Reduced-dose versus high-dose glucocorticoids added to rituximab on remission induction in ANCA-associated vasculitis: predefined 2-year follow-up study.

OBJECTIVES: The LoVAS trial reported non-inferiority in remission induction rates between the reduced-dose and conventional high-dose glucocorticoid regimens plus rituximab for antineutrophil cytoplasm antibody (ANCA)-associated vasculitis at 6 months; however, maintenance glucocorticoid requirements and long-term outcomes are unknown. METHODS: A total of 140 patients with new-onset ANCA-associated vasculitis without severe glomerulonephritis or alveolar haemorrhage were randomised to receive reduced-dose prednisolone (0.5 mg/kg/day) plus rituximab (375 mg/m2/week×4) or high-dose prednisolone (1 mg/kg/day) plus rituximab. After achieving remission, patients received the rituximab maintenance therapy (1 g/6 months). RESULTS: A total of 134 patients were analysed. Among patients who achieved remission with the protocolised treatments, the majority of patients in the reduced-dose group (89.7%) and 15.5% in the high-dose group discontinued prednisolone (median time to withdrawal, 150 and 375 days, respectively). During 24-month trial period, two patients in the reduced-dose group (2.8%) died, while five patients in the high-dose group (7.6%) died (p=0.225). Relapse occurred in nine patients in the reduced-dose group (13.0%) (two major and seven minor) and five in the high-dose group (7.6%) (two major and three minor) (p=0.311). Serious adverse events (SAEs) were less frequent in the reduced-dose group (36 events in 19 patients, 27.5%) than in the high-dose group (54 events in 30 patients, 46.2%) (p=0.025). CONCLUSION: At 24 months, frequencies of relapse did not differ between the groups, and SAEs were less frequent in the reduced-dose group due to the lower event rate in the 6-month induction phase. The bias to myeloperoxidase-ANCA positivity (85.8%) in the trial population should be noted. TRIAL REGISTRATION NUMBER: NCT02198248.

Short-term and long-term outcomes of patients with anti-melanoma differentiation-associated gene 5 antibody-positive dermatomyositis.

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.

Fibroblast growth factor receptor 1 as a potential marker of terminal effector peripheral T helper cells in rheumatoid arthritis patients.

OBJECTIVES: 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 MTX 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 Th (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 IL-21 and IFN-γ. CONCLUSION: Our study provides evidence that FGFR1 marks terminal effector Tph cells in patients with RA.

Clinical significance of cytomegalovirus (CMV) pp65 antigenemia in the prediction of CMV infection during immunosuppressive therapy for rheumatic disease.

To investigate the risk factors for CMV infection and to clarify the cut-off count of CMV pp65 antigenemia predicting clinical symptoms related to CMV infection in patients with rheumatic disease. We retrospectively analyzed 261 patients with rheumatic disease who were treated with immunosuppressive therapy. CMV infection was defined as positive > 1 CMV-positive cell per two slides (CMV pp65 antigenemia C10/C11). Patients with CMV infection were divided into two groups based on the presence of antiviral treatment for CMV disease. We determined a cut-off value of CMV-positive cells for the diagnosis of CMV disease. CMV infection was observed in 141 cases (54%). In a multivariate analysis, CMV infection was associated with three following factors: Age > 60 years (OR 1.87 [95% CI 1.04-3.36]); lymphocyte counts < 1000/µL (OR 3.34 [95% CI 1.88-6.05]); steroid pulse therapy (OR 2.60 [95% CI 1.27-5.55]). The cut-off level of CMV pp65 antigenemia indicating CMV disease was five positive cells average two slides by using receiver operating characteristic curve analysis (AUC 0.95, sensitivity 0.94, specificity 0.80). Age > 60 years, lymphocytopenia (< 1000/µL) and steroid pulse therapy are risk factors of CMV infection. We recommend that CMV pp65 antigenemia of > 5 cells average two slides (C10/C11) in patients with rheumatic disease should be the treated with antiviral drugs.

Effect of Reduced-Dose vs High-Dose Glucocorticoids Added to Rituximab on Remission Induction in ANCA-Associated Vasculitis: A Randomized Clinical Trial.

Importance: The current standard induction therapy for antineutrophil cytoplasm antibody (ANCA)-associated vasculitis is the combination of high-dose glucocorticoids and cyclophosphamide or rituximab. Although these regimens have high remission rates, they are associated with considerable adverse events presumably due to high-dose glucocorticoids. Objective: To compare efficacy and adverse events between a reduced-dose glucocorticoid plus rituximab regimen and the standard high-dose glucocorticoid plus rituximab regimen in remission induction of ANCA-associated vasculitis. Design, Setting, and Participants: This was a phase 4, multicenter, open-label, randomized, noninferiority trial. A total of 140 patients with newly diagnosed ANCA-associated vasculitis without severe glomerulonephritis or alveolar hemorrhage were enrolled between November 2014 and June 2019 at 21 hospitals in Japan. Follow-up ended in December 2019. Interventions: Patients were randomized to receive reduced-dose prednisolone (0.5 mg/kg/d) plus rituximab (375 mg/m2/wk, 4 doses) (n = 70) or high-dose prednisolone (1 mg/kg/d) plus rituximab (n = 70). Main Outcomes and Measures: The primary end point was the remission rate at 6 months, and the prespecified noninferiority margin was -20 percentage points. There were 8 secondary efficacy outcomes and 6 secondary safety outcomes, including serious adverse events and infections. Results: Among 140 patients who were randomized (median age, 73 years; 81 women [57.8%]), 134 (95.7%) completed the trial. At 6 months, 49 of 69 patients (71.0%) in the reduced-dose group and 45 of 65 patients (69.2%) in the high-dose group achieved remission with the protocolized treatments. The treatment difference of 1.8 percentage points (1-sided 97.5% CI, -13.7 to ∞) between the groups met the noninferiority criterion (P = .003 for noninferiority). Twenty-one serious adverse events occurred in 13 patients in the reduced-dose group (18.8%), while 41 occurred in 24 patients in the high-dose group (36.9%) (difference, -18.1% [95% CI, -33.0% to -3.2%]; P = .02). Seven serious infections occurred in 5 patients in the reduced-dose group (7.2%), while 20 occurred in 13 patients in the high-dose group (20.0%) (difference, -12.8% [95% CI, -24.2% to -1.3%]; P = .04). Conclusions and Relevance: Among patients with newly diagnosed ANCA-associated vasculitis without severe glomerulonephritis or alveolar hemorrhage, a reduced-dose glucocorticoid plus rituximab regimen was noninferior to a high-dose glucocorticoid plus rituximab regimen with regard to induction of disease remission at 6 months. Trial Registration: ClinicalTrials.gov Identifier: NCT02198248.

Serum periostin levels serve as a biomarker for both eosinophilic airway inflammation and fixed airflow limitation in well-controlled asthmatics.

OBJECTIVE: Periostin, a matricellular protein, is produced from airway epithelial cells and lung fibroblasts by IL-13. It has been suggested that periostin is involved in allergic inflammation and fibrosis. However, the usefulness of serum periostin measurement in the assessment of airway inflammation and remodeling and management of asthmatic patients is still debated. We aimed to determine whether serum periostin levels reflect eosinophilic airway inflammation and airway remodeling in asthma. METHODS: We examined the relationship of serum periostin levels with clinical features, biomarkers for eosinophilic airway inflammation, fraction of exhaled nitric oxide (FeNO) levels and blood eosinophil counts, and pulmonary functions in 235 well-controlled asthmatic patients on inhaled corticosteroids (ICS) treatment. RESULTS: Serum periostin levels were positively correlated with blood eosinophil counts (%) and age (r = 0.36 and 0.23, respectively), and were negatively correlated with body weight and FEV1/FVC (%) (r = -0.24 and - 0.23, respectively) in well-controlled asthmatic patients on ICS treatment (daily dose of 453 µg equivalent to fluticasone propionate). Blood eosinophil counts and serum periostin levels were similarly associated with increased FeNO levels (≥40 ppb) in the asthmatics. Serum periostin levels were better associated with fixed airflow limitation (FEV1/FVC ratio <70%) than FeNO levels, blood eosinophil counts or total IgE levels in the asthmatics. Multivariate analysis showed that fixed airflow limitation was significantly associated with high serum periostin levels (≥97 ng/ml) (Odds ratio 3.2). CONCLUSIONS: Serum periostin levels serve as a biomarker for both eosinophilic airway inflammation and fixed airflow limitation in well-controlled asthmatics on ICS treatment.

Long-term use of biologic agents does not increase the risk of serious infections in elderly patients with rheumatoid arthritis.

This study aimed to determine whether the long-term use of biologic agents increases serious infections in elderly patients with rheumatoid arthritis (RA) and to determine the risk factors of serious infections in biologics-treated elderly RA patients. We retrospectively analyzed the incidence rate of serious infections that required hospitalization between biologics-treated and non-biologic disease-modifying antirheumatic drug (DMARD)-treated elderly RA patients (aged over 65 years). We examined the risk factors for serious infections in biologics-treated elderly RA patients. We found that, during a 3-year observation period, the incidence rate of serious infections was not significantly different between biologics-treated and non-biologic DMARD-treated elderly RA patients [8.0 (95% CI 4.7-13.5) and 6.3 (95% CI 4.1-9.5) events per 100 person-years of follow-up, respectively, P = 0.78]. The time to the first serious infection did not significantly differ between the two groups by the analysis of the Kaplan-Meier curves, either (P = 0.46). We then found that prednisolone doses alone were significantly associated with serious infections in biologics-treated elderly RA patients. Furthermore, we found that prednisolone at 1-4 mg/day was associated with serious infections in biologics-treated patients, but not non-biologic DMARD-treated patients. On the other hand, prednisolone at greater than 5 mg/day was associated with serious infections in both biologics-treated and non-biologics-treated patients. We show that there is not a significant difference between the incidence of serious infections between biologics group and non-biologics group in elderly RA patients (≧65 years) and that even very low-dose glucocorticoid use (prednisolone 1-4 mg/day) is a risk factor for serious infections in biologics-treated elderly RA patients.

ß-glucan curdlan induces IL-10-producing CD4+ T cells and inhibits allergic airway inflammation.

A number of studies have suggested a correlation between a decreased incidence in infectious diseases and an increased incidence of allergic diseases, including asthma. Although several pathogen-derived products have been shown to possess therapeutic potential for allergic diseases, it remains largely unknown whether ß-glucan, a cell wall component of a variety of fungi, yeasts, and bacteria, has a regulatory potential for allergic diseases. In this study, we examined the effect of curdlan, a linear ß-(1-3)-glucan, on the development of allergic airway inflammation. We found that i.p. injection of curdlan significantly inhibited Ag-induced eosinophil recruitment and Th2 cytokine production in the airways. The activation of CD4(+) T cells in the presence of curdlan induced IL-10-producing CD4(+) T cells with high levels of c-Maf expression. Curdlan-induced development of IL-10-producing CD4(+) T cells required the presence of APCs and ICOS/ICOS ligand interaction. Curdlan-induced development of IL-10-producing CD4(+) T cells also required intrinsic expression of STAT6. Furthermore, the transfer of Ag-specific CD4(+) T cells that were stimulated in the presence of curdlan inhibited Ag-induced eosinophil recruitment into the airways. Taken together, these results suggest that curdlan is capable of inducing IL-10-producing CD4(+) T cells and inhibiting the development of eosinohilic airway inflammation, underscoring the therapeutic potential of curdlan for allergic diseases.

Prognosis of spontaneous pneumomediastinum occurring in dermatomyositis or polymyositis patients with interstitial lung disease according to antimelanoma differentiation-associated gene 5 antibody status: a retrospective cohort study.

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.

TAp63, a methotrexate target in CD4+ T cells, suppresses Foxp3 expression and exacerbates autoimmune arthritis.

Methotrexate (MTX) is a standard, first-line therapy for rheumatoid arthritis (RA); however, its precise mechanisms of action other than antifolate activity are largely unknown. We performed DNA microarray analyses of CD4+ T cells in patients with RA before and after MTX treatment and found that TP63 was the most significantly downregulated gene after MTX treatment. TAp63, an isoform of TP63, was highly expressed in human IL-17-producing Th (Th17) cells and was suppressed by MTX in vitro. Murine TAp63 was expressed at high levels in Th cells and at lower levels in thymus-derived Treg cells. Importantly, TAp63 knockdown in murine Th17 cells ameliorated the adoptive transfer arthritis model. RNA-Seq analyses of human Th17 cells overexpressing TAp63 and those with TAp63 knockdown identified FOXP3 as a possible TAp63 target gene. TAp63 knockdown in CD4+ T cells cultured under Th17 conditions with low-dose IL-6 increased Foxp3 expression, suggesting that TAp63 balances Th17 cells and Treg cells. Mechanistically, TAp63 knockdown in murine induced Treg (iTreg) cells promoted hypomethylation of conserved noncoding sequence 2 (CNS2) of the Foxp3 gene and enhanced the suppressive function of iTreg cells. Reporter analyses revealed that TAp63 suppressed the activation of the Foxp3 CNS2 enhancer. Collectively, TAp63 suppresses Foxp3 expression and exacerbates autoimmune arthritis.

Prevalence and risk factors of osteonecrosis of the femoral head in patients with ANCA-associated vasculitis: a multicentre cohort study.

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.

Lack of B and T lymphocyte attenuator exacerbates autoimmune disorders and induces Fas-independent liver injury in MRL-lpr/lpr mice.

MRL/Mp-Fas (lpr) (MRL-lpr) mice develop a systemic autoimmune disease and are considered to be a good model for systemic lupus erythematosus in humans. We have recently shown that mice lacking B and T lymphocyte attenuator (BTLA), an inhibitory co-receptor expressed mainly on lymphocytes, on a 129SvEv background spontaneously develop lymphocytic infiltration in multiple organs and an autoimmune hepatitis (AIH)-like disease. In this study, we investigated the role of BTLA in the pathogenesis of autoimmune diseases in MRL-lpr mice. We found that BTLA-deficient (BTLA(-/-)) MRL-lpr/lpr mice developed severe lymphocytic infiltration in salivary glands, lungs, pancreas, kidneys and joints as compared with BTLA-sufficient (BTLA(+/+)) MRL-lpr/lpr mice. In addition, although AIH-like disease was not found in BTLA(+/+) MRL-lpr/lpr mice, AIH-like disease was exacerbated in BTLA(-/-) MRL-lpr/lpr mice as compared with that in BTLA(-/-) 129SvEv mice. These results suggest that BTLA plays a protective role in autoimmune diseases in MRL-lpr mice and that AIH-like disease develops in BTLA(-/-) mice even in the absence of Fas-dependent signaling.

Roles of CRTH2+ CD4+ T cells in immunoglobulin G4-related lacrimal gland enlargement.

BACKGROUND: Lacrimal gland enlargement (LGE) is one of the characteristics of Mikulicz's disease (MD). Recently, marked serum immunoglobulin (Ig)G4 elevation and infiltration of IgG4-positive plasma cells in the enlarged exocrine glands have been reported in MD patients. Moreover, we have reported that in patients with LGE and elevated serum IgG4 levels (IgG4-related LGE), T helper type 2 (Th2) cell-mediated immune responses are enhanced. Although prostaglandin D2 (PGD2) and its receptor CRTH2 (chemoattractant receptor-homologous molecule expressed on Th2 cells) have been shown to be involved in Th2 cell-related diseases such as bronchial asthma, their roles in IgG4-related diseases remain unknown. AIM: The aim of this study is to address the role of CD4+ T cells expressing CRTH2 (CRTH2+ CD4+ T cells) in IgG4-related LGE. METHODS: We examined the expression of CCR4, CXCR3 and CRTH2 on peripheral blood CD4+ T cells in patients with IgG4-related LGE, in patients with bronchial asthma and in healthy controls. RESULTS: The ratio of CCR4+ to CXCR3+ in CD45RO+ CD4+ T cells was increased in patients with IgG4-related LGE when compared to that in healthy controls, confirming that Th2 cells are predominant in patients with IgG4-related LGE. In addition, the frequency of CRTH2+ cells in CD4+ T cells was significantly increased in these patients, compared to healthy controls. Furthermore, although not statistically significant, the frequency of CRTH2+ cells in CD4+ T cells tended to correlate with the levels of serum IgE and the number of blood eosinophils in patients with IgG4-related LGE. CONCLUSION: CRTH2+ CD4+ T cells may be involved in the pathogenesis of IgG4-related LGE.

B and T lymphocyte attenuator suppresses IL-21 production from follicular Th cells and subsequent humoral immune responses.

We recently showed that mice lacking B and T lymphocyte attenuator (BTLA), a third inhibitory coreceptor expressed on B cells and T cells, exhibit an increased Ag-specific IgG response and gradually develop hyper-gamma-globulinemia and autoantibody production. Recent studies revealed that follicular Th (Tfh) cells, which are non-Th1, non-Th2 effector T cells that express CXCR5 and provide help for B cells to produce Ig, also express BTLA. However, the role of BTLA in Tfh cell function remains unknown. In this study, we examined the regulatory role of BTLA in the development and function of Tfh cells. We found that CXCR5(+) Tfh cells expressed higher levels of BTLA than did CXCR5(-) conventional CD4(+) T cells. We also found that adoptive transfer of BTLA(-/-) CD4(+) T cells, stimulated under Tfh cell-inducing conditions (Tfh-like cells), to wild-type (WT) mice induced more Ag-specific IgG2a and IgG2b production compared with that of WT Tfh-like cells. By contrast, another adoptive-transfer experiment using BTLA(-/-) mice as recipients showed that the expression of BTLA on B cells was not involved in the regulation of Tfh-like cell-mediated Ag-specific IgG responses. Moreover, the development of IL-21-producing CXCR5(+) Tfh-like cells was significantly increased in BTLA(-/-) CD4(+) T cells compared with WT CD4(+) T cells. Furthermore, Tfh-like cell-mediated IgG responses were abolished when IL-21R(-/-) mice were used as recipients. These results suggest that BTLA signaling suppresses IL-21 production from Tfh cells and subsequent Tfh cell-mediated IgG responses.

Protective roles of B and T lymphocyte attenuator in NKT cell-mediated experimental hepatitis.

Although B and T lymphocyte attenuator (BTLA) was originally identified as an inhibitory coreceptor selectively expressed on Th1 cells and B cells, recent studies have revealed that BTLA is expressed on a variety of cells, including macrophages, dendritic cells, and NK cells, and modulates their functions. However, the role of BTLA in the regulation of NKT cell function remains unknown. In this study, we found that BTLA was expressed on NKT cells at the levels similar to those on T cells and that BTLA-deficient (BTLA(-/-)) NKT cells produced larger amounts of IL-4 and IFN-gamma upon alpha-glactosylceramide stimulation as compared with wild-type (WT) NKT cells. In vivo, BTLA(-/-) mice produced larger amounts of IL-4 and IFN-gamma upon Con A injection and were more susceptible to Con A-induced hepatitis than WT mice. In addition, the augmentation of Con A-induced hepatitis in BTLA(-/-) mice was not observed in BTLA/NKT-double deficient mice. Moreover, NKT(-/-) mice reconstituted with BTLA(-/-) NKT cells were significantly more susceptible to Con A-induced hepatitis as compared with NKT (-/-) mice reconstituted with WT NKT cells. These results suggest that BTLA functions as the inhibitory coreceptor of NKT cells and plays a critical role in the prevention of NKT cell-mediated liver injury.

Latent class analysis of 216 patients with adult-onset Still's disease.

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.

Proteolytic processing of Stat6 signaling in mast cells as a negative regulatory mechanism.

Accumulating evidence has shown the importance of Stat6-mediated signaling in allergic diseases. In this study, we show a novel regulatory mechanism of Stat6-mediated signaling in mast cells. When Stat6 is activated by interleukin (IL)-4 and translocated to the nucleus, Stat6 is cleaved by a nucleus-associated protease in mast cells. The cleaved 65-kD Stat6 lacks the COOH-terminal transactivation domain and functions as a dominant-negative molecule to Stat6-mediated transcription. The retrovirus-mediated expression of cleavage-resistant Stat6 mutants prolongs the nuclear accumulation of Stat6 upon IL-4 stimulation and enhances IL-4-induced gene expression and growth inhibition in mast cells. These results indicate that the proteolytic processing of Stat6 functions as a lineage-specific negative regulator of Stat6-dependent signaling in mast cells, and thus suggest that it may account for the limited role of Stat6 in IL-4 signaling in mast cells.

Protein geranylgeranylation regulates the balance between Th17 cells and Foxp3+ regulatory T cells.

Recent studies have suggested that statins, the inhibitors for 3-hydroxy-3-methyglutaryl (HMG)-CoA reductase in the mevalonate pathway, exhibit anti-inflammatory effects. However, the immune modulatory effects of statins on the differentiation of CD4(+) T cells and their underlying mechanisms are still largely unknown. To address these issues, we examined the effect of simvastatin and inhibitors for protein farnesylation and geranylgeranylation on the differentiation of IL-17-producing T cells (T(h)17 cells) and Foxp3(+) CD4(+) T cells. Simvastatin inhibited the differentiation of T(h)17 cells through the inhibition of HMG-CoA reductase activity but enhanced the differentiation of Foxp3(+) CD4(+) T cells. Geranylgeranyltransferase I inhibitor, GGTI-298, but not farnesyltransferase inhibitor, FTI-277, mimicked the effects of simvastatin, indicating that the inhibition of protein geranylgeranylation is responsible for the effects. Moreover, Foxp3(+) CD4(+) T cells developed in the presence of transforming growth factor-beta and GGTI-298 functioned as regulatory T cells (Tregs) in in vitro T cell proliferation assay as well as in an autoimmune colitis model. Finally, GGTI-298 induced SOCS3 expression and inhibited IL-6-induced signal transducers and activators of transcription3 phosphorylation in CD4(+) T cells. Taken together, these results indicate that protein geranylgeranylation enhances the differentiation of T(h)17 cells and inhibits the differentiation of Foxp3(+) Tregs partly via the inhibition of SOCS3 expression.

Role of Th2 cells in IgG4-related lacrimal gland enlargement.

BACKGROUND: Lacrimal gland enlargement (LGE) is one of the characteristics of Mikulicz's disease (MD). Recently, marked serum IgG4 elevation and infiltration of IgG4-positive plasmacytes in the enlarged exocrine glands have been reported in MD patients. However, little is known about the role of CD4+ T cells and their cytokines in IgG4-related diseases. The aim of this study was to evaluate the characteristics of CD4+ T cells in patients with IgG4-related diseases. METHODS: We investigated the clinical characteristics of 9 patients with LGE and elevated serum IgG4 levels (named IgG4-related LGE). We also examined mRNA expression of cytokines and transcription factors of peripheral blood CD4+ T cells in patients with IgG4-related LGE. RESULTS: All patients with IgG4-related LGE showed elevated serum IgE levels. In addition, 5 of 9 patients with IgG4-related LGE exhibited eosinophilia and asthma-like symptoms. In patients with IgG4-related LGE, mRNA expression of IL-4, IL-5, IL-10 and GATA-3 but not IFN-gamma or T-bet was enhanced on CD4+ T cells compared with that in healthy controls. CONCLUSIONS: Th2 cells may be involved in the pathogenesis of IgG4-related diseases.

Granulomatosis with polyangiitis complicated with refractory optic neuritis and maxillary osteomyelitis.

We report a case of a 61-year-old man with granulomatosis with polyangiitis (GPA) complicated with refractory optic neuritis and maxillary osteomyelitis. He had been treated with prednisolone (PSL) as cryptogenic organizing pneumonia in the respiratory department for 2 years. Afterward, he complained tenderness of paranasal sinuses and rapidly progressive visual loss of the left eye. Although both MPO-ANCA and PR3-ANCA were negative, he was diagnosed as GPA based on the American College of Rheumatology 1990 criteria. Ophthalmologic and oral examination revealed left optic neuritis and destructive maxillary bone. Magnetic resonance imaging (MRI) showed the optic neuritis and inflammation around the optic nerve. This finding suggested that the direct spread of inflammation from paranasal sinuses caused the optic neuritis. In a short time, increasing a dose of PSL and administration of intravenous cyclophosphamide were initiated. Antibiotics were also administered to treat sinusitis. Although his visual acuity of the left eye deteriorated to no light perception temporarily, it finally improved after treatment and findings of MRI were also improved. In contrast, destruction of maxilla bone had been progressing. This is a rare case of GPA complicated with optic neuritis due to sinusitis and maxillary osteomyelitis.