Early systemic sclerosis—opportunities for treatment

Ischemia-modified albumin in rheumatic diseases: A systematic review and meta-analysis

INTRODUCTION

The identification of novel, easily measurable disease biomarkers might enhance the diagnosis and management of patients with rheumatic diseases (RDs). We conducted a systematic review and meta-analysis of ischemia-modified albumin (IMA), a marker of oxidative stress, acidosis, and ischemia, in RD patients and healthy controls.

METHODS

We searched PubMed, Web of Science, and Scopus from inception to January 15, 2024. The risk of bias and the certainty of evidence were assessed using the Joanna Briggs Institute Critical Appraisal Checklist and GRADE, respectively.

RESULTS

In 20 studies investigating a total of 1188 RD patients (mean age 45 years, 64% females) and 981 healthy controls (mean age 44 years, 66% females), RD patients had significantly higher IMA concentrations when compared to controls (standard mean difference, SMD = 0.50, 95% CI: 0.18-0.83, p = .003; I2 = 92.4%, p < .001; low certainty of evidence). In subgroup analysis, the pooled SMD was significantly different in studies investigating ankylosing spondylitis (p < .001), Behçet's disease (p < .001), and rheumatoid arthritis (p = .033), but not familial Mediterranean fever (p = .48). Further associations were observed between the pooled SMD and the broad classification of autoimmune and/or autoinflammatory diseases, the study country, and the method used to measure IMA.

CONCLUSION

Our study suggests that IMA is a promising biomarker of oxidative stress, acidosis, and ischemia, as it can effectively discriminate between patients with different types of RDs and healthy controls. Our results warrant confirmation in longitudinal studies of patients with different types of RDs and different ethnicities (PROSPERO registration number: CRD42024509126).

Development and validation of a new diagnostic prediction model of ENHO and NOX4 for early diagnosis of systemic sclerosis

Objective

Systemic sclerosis (SSc) is a chronic autoimmune disease characterized by fibrosis. The challenge of early diagnosis, along with the lack of effective treatments for fibrosis, contribute to poor therapeutic outcomes and high mortality of SSc. Therefore, there is an urgent need to identify suitable biomarkers for early diagnosis of SSc.

Methods

Three skin gene expression datasets of SSc patients and healthy controls were downloaded from Gene Expression Omnibus (GEO) database (GSE130955, GSE58095, and GSE181549). GSE130955 (48 early diffuse cutaneous SSc and 33 controls) were utilized to screen differentially expressed genes (DEGs) between SSc and normal skin samples. Least absolute shrinkage and selection operator (LASSO) regression and support vector machine recursive feature elimination (SVM-RFE) were performed to identify diagnostic genes and construct a diagnostic prediction model. The results were further validated in GSE58095 (61 SSc and 36 controls) and GSE181549 (113 SSc and 44 controls) datasets. Receiver operating characteristic (ROC) curves were applied for assessing the level of diagnostic ability. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to verify the diagnostic genes in skin tissues of out cohort (10 SSc and 5 controls). Immune infiltration analysis were performed using CIBERSORT algorithm.

Results

A total of 200 DEGs were identified between SSc and normal skin samples. Functional enrichment analysis revealed that these DEGs may be involved in the pathogenesis of SSc, such as extracellular matrix remodeling, cell-cell interactions, and metabolism. Subsequently, two critical genes (ENHO and NOX4) were identified by LASSO and SVM-RFE. ENHO was found down-regulated while NOX4 was up-regulated in skin of SSc patients and their expression levels were validated by above three datasets and our cohort. Notably, these differential expressions were more pronounced in patients with diffuse cutaneous SSc than in those with limited cutaneous SSc. Next, we developed a novel diagnostic model for SSc using ENHO and NOX4, which demonstrated strong predictive power in above three cohorts and in our own cohort. Furthermore, immune infiltration analysis revealed dysregulated levels of various immune cell subtypes within early SSc skin specimens, and a negative correlation was observed between the levels of ENHO and Macrophages M1 and M2, while a positive correlation was observed between the levels of NOX4 and Macrophages M1 and M2.

Conclusion

This study identified ENHO and NOX4 as novel biomarkers that can be serve as a diagnostic prediction model for early detection of SSc and play a potential role in the pathogenesis of the disease.

Higher gamma-glutamyl transferase levels are associated with an increased risk of incident systemic sclerosis: a nationwide population-based study

Gamma-glutamyl transferase (GGT) is known to promote oxidative stress. As oxidative stress is a key component in the pathogenesis of systemic sclerosis (SSc), we investigated whether GGT levels are associated with the risk of incident SSc. A cohort of individuals without SSc who underwent national health examination in 2009 were extracted from the Korean National Health Insurance Service database. The incidence rate of SSc during the observation period, between 2009 and 2019, was estimated. GGT levels measured in 2009 were categorized into quartiles (Q1 [lowest], Q2, Q3, and Q4 [highest]). Multivariable Cox proportional hazard models were used to estimate the risk of incident SSc according to the quartiles of GGT, using Q1 as the reference. A total of 6,091,788 individuals were included. Incidence rate of SSc was 1.16 per 100,000 person-years over a mean observation period of 9.2 years. After adjusting for age, sex, body mass index, economic income, smoking status, alcohol consumption, physical activity, hypertension, type 2 diabetes, dyslipidemia, and chronic kidney disease, higher quartiles of GGT levels were significantly associated with a higher risk of incident SSc (Q4: adjusted hazard ratio [aHR] 1.807, 95% confidence interval CI 1.446-2.259; Q3: aHR 1.221, 95% CI 0.971-1.536; and Q2: aHR 1.034, 95% CI 0.807-1.324; p for trend < 0.001). Higher GGT levels were associated with a higher risk of incident SSc. These findings could lead to a closer monitoring for high risk individuals and an earlier diagnosis and treatment.

Association Between Lipid Profile and Risk of Incident Systemic Sclerosis: A Nationwide Population-Based Study

Background and Aims

Lipid metabolism is altered in systemic sclerosis (SSc), mediating activation of immune cells and fibroblasts. However, it is unclear whether altered lipid profile is associated with a risk of developing SSc. We aimed to assess the association between lipid profile and risk of incident SSc.

Methods

From a Korean nationwide database, individuals without SSc who underwent national health check-ups in 2009 were selected and followed-up through 2019. Serum levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglyceride were measured on the health check-up date in 2009. Individuals who developed SSc during follow-up were identified. Multivariable Cox models were performed to estimate the risk of incident SSc according to TC, HDL-C, LDL-C, and triglyceride levels, respectively.

Results

Of the 9,894,996 individuals selected, 1355 individuals developed SSc during a mean follow-up of 9.2 years (incidence rate=1.49 per 100,000 person-years). Levels of TC (adjusted hazard ratio [aHR] 0.959, 95% confidence interval [CI] 0.945-0.974), HDL-C (aHR 0.968, 95% CI 0.950-0.987), LDL-C (aHR 0.968, 95% CI 0.952-0.983) were inversely associated with the risk of incident SSc, whereas no significant association was observed between levels of triglyceride (aHR 1.004, 95% CI 0.998-1.011) and risk of incident SSc.

Conclusion

Serum levels of TC, HDL-C, and LDL-C were inversely associated with the risk of incident SSc. Our findings provide new insights that altered lipid profile could be considered a non-causal biomarker associated with incident SSc, which could help early diagnosis. The underlying mechanism for this association needs further studies.

A systematic review and meta-analysis of neopterin in rheumatic diseases

Introduction

Novel biomarkers of inflammation and oxidative stress might enhance the early recognition, management, and clinical outcomes of patients with rheumatic diseases (RDs). We assessed the available evidence regarding the pathophysiological role of neopterin, the oxidation product of 7,8-dihydroneopterin, a pteridine generated in macrophages activated by interferon-γ, by conducting a systematic review and meta-analysis of studies reporting its concentrations in biological fluids in RD patients and healthy controls.

Methods

We searched electronic databases for relevant articles published between inception and 31 August 2023. The risk of bias and the certainty of evidence were assessed using the Joanna Briggs Institute Critical Appraisal Checklist and the Grades of Recommendation, Assessment, Development and Evaluation Working Group system, respectively.

Results

In 37 studies, when compared to healthy controls, RD patients had significantly higher concentrations of neopterin both in plasma or serum (standard mean difference, SMD=1.31, 95% CI 1.01 to 1.61; p<0.001; moderate certainty of evidence) and in the urine (SMD=1.65, 95% CI 0.86 to 2.43, p<0.001; I2 = 94.2%, p<0.001; low certainty of evidence). The results were stable in sensitivity analysis. There were non-significant associations in meta-regression and subgroup analysis between the effect size and age, male to female ratio, year of publication, sample size, RD duration, C-reactive protein, erythrocyte sedimentation rate, specific type of RD, presence of connective tissue disease, analytical method used, or biological matrix investigated (plasma vs. serum). By contrast, the effect size was significantly associated with the geographical area in studies assessing serum or plasma and with the type of RD in studies assessing urine.

Discussion

Pending additional studies that also focus on early forms of disease, our systematic review and meta-analysis supports the proposition that neopterin, a biomarker of inflammation and oxidative stress, can be useful for the identification of RDs. (PROSPERO registration number: CRD42023450209).

Systematic review registration

PROSPERO, identifier CRD42023450209.

Hypoxia-Inducible Factor-1α (HIF-1α) as a Biomarker for Changes in Microcirculation in Individuals with Systemic Sclerosis

INTRODUCTION

Systemic sclerosis is an autoimmune disease characterized by tissue fibrosis and microangiopathy. Vascular changes such as a decrease in capillary density diminish blood flow and impair tissue oxygenation. Reliable ways to monitor disease activity and predict disease progression are desired in the process of patient selection for clinical trials and to optimize individual patient outcomes. Hypoxia-inducible factor-1 (HIF-1) is a dimeric protein complex that plays an integral role in the body's response to hypoxia. Our study aimed to investigate the potential abnormalities of HIF-1α plasma concentration and its possible association with disease activity and vascular abnormalities in patients with systemic sclerosis.

METHODS

Blood plasma levels of HIF-1α were measured in patients with systemic sclerosis (n = 50) and in healthy individuals (n = 30) using commercially available ELISA test kits.

RESULTS

The results showed a marked increase in HIF-1α levels in patients with systemic sclerosis (3.042 ng/ml [2.295-7.749]) compared to the control group (1.969 ng/ml [1.531-2.903] p < 0.01). Patients with diffuse cutaneous SSc (2.803 ng/ml, IQR 2.221-8.799) and limited cutaneous SSc (3.231 ng/ml, IQR 2.566-5.502) exhibited elevated serum HIF-1α levels compared to the control group (p < 0.01). We found a notable increase in HIF-1α plasma concentration in patients with an "active" pattern (6.625 ng/ml, IQR 2.488-11.480) compared to those with either an "early" pattern (2.739, IQR 2.165-3.282, p < 0.05) or a "late" pattern (2.983 ng/ml, IQR 2.229-3.386, p < 0.05). Patients with no history of digital ulcers had significantly higher levels of HIF-1α (4.367 ng/ml, IQR 2.488-9.462) compared to patients with either active digital ulcers (2.832 ng/ml, IQR 2.630-3.094, p < 0.05) or healed digital ulcers (2.668 ng/ml, IQR 2.074-2.983, p < 0.05).

CONCLUSIONS

Our results indicate that HIF-1α may serve as a biomarker in assessing microcirculatory changes in individuals with systemic sclerosis.

Nailfold Videocapillaroscopy is a Useful Tool to Recognize Definite Forms of Systemic Sclerosis and Idiopathic Inflammatory Myositis in Interstitial Lung Disease Patients

Nailfold videocapillaroscopy (NVC) is an easy tool used for the assessment of patients with Raynaud's phenomenon (RP) as possibly associated with systemic sclerosis (SSc). Recent insights have also highlighted its role in the diagnostic assessment of idiopathic inflammatory myopathies (IIMs). The aim of this study is to describe the diagnostic role of NVC in a series of 361 consecutive patients with interstitial lung disease (ILD). All the patients were assessed by clinical pulmonary and rheumatic examinations, blood exams, high-resolution computed tomography and NVC. NVC was considered positive only in the presence of avascular areas or giant capillaries, but also, the presence of bushy capillaries (BCs) was recorded. NVC was positive in 17.7% of ILD patients and in 78.1% of ILD patients associated with a diagnosis of connective tissue disease (CTD). In 25% of SSc-ILD patients, NVC proved necessary for a correct diagnosis. The presence of BCs and/or NVC positivity in ILD patients with normal levels of creatine phosphokinase is associated with amyopathic IIM, regardless the presence of RP. In conclusion, NVC is useful for the diagnostic assessment of incomplete forms of CTD and in amyopathic IIMs. NVC should be considered in the diagnostic assessment of ILD patients regardless of the presence of RP.

Targeting very early systemic sclerosis: a case-based review

It is unknown whether treatment in very early/early systemic sclerosis (SSc) can affect long-term outcomes. A case-based review was conducted (i) to assess the effect of rituximab (RTX) in very early SSc and (ii) to explore how many clinical trials in SSc targeted early disease and whether treatment of these patients led to better clinical outcomes. We identified cases of very early SSc from our department and performed a search in MEDLINE and Scopus databases for clinical trials in SSc during 2005-2018. Two cases are reported where RTX was administered within 24 months from the appearance of Raynaud's. In the first case, there was an improvement in interstitial lung disease as indicated by the improvement in pulmonary function tests and the regression of changes in high-resolution chest computed tomography. In the second case, a good clinical response in skin fibrosis was observed. The review revealed the following: (i) only one-third of the studies were specifically designed to target early disease, (ii) there is confusion related to disease duration definition across SSc clinical trials but an obvious trend towards improvement was evident during the past years, (iii) the question of whether early implementation of therapy may lead to better clinical outcomes cannot be definitely answered based on existing data and (iv) there is still a very low level of incorporation of the new classification criteria in SSc trials. This review suggests that there may be a window of opportunity in SSc and highlights the need for clinical trials targeting very early/early disease.

Low RUNX3 expression alters dendritic cell function in patients with systemic sclerosis and contributes to enhanced fibrosis

Objectives

Systemic sclerosis (SSc) is an autoimmune disease with unknown pathogenesis manifested by inflammation, vasculopathy and fibrosis in skin and internal organs. Type I interferon signature found in SSc propelled us to study plasmacytoid dendritic cells (pDCs) in this disease. We aimed to identify candidate pathways underlying pDC aberrancies in SSc and to validate its function on pDC biology.

Methods

In total, 1193 patients with SSc were compared with 1387 healthy donors and 8 patients with localised scleroderma. PCR-based transcription factor profiling and methylation status analyses, single nucleotide polymorphism genotyping by sequencing and flow cytometry analysis were performed in pDCs isolated from the circulation of healthy controls or patients with SSc. pDCs were also cultured under hypoxia, inhibitors of methylation and hypoxia-inducible factors and runt-related transcription factor 3 (RUNX3) levels were determined. To study Runx3 function, Itgax-Cre:Runx3f/f mice were used in in vitro functional assay and bleomycin-induced SSc skin inflammation and fibrosis model.

Results

Here, we show downregulation of transcription factor RUNX3 in SSc pDCs. A higher methylation status of the RUNX3 gene, which is associated with polymorphism rs6672420, correlates with lower RUNX3 expression and SSc susceptibility. Hypoxia is another factor that decreases RUNX3 level in pDC. Mouse pDCs deficient of Runx3 show enhanced maturation markers on CpG stimulation. In vivo, deletion of Runx3 in dendritic cell leads to spontaneous induction of skin fibrosis in untreated mice and increased severity of bleomycin-induced skin fibrosis.

Conclusions

We show at least two pathways potentially causing low RUNX3 level in SSc pDCs, and we demonstrate the detrimental effect of loss of Runx3 in SSc model further underscoring the role of pDCs in this disease.

Long-term effects of immunosuppressive therapy on lung function in scleroderma patients

The study aims to analyze the effects of induction treatment with cyclophosphamide (CYC) pulse therapy followed by maintenance treatment with other mild immunosuppressive agents on lung function in scleroderma (SSc) patients. Thirty patients with SSc (mean age 52 years, mean disease duration < 2 years) with forced vital capacity (FVC) ≤ 80% and/or diffusing capacity of carbon monoxide (DLco) ≤ 70% were included. Monthly CYC pulses were given for 6 months (induction treatment), followed by 3-monthly maintenance pulses for the next 18 months, and during the next 5 years patients received other mild immunosupressive therapy brought by the competent rheumatologist. The efficacy was evaluated by comparing FVC% and DLco% after 6, 24, and 84 months from the baseline. All patients completed induction and maintenance treatment with CYC. Three patients were lost to follow-up. The rest of 27 patients, during the next 5 years, received other immunosupressive agents (14 azathioprine, 9 methotrexate, and 4 mycophenolate mofetil). Three patients died in the 4 years of follow-up. By 6, 24, and 84 months, the mean FVC and DLco changes were + 0.47 and + 2.10, + 3.30 and - 2.49, and + 1.53 and - 3.76%, respectively. These changes were not significantly different from the baseline values. CYC does not appear to result in clinically significant improvement of pulmonary function but fulfilled criteria of stable disease. Maintenance treatment with other mild immunosupressive agents preserves the benefits achieved during CYC treatment.

Immunotherapy of systemic sclerosis

Systemic sclerosis (SSc) is a chronic systemic disease characterized by microvasculopathy, immune activation, and extensive collagen deposition. Microvasculopathy and immune activation occur very early in the disease process. Evidence from animal models and in vitro studies indicate that T-cells and B-cells activate fibroblasts to produce collagen. Traditional immunosuppressants, cyclophosphamide(CyP), methotrexate(MTX), and more recently mycophenolate mofetil(MMF), may prove more effective if used very early in the disease course. These drugs showed some benefit in skin (MTX, CyP, MMF) and lung function (CyP, MMF). Biologicals, such as intravenous immunoglobulin (IVIg), belimumab(Beli), tocilizumab(TCZ), abatacept(Aba), rituximab(RTX) and fresolimumab(Fresu) appear promising as they exhibited some benefit in skin (IVIg, Beli, TCZ, Aba, RTX, Fresu), hand function (IVIg), and joints (IVIg, TCZ, Aba). Autologous stem cell transplantation showed the best therapeutic efficacy on skin and internal organs, and looks very promising, as modification of transplantation immunosuppression is decreasing the early high mortality.

Adenosine A2a Receptor Blockade Diminishes Wnt/β-Catenin Signaling in a Murine Model of Bleomycin-Induced Dermal Fibrosis

Adenosine A_2a receptor (A_2aR) stimulation promotes the synthesis of collagens I and III, and we have recently demonstrated that there is crosstalk between the A_2aR and WNT/β-catenin signaling pathway. In in vitro studies, A_2aR signaling for collagen III expression was mediated by WNT/β-catenin signaling in human dermal fibroblasts; we further verified whether the crosstalk between A_2aR and Wnt/β-catenin signaling was involved in diffuse dermal fibrosis in vivo. Wnt-signaling reporter mice (Tcf/Lef:H2B-GFP) were challenged with bleomycin and treated with the selective A_2aR antagonist istradefylline (KW6002) or vehicle. Dermal fibrosis was quantitated and nuclear translocation of β-catenin in fibroblasts was assessed by double-staining for Green fluorescent protein or dephosphorylated β-catenin or β-catenin phosphorylated at Ser552, and vimentin. KW6002 significantly reduced skin thickness, skinfold thickness, breaking tension, dermal hydroxyproline content, myofibroblast accumulation, and collagen alignment in bleomycin-induced dermal fibrosis. Also, there was increased expression of Tcf/Lef:H2B-GFP reporter in bleomycin-induced dermal fibrosis, an effect that was diminished by treatment with KW6002. Moreover, KW6002 significantly inhibited nuclear translocation of Tcf/Lef:H2B-GFP reporter, as well as dephosphorylated β-catenin and β-catenin phosphorylated at Ser552. Our work supports the hypothesis that pharmacologic blockade of A_2aR inhibits the WNT/β-catenin signaling pathway, contributing to its capacity to inhibit dermal fibrosis in diseases such as scleroderma.

Evidence for a Derangement of the Microvascular System in Patients with a Very Early Diagnosis of Systemic Sclerosis

OBJECTIVE

To investigate whether patients with a very early diagnosis of systemic sclerosis (VEDOSS) may already present circulating markers and in vitro signs of microvascular dysfunction.

METHODS

Serum samples were obtained from 55 patients with systemic sclerosis (SSc), 25 patients with VEDOSS, and 55 matched healthy controls (HC). Serum levels of pan-vascular endothelial growth factor (VEGF) and soluble neuropilin-1 (sNRP-1) were measured by ELISA. Human dermal microvascular endothelial cells (H-MVEC) were cultured and stimulated with SSc, VEDOSS, and HC sera. Protein expression of NRP-1 was analyzed by Western blotting, cell proliferation by 5'-bromodeoxyuridine assay, migration capacity by wound-healing assay, and capillary-like tube formation by Matrigel assay.

RESULTS

Serum levels of pan-VEGF were increased in patients with VEDOSS and SSc versus HC (p = 0.05 and p = 0.003, respectively). Serum levels of sNRP-1 were significantly reduced in patients with VEDOSS and SSc compared with controls (p = 0.012 and p = 0.027, respectively). NRP-1 expression was decreased in H-MVEC stimulated with VEDOSS sera (p < 0.001 vs HC). Proliferation was reduced in H-MVEC stimulated either with VEDOSS or SSc sera in comparison with HC sera (p = 0.015 and p = 0.043, respectively). Wound healing was compromised in H-MVEC stimulated with VEDOSS and SSc sera versus HC sera (p < 0.01 for both). Capillarogenesis was decreased in H-MVEC stimulated with VEDOSS sera (p < 0.01) and SSc sera (p < 0.001) compared with cells stimulated with HC sera.

CONCLUSION

Similar to patients with SSc, patients with VEDOSS already present biological signs of endothelial dysfunction. Our data demonstrate that VEDOSS sera significantly modify endothelial cell behavior and impair the angiogenic potential of the microvascular system.

Meprin β and BMP-1 are differentially regulated by CaCl2

The two metalloproteases meprin β and bone morphogenetic protein 1 (BMP-1) are both members of the astacin protease family. They share specificity for negatively charged residues around the scissile bond and they are expressed in overlapping compartments of the human body. One important proteolytic substrate they share is pro-collagen I. Ablation of one of the two proteases however leads to different collagen I associated phenotypes in vivo. Over the last years calcium emerged as a regulator for the proteolytic activity of both enzymes. For meprin β a reduction and for BMP-1 an increase in activity was reported under increasing calcium concentrations. Here we revisit different compartments that rely on pro-collagen I maturation and explore the crystal structure of both proteases to highlight possible calcium binding sites. With this we aim to emphasize a to date underestimated regulator that influences both proteases.

Progress in understanding the diagnostic and pathogenic role of autoantibodies associated with systemic sclerosis

PURPOSE OF REVIEW

At the time of diagnosis, systemic sclerosis (SSc) is often well established with significant irreversible tissue and organ damage. Definitions of 'early SSc' have been proposed, which include the presence of SSc-associated autoantibodies. In addition, functional autoantibodies that are believed to be involved in SSc pathogenesis need to be considered. In this review, recent advances in the diagnostic utility and pathogenic role of autoantibodies in early SSc are summarized. Moreover, we propose a clinical care pathway illustrating how autoantibody testing along with key clinical features can be used to make an earlier diagnosis of SSc.

RECENT FINDINGS

Recent evidence has helped to develop a clearer understanding of the natural history, early clinical features, and autoantibodies that are predictors of SSc. The role of functional autoantibodies is leading to innovative approaches to evidence-based interventions and therapies that are based on mechanisms of disease.

SUMMARY

Despite substantial advances, the high morbidity and mortality that currently characterizes SSc can largely be attributed to a delay in diagnosis, gaps in our understanding of the role of autoantibodies in early disease, and limited effective therapeutic options. An early and accurate diagnosis of SSc and use of autoantibody testing embedded in evidence-based clinical care pathways will help improve SSc-associated clinical outcomes and healthcare expenditures.

Systemic sclerosis: New evidence re-enforces the role of B cells

Systemic sclerosis (SSc) is characterized by widespread fibrosis, microangiopathy (vasospasms and stenosis), and formation of autoantibodies. T cell activation has been shown to contribute to fibrosis and microvasculopathy in SSc. However, recent evidence suggests that B cells are also likely to contribute in the pathogenesis of the disease. B cells are hyperactivated in SSc, as indicated by the overexpression of the stimulatory CD19 receptor and impairment of the inhibitory CD22 receptor. They lead to the production of many autoantibodies, some of which induce collagen production and vasoconstriction. They promote fibroblast collagen production through cell contact. Furthermore, B cells can function as antigen-presenting cells to T cells and induce dendritic cell maturation that promotes profibrotic Th2 response. Lately, interleukin (IL)-10-producing B regulatory cells, which induce generation of T regulatory cells and can ameliorate autoimmune diseases, were found to be reduced in SSc, favoring autoaggression of B cells in this disease. Finally, B cell depletion with rituximab improves or stabilizes skin fibrosis and lung function. These finding suggest that new therapeutic strategies targeting B cell function(s) can be developed for SSc.