Role of B-Cell in the Pathogenesis of Systemic Sclerosis

CAR T-Cell Therapy for Rheumatic Diseases: What Does the Future Hold?

Chimeric antigen receptor (CAR) T-cell therapy, initially successful in treating hematological malignancies, is emerging as a potential treatment for autoimmune diseases, including rheumatic conditions. CAR T cells, engineered to target and eliminate autoreactive B cells, offer a novel approach to managing diseases like systemic lupus erythematosus (SLE), systemic sclerosis (SSc), and inflammatory myopathies, where B cells play a pivotal role in disease pathology. Early case reports have demonstrated promising results, with patients achieving significant disease remission, normalization of serological markers, and the ability to discontinue traditional immunosuppressive therapies, which supported the initiation of several clinical trials. However, the application of CAR T-cell therapy in chronic inflammatory rheumatic disorders poses unique challenges, including patient heterogeneity, the risk of adverse effects such as cytokine release syndrome, and the high costs associated with the therapy. Despite these challenges, the potential for CAR T cells to provide long-term remission or even a cure in refractory autoimmune diseases is significant. Ongoing research aims to optimize CAR T-cell constructs and improve safety profiles, paving the way for broader application in rheumatic diseases. If these challenges can be addressed, CAR T-cell therapy could revolutionize the treatment landscape for chronic inflammatory rheumatic disorders, offering new hope for patients with severe, treatment-resistant conditions.

Advances in chimeric antigen receptor T cell therapy for autoimmune and autoinflammatory diseases and their complications

Chimeric antigen receptor T (CAR-T) cells are genetically engineered T cells expressing transmembrane chimeric antigen receptors with specific targeting abilities. As an emerging immunotherapy, the use of CAR-T cells has made significant breakthroughs in cancer treatment, particularly for hematological malignancies. The success of CAR-T cell therapy in blood cancers highlights its potential for other conditions in which the clearance of pathological cells is therapeutic, such as liver diseases, infectious diseases, heart failure, and diabetes. Given the limitations of current therapies for autoimmune diseases, researchers have actively explored the potential therapeutic value of CAR-T cells and their derivatives in the field of autoimmune diseases. This review focuses on the research progress and current challenges of CAR-T cells in autoimmune diseases with the aim of providing a theoretical basis for the precise treatment of autoimmune diseases. In the future, CAR-T cells may present new therapeutic modalities and ultimately provide hope for patients with autoimmune diseases.

Autoimmune effector mechanisms associated with a defective immunosuppressive axis in immune thrombocytopenia (ITP)

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by an isolated thrombocytopenia and variable phenotype as some patients suffer no bleeding whilst others have bleeding from mild to severe, which may be fatal. This variability probably reflects the disease's complex pathophysiology; a dysregulated hyperreactive immune effector cell response involving the entire adaptive immune system (e.g. B and T cell subsets) that leads to platelet and megakaryocyte (MK) destruction. It appears that these effector responses are due to a breakdown in immune tolerance, and this is characterized by defects in several immunosuppressive cell types. These include defective T regulatory cells (Tregs), B regulatory cells (Bregs) and Myeloid-derived suppressor cells (MDSC), all of which are all intimately associated with antigen presenting cells (APC) such as dendritic cells (DC). The loss of this immunosuppressive axis allows for the activation of unchecked autoreactive T cells and B cells, leading to the development of autoantibodies and cytotoxic T cells (CTL), which can directly destroy platelets in the periphery and inhibit MK platelet production in the bone marrow (BM). This review will focus on the effector cell mechanisms in ITP and highlight the defective immunosuppressive axis that appears responsible for this platelet-specific immune hyperreactivity.

Stratification according to autoantibody status in systemic sclerosis reveals distinct molecular signatures

OBJECTIVES

Systemic sclerosis (SSc) is a heterogeneous disease, complicating its management. Its complexity and the insufficiency of clinical manifestations alone to delineate homogeneous patient groups further challenge this task. However, autoantibodies could serve as relevant markers for the pathophysiological mechanisms driving the disease. Identifying specific immunological mechanisms based on patients' serological statuses might facilitate a deeper understanding of the diversity of the disease.

METHODS

A cohort of 206 patients with SSc enrolled in the PRECISESADS cross-sectional study was examined. Patients were stratified based on their anti-centromere (ACA) and anti-SCL70 (SCL70) antibody statuses. Comprehensive omics analyses including transcriptomic, flow cytometric, cytokine and metabolomic data were analysed to characterise the differences between these patient groups.

RESULTS

Patients with SCL70 antibodies showed severe clinical features such as diffuse cutaneous sclerosis and pulmonary fibrosis and were biologically distinguished by unique transcriptomic profiles. They exhibit a pro-inflammatory and fibrotic signature associated with impaired tissue remodelling and increased carnitine metabolism. Conversely, ACA-positive patients exhibited an immunomodulation and tissue homeostasis signature and increased phospholipid metabolism.

CONCLUSIONS

Patients with SSc display varying biological profiles based on their serological status. The findings highlight the potential utility of serological status as a discriminating factor in disease severity and suggest its relevance in tailoring treatment strategies and future research directions.

Safety and Tolerability of Rituximab in the Treatment of Systemic Sclerosis

Rituximab (RTX) has been used for the treatment of systemic sclerosis (SSс) for a long time and has shown good efficacy for skin fibrosis and interstitial lung disease (ILD). However, data on tolerability and long-term adverse events (AEs) during RTX therapy in SSc are insufficient. The objective of this study was to assess the tolerability and safety of RTX in patients with SSс in a long-term prospective follow-up. Our open-label prospective study included 151 SSс patients who received at least one RTX infusion. The mean age of the patients was 47.9 ± 13.4 years; the majority of them were women (83%). The mean disease duration was 6.4 ± 5.8 years. The mean follow-up period after the first RTX infusion was 5.6 ± 2.6 years (845.6 patient-years (PY)). All patients received RTX in addition to ongoing therapy with prednisone and/or immunosuppressants. AEs were assessed and recorded by a doctor in the hospital immediately after RTX infusion and then by patient's reported outcome during the observation period. All causes of death were considered, regardless of treatment. A total of 85 AEs (56%) were registered, the overall incidence of AEs was 10/100 PY (95% confidence interval (CI) 8-12). The highest frequency of all AEs was observed in the first 2-6 months after the first course of RTX, however, these were mainly mild and moderate AEs (71%). The most frequent AEs were infections, they were observed in 40% of cases, with no serious opportunistic infections reported. The overall incidence of all infections was 7.1/100 PY (95% CI 5.5-9), serious infections-1.5/100 PY (95% CI 0.9-2.6). Infusion reactions occurred in 8% of patients. Other AEs were noted in 3% (0.6/100 PY, 95% CI 0.3-1.4). The overall incidence of serious AEs was 18%-3.2/100 PY (95% CI 2.2-4.6). There was a significant decrease of the immunoglobulin G (Ig G) during follow-up; however, its average values remained within normal limits. There were 17 deaths (11%) (2/100 PY, 95% CI 1.3-3.2). In most cases, patients died from the progression of the major organ failure, which arose before RTX treatment. In our study, the safety profile of RTX in SSс was assessed as favorable. It was similar to the AE profile in other autoimmune diseases treated with RTX. With an increase in the cumulative dose of RTX, no increase in AEs was observed. The mortality is comparable to the other severe autoimmune diseases in observational studies. Monitoring of IgG may be useful for patients with SSс on RTX therapy for early detection of the risk of developing infectious complications. RTX could be considered as a relatively safe drug for the complex therapy of SSс when standard therapy is ineffective or impossible.

Toll-like Receptor Homologue CD180 Ligation of B Cells Upregulates Type I IFN Signature in Diffuse Cutaneous Systemic Sclerosis

Type I interferon (IFN-I) signaling has been shown to be upregulated in systemic sclerosis (SSc). Dysregulated B-cell functions, including antigen presentation, as well as antibody and cytokine production, all of which may be affected by IFN-I signaling, play an important role in the pathogenesis of the disease. We investigated the IFN-I signature in 71 patients with the more severe form of the disease, diffuse cutaneous SSc (dcSSc), and 33 healthy controls (HCs). Activation via Toll-like receptors (TLRs) can influence the IFN-I signaling cascade; thus, we analyzed the effects of the TLR homologue CD180 ligation on the IFN-I signature in B cells. CD180 stimulation augmented the phosphorylation of signal transducer and activator of transcription 1 (STAT1) in dcSSc B cells (p = 0.0123). The expression of IFN-I receptor (IFNAR1) in non-switched memory B cells producing natural autoantibodies was elevated in dcSSc (p = 0.0109), which was enhanced following anti-CD180 antibody treatment (p = 0.0125). Autoantibodies to IFN-Is (IFN-alpha and omega) correlated (dcSSc p = 0.0003, HC p = 0.0192) and were present at similar levels in B cells from dcSSc and HC, suggesting their regulatory role as natural autoantibodies. It can be concluded that factors other than IFN-alpha may contribute to the elevated IFN-I signature of dcSSc B cells, and one possible candidate is B-cell activation via CD180.

Disease-specific prioritization of non-coding GWAS variants based on chromatin accessibility

Non-protein-coding genetic variants are a major driver of the genetic risk for human disease; however, identifying which non-coding variants contribute to diseases and their mechanisms remains challenging. In silico variant prioritization methods quantify a variant's severity, but for most methods, the specific phenotype and disease context of the prediction remain poorly defined. For example, many commonly used methods provide a single, organism-wide score for each variant, while other methods summarize a variant's impact in certain tissues and/or cell types. Here, we propose a complementary disease-specific variant prioritization scheme, which is motivated by the observation that variants contributing to disease often operate through specific biological mechanisms. We combine tissue/cell-type-specific variant scores (e.g., GenoSkyline, FitCons2, DNA accessibility) into disease-specific scores with a logistic regression approach and apply it to ∼25,000 non-coding variants spanning 111 diseases. We show that this disease-specific aggregation significantly improves the association of common non-coding genetic variants with disease (average precision: 0.151, baseline = 0.09), compared with organism-wide scores (GenoCanyon, LINSIGHT, GWAVA, Eigen, CADD; average precision: 0.129, baseline = 0.09). Further on, disease similarities based on data-driven aggregation weights highlight meaningful disease groups, and it provides information about tissues and cell types that drive these similarities. We also show that so-learned similarities are complementary to genetic similarities as quantified by genetic correlation. Overall, our approach demonstrates the strengths of disease-specific variant prioritization, leads to improvement in non-coding variant prioritization, and enables interpretable models that link variants to disease via specific tissues and/or cell types.

Engineered immune cells as therapeutics for autoimmune diseases

Current treatment options for autoimmune disease (AID) are essentially immunosuppressive, inhibiting the inflammatory cascade, without curing the disease. Therapeutic monoclonal antibodies (mAbs) that target B cells showed efficacy, emphasizing the importance of B lymphocytes in autoimmune pathogenesis. Treatments that eliminate more potently B cells would open a new therapeutic era for AID. Immune cells can now be bioengineered to express constructs that enable them to specifically eradicate pathogenic B lymphocytes. Engineered immune cells (EICs) have shown therapeutic promise in both experimental models and in clinical trials in AID. Next-generation platforms are under development to optimize their specificity and improve safety. The profound and durable B cell depletion achieved reinforces the view that this biotherapeutic option holds promise for treating AID.

Application of blinatumomab, a bispecific anti-CD3/CD19 T-cell engager, in treating severe systemic sclerosis: A case study

Systemic sclerosis, a severe inflammatory autoimmune disease, shares a common thread with cancer through the underlying mechanism of inflammation. This inflammatory milieu not only drives the immune dysregulation characteristic of autoimmune diseases but also plays a pivotal role in the pathogenesis of cancer. Among the cellular components involved, B cells have emerged as key players in hematologic tumor and autoimmune disease, contributing to immune dysregulation and persistent tissue fibrosis in systemic sclerosis, as well as tumor progression and immune evasion in cancer. Consequently, novel therapeutic strategies targeting B cells hold promise in both conditions. Recent exploration of CD19 CAR T cells in severe systemic sclerosis patients has shown great potential, but also introduced possible risks and drawbacks associated with viral vectors, prolonged CAR T cell persistence, lengthy production timelines, high costs, and the necessity of conditioning patients with organotoxic and fertility-damaging chemotherapy. Given these challenges, alternative CD19-depleting approaches are of high interest for managing severe systemic autoimmune diseases. Here, we present the pioneering use of blinatumomab, a bispecific anti-CD3/anti-CD19 T cell engager in a patient with progressive, severe systemic sclerosis, offering a promising alternative for such challenging cases.

Interstitial Lung Disease Associated with Systemic Sclerosis

Systemic sclerosis (SSc) is a rare autoimmune disease characterized by a tripod combining vasculopathy, fibrosis, and immune-mediated inflammatory processes. The prevalence of interstitial lung disease (ILD) in SSc varies according to the methods used to detect it, ranging from 25 to 95%. The fibrotic and vascular pulmonary manifestations of SSc, particularly ILD, are the main causes of morbidity and mortality, contributing to 35% of deaths. Although early trials were conducted with cyclophosphamide, more recent randomized controlled trials have been performed to assess the efficacy and tolerability of several medications, mostly mycophenolate, rituximab, tocilizumab, and nintedanib. Although many uncertainties remain, expert consensus is emerging to optimize the therapeutic management and to provide clinicians with evidence-based clinical practice guidelines for patients with SSc-ILD. This article provides an overview, in the light of the latest advances, of the available evidence for the diagnosis and management of SSc-ILD.

Current evidence on the role of fibroblasts in large-vessel vasculitides: From pathogenesis to therapeutics

Large-vessel vasculitides (LVV) comprise a group of chronic inflammatory diseases of the aorta and its major branches. The most common forms of LVV are giant cell arteritis (GCA) and Takayasu arteritis (TAK). Both GCA and TAK are characterized by granulomatous inflammation of the vessel wall accompanied by a maladaptive immune and vascular response that promotes vascular damage and remodeling. The inflammatory process in LVV starts in the adventitia where fibroblasts constitute the dominant cell population. Fibroblasts are traditionally recognized for synthesizing and renewing the extracellular matrix thereby being major players in maintenance of normal tissue architecture and in tissue repair. More recently, fibroblasts have emerged as a highly plastic cell population exerting various functions, including the regulation of local immune processes and organization of immune cells at the site of inflammation through production of cytokines, chemokines and growth factors as well as cell-cell interaction. In this review, we summarize and discuss the current knowledge on fibroblasts in LVV. Furthermore, we identify key questions that need to be addressed to fully understand the role of fibroblasts in the pathogenesis of LVV.

Outcomes in progressive systemic sclerosis treated with autologous hematopoietic stem cell transplantation compared with combination therapy

OBJECTIVES

Autologous hematopoietic stem cell transplantation (AHSCT) has been shown to improve long-term survival for early diffuse progressive SSc compared with CYC. CYC, however, does not provide a long-term benefit in SSc. The combination of MMF and rituximab is a potent alternative regimen. We aimed to retrospectively compare the outcomes of SSc patients who underwent AHSCT to patients who met the eligibility criteria for AHSCT but received upfront combination therapy with MMF and rituximab.

METHODS

Repeated assessments of modified Rodnan Skin Score (mRSS), forced vital capacity (FVC), and diffusing capacity (DLCO) values were conducted. Clinical improvement was defined as an mRSS decrease >25% or an FVC increase >10%. Event-free survival (EFS) was defined in the absence of persistent major organ failure or death.

RESULTS

Twenty-one SSc patients in the combination therapy group were compared with 16 in the AHSCT group. Age, sex and disease duration were similar between the two groups. Clinical improvement at 12 months was seen in 18 (86%) patients in the combination group compared with 13 (81%) in the AHSCT group (P = 0.7). The hazard ratio for EFS at 24 months favoured the combination group (HR = 0.09, P = 0.04). During follow-up, both groups exhibited a significant and comparable reduction in mRSS and an increase in FVC values at each time interval up to 24 months.

CONCLUSION

MMF and rituximab compared with AHSCT in SSc patients eligible for AHSCT resulted in similar skin and lung clinical improvement with a better safety profile at 24 months.

Alterations in peripheral T- and B-cell subsets in patients with systemic sclerosis

OBJECTIVES

To determine the alteration of peripheral T and B cell subsets in patients with systemic sclerosis (SSc) and to evaluate their correlation with the progression of SSc.

METHODS

We recruited 47 SSc patients and 45 healthy controls (HCs) in this study. Demographic and clinical data were then collected. Flow cytometry was used to detect the proportions of 44 different T and B cell subsets in circulating blood.

RESULTS

The proportion of total B cells (p = .043) decreased in SSc patients, together with similar frequencies of total T cells, CD4+ T cells, and CD8+ T cells in both groups. Several subsets of T and B cells differed significantly between these two groups. Follicular helper T cells-1 (Tfh1) (p < .001), helper T cells-1 (Th1) (p = .001), regulatory T cells (Treg) (p = .004), effector memory CD8+ T cells (p = .041), and cytotoxic T cells-17 (Tc17) (p = .01) were decreased in SSc patients. Follicular helper T cells-2 (Tfh2) (p = .001) and, helper T cells-2 (Th2) (p = .001) levels increased in the SSc group. Regulatory B cells (Breg) (p = .015) were lower in the SSc group, together with marginal zone (MZ) B cells (p < .001), memory B cells (p = .001), and non-switched B cells (p = .005). The modified Rodnan skin score (mRSS) correlated with helper T cells-17 (Th17) (r = -.410, p = .004), Tfh1 (r = -.321, p = .028), peripheral helper T cells (Tph) (r = -.364, p = .012) and plasma cells (r = -.312, p = .033).

CONCLUSIONS

The alterations in T and B cells implied immune dysfunction, which may play an essential role in systemic sclerosis.

Pulmonary arterial hypertension associated with connective tissue diseases (CTD-PAH): Recent and advanced data

Pulmonary arterial hypertension (PAH), corresponding to group 1 of pulmonary hypertension classification, is a rare disease with a major prognostic impact on morbidity and mortality. PAH can be either primary in idiopathic and heritable forms or secondary to other conditions including connective tissue diseases (CTD-PAH). Within CTD-PAH, the leading cause of PAH is systemic sclerosis (SSc) in Western countries, whereas systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD) are predominantly associated with PAH in Asia. Although many advances have been made during the last two decades regarding classification, definition early screening and risk stratification and therapeutic aspects with initial combination treatment, the specificities of CTD-PAH are not yet clear. In this manuscript, we review recent literature data regarding the updated definition and classification of PAH, pathogenesis, epidemiology, detection, prognosis and treatment of CTD-PAH.

Immunological Profiles in Parry-Romberg Syndrome: A Case-Control Study

Background: Parry-Romberg syndrome (PRS) is a rare craniofacial disorder. The aim of this study is to provide information on the immunological profile of this pathology. Since PRS can be included in a wider spectrum of sclerodermic diseases, we propose a case-control study comparing a patient affected by PRS with one with a diagnosis of scleroderma, herein used as control (CTR). Methods: B lymphocyte, T lymphocyte, and monocyte phenotypes and functions were assessed by flow cytometry in influenza (Flu)- or anti cluster differentiation (CD)3/CD28-stimulated peripheral blood mononuclear cells (PBMCs). Cytokine concentration was evaluated as well in PBMC supernatants, plasma, and saliva by Luminex assay. Results: T and B lymphocytes were similarly activated in unstimulated PRS and CTR cells but differed following antigen stimulation. T helper (Th)17 lymphocytes were expanded in PRS compared to CTR; this increase correlated with higher interleukin (IL)-17 concentration. Conclusions: Our case-control study is the first to compare the immunological profiles of PRS and scleroderma patients. The higher percentage of Th17 cells in PRS suggests the use of anti-IL17 receptor monoclonal antibody in this rare disease; however, further studies with larger numbers of patients are needed to confirm our findings.

Autoantibodies Targeting G-Protein-Coupled Receptors: Pathogenetic, Clinical and Therapeutic Implications in Systemic Sclerosis

Systemic sclerosis (SSc) is a multifaceted connective tissue disease whose aetiology remains largely unknown. Autoimmunity is thought to play a pivotal role in the development of the disease, but the direct pathogenic role of SSc-specific autoantibodies remains to be established. The recent discovery of functional antibodies targeting G-protein-coupled receptors (GPCRs), whose presence has been demonstrated in different autoimmune conditions, has shed some light on SSc pathogenesis. These antibodies bind to GPCRs expressed on immune and non-immune cells as their endogenous ligands, exerting either a stimulatory or inhibitory effect on corresponding intracellular pathways. Growing evidence suggests that, in SSc, the presence of anti-GPCRs antibodies correlates with specific clinical manifestations. Autoantibodies targeting endothelin receptor type A (ETAR) and angiotensin type 1 receptor (AT1R) are associated with severe vasculopathic SSc-related manifestations, while anti-C-X-C motif chemokine receptors (CXCR) antibodies seem to be predictive of interstitial lung involvement; anti-muscarinic-3 acetylcholine receptor (M3R) antibodies have been found in patients with severe gastrointestinal involvement and anti-protease-activated receptor 1 (PAR1) antibodies have been detected in patients experiencing scleroderma renal crisis. This review aims to clarify the potential pathogenetic significance of GPCR-targeting autoantibodies in SSc, focusing on their associations with the different clinical manifestations of scleroderma. An extensive examination of functional autoimmunity targeting GPCRs might provide valuable insights into the underlying pathogenetic mechanisms of SSc, thus enabling the development of novel therapeutic strategies tailored to target GPCR-mediated pathways.

An interleukin 6 responsive plasma cell signature is associated with disease progression in systemic sclerosis interstitial lung disease

Systemic sclerosis (SSc) interstitial lung disease (ILD) is among the leading causes of SSc-related morbidity and mortality. Tocilizumab (TCZ, anti-IL6RA) has demonstrated a reduced rate of pulmonary function decline in two phase 2/3 trials (faSScinate and focuSSced) in SSc-ILD patients. We performed transcriptome analysis of skin biopsy samples collected in the studies to decipher gene networks that were potentially associated with clinical responses to TCZ treatment. One module correlated with disease progression showed pharmacodynamic changes with TCZ treatment, and was characterized by plasma cell (PC) genes. PC signature gene expression levels were also significantly increased in both fibrotic SSc and IPF lungs compared to controls. scRNAseq analyses confirmed that PC signature genes were co-expressed in CD38 and CD138 expressing PC subsets in SSc lungs. These data provide insights into the potential role of PC in disease progression and mechanisms of action of TCZ in fibrotic interstitial lung diseases.

Role of rituximab in the treatment of systemic sclerosis: A literature review

This literature review aimed to evaluate the effectiveness of rituximab (RTX) in patients with systemic sclerosis (SSc). PubMed was searched for articles, published through 31 March 2022, on any controlled studies using RTX in the treatment of SSc. Of 85 identified articles, 9 were selected by title/abstract screening and full text examination. All nine articles reported outcomes of forced vital capacity (%FVC), and seven reported those of modified Rodnan skin scores (mRSS). The results showed that among the seven controlled studies evaluating skin lesions in patients with SSc, four showed a significant improvement of mRSS by RTX when compared with a control group, whereas three showed no significant effect. Among the nine controlled studies evaluating lung lesions, five showed a significant improvement of %FVC compared with a control group, whereas four showed no significant effect. In conclusion, RTX may be effective in the treatment of skin and lung lesions in patients with SSc. The profiles of SSc patients for whom RTX was indicated were unclear, although patients with diffuse cutaneous SSc and those positive for anti-topoisomerase I antibody were considered potential targets. Additional studies are needed to assess the long-term effectiveness of RTX in the treatment of patients with SSc.

Targeting B cells for treatment of systemic sclerosis

PURPOSE OF REVIEW

The pathogenesis of systemic sclerosis (SSc) has been linked to dysfunctional B cells as demonstrated in previous research. This review aims to show the evidence and ongoing clinical trials of B cell-targeted therapy and overview the various aspects of B cell involvement in SSc.

RECENT FINDINGS

We provide an overview of the current understanding and therapeutic strategies targeting B cells in SSc patients. Several molecular targets of B cells have been identified for treating SSc, including CD20, CD19, B-cell activating factor (BAFF), and proteasome.

SUMMARY

Many clinical trials have demonstrated that B cells play a critical role in the pathogenesis of SSc and may be a potential therapeutic target to improve disease symptoms. Although large-scale clinical studies are needed, various B cell-targeted therapies have the potential to address the unmet needs of SSc patients.

The role of inflammation in autoimmune disease: a therapeutic target

Autoimmune diseases (AIDs) are immune disorders whose incidence and prevalence are increasing year by year. AIDs are produced by the immune system's misidentification of self-antigens, seemingly caused by excessive immune function, but in fact they are the result of reduced accuracy due to the decline in immune system function, which cannot clearly identify foreign invaders and self-antigens, thus issuing false attacks, and eventually leading to disease. The occurrence of AIDs is often accompanied by the emergence of inflammation, and inflammatory mediators (inflammatory factors, inflammasomes) play an important role in the pathogenesis of AIDs, which mediate the immune process by affecting innate cells (such as macrophages) and adaptive cells (such as T and B cells), and ultimately promote the occurrence of autoimmune responses, so targeting inflammatory mediators/pathways is one of emerging the treatment strategies of AIDs. This review will briefly describe the role of inflammation in the pathogenesis of different AIDs, and give a rough introduction to inhibitors targeting inflammatory factors, hoping to have reference significance for subsequent treatment options for AIDs.

Treatable Traits in Systemic Sclerosis

Systemic sclerosis (SSc) is a chronic systemic disease within the spectrum of connective tissue diseases, specifically characterized by vascular abnormalities and inflammatory and fibrotic involvement of the skin and internal organs resulting in high morbidity and mortality. The clinical phenotype of SSc is heterogeneous, and serum autoantibodies together with the extent of skin involvement have a predictive value in the risk stratification. Current recommendations include an organ-based management according to the predominant involvement with only limited individual factors included in the treatment algorithm. Similar to what has been proposed for other chronic diseases, we hypothesize that a "treatable trait" approach based on relevant phenotypes and endotypes could address the unmet needs in SSc stratification and treatment to maximize the outcomes. We provide herein a comprehensive review and a critical discussion of the literature regarding potential treatable traits in SSc, focusing on established and candidate biomarkers, with the purpose of setting the bases for a precision medicine-based approach. The discussion, structured based on the organ involvement, allows to conjugate the pathogenetic mechanisms of tissue injury with the proposed predictors, particularly autoantibodies and other serum biomarkers. Ultimately, we are convinced that precision medicine is the ideal guide to manage a complex condition such as SSc for which available treatments are largely unsatisfactory.

Potential angiogenic, immunomodulatory, and antifibrotic effects of mesenchymal stem cell-derived extracellular vesicles in systemic sclerosis

Systemic sclerosis (SSc) is an intricate systemic autoimmune disease with pathological features such as vascular injury, immune dysregulation, and extensive fibrosis of the skin and multiple organs. Treatment options are limited; however, recently, mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have been acknowledged in preclinical and clinical trials as being useful in treating autoimmune diseases and are likely superior to MSCs alone. Recent research has also shown that MSC-EVs can ameliorate SSc and the pathological changes in vasculopathy, immune dysfunction, and fibrosis. This review summarizes the therapeutic effects of MSC-EVs on SSc and the mechanisms that have been discovered to provide a theoretical basis for future studies on the role of MSC-EVs in treating SSc.

Differentially expressed genes in systemic sclerosis: Towards predictive medicine with new molecular tools for clinicians

Systemic sclerosis (SSc) is a rare and chronic autoimmune disease characterized by a pathogenic triad of immune dysregulation, vasculopathy, and progressive fibrosis. Clinical tools commonly used to assess patients, such as the modified Rodnan skin score, difference between limited or diffuse forms of skin involvement, presence of lung, heart or kidney involvement, or of various autoantibodies, are important prognostic factors, but still fail to reflect the large heterogeneity of the disease. SSc treatment options are diverse, ranging from conventional drugs to autologous hematopoietic stem cell transplantation, and predicting response is challenging. Genome-wide technologies, such as high throughput microarray analyses and RNA sequencing, allow accurate, unbiased, and broad assessment of alterations in expression levels of multiple genes. In recent years, many studies have shown robust changes in the gene expression profiles of SSc patients compared to healthy controls, mainly in skin tissues and peripheral blood cells. The objective analysis of molecular patterns in SSc is a powerful tool that can further classify SSc patients with similar clinical phenotypes and help predict response to therapy. In this review, we describe the journey from the first discovery of differentially expressed genes to the identification of enriched pathways and intrinsic subsets identified in SSc, using machine learning algorithms. Finally, we discuss the use of these new tools to predict the efficacy of various treatments, including stem cell transplantation. We suggest that the use of RNA gene expression-based classifications according to molecular subsets may bring us one step closer to precision medicine in Systemic Sclerosis.

Molecular Mechanisms Behind the Role of Plasmacytoid Dendritic Cells in Systemic Sclerosis

Systemic sclerosis (SSc) is a debilitating autoimmune disease that affects multiple systems. It is characterized by immunological deregulation, functional and structural abnormalities of small blood vessels, and fibrosis of the skin, and, in some cases, internal organs. Fibrosis has a devastating impact on a patient's life and lung fibrosis is associated with high morbimortality. Several immune populations contribute to the progression of SSc, and plasmacytoid dendritic cells (pDCs) have been identified as crucial mediators of fibrosis. Research on murine models of lung and skin fibrosis has shown that pDCs are essential in the development of fibrosis, and that removing pDCs improves fibrosis. pDCs are a subset of dendritic cells (DCs) that are specialized in anti-viral responses and are also involved in autoimmune diseases, such as SSc, systemic lupus erythematosus (SLE) and psoriasis, mostly due to their capacity to produce type I interferon (IFN). A type I IFN signature and high levels of CXCL4, both derived from pDCs, have been associated with poor prognosis in patients with SSc and are correlated with fibrosis. This review will examine the recent research on the molecular mechanisms through which pDCs impact SSc.

Identification of lncRNA-miRNA-mRNA networks in circulating exosomes as potential biomarkers for systemic sclerosis

Objective

This study aimed to analyze potential biomarkers for systemic sclerosis (SSc) by constructing lncRNA-miRNA-mRNA networks in circulating exosomes (cirexos).

Materials and methods

Differentially expressed mRNAs (DEmRNAs) and lncRNAs (DElncRNAs) in SSc cirexos were screened using high-throughput sequencing and detected with real-time quantitative PCR (RT-qPCR). Differentially expressed genes (DEGs) were analyzed using the DisGeNET, GeneCards, GSEA4.2.3, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Receiver operating characteristic (ROC) curves, correlation analyses, and a double-luciferase reporter gene detection assay were used to analyze competing endogenous RNA (ceRNA) networks and clinical data.

Results

In this study, 286 DEmRNAs and 192 DElncRNAs were screened, of which 18 DEGs were the same as the SSc-related genes. The main SSc-related pathways included extracellular matrix (ECM) receptor interaction, local adhesion, platelet activation, and IgA production by the intestinal immune network. A hub gene, COL1A1, was obtained by a protein-protein interaction (PPI) network. Four ceRNA networks were predicted through Cytoscape. The relative expression levels of COL1A1, ENST0000313807, and NON-HSAT194388.1 were significantly higher in SSc, while the relative expression levels of hsa-miR-29a-3p, hsa-miR-29b-3p, and hsa-miR-29c-3p were significantly lower in SSc (P < 0.05). The ROC curve showed that the ENST00000313807-hsa-miR-29a-3p-COL1A1 network as a combined biomarker of SSc is more valuable than independent diagnosis, and that it is correlated with high-resolution CT (HRCT), Scl-70, C-reactive protein (CRP), Ro-52, IL-10, IgM, lymphocyte percentage, neutrophil percentage, albumin divided by globulin, urea, and RDW-SD (P < 0.05). Double-luciferase reporter gene detection showed that ENST00000313807 interacts with hsa-miR-29a-3p, which interacts with COL1A1.

Conclusion

The ENST00000313807-hsa-miR-29a-3p-COL1A1 network in plasma cirexos represents a potential combined biomarker for the clinical diagnosis and treatment of SSc.

Increased expression of the ectoenzyme CD38 in peripheral blood plasmablasts and plasma cells of patients with systemic sclerosis

Objective

CD38 is a type II glycoprotein highly expressed on plasmablasts and on short- and long-lived plasma cells, but weakly expressed by lymphoid, myeloid, and non-hematopoietic cells. CD38 is a target for therapies aimed at depleting antibody-producing plasma cells. Systemic sclerosis (SSc) is an immune-mediated disease with a well-documented pathogenic role of B cells. We therefore analyzed CD38 expression in different subsets of peripheral blood mononuclear cells (PBMCs) from a cohort of SSc patients.

Methods

Cell surface expression of CD38 was evaluated on PBMCs from SSc patients using eight-color flow cytometry analysis performed with a FacsCanto II (BD). Healthy individuals were used as controls (HC).

Results

Forty-six SSc patients (mean age 56, range 23-79 years; 38 females and 8 males), and thirty-two age- and sex-matched HC were studied. Twenty-eight patients had the limited cutaneous form and eighteen the diffuse cutaneous form of SSc. The mean disease duration was 7 years. Fourteen patients were on immunosuppressive therapy (14 MMF, 5 RTX). The total percentages of T, B and NK cells were not different between SSc and HC. Compared to HC, SSc patients had higher levels of CD3+CD38+ T cells (p<0.05), higher percentage (p<0.001) of CD3+CD4+CD25+FOXP3+ regulatory T cells, lower percentage (p<0.05) of CD3+CD56+ NK T cells. Moreover, SSc patients had higher levels of CD24^highCD19+CD38^high regulatory B cells than HC (p<0.01), while the amount of CD24+CD19+CD38+CD27+ memory B cells was lower (p<0.001). Finally, the percentages of circulating CD38^highCD27+ plasmablasts and CD138+CD38^high plasma cells were both higher in the SSc group than in HC (p<0.001). We did not observe any correlations between these immunophenotypes and disease subsets or duration, and ongoing immunosuppressive treatment.

Conclusions

The increased expression of CD38 in peripheral blood plasmablasts and plasma cells of SSc patients may suggest this ectoenzyme as a candidate therapeutic target, under the hypothesis that depletion of these cells may beneficially downregulate the chronic immune response in SSc patients. Validation of this data in multicenter cohorts shall be obtained prior to clinical trials with existing anti-CD38 drugs.

The Microbiome in Systemic Sclerosis: Pathophysiology and Therapeutic Potential

Systemic sclerosis (SSc), also known as scleroderma, is an autoimmune disease with unknown etiology characterized by multi-organ fibrosis. Despite substantial investigation on SSc-related cellular and molecular mechanisms, effective therapies are still lacking. The skin, lungs, and gut are the most affected organs in SSc, which act as physical barriers and constantly communicate with colonized microbiota. Recent reports have documented a unique microbiome signature, which may be the pathogenic trigger or driver of SSc. Since gut microbiota influences the efficacy and toxicity of oral drugs, evaluating drug-microbiota interactions has become an area of interest in disease treatment. The existing evidence highlights the potential of the microbial challenge as a novel therapeutic option in SSc. In this review, we have summarized the current knowledge about molecular mechanisms of SSc and highlighted the underlying role of the microbiome in SSc pathogenesis. We have also discussed the latest therapeutic interventions using microbiomes in SSc, including drug-microbiota interactions and animal disease models. This review aims to elucidate the pathophysiological connection and therapeutic potential of the microbiome in SSc. Insights into the microbiome will significantly improve our understanding of etiopathogenesis and developing therapeutics for SSc.