中島 裕史

Group 2 innate lymphoid cells (ILC2s) are a subset of innate lymphocytes that produce type 2 cytokines, including IL-4, IL-5, and IL-13. GATA3 is a critical transcription factor for ILC2 development at multiple stages. However, when and how GATA3 is induced to the levels required for ILC2 development remains unclear. Herein, we identify ILC2-specific GATA3-related tandem super-enhancers (G3SE) that induce high GATA3 in ILC2-committed precursors. G3SE-deficient mice exhibit ILC2 deficiency in the bone marrow, lung, liver, and small intestine with minimal impact on other ILC lineages or Th2 cells. Single-cell RNA-sequencing and subsequent flow cytometry analysis show that GATA3 induction mechanism, which is required for entering the ILC2 stage, is lost in IL-17RB+PD-1- late ILC2-committed precursor stage in G3SE-deficient mice. Cnot6l, part of the CCR4-NOT deadenylase complex, is a possible GATA3 target during ILC2 development. Our findings implicate a stage-specific regulatory mechanism for GATA3 expression during ILC2 development.

Asthma is a widespread airway disorder where GATA3-dependent Type-2 helper T (Th2) cells and group 2 innate lymphoid cells (ILC2s) play vital roles. Asthma-associated single nucleotide polymorphisms (SNPs) are enriched in a region located 926-970 kb downstream from GATA3 in the 10p14 (hG900). However, it is unknown how hG900 affects the pathogenesis of allergic airway inflammation. To investigate the roles of the asthma-associated GATA3 enhancer region in experimental allergic airway inflammation, we first examined the correlation between GATA3 expression and the activation of the hG900 region was analyzed by flow cytometry and ChIP-qPCR. We found that The activation of enhancers in the hG900 region was strongly correlated to the levels of GATA3 in human peripheral T cell subsets. We next generated mice lacking the mG900 region (mG900KO mice) were generated by the CRISPR-Cas9 system, and the development and function of helper T cells and ILCs in mG900KO mice were analyzed in steady-state conditions and allergic airway inflammation induced by papain or house dust mite (HDM). The deletion of the mG900 did not affect the development of lymphocytes in steady-state conditions or allergic airway inflammation induced by papain. However, mG900KO mice exhibited reduced allergic inflammation and Th2 differentiation in the HDM-induced allergic airway inflammation. The analysis of the chromatin conformation around Gata3 by circular chromosome conformation capture coupled to high-throughput sequencing (4C-seq) revealed that the mG900 region interacted with the transcription start site of Gata3 with an influencing chromatin conformation in Th2 cells. These findings indicate that the mG900 region plays a pivotal role in Th2 differentiation and thus enhances allergic airway inflammation.

Immune checkpoint inhibitors (ICIs) sometimes induce immune-related adverse events (irAEs), and arthritis is one of the irAE symptoms. Recently, crystal-induced arthritis, such as calcium pyrophosphate (CPP) crystal deposition disease and gout, has been reported to occur after ICI administration. However, the distinction between ICI-associated crystal arthritis and ICI-induced non-crystal arthritis is difficult because their symptoms are similar. Besides, optimal treatment for ICI-associated crystal arthritis has not been established. Here, we report a patient who developed CPP crystal arthritis twice after pembrolizumab (ICI) administration and was successfully treated with intra-articular glucocorticoid injection. He suffered arthritis and acute interstitial nephritis simultaneously after ICI administration. Musculoskeletal ultrasound of his affected joint suggests that his arthritis was crystal-induced arthritis, and arthrocentesis detected CPP crystal in synovial fluid. Thus, we diagnosed his arthritis as ICI-associated cystal arthritis. Therefore, our case encourages the use of musculoskeletal ultrasound in patients with arthritis after treatment with ICI because it may distinguish between ICI-associated crystal arthritis and ICI-induced non-crystal arthritis. Besides, ICI-associated crystal arthritis could be treatable by intra-articular glucocorticoid injection.

Foxp3+ T regulatory (Treg) cells prevent allograft rejection and graft-versus-host disease. Although polyclonal Tregs have been used both in animal models and in humans, the fine specificity of their suppressive function is poorly defined. We have generated mouse recipient-derived alloantigen-specific Tregs in vitro and explored the fine specificity of their suppressive function and their mechanism of action in vitro and in vivo. In vitro, when alloantigen and peptide Ag were both presented on the same dendritic cell, both responses were suppressed by iTregs specific either for the alloantigen or for the peptide Ag. In vivo, iTreg suppression was limited to the cognate Ag, and no bystander suppression was observed when both allo-antigen and peptide Ag were present on the same dendritic cell. In vitro, alloantigen-specific Tregs captured cognate MHC but failed to capture noncognate MHC. Our results demonstrate that a polyclonal population of iTregs generated from naive T cells can mediate highly specific function in vivo and support the view that Treg therapy, even with unselected polyclonal populations, is likely to be target antigen-specific and that bystander responses to self-antigens or to infectious agents are unlikely.

Abstract The lungs serve as the primary organ for respiration, facilitating the vital exchange of gases with the bloodstream. Given their perpetual exposure to external particulates and pathogens, they possess intricate protective barriers. Cellular adhesion in the lungs is robustly maintained through tight junctions, adherens junctions, and desmosomes. Furthermore, the pulmonary system features a mucociliary clearance mechanism that synthesizes mucus and transports it to the outside. This mucus is enriched with chemical barriers like antimicrobial proteins and immunoglobulin A (IgA). Additionally, a complex immunological network comprising epithelial cells, neural cells, and immune cells plays a pivotal role in pulmonary defense. A comprehensive understanding of these protective systems offers valuable insights into potential pathologies and their therapeutic interventions.

INTRODUCTION: Glomerulonephritis is frequent in antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) and crucial to disease outcomes. We conducted a detailed assessment of renal pathology in Japanese patients with AAV, and developed a new score that would predict renal outcome. METHODS: Two hundred twenty-one patients who were diagnosed with AAV and underwent a kidney biopsy were enrolled. Data on glomerular, tubular, interstitial, and vascular lesions from kidney biopsies were analyzed; the 3 established classification and prognostic scoring systems (Berden Classification, Mayo Clinic/RPS Chronicity Score [MCCS], and ANCA Renal Risk Score [ARRS]) were validated. Further, we developed a new prognostic score by including variables relevant for Japanese patients with ANCA-glomerulonephritis. RESULTS: Median follow-up was 60 months (interquartile range: 6-60). End-stage kidney disease (ESKD) risk prediction by the MCCS and the ARRS was confirmed. Moreover, our analysis identified 4 items with significant ESKD risk prediction capacity, namely percentage of cellular, fibrocellular, and fibrous crescents; and sclerotic glomeruli. Based on our findings, we created a score evaluating the percentage of these lesions to total glomeruli, the Percentage of ANCA Crescentic Score (PACS). The area under the receiver operating characteristic (ROC) curve evaluating PACS was 0.783. The PACS had a comparable performance as the ARRS in predicting ESKD. The optimal PACS cut-off for ESKD risk over 60 months was 43%. In addition, the percentage of cellular crescents and presence of interstitial inflammation were independent predictors of kidney function recovery. CONCLUSION: We developed a new score predicting renal prognosis using histopathological data of Japanese patients with ANCA-glomerulonephritis. Studies are needed to validate our results in international cohorts.

OBJECTIVES: This study aimed to determine the immunogenicity and the influence on disease activity of an adjuvanted recombinant varicella-zoster virus (VZV) subunit vaccine (RZV) in patients with rheumatoid arthritis (RA) treated with disease-modifying antirheumatic drugs (DMARDs). METHODS: This prospective longitudinal study enrolled 53 patients with RA (aged ≥50 years) treated with DMARDs (conventional synthetic (cs)DMARDs 20, biological (b)DMARDs 23 and targeted synthetic (ts)DMARDs 10) and 10 control individuals. The participants received two intramuscular RZV 2 months apart. VZV-specific CD4+ T cell responses (cell-mediated immunity; CMI) and IgG antibody responses (humoral immunity; HI) were assessed at 0 and 3 months after the first RZV administration using flow cytometry and enzyme immunoassay, respectively. Disease activity (Disease Activity Score 28-C reactive protein and Clinical Disease Activity Index), flares and adverse events were monitored for 6 months after the first vaccination. RESULTS: VZV-specific CMI and HI significantly increased in the three DMARDs-treated patients with RA after RZV administration compared with the corresponding prevaccination values (p<0.001-0.014), and the magnitudes and fold-increases of those responses were not significantly different among the three DMARDs-treated patients with RA. Furthermore, the vaccine response rates of CMI and HI were not significantly different between csDMARDs-treated patients and b-DMARDs or ts-DMARDs-treated patients. Meanwhile, no significant increases in disease activity indices or adverse events were observed in these patients during the 6-month follow-up period after the first vaccination. RZV-induced RA flares occurred in two patients (3.8%) but were mild and controllable. CONCLUSION: RZV is robustly immunogenic and has a clinically acceptable safety profile in elderly patients with RA receiving DMARDs.

OBJECTIVES: IgG4-related disease (IgG4-RD) is a systemic autoimmune disease with an unknown etiology, affecting single/multiple organ(s). Pathological findings include the infiltration of IgG4-producing plasma cells, obliterative phlebitis, and storiform fibrosis. Although immunological studies have shed light on the dysregulation of lymphocytes in IgG4-RD pathogenesis, the role of non-immune cells remains unclear. This study aimed to investigate the demographics and characteristics of non-immune cells in IgG4-RD and explore potential biomarkers derived from non-immune cells in the sera. METHODS: We conducted single-cell RNA sequence (scRNA-seq) on non-immune cells isolated from submandibular glands of IgG4-RD patients. We focused on fibroblasts expressing collagen type XV and confirmed the presence of those fibroblasts using immunohistochemistry. Additionally, we measured the levels of collagen type XV in the sera of IgG4-RD patients. RESULTS: The scRNA-seq analysis revealed several distinct clusters consisting of fibroblasts, endothelial cells, ductal cells, and muscle cells. Differential gene expression analysis showed upregulation of COL15A1 in IgG4-RD fibroblasts compared to control subjects. Notably, COL15A1-positive fibroblasts exhibited a distinct transcriptome compared to COL15A1-negative counterparts. Immunohistochemical analysis confirmed a significant presence of collagen type XV-positive fibroblasts in IgG4-RD patients. Furthermore, immune-suppressive therapy in active IgG4-RD patients resulted in decreased serum levels of collagen type XV. CONCLUSIONS: Our findings suggest that collagen type XV-producing fibroblasts may represent a disease-characterizing non-immune cell population in IgG4-RD and hold potential as a disease-monitoring marker.

OBJECTIVES: Anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive dermatomyositis (MDA5-DM) is a subtype of dermatomyositis characterized by frequent interstitial lung disease and reduced muscle involvement. This study aimed to determine the short-term and long-term outcomes of patients with MDA5-DM. METHODS: Information on baseline characteristics, treatments, and short-term and long-term outcomes of patients with MDA5-DM including survival, relapse, and the titer of anti-MDA5 antibody, was retrospectively collected. Descriptive statistics regarding clinical outcomes were calculated, and a comparison of clinical parameters between patients with and without relapse was performed. The short-term survival according to the use of Janus kinase inhibitors (JAKi) was also assessed. RESULTS: A total of 154 patients with MDA5-DM were included in the study. Forty patients (25.9%) died during the remission induction phase, with respiratory failure being the most common cause of mortality. Among the 114 patients who survived the remission induction phase, the 5-year cumulative survival and relapse-free survival rates were 96.8% and 77.4%, respectively, and 7.9% of patients achieved complete drug-free remission. Fifty-four patients achieved normalization of anti-MDA5 antibody titers and only two of them relapsed after normalization. In the severe patients, the 6-month survival rate became significantly higher after the emergence of the JAKi treatment compared with before its existence (p= 0.03). CONCLUSIONS: Although relapse often occurs, the long-term survival of MDA5-DM patients who survived the remission induction phase is generally favorable. The status of the anti-MDA5 antibody is associated with relapse. JAKi may improve the survival of refractory patients with severe MDA5-DM.

Based on the efficacy of intravenous immunoglobulin (IVIg) for the treatment of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), we developed a recombinant single-chain-fragment variable clone, VasSF, therapeutic against AAV in a mouse model (SCG/Kj mice). VasSF is thought to bind to vasculitis-associated apolipoprotein A-II (APOA2) as a target molecule. VasSF is a promising new drug against AAV, but difficulties in the yield and purification of VasSF remain unresolved. We produced monomers of new VasSF molecules by modifying the plasmid structure for VasSF expression and simplifying the purification method using high-performance liquid chromatography. We compared the therapeutic effects between 5-day continuous administration of the monomers, as in IVIg treatment, and single shots of 5-day-equivalent doses. We also evaluated the life-prolonging effect of the single-shot treatment. Two-dimensional Western blots were used to examine the binding of VasSF to APOA2. Our improved manufacturing method resulted in a 100-fold higher yield of VasSF than in our previous study. Monomerization of VasSF stabilized its efficacy. Single shots of a small amount (1/80,000 of IVIg) produced sufficient therapeutic effects, including decreased glomerular crescent formation, a decreasing trend of serum ANCA against myeloperoxidase (MPO-ANCA), decreases in multiple proinflammatory cytokines, and a trend toward prolonged survival. Two-dimensional Western blots confirmed the binding of VasSF to APOA2. The newly produced pure VasSF monomers are stable and therapeutic for AAV with a single low-dose injection, possibly by removing vasculitis-associated APOA2. Thus, the new VasSF described herein is a promising drug against AAV.

Myocarditis has been reported as a life-threatening complication of adult-onset Still's disease (AOSD), but fulminant myocarditis with AOSD is very rare. We hereby report a case of a 43-year-old female with fulminant myocarditis with AOSD. She had a refractory AOSD and cardiogenic shock with markedly elevated ferritin level up to 67,370 ng/mL. She was successfully treated with canakinumab and mechanical circulatory support (MCS) such as venoarterial extracorporeal membrane oxygenation and Impella CP. We also reviewed the previous cases of fulminant myocarditis with AOSD published from 1976 to December 2022, and only 8 cases of fulminant myocarditis with AOSD have been reported. The characteristics of these cases showed that the average age at presentation was 37.6 years (range 24-47 years). The time to myocarditis from the onset of AOSD ranged from 2 weeks to 2 years; however, most cases developed myocarditis within 1 year. Initial presenting symptoms included fever, dyspnea, chest pain, myalgia, rash, and sore throat. The median peak ferritin was 13,000 ng/mL. Left ventricular ejection fractions were not greater than 35%. Our case was the first reported case successfully treated with canakinumab and MCS. This review suggests that myocarditis may be an early phase of the complication in patients with AOSD, and the severity of AOSD may correlate with the severity of myocarditis. Canakinumab for AOSD and MCS for fulminant myocarditis may be one of the choices for overcoming the comorbidities.

Murine IL-17-producing γδT (γδT17) cells are divided into two subsets: natural γδT17 (nγδT17) cells, whose development is restricted to the fetal thymus, and inducible γδT17 cells, which require antigen exposure for their IL-17 production and are presumed to develop from Rorc⁺Il17a^-CCR9⁺ immature γδT17 cells in the adult thymus and whose T cell receptor (TCR) is biased toward Vγ4. Although IL-23 is known to be involved in developing γδT17 cells, the roles of other cytokines, such as IL-21, which is involved in developing Th17 cells like IL-23, in the development, maintenance, and pathophysiology of γδT17 cells remain unknown. Here, we show that IL-21 is dispensable for the fetal thymic development of nγδT17 cells but is required for the peripheral maintenance of Vγ4⁺nγδT17 cells. Upon stimulation with γδTCR, IL-1 plus IL-21 induces the proliferation of Vγ4⁺nγδT17 cells via STAT3 as effectively as IL-1 plus IL-23. Using bone marrow chimeric mice, we demonstrated that immature γδT17 cells are produced de novo in the adult mice from donor adult bone marrow cells and that IL-21 is dispensable for their development. Instead, IL-21 is required to expand newly induced Vγ4⁺γδT17 cells in the periphery upon immunization. Finally, using adoptive transfer experiments of γδT17 cells, we found that IL-21 receptors on γδT17 cells are involved in maintaining Vγ4⁺γδT17 cells, subsequent infiltration of Th17 cells into the spinal cord, and exacerbation of experimental autoimmune encephalomyelitis. Collectively, IL-21 plays a vital role in the maintenance and pathogenesis of Vγ4⁺γδT17 cells.

OBJECTIVE: Predicting the efficacy of biological disease-modifying anti-rhematic drugs (bDMARDs) is challenging. In this study, we aimed to explore markers that predict the efficacy of abatacept in rheumatoid arthritis (RA) patients. METHODS: Thirty RA patients receiving abatacept were recruited, and peripheral blood mononuclear cells (PBMCs) from the participants were subjected to DNA microarray analysis. The expression of CCR4, which was selected by the result of DNA microarray, was determined by flow cytometry in 16 newly diagnosed treatment-naïve RA patients. CCR4 expression on each helper T cell subset was also measured. RESULTS: CCR4 was upregulated in the abatacept responder. The expression levels of CCR4 were significantly correlated with the improvement of clinical disease activity index (CDAI). CCR4 expression was predominantly observed in CD4+ T cells in PBMCs. The percentage of CCR4-expressing CD4+ T cells was significantly higher in RA patients than in healthy individuals. Interestingly, Th17 and Treg cells expressed high levels of CCR4 compared to non-Th17-related helper T cells. CONCLUSION: CCR4 is a Th17- and Treg-related gene, and the high CCR4 expression in peripheral blood samples may predict the efficacy of abatacept in RA.

OBJECTIVES: To evaluate the effectiveness of early initiation of angiotensin-converting enzyme inhibitor (ACEi) in patients with scleroderma renal crisis (SRC). METHODS: This was a retrospective cohort study using a nationwide inpatient database in Japan from July 2010 to March 2020. All hospitalized patients with SRC were divided into those who received ACEi within two days of admission (early ACEi group) and those who did not (control group). Propensity-score overlap weighting analysis was performed to adjust for confounding factors. The primary outcome was the composite of in-hospital mortality or hemodialysis dependence at discharge. RESULTS: Of the 475 eligible patients, 248 (52.2%) were in the early ACEi group and 227 (47.8%) were in the control group. After overlap weighting, the primary outcome was significantly lower in the early ACEi group than in the control group (40.1% vs. 49.0%; odds ratio, 0.69; 95% confidence interval, 0.48-1.00; P= 0.049). CONCLUSIONS: The present study showed that early initiation of ACEi was associated with lower composite outcome of in-hospital mortality or hemodialysis dependence at discharge in patients with SRC. Further prospective studies are warranted to verify the present findings.

Abstract Objectives Rheumatoid arthritis (RA) is an autoimmune disease characterized by destructive polyarthritis. CD4+ T cells are pivotal to its pathogenesis, and our previous study revealed the expression of fibroblast growth factor receptor 1 (FGFR1) is modulated by methotrexate treatment in CD4+ T cells of RA patients; however, the roles of FGFR1 in CD4+ T cells in the pathogenesis of RA is unclear. Therefore, in this study, we aimed to characterize FGFR1-positive CD4+ T cells in RA patients. Methods The abundance of FGFR1-positive CD4+ T cells in peripheral blood and synovium was determined. Single-cell RNA sequencing (scRNA-seq) was performed on synovial CD4+ T cells to characterize FGFR1-positive cells. In addition, T cell activation status and cytokine production were determined using flow cytometry. Results The percentage of FGFR1-positive CD4+ T cells in the peripheral blood was higher in RA patients than in healthy controls (P= 0.0035). They were also present in the synovium of active RA patients. The results of scRNA-seq revealed that peripheral T helper (Tph) cells preferentially expressed FGFR1. Additionally, these FGFR1-positive Tph cells displayed a terminal effector cell phenotype. Consistent with this finding, FGFR1-positive CD4+ T cells in peripheral blood expressed interleukin-21 and interferon-γ. Conclusion Our study provides evidence that FGFR1 marks terminal effector Tph cells in patients with RA.

Abstract Background Systemic lupus erythematosus (SLE) is heterogeneous in organ involvement and disease severity, presenting a broad clinical phenotype. Systemic type I interferon (IFN) activity has been shown to be associated with lupus nephritis, autoantibodies, and disease activity in treated SLE patients; however, these relationships are unknown in treatment-naive patients. We aimed to determine the relationship of systemic IFN activity with clinical phenotypes, disease activity, and damage accrual in treatment-naive SLE patients before and after induction and maintenance therapy. Methods Forty treatment-naive SLE patients were enrolled for this retrospective longitudinal observational study to examine the relationship between serum IFN activity and clinical manifestations of EULAR/ACR-2019 criteria domains, disease activity measures, and damage accrual. As controls, 59 other treatment-naive rheumatic disease patients and 33 healthy individuals were recruited. Serum IFN activity was measured by WISH bioassay and presented as an IFN activity score. Results Treatment-naive SLE patients had significantly higher serum IFN activity than other rheumatic disease patients (score: 97.6 and 0.0, respectively, p &lt; 0.001). High serum IFN activity was significantly associated with fever, hematologic disorders (leukopenia), and mucocutaneous manifestations (acute cutaneous lupus and oral ulcer) of EULAR/ACR-2019 criteria domains in treatment-naive SLE patients. Serum IFN activity at baseline significantly correlated with SLEDAI-2K scores and decreased along with a decrease in SLEDAI-2K scores after induction and maintenance therapy (R² = 0.112, p = 0.034). SLE patients who developed organ damage (SDI ≥ 1) had higher serum IFN activity at baseline than those who did not (SDI = 0) (150.0 versus 57.3, p= 0.018), but the multivariate analysis did not detect its independent significance (p = 0.132). Conclusions Serum IFN activity is characteristically high and is linked to fever, hematologic disorders, and mucocutaneous manifestations in treatment-naive SLE patients. Serum IFN activity at baseline correlates with disease activity and decreases in parallel with a decrease in disease activity after induction and maintenance therapy. Our results suggest that IFN plays an important role in the pathophysiology of SLE and that serum IFN activity at baseline may be a potential biomarker for the disease activity in treatment-naive SLE patients.

OBJECTIVE: We aimed to determine the prevalence and risk factors for osteonecrosis of the femoral head (ONFH) in a multicentre cohort of patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV). METHODS: One hundred and eighty-six AAV patients who underwent radiographs and MRI screening of bilateral hip joints at more than 6 months after initial remission induction therapy (RIT) were retrospectively assessed for the presence of ONFH. RESULTS: Among 186 AAV patients, 33 (18%) were diagnosed with ONFH. Among the patients with ONFH, 55% were asymptomatic and 64% had bilateral ONFH. Seventy-six per cent of ONFH joints were in precollapse stages (stage ≤2), whereas 24% of ONFH joints were in collapse stages (stage ≥3). Moreover, 56% of the precollapse stage joints were already at risk of future collapse (type ≥C-1). Even in asymptomatic ONFH patients, 39% of the precollapse stage joints were type ≥C-1. Prednisolone dose of ≥20 mg/day on day 90 of RIT was an independent risk factor for ONFH in AAV patients (OR 1.072, 95% CI 1.017 to 1.130, p=0.009). Rituximab use was a significant beneficial factor against ONFH (p=0.019), but the multivariate analysis rejected its significance (p=0.257). CONCLUSION: Eighteen per cent of AAV patients developed ONFH, and two-thirds of the ONFH joints were already in collapse stages or at risk of future collapse. Prednisolone dose of ≥20 mg/day on day 90 of RIT was an independent risk factor for ONFH. A rapid reduction of glucocorticoids in RIT and early detection of precollapse ONFH by MRI may decrease and intervene ONFH development in AAV patients.

Objectives Spontaneous pneumomediastinum (SPNM) historically has been considered a poor prognostic factor in dermatomyositis/polymyositis patients complicated with interstitial lung disease (ILD). However, there is a lack of actual data regarding the association between SPNM occurrence and mortality in dermatomyositis/polymyositis patients. This study aimed to assess the association between SPNM occurrence and mortality in myositis patients with ILD according to antimelanoma differentiation-associated gene 5 (MDA5) antibody status. Methods Dermatomyositis/polymyositis patients with ILD who were hospitalised at five Japanese hospitals from 2016 to 2020 were included in this retrospective observational study. We collected data about baseline characteristics including myositis-specific autoantibodies, treatments, SPNM and death within 1 year from therapy initiation or strengthening. Baseline characteristics and outcomes were compared between patients with and without SPNM (the SPNM group and the non-SPNM group, respectively). Results A total of 119 patients were analysed. SPNM occurred in 23 patients, and 15 patients died. Fifteen patients with SPNM were anti-MDA5 antibody positive. The mortality rate was significantly higher in the SPNM group (34.8%) than in the non-SPNM group (7.3%) (p=0.001). All deaths in the SPNM group occurred in anti-MDA5 antibody-positive patients (8/15), whereas none of the anti-MDA5 antibody-negative patients in the SPNM group died (0/8). In anti-MDA5 antibody-positive patients, the mortality rate was significantly higher in patients with SPNM occurrence (53.3%) than in those without SPNM occurrence (4.0%) (p=0.001). Conclusion SPNM occurred more frequently in anti-MDA5 antibody-positive than in anti-MDA5 antibody-negative myositis patients. SPNM occurrence was associated with higher mortality risk, especially in anti-MDA5 antibody-positive patients.

Abstract Epithelial cells control a variety of immune cells by secreting cytokines to maintain tissue homeostasis on mucosal surfaces. Regulatory T (Treg) cells are essential for immune homeostasis and for preventing tissue inflammation; however, the precise molecular mechanisms by which epithelial cell-derived cytokines function on Treg cells in the epithelial tissues are not well understood. Here, we show that peripheral Treg cells preferentially respond to thymic stromal lymphoprotein (TSLP). Although TSLP does not affect thymic Treg differentiation, TSLP receptor-deficient induced Treg cells derived from naïve CD4⁺ T cells are less activated in an adoptive transfer model of colitis. Mechanistically, TSLP activates induced Treg cells partially through mTORC1 activation and fatty acid uptake. Thus, TSLP modulates the activation status of induced Treg through the enhanced uptake of fatty acids to maintain homeostasis in the large intestine.

Visceral disseminated varicella zoster virus infection (VD-VZV) is a rare complication in immunocompromised patients. Although systemic lupus erythematosus (SLE) patients have a higher risk of VZV infection, only a few reports describe VD-VZV in SLE. Here, we report a 48-year-old woman with SLE who had received maintenance therapy. She was transferred to the hospital because of severe epigastric pain. There were no significant abnormalities in abdominal computed tomography and upper gastrointestinal endoscopy. On hospital day 4, she developed vesicular eruption on her face and abdomen. VZV antigen was detected in specimens obtained from skin lesions, and treatment with acyclovir was started. VZV DNA in blood turned out to be positive, and the epigastric pain was thought to be caused by VD-VZV. There is a risk of VD-VZV in patients with SLE, even in those receiving non-intensive maintenance therapy.

Anti-melanoma differentiation-associated protein 5 (MDA5) antibody-positive dermatomyositis (MDA5-DM) is frequently complicated with rapidly progressive-interstitial lung disease (RP-ILD). The prognosis of MDA5-DM with RP-ILD is mostly poor despite intensive treatment with a combination of high-dose glucocorticoids and single conventional immunosuppressants. It was reported that the triple therapy (high-dose glucocorticoids, cyclophosphamide and tacrolimus) was more effective than a combination of high-dose glucocorticoids and stepwise addition of immunosuppressants. In addition, the efficacy of tofacitinib 10 mg/day for MDA5-DM with RP-ILD refractory to the triple therapy was suggested. However, the effect of those therapies was evaluated only in comparison to the historical control. Moreover, more importantly, there are still refractory patients even if treated with those therapies. In this case series, we report six MDA5-DM cases with RP-ILD in which the dose of tofacitinib was increased from 10 mg to 20 mg/day due to poor response to the triple therapy, followed by tofacitinib 10 mg/day. Four of six patients improved after dose escalation of tofacitinib, while two non-responders died. All six patients developed at least one infection including five cases of cytomegalovirus reactivation, one pulmonary aspergillosis, one herpes zoster and one herpes simplex keratitis. These cases suggest that the dose escalation of tofacitinib can be an option for MDA5-DM patients refractory to 10 mg/day of tofacitinib and other immunosuppressants although the risk of infection is a concern. The risk-benefit balance of the dose escalation of tofacitinib should be carefully assessed in each case.

Asthma is characterized by increased airway hyperresponsiveness, reversible airflow limitation, and remodeling due to allergic airway inflammation. Asthma has been proposed to be classified into various phenotypes by cluster analyses integrating clinical information and laboratory data. Recently, asthma has been classified into two major endotypes, Type 2-high and Type 2-low asthma, and various subtypes based on the underlying molecular mechanisms. In Type 2-high asthma, Th2 cells, together with group 2 innate lymphoid cells (ILC2s), produce type 2 cytokines such as IL-4, IL-5, IL-9, and IL-13, which play crucial roles in causing airway inflammation. The roles of ILC2s in asthma pathogenesis have been analyzed primarily in murine models, demonstrating their importance not only in IL-33- or papain-induced innate asthma models but also in house dust mite (HDM)- or ovalbumin (OVA)-induced acquired asthma models evoked in an antigen-specific manner. Recently, evidence regarding the roles of ILC2s in human asthma is also accumulating. This minireview summarizes the roles of ILC2s in asthma, emphasizing human studies.

Abstract Objectives Methotrexate (MTX) is an anchor drug for the treatment of rheumatoid arthritis (RA). However, the precise mechanisms by which MTX stalls RA progression and alleviates the ensuing disease effects remain unknown. The aim of the present study was to identify novel therapeutic target molecules, the expression patterns of which are affected by MTX in patients with RA. Methods CD4⁺ T cells from 28 treatment-naïve patients with RA before and 3 months after the initiation of MTX treatment were subjected to DNA microarray analyses. The expression levels of semaphorin 3G, a differentially expressed gene, and its receptor, neuropilin-2, were evaluated in the RA synovium and collagen-induced arthritis synovium. Collagen-induced arthritis and collagen antibody-induced arthritis were induced in semaphorin3G-deficient mice and control mice, and the clinical score, histological score, and serum cytokines were assessed. The migration and proliferation of semaphorin 3G-stimulated bone marrow-derived macrophages were analyzed in vitro. The effect of local semaphorin 3G administration on the clinical score and number of infiltrating macrophages during collagen antibody-induced arthritis was evaluated. Results Semaphorin 3G expression in CD4⁺ T cells was downregulated by MTX treatment in RA patients. It was determined that semaphorin 3G is expressed in RA but not in the osteoarthritis synovium; its receptor neuropilin-2 is primarily expressed on activated macrophages. Semaphorin3G deficiency ameliorated collagen-induced arthritis and collagen antibody-induced arthritis. Semaphorin 3G stimulation enhanced the migration and proliferation of bone marrow-derived macrophages. Local administration of semaphorin 3G deteriorated collagen antibody-induced arthritis and increased the number of infiltrating macrophages. Conclusions Upregulation of semaphorin 3G in the RA synovium is a novel mechanism that exacerbates joint inflammation, leading to further deterioration, through macrophage accumulation.

Abstract Background Adult-onset Still’s disease (AOSD) is a rare systemic autoinflammatory disease which encompasses patients with heterogenous presentation and a wide range of clinical courses. In this study, we aimed to identify potential subgroups of AOSD and reveal risk factors for relapse. Methods We included a total of 216 AOSD patients who received treatment in nine hospitals between 2000 and 2019. All patients fulfilled the Yamaguchi classification criteria. We retrospectively collected information about baseline characteristics, laboratory tests, treatment, relapse, and death. We performed latent class analysis and time-to-event analysis for relapse using the Cox proportional hazard model. Results The median age at disease onset was 51.6 years. The median follow-up period was 36.8 months. At disease onset, 22.3% of the patients had macrophage activation syndrome. The median white blood cell count was 12,600/μL, and the median serum ferritin level was 7230 ng/mL. Systemic corticosteroids were administered in all but three patients (98.6%) and the median initial dosage of prednisolone was 40mg/day. Ninety-six patients (44.4%) were treated with concomitant immunosuppressants, and 22 (10.2%) were treated with biologics. Latent class analysis revealed that AOSD patients were divided into two subgroups: the typical group (Class 1: 71.8%) and the elderly-onset group (Class 2: 28.2%). During the follow-up period, 13 of 216 patients (6.0%) died (12 infections and one senility), and 76 of 216 patients (35.1%) experienced relapses. Overall and relapse-free survival rates at 5 years were 94.9% and 57.3%, respectively, and those rates were not significantly different between Class 1 and 2 (p=0.30 and p=0.19). Time-to-event analysis suggested higher neutrophil count, lower hemoglobin, and age ≥65 years at disease onset as risk factors for death and age ≥65 years at disease onset as a risk factor for relapse. Conclusions AOSD patients were divided into two subgroups: the typical group and the elderly-onset group. Although the survival of patients with AOSD was generally good, the patients often experienced relapses. Age ≥65 years at disease onset was the risk factor for relapse.

OBJECTIVE: We compared the incidences of four opportunistic infections (OI) in patients with rheumatoid arthritis (RA) treated with molecular-targeted drugs from big claims data. MATERIALS AND METHODS: We identified 205 906 patients with RA who were prescribed molecular-targeted drugs 2010-2017 from the National Database of Japan, and calculated the incidence of four OIs (Pneumocystis pneumonia [PCP], tuberculosis [TB], nontuberculous mycobacterial infection [NTM], and herpes zoster [HZ]). RESULTS: The total number of PCP, TB, NTM, and HZ patients with biological disease-modifying antirheumatic drugs (bDMARDs) or tofacitinib treatment history in RA were 765, 1158, 834, and 18 336, respectively. The incidence rates (IRs) of each OI for all bDMARDs were 0.14, 0.14, 0.09, and 2.40 per 100 person-years, respectively; while for tofacitinib they were 0.22, 0.22, 0.07, and 7.00 per 100 person-years. No big difference was observed among bDMARDs. All OIs showed higher incidence in those older than 65 years; but PCP, NTM and HZ showed no difference between those 65-74 years old and those over 75 years old. The median of occurrence was the third, seventh, ninth, and thirteenth month after treatment, respectively. CONCLUSION: We counted real IRs of OIs for the whole nation from big claims data.

Symptoms of adverse reactions to vaccines evolve over time, but traditional studies have focused only on the frequency and intensity of symptoms. Here, we attempt to extract the dynamic changes in vaccine adverse reaction symptoms as a small number of interpretable components by using non-negative tensor factorization. We recruited healthcare workers who received two doses of the BNT162b2 mRNA COVID-19 vaccine at Chiba University Hospital and collected information on adverse reactions using a smartphone/web-based platform. We analyzed the adverse-reaction data after each dose obtained for 1,516 participants who received two doses of vaccine. The non-negative tensor factorization revealed four time-evolving components that represent typical temporal patterns of adverse reactions for both doses. These components were differently associated with background factors and post-vaccine antibody titers. These results demonstrate that complex adverse reactions against vaccines can be explained by a limited number of time-evolving components identified by tensor factorization.

The mortality of coronavirus disease 2019 (COVID-19) is strongly correlated with pulmonary vascular pathology accompanied by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection-triggered immune dysregulation and aberrant activation of platelets. We combined histological analyses using field emission scanning electron microscopy with energy-dispersive X-ray spectroscopy analyses of the lungs from autopsy samples and single-cell RNA sequencing of peripheral blood mononuclear cells to investigate the pathogenesis of vasculitis and immunothrombosis in COVID-19. We found that SARS-CoV-2 accumulated in the pulmonary vessels, causing exudative vasculitis accompanied by the emergence of thrombospondin-1-expressing noncanonical monocytes and the formation of myosin light chain 9 (Myl9)-containing microthrombi in the lung of COVID-19 patients with fatal disease. The amount of plasma Myl9 in COVID-19 was correlated with the clinical severity, and measuring plasma Myl9 together with other markers allowed us to predict the severity of the disease more accurately. This study provides detailed insight into the pathogenesis of vasculitis and immunothrombosis, which may lead to optimal medical treatment for COVID-19.

INTRODUCTION: Vaccine effectiveness against SARS-CoV-2 infections decreases due to waning immunity, and booster vaccination was therefore introduced. We estimated the anti-spike antibody (AS-ab) recovery by booster vaccination and analyzed the risk factors for SARS-CoV-2 infections. METHODS: The subjects were health care workers (HCWs) in a Chiba University Hospital vaccination cohort. They had received two doses of vaccine (BNT162b2) and a booster vaccine (BNT162b2). We retrospectively analyzed AS-ab titers and watched out for SARS-CoV-2 infection for 90 days following booster vaccination. RESULTS: AS-ab titer eight months after two-dose vaccinations had decreased to as low as 587 U/mL (median, IQR (interquartile range) 360-896). AS-ab titer had then increased to 22471 U/mL (15761-32622) three weeks after booster vaccination. There were no significant differences among age groups. A total of 1708 HCWs were analyzed for SARS-CoV-2 infection, and 48 of them proved positive. SARS-CoV-2 infections in the booster-vaccinated and non-booster groups were 1.8% and 4.0%, respectively, and were not significant. However, when restricted to those 20-29 years old, SARS-CoV-2 infections in the booster-vaccinated and non-booster groups were 2.9% and 13.6%, respectively (p = 0.04). After multivariate logistic regression, COVID-19 wards (adjusted odds ratio (aOR):2.9, 95% confidence interval (CI) 1.5-5.6) and those aged 20-49 years (aOR:9.7, 95%CI 1.3-71.2) were risk factors for SARS-CoV-2 infection. CONCLUSIONS: Booster vaccination induced the recovery of AS-ab titers. Risk factors for SARS-CoV-2 infection were HCWs of COVID-19 wards and those aged 20-49 years. Increased vaccination coverage, together with implementing infection control, remains the primary means of preventing HCWs from SARS-CoV-2 infection.

INTRODUCTION: The usefulness of smartphone-based application software as a way to manage adverse events (AEs) after vaccination is well known. The purpose of this study is to clarify the usefulness and precautions of employing a smartphone application for collecting AEs after the administration of Comirnaty®️. METHODS: Healthcare workers (HCWs) who were vaccinated with Comirnaty®️ were asked to register for the application software and to report AEs for 14 days after vaccination. AEs were self-reported according to severity. The software was set to output an alert in case of fever. RESULTS: The number of HCWs who received the first dose was 2,551, and 2,406 (94.3%) reported their vaccinations. 2,547 received the second dose, and 2,347 (92.1%) reported their vaccinations. With the first dose, the reporting rate stayed above 83.3% until the final day. On the other hand, that of the second dose decreased rapidly after 6 days. The most frequent symptom was "pain at injection site" (more than 70%). Severe AEs were 6.6% after the second dose, with 0.6% visiting a clinic. Many AEs peaked on the day after administration and disappeared within 1 week. There were few reports of fever. CONCLUSION: Smartphone applications can be used to collect information on AEs after vaccination. Application settings and dissemination are necessary to maintain the reporting rate of HCWs.

Recent studies have identified NF-κB1 as a new disease susceptibility gene for psoriasis. Although accumulating evidence has shown the importance of NF-κB signaling in various cell types in the pathogenesis of psoriasis, it remains unclear how NF-κB1 contributes to the pathogenesis of psoriasis. In this study, we examined psoriasis-like skin diseases induced by topical administration of imiquimod in Nf-κb1‒deficient (Nf-κb1-/-) mice and littermate wild-type (WT) mice. Compared with WT mice, Nf-κb1-/- mice exhibited attenuated skin inflammation. The numbers of Vγ4+Vδ4+γδT17 cells, which cause skin inflammation in this model, were significantly reduced in the skin and draining lymph nodes in imiquimod-treated Nf-κb1-/- mice. Nf-κb1 is preferentially phosphorylated in Vγ4+Vδ4+γδT17 cells in WT mice. In vitro proliferation of Vγ4+Vδ4+γδT17 cells but not conventional CD4+ T cells was significantly impaired in Nf-κb1-/- mice compared with that in WT mice. RNA-sequencing analyses revealed that the expression of E2 factor target genes was decreased in Vγ4+Vδ4+γδT cells by the absence of NF-κB1. Consistently, the cell cycle progression of Vγ4+Vδ4+γδT cells was reduced in Nf-κb1-/- mice compared with that in WT mice. These results suggest that Nf-κb1 plays a crucial role in the pathogenesis of imiquimod-induced psoriasis-like skin inflammation by promoting the proliferation of Vγ4+Vδ4+γδT17 cells.