Published papers

Objectives Recent studies have implicated cytotoxic CD4 and CD8 T cells in primary Sjögren’s syndrome (pSS) and IgG4-related disease (IgG4-RD), but their association with immune aging and organ-specific clinical features remain unclear. CX3CR1 is expressed on cytotoxic CD4 and CD8 T cells. The aim of this study was to determine associations of peripheral CX3CR1+CD4 and CX3CR1+CD8 T cells with aging and clinical features. Methods Whole blood samples were freshly obtained from consecutive patients with active, treatment-naïve pSS (n=57), IgG4-RD (n=54), and healthy individuals (n=40) and analysed by flow cytometry for CX3CR1+CD4 and CX3CR1+CD8 proportions. Associations of those T cells with aging and clinical features were determined. Results CX3CR1+CD4 and CX3CR1+CD8 T cells selectively expressed perforin and granzyme B. Proportions of CX3CR1+CD4 and CX3CR1+CD8 T cells were significantly higher in pSS and IgG4-RD than in healthy individuals. Higher proportions of CX3CR1+CD8 T cells were associated with aging in pSS and IgG4-RD but not in healthy individuals. Sex differences were not associated with proportions of CX3CR1+CD8 T cells. Furthermore, patients with pSS with interstitial lung disease showed higher proportions of CX3CR1+CD8 T cells than those without interstitial lung disease. IgG4-RD patients with retroperitoneal fibrosis and/or aortitis exhibited higher proportions of CX3CR1+CD8 T cells compared with those with Mikulicz’s disease. Moreover, proportions of CX3CR1+CD8 T cells were decreased following glucocorticoid treatment in paralleled with clinical improvements in IgG4-RD. Conclusion CX3CR1+CD8 T cells might be involved in immune aging and distinct clinical phenotypes of patients with pSS or IgG4-RD.

Sodium benzoate (SB), a known D-amino acid oxidase (DAO) enzyme inhibitor, has an anti-inflammatory effect, although its role in renal damage has not been explored. 2,8-dihydroxyadenine crystal induced chronic kidney disease, in which TNF-α is involved in the pathogenesis, was established by oral adenine administration in C57BL/6JJcl mice (AdCKD) with or without SB to investigate its renal protective effects. SB significantly attenuated AdCKD by decreasing serum creatinine and urea nitrogen levels, and kidney interstitial fibrosis and tubular atrophy scores. The survival of AdCKD mice improved 2.6-fold by SB administration. SB significantly decreased the number of infiltrating macrophages observed in the positive F4/80 immunohistochemistry area and reduced the expression of macrophage markers and inflammatory genes, including TNF-α, in the kidneys of AdCKD. Human THP-1 cells stimulated with either lipopolysaccharide or TNF-α showed increased expression of inflammatory genes, although this was significantly reduced by SB, confirming the anti-inflammatory effects of SB. SB exhibited renal protective effects in AdCKD in DAO enzyme deficient mice, suggesting that anti-inflammatory effect of SB was independent of DAO enzyme activity. Moreover, binding to motif DNA sequence, protein level, and mRNA level of NF-κB RelB were significantly inhibited by SB in AdCKD kidneys and lipopolysaccharide treated THP-1 cells, respectively. We report that anti-inflammatory property of SB is independent of DAO enzymatic activity and is associated with down regulated NF-κB RelB as well as its downstream inflammatory genes such as TNF-α in AdCKD.

Recent technological progress has greatly advanced our understanding of human immunology. In particular, the discovery of human T follicular helper (Tfh) and T peripheral helper (Tph) cells has significantly advanced our understanding of human adaptive immune system. Tfh and Tph cells share similar molecular characteristics and both play critical roles in B cell differentiation and maturation. However, they differ in their functional properties, such as chemokine receptor expression and cytokine production. As a result, Tfh cells are mainly involved in B cell differentiation and maturation in germinal centres of secondary lymphoid tissues, while Tph cells are involved in B cell differentiation and tissue damage in peripheral inflammatory lesions. Importantly, the involvement of Tfh and Tph cells in the pathogenesis of rheumatic and musculoskeletal diseases has become clear. In rheumatoid arthritis and systemic lupus erythematosus, Tph cell infiltration is predominant in peripheral inflammatory lesions, whereas Tfh cell infiltration is predominant in the affected lesions of IgG4-related disease. Therefore, the contribution of Tfh and Tph cells to the development of rheumatic and musculoskeletal diseases varies depending on each disease. In this review, we provide an overview of human Tfh and Tph cells and summarise the latest findings on these novel T cell subsets in various rheumatic and musculoskeletal diseases.

Background: It is thought that systemic sclerosis (SSc) might be a T helper 17 (Th17) cell-driven autoimmune disease. Noticeably, pulmonary arterial hypertension (PAH) is a leading cause of death in patients with SSc. Here, we investigated the association between serum Th17-related cytokines and prevalence of PAH in SSc patients. Methods: This study included 72 SSc patients and 51 healthy controls (HC). We determined clinical manifestations, immunophenotypes including Th subsets in peripheral blood lymphocytes, and the serum levels of interleukin (IL)-17A, IL-17A/F, IL-17B. IL-17C, IL-17D. IL-1β, IL-6, IL-21, IL-22, and IL-23. Results: The frequency of Th17 cells was significantly increased in SSc patients compared to HC and was positively correlated with the modified Rodnan skin scores. Furthermore, the serum levels of IL-17A, IL-17D, IL-1β, and IL-6 were significantly increased in SSc patients compared to HC. SSc patients with detected IL-17A showed high levels of IL-17A/F, IL-1β, IL-6, and IL-22, and high frequency of Th17 cells. Interestingly, these patients exhibited the reduced lung functions and increased prevalence of PAH significantly compared to patients with undetected IL-17A. Similarly, SSc patients with detected IL-17A and high IL-6 (≥1.2 pg/mL) exhibited the decreased lung functions and increased prevalence of PAH compared to patients with undetected IL-17A and low IL-6. Conclusion: We found that SSc patients with high levels of serum IL-17A or both IL-17A and IL-6 show reduced lung functions and high prevalence of PAH. Consequently, it is highly probable that Th17/IL-17A axis is critical for the prevalence of PAH in SSc patients.

Objectives: The regulation system for oxidative stress in systemic sclerosis (SSc) remains unclear. This study aimed to clarify the possible involvement of ataxia telangiectasia mutated (ATM), which plays a key role in DNA repair and redox balance, in the pathogenesis of SSc. Methods: Thirty patients with SSc and 15 healthy controls were enrolled. Expression of ATM and phosphorylated ATM (pATM), an activated form of ATM, in phagocytes in whole blood samples was analysed by FACS. Correlations between expression levels of ATM/pATM and clinical parameters of SSc patients were statistically analysed. Peripheral monocytes were cultured with an ATM-specific inhibitor (KU55933), and reactive oxygen species production in the cells was measured. Results: Expression level of pATM in peripheral monocytes and neutrophils from SSc patients was significantly lower than those in healthy controls (P = 0.04 and P < 0.001, respectively), while no significant difference in total ATM expression was observed between SSc and healthy controls. In addition, pATM expression in monocytes of SSc patients with interstitial lung disease or digital pitting scar was remarkably lower than in the patients without these clinical features (P = 0.02 and P = 0.03), respectively. Moreover, pATM expression in monocytes positively correlated with forced vital capacity and negatively correlated with the serum Krebs von den Lungen-6 level. Notably, KU55933, an ATM-specific inhibitor, enhanced reactive oxygen species production by monocytes under oxidative stress. Conclusion: Our data revealed that decreased ATM activation in monocytes was associated with SSc-interstitial lung disease and that impaired ATM activation in monocytes may contribute to the disease process of SSc via uncontrolled reactive oxygen species production.

Background: Lymphoproliferative disorder (LPD), including malignant lymphoma, is a relatively rare but life-threatening complication in RA patients under methotrexate (MTX) therapy. Spontaneous regression of LPD after MTX withdrawal is regarded as a distinct characteristic in part of such LPDs. Objective: The present study aimed to investigate the immunological difference in regressive LPD and persistent LPD. Methods: We studied RA patients who developed LPD during MTX administration (n = 35) and clinically matched controls (n = 35). The time of MTX cessation was defined as week 0, and LPD patients were divided into two groups according to LPD status at week 12: regressive group (n = 22) and persistent group (n = 13). Flow cytometric analysis of whole blood samples and serum cytokine assays were conducted for LPD (n = 10) and control patients (n = 10) at weeks 0, 4, and 12. Results: There was a significant decrease in peripheral lymphocytes and the proportion of T helper 1 cells (Th1 cells), effector memory CD8+ T cells (EMCD8+ T) and Epstein-Barr virus (EBV)-specific CD8+ T cells at the time of LPD diagnosis, and a significant increase after MTX cessation was observed in the regressive group but not in the persistent group. The expansion of Th1 cells and EMCD8+ T cells significantly correlated with an increase in serum interferon (IFN)-γ concentration. Conclusion: Changes in Th1 cells, EMCD8+ T cells and EBV-specific CD8+ T cells, which coincided with an increase in IFN-γ, were significantly different between regressive LPD and persistent LPD after MTX cessation.

Objectives: Multiple studies suggest that interleukin (IL)-21 plays a pivotal role in the differentiation of B cells and activation of cytotoxic T cells and is involved in the pathogenesis of IgG4-related disease (IgG4-RD). T cell immunoreceptor with immunoglobulin and ITIM domain (TIGIT) is a new marker of T follicular helper (Tfh) cells, yet its significance remains unknown. The objective of this study was to investigate whether TIGIT expression could detect high IL-21-producing peripheral Tfh populations and their association with disease activity in IgG4-RD. Methods: TIGIT expression in peripheral CD4+T cell subsets was comprehensively analyzed by multi-color flow cytometry. Single cell mapping was performed by t-SNE method, and IL-21 production was compared in TIGIT+ and TIGIT-T cells. The effect of OX40 signal on cytokine expression was analyzed by RNA-sequencing. Clinical significance of TIGIT+ and TIGIT- peripheral T cells was analyzed in active patients with IgG4-RD, both at baseline and after 12 weeks of glucocorticoid treatment. Results: Unbiased single cell mapping revealed two high IL-21-producing peripheral T cell populations; TIGIT+ Tfh and TIGIT-T helper cells. OX40 signal was associated with high IL-21 production in TIGIT+ Tfh and TIGIT-T helper cells. IL-21 production in Tfh cells correlated with the proportion of TIGIT+ cells in Tfh cells, serum IgG4 level, and scores of disease activity. Furthermore, the skewing toward peripheral TIGIT+ Tfh cells, particularly TIGIT+Tfh2 subset correlated with disease activity and was corrected by glucocorticoid treatment in IgG4-RD. Conclusions: OX40 is associated with high IL-21 production in peripheral TIGIT+ Tfh cells, and the increase in peripheral TIGIT+ Tfh cells reflects disease activity in IgG4-RD.

Neutrophils form neutrophil extracellular traps (NETs), which are involved in the pathogenesis of ANCA-associated vasculitis (AAV). Recent reports suggest that platelets stimulated via toll-like receptor (TLR) pathways can induce NETs formation. However, the mechanism underlying the involvement of platelets in NETs formation in AAV is unknown. We investigated the role of platelets in the pathogenesis of AAV. Platelets from AAV patients and healthy controls (HCs) were co-cultured with peripheral neutrophils, and NETs formation was visualized and quantified. The expression levels of TLRs on platelets were examined by flow cytometry. Platelets were treated with a TLR agonist, platelet-derived humoral factor, CXCL4 (platelet factor 4: PF4), and/or anti-CXCL4 antibody to investigate the effects of TLR–CXCL4 signaling on NETs formation. Platelets from AAV significantly upregulated NETs formation in vitro. Flow cytometric analysis revealed that the proportion of TLR9 positive platelets was significantly higher in AAV than HCs. CXCL4 released from TLR9 agonist-stimulated platelets was significantly enhanced in AAV, which subsequently increased NETs formation. Further, neutralizing anti-CXCL4 antibody significantly inhibited NETs formation enhanced by platelets from AAV. TLR9 signaling and CXCL4 release underlie the key role that platelets play in NETs formation in the pathogenesis of AAV.

Background: Large vessel vasculitis (LVV) is a type of vasculitis characterized by granulomatous inflammation of medium- and large-sized arteries. Clinical assessment of acute phase reactants has been conventionally used to diagnose and monitor diseases; however, accurate assessment of vascular disease activity status can be difficult. In this study, we investigated comprehensive immuno-phenotyping to explore useful biomarkers associated with clinical characteristics. Methods: Consecutive patients with newly diagnosed LVV who visited our institution between May 2016 and May 2019 were enrolled. The number of circulating T cells, B cells, natural killer cells, dendritic cells, monocytes, and granulocytes was examined and chronologically followed. Baseline and time-course changes in immuno-phenotyping associated with disease activity were assessed. Results: Comprehensive immuno-phenotyping data from 90 samples from each of 20 patients with LVV were compared with those from healthy controls (HCs). The number of helper T (Th), follicular helper T (Tfh), CD8+ T, CD14++ CD16+ monocytes, and neutrophils were higher in patients with giant cell arteritis (GCA) and/or Takayasu arteritis (TAK) than in HCs. Among them, the number of CD8+ T and CD8+ Tem were higher in patients with TAK than in GCA. Notably, memory CD4+ and CD8+ T cells in patients with TAK remained high even in the remission phase. Further analysis revealed that the number of Th1, Th17, and Tfh cells was associated with disease relapse in GCA and TAK and that the number of CD8+ T cells was associated with relapse in TAK. Th1, Th17, and Tfh cells decreased after treatment with biologic agents, while CD8+ T cells did not. Conclusions: Our results from peripheral immuno-phenotyping analysis indicate that the numbers of Th and Tfh cells changed along with the disease condition in both GCA and TAK, while that of CD8+ T cells did not, especially in TAK. Treatment with biologic agents decreased the proportion of Th and Tfh cells, but not CD8+ T cells, in the patients. Chronological immuno-phenotyping data explained the difference in therapeutic response, such as reactivities against biologics, between GCA and TAK.

Objectives: To elucidate the association between clinical characteristics and immuno-phenotypes in patients with ANCA-associated vasculitis (AAV). Methods: Peripheral blood from 36 patients with active AAV and 18 healthy controls was examined for numbers of circulating T cells, B cells, NK cells, dendritic cells, monocytes and granulocytes using flow cytometry. These immuno-phenotyping data were subjected to cluster analysis and principal components analysis to divide AAV patients into subgroups. Associated organ involvement or therapeutic prognosis were assessed for each subgroup. Results: AAV patients had higher proportions of plasma cells, plasmablasts, activated T cells, CD14++ CD16+ monocytes, eosinophils and neutrophils than healthy controls. Immuno-phenotyping findings were similar between patients with microscopic polyangiitis, granulomatosis with polyangiitis and eosinophilic granulomatosis with polyangiitis. Cluster analysis indicated that AAV patients could be divided into three subgroups according to peripheral immune cell numbers: antibody production-related (n = 9), cytotoxic activity-related (n = 4) and neutrocytosis/lymphocytopenia-related (n = 23). The antibody production-related or cytotoxic activity-related group was associated with CNS involvement, and the neutrocytosis/lymphocytopenia-related group was associated with high incidence of kidney involvement. Incidence of severe infection was markedly higher in the neutrocytosis/lymphocytopenia-related group than the other two groups. Incidence of disease relapse was comparable among the three groups. Conclusion: Patients with active AAV can be divided into three subgroups based on immuno-phenotyping. These results may provide a hint to understanding disease pathophysiology and prognosis, and determining appropriate treatment.

Objectives: Tocilizumab (TCZ) is a humanised anti-interleukin (IL)-6 receptor (IL-6R) monoclonal antibody that is a promising agent to treat various autoimmune diseases. However, the mechanism of TCZ efficacy is unclear. This study aims to elucidate the relationship between Tregs and IL-6R blockade in autoimmunity-mediated renal disease based on a TCZ-treated cohort of patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) and in an experimental model of crescentic glomerulonephritis (cGN). Methods: We examined multiple serum levels of cytokines and chemokines and peripheral blood mononuclear cells in patients with AAV who received TCZ monotherapy and achieved drug-free remission. Moreover, we investigated the mechanistic role of IL-6R blockade in accelerated cGN model to analyse the local sites of inflammation. Results: Serum chemokines CCL22 and CCL17, in addition to the CCR4+Foxp3+ Treg population, increased in patients who demonstrated drug-free remission after the cessation of TCZ. In the cGN model, IL-6R blockade ameliorated the disease, elevated CCL22/17 in CD206+CD11b+CD11c+ kidney M2-like type macrophages, and increased the migration of Tregs into the kidney and regional lymph nodes. The local administration of CCL22 in the kidney facilitated Treg accumulation and reduced glomerular crescent formation. Conclusions: This study revealed a new mechanism whereby effector Tregs migrate into the inflammatory kidney via the CCL22/17–CCR4 axis that is facilitated by M2-like type macrophages that are induced by IL-6R blockade.

Sustained clinical remission (CR) without drug treatment has not been achieved in patients with rheumatoid arthritis (RA). This implies a substantial difference between CR and the healthy state, but it has yet to be quantified. We report a longitudinal monitoring of the drug response at multi-omics levels in the peripheral blood of patients with RA. Our data reveal that drug treatments alter the molecular profile closer to that of HCs at the transcriptome, serum proteome, and immunophenotype level. Patient follow-up suggests that the molecular profile after drug treatments is associated with long-term stable CR. In addition, we identify molecular signatures that are resistant to drug treatments. These signatures are associated with RA independently of known disease severity indexes and are largely explained by the imbalance of neutrophils, monocytes, and lymphocytes. This high-dimensional phenotyping provides a quantitative measure of molecular remission and illustrates a multi-omics approach to understanding drug response.

IgG4-related disease (IgG4-RD) is a systemic disorder characterized by elevated serum IgG4 level, which is mediated by T follicular helper 2 (Tfh2) cell. However, the cytokines responsible for enhancing IgG4 production remain unclear in IgG4-RD. The aim of this study was to identify responsible Tfh2-related cytokines (interleukin (IL)-4 and IL-21) for enhancing IgG4 production in IgG4-RD. Peripheral blood mononuclear cells obtained from consecutive patients with active, untreated IgG4-RD and healthy controls were examined. The production of both IgG and IgG4 were significantly increased by stimulation with IL-4 alone as well as IL-21 alone compared to background stimulation with anti-CD40 antibody in IgG4-RD. On the other hand, the IgG4/IgG ratio was statistically higher by stimulation with IL-4 alone compared to the other Tfh2-related cytokines including IL-21 in IgG4-RD. IgG4 production was not increased by stimulation with IL-4 in healthy controls. These results suggest that IL-4 can contribute to the shift of balance of IgG subclasses toward IgG4 compared to the other Tfh2-related cytokines in IgG4-RD.

Background: Interstitial lung disease (ILD) is a serious complication of connective tissue diseases (CTDs). Although immune dysregulation triggered by genetic and environmental factors is thought to provoke inflammation and subsequent fibrosis, precise mechanisms of these processes remain unclear. Recent reports suggest that activation of aryl hydrocarbon receptor (AhR) signals by various ligands such as tryptophan derivatives can induce hyper-immune responses and are involved in autoimmunity. We investigated the effects of AhR signals on the process of lung fibrosis and changes in immunological features using a bleomycin (BLM)-induced lung fibrosis mouse model. Methods: BLM was administered intratracheally to C57BL/6JJcl mice and either 5,11-dihydroindolo[3,2-b]carbazole-6-carboxaldehyde (FICZ), a natural AhR ligand, or vehicle was subsequently injected intraperitoneally on day 0, 1, and 2 from BLM administration. Mice were sacrificed at week 3, and lung fibrosis was quantified by the histological changes using the Ashcroft score and deposition of soluble collagen levels in the lung using Sircol assay. The population of immune cells infiltrated into the lungs was analyzed using flow cytometry. Results: Both the Ashcroft score and soluble collagen level in FICZ-treated mice were significantly lower than those in the vehicle group. Moreover, the survival rate of FICZ-treated mice was significantly higher than that of control mice during the 3 weeks after treatment. Interestingly, flow cytometric analysis revealed that the number of CD4+Foxp3+ regulatory T cells (Tregs) was significantly increased and CD4+IFNγ+ and γδ+IL-17A+ T cells were decreased in the lungs of FICZ-treated mice, while the total number of T, B, and NK cells were unaffected by FICZ treatment. Conclusions: Our findings suggest that stimulation of AhR signals attenuated lung fibrosis by increasing Tregs and suppressing inflammatory T cell subsets in a BLM-induced fibrosis model. AhR signaling pathways may therefore be useful therapeutic targets for connective tissue disease-associated ILD.

Background: We reported that the production of BAFF (B cell-activating factor) and IL-6, both of which are involved in survival and differentiation of B cells, is dysregulated in monocytes of patients with primary Sjögren's syndrome (pSS). In this study, we investigate the relationship between possible aberrations of pSS monocytes and clinical features of pSS patients and the contribution of monocytes to B cell activation, a mechanism involved in the pathogenesis of pSS. Methods: Expression of BAFF-receptor (BR3) on peripheral monocytes from patients with pSS (n = 67) and healthy controls (HC: n = 37) was analyzed by FACS. Peripheral monocytes were stimulated with BAFF, and IL-6 production by the cells was measured by ELISA. Peripheral B cells were cultured with BAFF-stimulated monocytes in the presence or absence of anti-IL-6 receptor antibody, and IgG production by the cells was measured by ELISA. Patients' serological data were collected from their clinical records. Patients' disease activity was quantified based on their EULAR Sjögren's syndrome disease activity index (ESSDAI) scores. Results: The proportion of peripheral BR3-positive monocytes (BR3+/CD14+) was significantly increased in pSS patients compared to HC. Moreover, IL-6 production by BAFF-stimulated monocytes was remarkably higher than HC and was significantly correlated with BR3+/CD14+ ratios of patients. In addition, BR3 expression on pSS monocytes was elevated in anti-Ro/SSA and/or anti-La/SSB positive compared to negative patients. Remarkably, BR3 expression on peripheral monocytes was positively and significantly correlated with patients' serum IgG and IgM levels and ESSDAI scores. Moreover, the amount of IgG produced by B cells was markedly higher in pSS patients compared to HC when the cells were co-cultured with BAFF-stimulated autologous monocytes in vitro. Notably, addition of anti-IL-6 receptor antibody into the co-culture system led to inhibition of IgG production by B cells. Conclusions: Our data suggest that elevated BR3 expression in monocytes is associated with clinical features in pSS patients and that enhanced production of IL-6 by BAFF-stimulated monocytes plays a part in the overproduction of IgG by B cells in pSS. These results suggest that BAFF signaling pathways through BR3 in monocytes are possible therapeutic targets for pSS.

Background: Leukocyte activation by anti-neutrophil cytoplasmic antibody (ANCA) and the subsequent leukocyte–endothelium interaction play a key role in the development of endothelial damage in ANCA-associated vasculitis (AAV). In contrast to that of leukocyte activation, the exact role of the leukocyte–endothelium interaction via integrin remains unclear. Here, we performed microarray and validation analyses to explore association between the expression levels of lymphocyte function-associated antigen-1 (LFA-1) and the clinical characteristics of patients with AAV. Methods: We performed gene set enrichment analysis (GSEA) to identify the functional gene sets differentially expressed between patients with AAV and other types of vasculitis and the healthy controls (HCs). Flow cytometry was performed to validate the GSEA results. Treatment-naïve patients were monitored until 24 weeks of treatment. To examine the role of LFA-1 in the neutrophil–endothelium interaction, we performed a leukocyte adhesion and transmigration assay using peripheral blood and human umbilical vein endothelial cells (HUVECs). Results: GSEA revealed that the molecular pathways involving integrin-related genes were significantly upregulated in patients with AAV compared to that in patients with other types of vasculitis and the HCs. Flow cytometry revealed that the percentage of neutrophils expressing LFA-1 was significantly higher in patients with AAV than in those with large-vessel vasculitis or polyarteritis nodosa and the HCs. LFA-1 levels in the neutrophils were higher in patients with MPO-ANCA-positive expression than in those with a positive PR3-ANCA expression and correlated with the peripheral eosinophil count, serum rheumatoid factor titre, serum C-reactive protein levels, and the vasculitis activity score of systemic and chest components. After 24 weeks of treatment, including prednisolone, cyclophosphamide, rituximab, azathioprine, methotrexate, and/or tacrolimus, neutrophil LFA-1 expression remained high in the non-responder patients, but decreased in the responder patients. The in vitro assay showed that leukocyte migration toward HUVECs was dependent on the interaction between LFA-1 and intercellular adhesion molecule-1 (ICAM1); the migration of leukocytes was inhibited by blocking the adhesion of LFA-1 to ICAM1. Conclusions: The expression of LFA-1 in neutrophils is increased in patients with AAV. Neutrophil LFA-1 levels correlate with the clinical features of AAV. Inhibiting the adhesion of LFA-1 and ICAM1 impedes the neutrophil–endothelium interaction and may have a therapeutic role in AAV.

We investigated the correlation between the increased proportion of peripheral B cell subsets and clinical and immunological features in primary Sjögren's syndrome (pSS). We found that the proportion of CD19 + B cells was significantly increased in pSS as compared with HC and was correlated with serum IgG levels. Moreover, in vitro IgG production by CD19 + B cells was significantly increased in pSS and was positively and significantly correlated with serum IgG levels. FACS analysis revealed that the proportions of peripherally CD38 high IgD + B cells and CD38 high IgD − B cells were significantly increased in pSS. In addition, the proportion of CD38 high IgD + B cells positively correlated with ESSDAI scores and serum levels of IgG, anti-Ro/SSA and anti-La/SSB antibodies while that of CD38 high IgD − B cells showed no correlation with these parameters. Our data suggest that increased proportion of CD38 high IgD + B cells in pSS is involved in IgG overproduction including autoantibodies, and correlates with disease progression.

Objectives: Large vessel vasculitis (LVV) is characterised by a high relapse rate. Because accurate assessment of the LVV disease status can be difficult, an accurate prognostic marker for initial risk stratification is required. We conducted a comprehensive longitudinal investigation of next-generation RNA-sequencing data for patients with LVV to explore useful biomarkers associated with clinical characteristics. Methods: Key molecular pathways relevant to LVV pathogenesis were identified by examining the whole blood RNA from patients with LVV and healthy controls (HCs). The data were examined by pathway analysis and weighted gene correlation network analysis (WGCNA) to identify functional gene sets that were differentially expressed between LVV patients and HCs, and associated with clinical features. We then compared the expression of the selected genes during week 0, week 6, remission and relapse. Results: The whole-transcriptome gene expression data for 108 samples obtained from LVV patients (n = 27) and HCs (n = 12) were compared. The pathway analysis and WGCNA revealed that molecular pathway related to interleukin (IL)-1 was significantly upregulated in LVV patients compared with HCs, which correlated with the positron emission tomography vascular activity score, a disease-extent score based on the distribution of affected arteries. Further analysis revealed that the expression levels of genes in the IL-1 signalling pathway remained high after conventional treatment and were associated with disease relapse. Conclusion: Upregulation of the IL-1 signalling pathway was a characteristic of LVV patients and was associated with the extent of disease and a poor prognosis.

Background: Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is an autoimmune disease that affects small- to medium-sized blood vessels. Despite treatments having been improved, patients often experience disease relapses. It remains unclear how the immune cells involve in the development of vasculitis and how they fluctuate over the course of treatment. In this study, we aimed to identify the immune subsets and serum cytokines associated with disease relapse by comprehensive immuno-phenotyping in AAV patients. Methods: We reviewed consecutive patients (n = 29) from Keio University Hospital who had been newly diagnosed with AAV from January 2015 to February 2019 and chronologically followed until 52 weeks. Numbers of circulating T cells, B cells, monocytes, and granulocytes were analyzed by flow cytometry (FACS). Serum levels of cytokines were measured by electrochemiluminescence enzyme immunoassay. Clinical information was obtained from patients' records and association with time-course changes in immuno-phenotypes and serum levels of cytokines were assessed. Results: Comprehensive immuno-phenotyping data from 161 samples from 29 AAV patients at diagnosis; at weeks 4, 12, 24, and 52 of treatment; and at time of major relapse were examined. FACS analysis from patients with relapse revealed that CD14++ CD16+ intermediate monocytes and plasma cells concomitantly changed associated with disease relapse, which were independent from treatment regimen, ANCA status, or disease phenotype. In particular, the number of CD14++ CD16+ intermediate monocytes at relapse was significantly higher than that in remission or in healthy controls. Serum cytokine measurement revealed that changes of monocyte-derived proinflammatory cytokines such as IL-1β, IL-6, IL-8, and TNF-α were associated with disease status. Conclusions: Chronological changes in CD14++ CD16+ intermediate monocyte counts can be a marker of disease relapse in AAV patients.

Background: Milk fat globule epidermal growth factor (MFG-E8) is related secreted protein which links phosphatidylserine on apoptotic cells and integrin αvβ3/5 on phagocytes. To clarify the clinical significance of MFG-E8 in SLE, we analyzed the correlation between expression level of MFG-E8 in circulating phagocytic leukocytes and clinical parameters of patients. Methods: The study was conducted under a multi-center, prospective cohort design. Patients with one or both BILAG A or B, or SLEDAI- 2 K ≥ 4 with clinical symptoms were defined as the active SLE group. Expression of MFG-E8 on monocytes and concentration in serum were measured by FACS and ELISA, respectively. Results: 96 subjects were enrolled. The absolute number and proportion of MFG-E8-positive monocytes to total monocytes were significantly higher in the active SLE group (p < 0.01). Importantly, the proportion was also significantly correlated with SLEDAI-2K, clinical SLEDAI, as well as serum levels of anti-ds-DNA antibody and complement and C1q. In addition, the proportion of MFG-E8-positive monocytes to total monocytes was significantly decreased from baseline in active SLE patients after 6 months’ treatment and increased concordantly with disease activity in 6 refractory cases. Further, in receiver operating characteristic curve analysis for discrimination between active and inactive SLE, the AUC of the proportion of MFG-E8 was 0.854, which was equivalent to classical activity markers such as anti-ds DNA antibody (0.776), complement (0.897) and C1q (0.815) Conclusions: The proportion of MFG-E8-positive monocytes to total monocytes in peripheral blood was positively associated with disease activity in SLE and may be a novel biomarker of disease activity.