Successful high-dose glucocorticoid therapy for anti-mitochondrial antibody-positive myocarditis arising during tocilizumab and low-dose glucocorticoid therapy for rheumatoid arthritis.

Anti-mitochondrial antibody (AMA)-positive myopathy, a recently identified condition with significant cardiac involvement, poses a serious challenge in treatment consensus due to its extreme rarity. While several studies demonstrate the efficacy of high-dose prednisolone in managing this disease, the current literature lacks substantial evidence regarding the effectiveness of biologic therapy or low-dose prednisolone for remission induction. Here, we present a case of AMA-positive myocarditis that emerged during rheumatoid arthritis treatment with tocilizumab (TCZ) and low-dose prednisolone (PSL). Successfully, intensive immunosuppressive therapy with high-dose PSL proved effective in stabilizing this condition. Our case highlights the necessity of a robust immunosuppressive approach, favoring high-dose PSL over the combination of low-dose PSL and TCZ in this disease.

Cytotoxic Tph subset with low B-cell helper functions and its involvement in systemic lupus erythematosus.

T peripheral helper (Tph) cells are thought to contribute to extra-follicular B cell activation and play a pathogenic role in autoimmune diseases. However, the role of Tph subsets is not fully elucidated. Here, we investigate the immunological functions of Tph subsets and their involvement in systemic lupus erythematosus (SLE). We have defined four Tph subsets (Tph1: CXCR3+CCR6-, Tph2: CXCR3-CCR6-, Tph17: CXCR3-CCR6+, and Tph1-17: CXCR3+CCR6+) and performed RNA sequencing after cell sorting. Tph1 and Tph17 subsets express substantial levels of IL21, indicating B cell helper functions. However, Tph2 and Tph1-17 subsets express low IL21. Interestingly, we have found Tph2 subset express high levels of CX3CR1, GZMB, PRF1, GLNY, S1PR5, TBX21, EOMES, ZNF863, and RUNX3, indicating a feature of CD4+ cytotoxic T lymphocytes. In SLE patients, the frequency of Tph1 and Tph2 subsets are significantly increased and positively correlated with SLE disease activity indexes. Tph1 cells expansion has been observed in patients with cutaneous and musculoskeletal manifestations. On the other hand, Tph2 cell expansion has been found in patients with lupus nephritis in addition to the above manifestations. Our findings imply that Tph1 and Tph2 subsets exert distinct immunological functions and are contributed to the complexity of clinical manifestations in SLE.

A Case of Successful Immunosuppressive Therapy for Interstitial Lung Disease Associated with Sjögren's Syndrome With Double-positive Anti-SS-A and Anti-centromere Antibodies.

Sjögren's syndrome (SS) can present with extraglandular organs, such as interstitial lung disease (ILD). Anti-SS-A antibody is frequently found in SS cases, whereas anti-centromere antibody (ACA) is detected in some SS cases. Notably, the anti-SS-A and ACA double-positive cases exhibited distinct features with a higher prevalence of ILD. However, there have so far been no reports on the treatment of ILD in anti-SS-A and ACA double-positive cases. We herein present a case of ILD with anti-SS-A and ACA double-positive SS that was successfully treated with immunosuppressive therapy. Our case suggests the potential efficacy of immunosuppressive therapy for this poorly understood condition.

Successful Treatment of Rosai-Dorfman Disease with Cutaneous Involvement and Arthritis with Methotrexate and Infliximab.

Rosai-Dorfman disease (RDD) is a rare histiocytic proliferative disorder characterized by lymphadenopathy and extra-nodal manifestations. Some patients with RDD require systemic treatment, but there is no consensus on the treatment strategy owing to its extreme rarity. Overexpression of tumor necrosis factor α (TNF-α) has been reported in lesions of patients with RDD and is thought to be involved in its pathogenesis. We herein report the first case of RDD with cutaneous involvement and arthritis that was successfully treated with methotrexate and infliximab. This case highlights the potential efficacy of anti-TNF-α therapy for RDD, offering a novel treatment option for this rare condition.

Th17/IL-17A axis is critical for pulmonary arterial hypertension (PAH) in systemic sclerosis (SSc): SSc patients with high levels of serum IL-17A exhibit reduced lung functions and increased prevalence of PAH.

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-1ß, 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-1ß, 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-1ß, 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.

Does a window of opportunity for rheumatoid arthritis-associated interstitial lung disease exist?

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammatory synovitis, eventually leading to joint destruction. Remarkable advancements in the emergence of molecular targeted therapies and the treatment strategy based on treat-to-target have made it possible for patients to lead their daily lives without disabilities. Specifically, early diagnosis and appropriate treatment without missing a 'window of opportunity' are crucial for improving joint outcomes. On the other hand, interstitial lung disease (ILD) is an extra-articular complication of RA and has an impact on life prognosis. Importantly, it has become evident that achieving remission of arthritis is critical not only for joint outcomes but also to prevent the irreversible progression of pulmonary fibrosis in RA-ILD. Therefore, a 'window of opportunity' may exist not only for joints but also for RA-ILD. However, within RA-ILD, there are cases that progress from an NSIP pattern or airway involvement to a UIP pattern, while there are cases without progression, suggesting that their disease behavior may be diverse. Thus, accumulating evidence is necessary to accurately determine the disease behavior of RA-ILD. This review provides an overview of clinical and radiological features and treatment strategies for RA-ILD, incorporating the latest findings.

Re-emphasising the importance of catheter-based angiography to differentiate polyarteritis nodosa from cutaneous arteritis: Two case reports.

Polyarteritis nodosa (PAN) is a systemic necrotising vasculitis with a poor prognosis, characterised by inflammation and necrosis of medium-sized arteries. PAN patients can present with a wide range of systemic manifestations, whereas cutaneous arteritis (CA) is a restricted manifestation to skin of the disease with a more favourable prognosis. Thus, differentiation between PAN and CA is crucial. Here, we present two cases that were initially diagnosed as CA due to the limited presence of systemic symptoms, but were finally diagnosed as PAN through catheter-based angiography. Although contrast-enhanced computed tomography and computed tomographic angiography are increasingly used to diagnose PAN, neither case had any abnormal findings on these examinations. Our cases therefore underscore that catheter-based angiography is critical for differentiation between PAN and CA, even in cases with limited systemic symptoms.

Significant association of CX3CR1+CD8 T cells with aging and distinct clinical features in Sjögren's syndrome and IgG4-related disease.

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. CONCLUSIONS: CX3CR1+CD8 T cells might be involved in immune aging and distinct clinical phenotypes of patients with pSS or IgG4-RD.

Sarcopenia in patients with rheumatic musculoskeletal diseases.

AIM: To investigate the impact of high-dose glucocorticoid therapy on sarcopenia in hospitalized patients with rheumatic musculoskeletal diseases (RMDs). METHODS: We included patients with RMDs who were hospitalized between 2020 and 2022 for remission induction treatment and collected information on skeletal mass index (SMI) before high-dose glucocorticoid therapy and 1 month later. We divided the patients into 2 groups according to the progression of sarcopenia, defined as a >10% decrease in SMI, and compared their clinical characteristics. RESULTS: Forty-nine patients were included in this analysis. The mean age was 53.3 years, 73.5% were female, and the mean SMI was 5.3 kg/m2 . Before treatment, 83.7% had already met the definition of sarcopenia, and 57.1% experienced further sarcopenia progression after 1 month of high-dose glucocorticoid treatment. Patients with sarcopenia progression were predominantly male (P = 0.025), had a higher body weight (P = 0.048), and showed a higher SMI than those without sarcopenia at baseline (P = 0.008). Multivariable analysis revealed that body weight increase from 0 to week 1 of high-dose glucocorticoid treatment was associated with sarcopenia progression (odds ratio: 0.22, 95% CI: 0.04-0.61, P = 0.007) with a cut-off of -1.8 kg. During a mean observation period of 30.2 days, the incidence of infection was significantly higher in patients with progressive sarcopenia (P = 0.042). CONCLUSIONS: One-month hospitalization with high-dose glucocorticoid therapy is associated with sarcopenia progression in patients with RMDs. An early decrease in body weight can be used to predict muscle volume loss.

T follicular helper cells and T peripheral helper cells in rheumatic and musculoskeletal diseases.

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.

Successful treatment of PR3-ANCA-positive interstitial pneumonia with a moderate dose of glucocorticoid and rituximab.

Antineutrophil cytoplasmic antibody (ANCA)-positive interstitial pneumonia (IP) is reported as IP that is ANCA-positive and does not involve organ damage associated with vasculitis other than the lungs. While the combination of glucocorticoid and rituximab is effective in ANCA-associated vasculitis, the treatment strategy for ANCA-positive IP has not been established. Here, we report the first case of successful treatment of proteinase 3 (PR3)-ANCA-positive IP with a moderate dose of glucocorticoid and rituximab. The patient was an 80-year-old male who presented with subacute dry cough and dyspnoea. Blood tests revealed elevated levels of C-reactive protein, Krebs von den Lungen 6 (KL-6), and PR3-ANCA. Chest computed tomography (CT) showed interstitial shadows and infiltrates around honeycomb cysts. 18F-fluorodeoxyglucose (FDG) positron emission tomography CT revealed an uptake of FDG in the IP area. After starting treatment with a moderate dose of prednisolone and rituximab, the patient's clinical symptoms disappeared, C-reactive protein and KL-6 turned to be normal, and infiltrates around the cysts of honeycomb lungs disappeared. Prednisolone was gradually decreased to 2 mg, and no relapse or adverse events were observed during the course of treatment. Our case suggests that early treatment with a moderate dose of glucocorticoid and rituximab is effective for PR3-ANCA-positive IP.

Atypical Cogan's Syndrome with Large-vessel Vasculitis Successfully Treated with Tocilizumab.

A 61-year-old man presented with weight loss, bilateral ocular redness, blurred vision, and sensorineural hearing loss. Fluorodeoxyglucose-position emission tomography/computed tomography demonstrated an uptake in the ascending and descending aorta, abdominal aorta and femoral arteries. Atypical Cogan's syndrome complicated with large-vessel vasculitis (LVV) was diagnosed. He was treated with high-dose prednisolone and subcutaneous tocilizumab (162 mg/week), resulting in successful improvements in his ocular and vascular involvements. Although there is currently no established treatment strategy for LVV associated with Cogan's syndrome, our case and literature review suggest that tocilizumab is a viable treatment option for this rare but life-threatening complication.

Deficiency of the CD155-CD96 immune checkpoint controls IL-9 production in giant cell arteritis.

Loss of function of inhibitory immune checkpoints, unleashing pathogenic immune responses, is a potential risk factor for autoimmune disease. Here, we report that patients with the autoimmune vasculitis giant cell arteritis (GCA) have a defective CD155-CD96 immune checkpoint. Macrophages from patients with GCA retain the checkpoint ligand CD155 in the endoplasmic reticulum (ER) and fail to bring it to the cell surface. CD155low antigen-presenting cells induce expansion of CD4+CD96+ T cells, which become tissue invasive, accumulate in the blood vessel wall, and release the effector cytokine interleukin-9 (IL-9). In a humanized mouse model of GCA, recombinant human IL-9 causes vessel wall destruction, whereas anti-IL-9 antibodies efficiently suppress innate and adaptive immunity in the vasculitic lesions. Thus, defective surface translocation of CD155 creates antigen-presenting cells that deviate T cell differentiation toward Th9 lineage commitment and results in the expansion of vasculitogenic effector T cells.

A severe cerebral infarction associated with giant cell arteritis, which developed during tocilizumab therapy and was successfully treated with intravenous cyclophosphamide.

Giant cell arteritis (GCA) is a large vessel vasculitis that primarily involves aorta and its major branches. Cerebral infarction is a serious complication that can occur secondary to GCA in up to 3% of patients with a mortality rate of over 50%. Due to the rarity of this severe complication, no therapeutic strategies are currently available. Furthermore, despite the recent progress in molecular-targeted therapy for GCA, it remains unknown whether tocilizumab is effective for severe ischemic complications such as cerebral infarction. The accumulation of individual cases in which this fatal complication could be treated is apparently required to build a better management of the disease. We present our case of GCA that developed severe cerebral infarction during high-dose glucocorticoid and tocilizumab therapy, and its symptoms and image findings were improved by switching to intravenous cyclophosphamide. Our case suggests that an intensive immunosuppressive therapy, including cyclophosphamide, may be necessary to stabilise this fatal complication of GCA.

Distinct impact of malignancy and allergy on the clinical and immunological features of IgG4-related disease.

OBJECTIVES: To clarify the clinical and immunological characteristics of IgG4-RD based on the underlying diseases. METHODS: Consecutive patients with IgG4-RD treated at Keio University Hospital between 2010 and 2021 were divided according to the presence of malignancy or allergy into three groups. The clinical characteristics and 56 immune cell subsets in the peripheral blood were compared among the groups. RESULTS: Among 123 patients, 18 (14.6%) had malignancy including 4 with allergy (malignancy group), 57 (46.3%) had allergy alone (allergy group), and 48 (39.0%) had neither (idiopathic group). In the malignancy group, the patients were older (70.1 vs. 54.4 vs. 64.9 years, p<0.001), male-dominant (83.3 vs. 42.1 vs. 54.2%, p=0.008), and had smoking habits (77.8 vs. 42.1 vs. 43.8%, p=0.02). They also had significant involvement of the aorta/large vessels (33.3 vs. 7.0 vs. 20.8%, p=0.02), while the patients in the allergy group tended to have orbital/lacrimal gland involvement. Remission and relapse rates were not different between the groups; however, overall survival was significantly poorer in the malignancy group (p=0.02). Comprehensive immunophenotyping of the peripheral blood revealed that the increase in CXCR5+CD2-double negative T cells and the decrease in naive CD8 T cells were characteristic of the malignancy group. CONCLUSIONS: The clinical and immunological phenotypes of IgG4-RD differ among those with underlying diseases.

Disease-specific expansion of CD29+IL-17RA+ T effector cells possessing multiple signalling pathways in spondyloarthritis.

OBJECTIVES: T cells adhere to enthesis fibrocartilage via integrins and intrinsically require IL-17RA-mediated signals to maintain their effector function. We analysed CD29+IL-17RA+ T cells in inflamed lesions and peripheral blood in patients with SpA and investigated their association with disease activity and therapeutic response. METHODS: Transcriptome analysis of synovial fluid T cells from PsA was performed using publicly available bulk cell RNA sequencing data. Blood samples were obtained from healthy controls (n = 37), RA (n = 12), IgG4-related disease (IgG4-RD; n = 12), large vessel vasculitis (LVV; n = 12) and SpA (n = 28) and were analysed by flow cytometry. RESULTS: T cells in the inflamed joints of PsA showed CD29 and IL-17RA expression. CD29+IL-17RA+ T cells showed enriched CXCR3+CD45RA+ effector cells and activation of spleen tyrosine kinase (Syk), nuclear factor κB (NF-κB) and Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathways. The proportion of peripheral blood CD29+IL-17RA+ T cells was significantly increased in patients with SpA compared with patients with RA, IgG4-RD or LVV and in healthy controls. Based on the ASDAS-CRP scores, the proportion of CD29+IL-17RA+ T cells was positively correlated with disease activity in treatment-naïve patients with active SpA. Anti-IL-17 but not anti-TNF monoclonal antibodies reduced CD29+IL-17RA+ T cells. CONCLUSIONS: CD29+IL-17RA+ T effector cells with enhanced Syk, NF-κB and JAK-STAT pathways were specifically increased in SpA and were correlated with disease activity, implicating a role of this newly identified T cell population in the pathogenesis. Anti-IL-17 monoclonal antibodies may be effective for patients by reducing this pathogenic T cell population.