillamine or calcineurin inhibitor (p < 0.01). The correlation between antibody titre and treatment was significant after adjusting for age, gender, and glucocorticoid dose (p < 0.01). CONCLUSIONS: Additional early vaccination is required in patients treated with Tumour necrosis factor inhibitor and methotrexate, abatacept, MMF, MMF or mizoribine combined with calcineurin inhibitor and rituximab or cyclophosphamide.

Biological insights into systemic lupus erythematosus through an immune cell-specific transcriptome-wide association study.

OBJECTIVE: Genome-wide association studies (GWAS) have identified >100 risk loci for systemic lupus erythematosus (SLE), but the disease genes at most loci remain unclear, hampering translation of these genetic discoveries. We aimed to prioritise genes underlying the 110 SLE loci that were identified in the latest East Asian GWAS meta-analysis. METHODS: We built gene expression predictive models in blood B cells, CD4+ and CD8+ T cells, monocytes, natural killer cells and peripheral blood cells of 105 Japanese individuals. We performed a transcriptome-wide association study (TWAS) using data from the latest genome-wide association meta-analysis of 208 370 East Asians and searched for candidate genes using TWAS and three data-driven computational approaches. RESULTS: TWAS identified 171 genes for SLE (p<1.0×10-5); 114 (66.7%) showed significance only in a single cell type; 127 (74.3%) were in SLE GWAS loci. TWAS identified a strong association between CD83 and SLE (p<7.7×10-8). Meta-analysis of genetic associations in the existing 208 370 East Asian and additional 1498 cases and 3330 controls found a novel single-variant association at rs72836542 (OR=1.11, p=4.5×10-9) around CD83. For the 110 SLE loci, we identified 276 gene candidates, including 104 genes at recently-identified SLE novel loci. We demonstrated in vitro that putative causal variant rs61759532 exhibited an allele-specific regulatory effect on ACAP1, and that presence of the SLE risk allele decreased ACAP1 expression. CONCLUSIONS: Cell-level TWAS in six types of immune cells complemented SLE gene discovery and guided the identification of novel genetic associations. The gene findings shed biological insights into SLE genetic associations.

Activation of caspase-1 is mediated by stimulation of interferon genes and NLR family pyrin domain containing 3 in monocytes of active systemic lupus erythematosus.

OBJECTIVES: Emerging evidence has shown the importance of inflammasome activation in the progression of autoimmune diseases. In this study, we aimed to identify the main cell types activating inflammasome in autoimmune diseases and to clarify the intracellular pathway of inflammasome activation in systemic lupus erythematosus (SLE). METHODS: Active caspase-1 in each subset of human peripheral blood cells from healthy controls (n=18), SLE (n=51), and other rheumatic diseases (n=36) were fluorescently probed with FLICA™-caspase-1 followed by flow cytometric analysis. The correlation of caspase-1 activation in monocytes and clinical parameters in SLE patients were evaluated. In-vitro experiments were performed to identify the pathway involved in caspase-1 activation induced by SLE serum in monocytes. RESULTS: Active caspase-1 in monocytes was upregulated in SLE patients. Cluster of differentiation 14 (CD14)-positive and CD16-positive monocytes showed considerable activation of caspase-1 compared with the other subsets of monocytes. Serum titres of anti-double stranded DNA antibodies were positively correlated with active caspase-1 in monocytes, and serum complement component 3 and platelet count were negatively correlated with active caspase-1 in monocytes. The SLE serum-induced activation of caspase-1 and IL-1ß secretion were down-regulated by inhibition of NLR family pyrin domain containing 3 (NLRP3), cyclic GMP-AMP synthase (cGAS), or stimulator of interferon genes (STING). CONCLUSIONS: These findings suggest that targeting inflammasome by regulating cGAS/STING and NLRP3 are potential therapeutic strategies for SLE.

Homeostatic Milieu Induces Production of Deoxyribonuclease 1-like 3 from Myeloid Cells.

DNase 1-like 3 (DNase1L3), which belongs to DNase1 family, was originally identified as one of apoptosis- and necrosis-related endonucleases that fragmentate intranucleosomal DNA. A loss-of-function mutation has been reported in murine models of systemic lupus erythematosus (SLE) and in familial SLE patients. These reports suggest DNase1L3 plays an important role in the prevention of developing SLE; however, expression and function of DNase1L3 in human immune systems have been largely unclarified. As previous reports showed DNase1L3 is expressed in hematopoietic organs, we first analyzed expression levels of DNase1L3 in each subset of human peripheral blood cells by quantitative real-time PCR. Plasmacytoid dendritic cells showed the highest expression levels of DNase1L3 mRNA among peripheral blood cells. IL-4 enhanced DNase1L3 expression in monocytes, monocyte-derived dendritic cells, and monocyte-derived macrophages (MDMs), but not in T cells, B cells, or plasmacytoid dendritic cells. Together with IL-4, all-trans retinoic acid and apoptotic cells efficiently upregulated expression of DNalse1L3 in MDMs. As a result of intracellular signaling analysis, Jak1-IRS2-ERK/PI3K pathway was essential for IL-4-induced DNase1L3 expression. IL-4-treated monocyte-derived dendritic cells and MDMs secreted active DNase1L3 protein that could degrade liposome-DNA complexes, which were resistant to DNase1. Our results indicate DNase1L3 is secreted by innate immune cells and may play a critical role in the tissue homeostasis and on prevention of developing autoimmunity by degrading self-DNA.

Hydroxychloroquine versus tacrolimus for the treatment of persistently active systemic lupus erythematosus.

OBJECTIVES: We aimed to reveal the effectiveness of hydroxychloroquine (HCQ) compared with tacrolimus (TAC), an immunosuppressive agent, in patients with systemic lupus erythematosus (SLE) with persistent activity on standard treatment. METHODS: We retrospectively compared the efficacy and safety of the treatment between 18 patients receiving HCQ and 27 patients receiving TAC. None of the patients were in the lupus low disease activity state (LLDAS) at the beginning of this study. The efficacy end points were the cumulative incidence of LLDAS attainment without additional immunosuppressive agents, drug continuation rate, and treatment failure-free survival. The safety end point was the frequency of adverse events. RESULTS: Eight (44.4%) patients in the HCQ group and 10 (37.0%) patients in the TAC group achieved LLDAS during the follow-up period; thus, the cumulative incidences of LLDAS attainment of the two treatments were nearly identical. The drug continuation and treatment failure-free survival rates were also not different between the two groups. The frequency of adverse events showed no clear differences between the two groups. CONCLUSIONS: The efficacy and safety of an add-on treatment with HCQ are similar to those with TAC. Patients with persistently active SLE can benefit from HCQ in efforts to achieve at least low disease activity.

Establishing clinical remission criteria and the framework of a treat-to-target algorithm for Takayasu arteritis: Results of a Delphi exercise carried out by an expert panel of the Japan Research Committee of the Ministry of Health, Labour and Welfare for intractable vasculitis.

OBJECTIVES: To develop a proposal for remission criteria and a framework for a treat-to-target (T2T) algorithm for Takayasu arteritis (TAK). METHODS: A study group of the large-vessel vasculitis group of the Japanese Research Committee of the Ministry of Health, Labour and Welfare for Intractable Vasculitis consists of 10 rheumatologists, 5 cardiologists, 1 nephrologist, 1 vascular surgeon, 1 cardiac surgeon, and 2 paediatric rheumatologists. A Delphi survey of remission criteria items was circulated among the study group over four reiterations. To develop the T2T algorithm, the study group conducted four face-to-face meetings and two rounds of Delphi together with three patients. RESULTS: Initial literature review resulted in a list of 117 candidate items for remission criteria, of which 56 items with a mean score of ≥4 (0-5) were extracted including disease activity domains and treatment/comorbidity domains. The study group provided six overarching principles for the T2T algorithm, two recommendations on treatment goals, five on evaluation of disease activity and imaging findings including positron emission tomography-computed tomography, and two on treatment intensification. CONCLUSIONS: We developed a T2T algorithm and proposals for standardised remission criteria by means of a Delphi exercise. These will guide future evaluation of different TAK treatment regimens.

Outcomes of methotrexate-associated lymphoproliferative disorders in rheumatoid arthritis patients treated with disease-modifying anti-rheumatic drugs.

Recently, the use of targeted synthetic or biological disease-modifying anti-rheumatic drugs (ts/bDMARDs) in addition to conventional synthetic (cs)DMARDs including methotrexate (MTX) for rheumatoid arthritis (RA) has increased. However, whether ts/bDMARDs are associated with the development and clinicopathological features of MTX-associated lymphoproliferative disorder (MTX-LPD) in patients with RA remains unknown. Therefore, we evaluated the clinical outcomes of 121 patients with MTX-LPD. Results showed that prior use of ts/bDMARDs was not associated with the different histopathological subtypes of MTX-LPD. Patients with polymorphic-type LPD had a better event-free survival than those with diffuse large B-cell lymphoma (DLBCL), classical Hodgkin lymphoma and peripheral T-cell lymphoma. The pathological subtype of lymphoma could predict the clinical outcome of MTX-LPD. In patients with DLBCL, the use of tumour necrosis factor-alpha (TNF-α) inhibitors prior to MTX-LPD onset was associated with a higher non-relapse mortality. Further, patients with RA previously treated with Janus kinase (JAK) inhibitors more commonly required chemotherapy than those treated with csDMARDs alone, indicating disease aggressiveness. Hence, special caution should be observed when managing patients with MTX-LPD previously treated with JAK or TNF-α inhibitors for RA.

Meta-analysis of 208370 East Asians identifies 113 susceptibility loci for systemic lupus erythematosus.

OBJECTIVE: Systemic lupus erythematosus (SLE), an autoimmune disorder, has been associated with nearly 100 susceptibility loci. Nevertheless, these loci only partially explain SLE heritability and their putative causal variants are rarely prioritised, which make challenging to elucidate disease biology. To detect new SLE loci and causal variants, we performed the largest genome-wide meta-analysis for SLE in East Asian populations. METHODS: We newly genotyped 10 029 SLE cases and 180 167 controls and subsequently meta-analysed them jointly with 3348 SLE cases and 14 826 controls from published studies in East Asians. We further applied a Bayesian statistical approach to localise the putative causal variants for SLE associations. RESULTS: We identified 113 genetic regions including 46 novel loci at genome-wide significance (p<5×10-8). Conditional analysis detected 233 association signals within these loci, which suggest widespread allelic heterogeneity. We detected genome-wide associations at six new missense variants. Bayesian statistical fine-mapping analysis prioritised the putative causal variants to a small set of variants (95% credible set size ≤10) for 28 association signals. We identified 110 putative causal variants with posterior probabilities ≥0.1 for 57 SLE loci, among which we prioritised 10 most likely putative causal variants (posterior probability ≥0.8). Linkage disequilibrium score regression detected genetic correlations for SLE with albumin/globulin ratio (rg=-0.242) and non-albumin protein (rg=0.238). CONCLUSION: This study reiterates the power of large-scale genome-wide meta-analysis for novel genetic discovery. These findings shed light on genetic and biological understandings of SLE.

Type 1 helper T cells generate CXCL9/10-producing T-bet+ effector B cells potentially involved in the pathogenesis of rheumatoid arthritis.

Efficacy of B-cell depletion therapy highlights the antibody-independent effector functions of B cells in rheumatoid arthritis (RA). Given type 1 helper T (Th1) cells abundant in synovial fluid (SF) of RA, we have determined whether Th1 cells could generate novel effector B cells. Microarray and qPCR analysis identified CXCL9/10 transcripts as highly expressed genes upon BCR/CD40/IFN-γ stimulation. Activated Th1 cells promoted the generation of CXCL9/10-producing T-bet+ B cells. Expression of CXCL9/10 was most pronounced in CXCR3+ switched memory B cells. Compared with peripheral blood, SFRA enriched highly activated Th1 cells that coexisted with abundant CXCL9/10-producing T-bet+ B cells. Intriguingly, anti-IFN-γ antibody and JAK inhibitors significantly abrogated the generation of CXCL9/10-producing T-bet+ B cells. B cell derived CXCL9/10 significantly facilitated the migration of CD4+ T cells. These findings suggest that Th1 cells generate the novel CXCL9/10-producing T-bet+ effector B cells that could be an ideal pathogenic B cell target for RA therapy.

Predictive factors of fetal and maternal pregnancy outcomes in Japanese patients with systemic lupus erythematosus.

OBJECTIVE: The number of pregnant and delivery cases in systemic lupus erythematosus (SLE) patients are increasing due to the advances in therapies. However, there are many problems such as the exacerbation of SLE during pregnancy and the risk of fetal complications. We investigated the impact of both pregnancy on lupus and lupus on pregnancy in Japanese patients. METHODS: We retrospectively analyzed 64 pregnancies in 39 cases of lupus patients at Kyushu University Hospital, Japan, from October 2002 to July 2018 and then assessed the clinical profiles and maternal and fetal outcomes. RESULTS: In terms of the impact of pregnancy on SLE, 29.7% of patients had lupus flare during pregnancy. Multivariate analysis showed that flare rates were significantly higher in patients who discontinued the immunosuppressants when pregnancy was detected or before pregnancy. Pregnancy results were 25.0% for preterm birth, 39.1% for low birth weight infants, and 31.3% for small-for-gestational-age infants. Regarding the effect of SLE on fetal death, the rates of stillbirth were significantly higher in cases whose C3 value at 12 weeks of gestation was lower than before conception. Preterm birth was associated with disease duration and lupus flare during pregnancy. CONCLUSIONS: Discontinuation of immunosuppressive drugs was a predictive factor for lupus flare during pregnancy. Further, the decrease of C3 levels at 12 weeks of gestation from baseline was a predictive factor for fetal loss. It is essential for lupus pregnant patients to prevent flares, even with the use of immunosuppressive medications.

Rituximab maintenance therapy for patients with antineutrophil cytoplasmic antibody-associated vasculitis in Japan.

OBJECTIVES: We examined the efficacy and safety of rituximab (RTX) maintenance therapy for patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) in Japan. METHODS: We conducted a retrospective study using a multi-center cohort database of vasculitis patients. All maintenance treatment courses were divided into three groups: a RTX group, a group treated with other immunosuppressant drugs (IS) and a group receiving glucocorticoid monotherapy (GC). The primary endpoint was the comparison of relapse-free survival after 1 year. We also analyzed the occurrence of severe adverse events (SAEs) to assess safety. RESULTS: We included 123 courses of 107 patients (RTX n = 14, IS n = 64, GC n = 45). Twelve of 14 in the RTX group patients were diagnosed with granulomatosis with polyangiitis (GPA). The relapse-free survival of RTX maintenance therapy was comparable to that in the other groups (p = .122). After 1 year of treatment, the RTX group was administered lower steroid doses and one-third of them could withdraw corticosteroid. The overall incidence of SAE was 0.54/patient-year in the RTX group, 0.39/patient-year in the IS group and 0.34/patient-year in the GC group. CONCLUSION: RTX maintenance therapy could be effective and safe in Japanese GPA patients.