Emerging cellular and immunotherapies for systemic sclerosis: from mesenchymal stromal cells to CAR-T cells and vaccine-based approaches

An international perspective on the future of systemic sclerosis research

Systemic sclerosis (SSc) remains a challenging and enigmatic systemic autoimmune disease, owing to its complex pathogenesis, clinical and molecular heterogeneity, and the lack of effective disease-modifying treatments. Despite a century of research in SSc, the interconnections among microvascular dysfunction, autoimmune phenomena and tissue fibrosis in SSc remain unclear. The absence of validated biomarkers and reliable animal models complicates diagnosis and treatment, contributing to high morbidity and mortality. Advances in the past 5 years, such as single-cell RNA sequencing, next-generation sequencing, spatial biology, transcriptomics, genomics, proteomics, metabolomics, microbiome profiling and artificial intelligence, offer new avenues for identifying the early pathogenetic events that, once treated, could change the clinical history of SSc. Collaborative global efforts to integrate these approaches are crucial to developing a comprehensive, mechanistic understanding and enabling personalized therapies. Challenges include disease classification, clinical heterogeneity and the establishment of robust biomarkers for disease activity and progression. Innovative clinical trial designs and patient-centred approaches are essential for developing effective treatments. Emerging therapies, including cell-based and fibroblast-targeting treatments, show promise. Global cooperation, standardized protocols and interdisciplinary research are vital for advancing SSc research and improving patient outcomes. The integration of advanced research techniques holds the potential for important breakthroughs in the diagnosis, treatment and care of individuals with SSc.

Preliminary nomogram model for predicting irreversible organ damage of patients with systemic sclerosis

OBJECTIVE

To investigate predictive factors for irreversible organ damage in systemic sclerosis (SSc) and establish a nomogram model.

METHODS

This retrospective study included patients with SSc who were treated at our hospital between March 2013 and March 2023. Irreversible organ damage included heart failure, respiratory failure, renal failure, and gangrene of the hands and feet. Cox and LASSO regression analyses were performed to determine the predictive factors. Based on the results, a nomogram model was developed. The model was evaluated using the C-indices, calibration plots and DCA.

RESULTS

A total of 361 patients with systemic sclerosis were randomly divided into the development (n = 181) and validation (n = 180) groups. Multivariate Cox regression analysis showed that age ≥65 years, weight loss, digital ulcers, mRSS ≥16, elevated creatinine, elevated myoglobin, elevated C-reactive protein, renal involvement and cardiac involvement were independent risk factors. Based on the LASSO analysis, a nomogram model of irreversible organ damage was established. The C-indices of the development group at 24, 60 and 96 m were 96.7, 84.5 and 85.7, whereas those of the validation group at 24, 60 and 96 m were 86.6, 79.1 and 78.5, respectively. The results of the DCA showed that the nomogram can be used as a valuable tool to predict irreversible organ damage in patients with SSc.

CONCLUSION

We included commonly used clinical indicators. According to the nomogram, the probability of irreversible organ damage can be calculated and high-risk patients can be identified.

The B-cells paradigm in systemic sclerosis: an update on pathophysiology and B-cell-targeted therapies

Systemic sclerosis (SSc) is considered a rare autoimmune disease in which there are alterations of both the innate and adaptive immune response resulting in the production of autoantibodies. Abnormalities of the immune system compromise the normal function of blood vessels leading to a vasculopathy manifested by Raynaud's phenomenon, an early sign of SSc . As a consequence of this reactive picture, the disease can evolve leading to tissue fibrosis. Several SSc-specific autoantibodies are currently known and are associated with specific clinical manifestations and prognosis. Although the pathogenetic role of these autoantibodies is still unclear, their production by B cells and plasma cells suggests the importance of these cells in the development of SSc. This review narratively examines B-cell dysfunctions and their role in the pathogenesis of SSc and discusses B-cell-targeted therapies currently used or potentially useful for the management of end-organ complications.

Innovative cell therapies for systemic sclerosis: available evidence and new perspectives

INTRODUCTION

Systemic sclerosis (SSc) is the rheumatic disease with the highest individual mortality rate with a detrimental impact on quality of life. Cell-based therapies may offer new perspectives for this disease as recent phase I trials support the safety of IV infusion of allogeneic mesenchymal stromal cells in SSc and case reports highlight the potential use of Chimeric Antigen Receptor (CAR)-T cells targeting CD19 in active SSc patients who have not responded to conventional immunosuppressive therapies.

AREAS COVERED

This narrative review highlights the most recent evidence supporting the use of cellular therapies in SSc as well as their potential mechanisms of action and discusses future perspectives for cell-based therapies in SSc. Medline/PubMed was used to identify the articles of interest, using the keywords 'Cellular therapies,' 'Mesenchymal stromal cells,' 'Chimeric Antigen Receptor' AND 'systemic sclerosis.' Milestones articles reported by the authors were also used.

EXPERT OPINION

Cellular therapies may represent an opportunity for long-term remission/cure in patients with different autoimmune diseases, including SSc who have not responded to conventional therapies. Multiple ongoing phase I/II trials will provide greater insights into the efficacy and toxicity of cellular therapies.

Critical Analysis of Cytoplasmic Progression of Inflammatory Signaling Suggests Potential Pharmacologic Targets for Wound Healing and Fibrotic Disorders

Successful skin wound healing is dependent on an interplay between epidermal keratinocytes and dermal fibroblasts as they react to local extracellular factors (DAMPs, PAMPs, cytokines, etc.) surveyed from that environment by numerous membrane receptors (e.g., TLRs, cytokine receptors, etc.). In turn, those receptors are the start of a cytoplasmic signaling pathway where balance is key to effective healing and, as needed, cell and matrix regeneration. When directed through NF-κB, these signaling routes lead to transient responses to the benefit of initiating immune cell recruitment, cell replication, local chemokine and cytokine production, and matrix protein synthesis. The converse can also occur, where ongoing canonical NF-κB activation leads to chronic, hyper-responsive states. Here, we assess three key players, TAK1, TNFAIP3, and TNIP1, in cytoplasmic regulation of NF-κB activation, which, because of their distinctive and yet inter-related functions, either promote or limit that activation. Their balanced function is integral to successful wound healing, given their significant control over the expression of inflammation-, fibrosis-, and matrix remodeling-associated genes. Intriguingly, these three proteins have also been emphasized in dysregulated NF-κB signaling central to systemic sclerosis (SSc). Notably, diffuse SSc shares some tissue features similar to an excessive inflammatory/fibrotic wound response without eventual resolution. Taking a cue from certain instances of aberrant wound healing and SSc having some shared aspects, e.g., chronic inflammation and fibrosis, this review looks for the first time, to our knowledge, at what those pathologies might have in common regarding the cytoplasmic progression of NF-κB-mediated signaling. Additionally, while TAK1, TNFAIP3, and TNIP1 are often investigated and reported on individually, we propose them here as three proteins whose consequences of function are very highly interconnected at the signaling focus of NF-κB. We thus highlight the emerging promise for the eventual clinical benefit derived from an improved understanding of these integral signal progression modulators. Depending on the protein, its indirect or direct pharmacological regulation has been reported. Current findings support further intensive studies of these points in NF-κB regulation both for their basic function in healthy cells as well as with the goal of targeting them for translational benefit in multiple cutaneous wound healing situations, whether stemming from acute injury or a dysregulated inflammatory/fibrotic response.

Transcriptomic analyses of lung tissues reveal key genes associated with progression of systemic sclerosis-interstitial lung disease (SSc-ILD)

OBJECTIVE

Systemic sclerosis-interstitial lung disease (SSc-ILD) is the leading cause of death in SSc, affecting around 50 % of the patients. Lung tissue of patients with early-stage SSc-ILD is characterized by a predominant inflammatory response with inconspicuous fibrosis, which may progress to honeycombing fibrosis. Hence, a better understanding of the molecular mechanisms underpinning SSc-ILD pathogenesis is needed to improve treatment options and progression prediction. This transcriptomic study aims to reveal the differential gene expression between control (ctrl) lung tissue and inflammatory, prefibrotic and fibrotic lung tissue to capture progression of early to late phase SSc-ILD.

METHODS

Twelve explanted lungs from patients with SSc-ILD were used to analyze gene expression from formalin-fixed paraffin-embedded lung tissues with varying stages of ILD (n = 18) and control lung tissue (n = 6). The SSc-ILD tissues were stratified into three ROIs: inflammatory, prefibrotic, and fibrotic using histological assessments to define a longitudinal simulation of early to late phases of SSc-ILD. The nanoString (nS) nCounter Human Fibrosis Panel was used to profile the transcriptome in the regions of interest. Validation of potential targetswas performed with immunohistochemistry in the same tissues that were used for transcriptome analysis.

RESULTS

To validate our simulation model, we performed subgroup analysis that showed an incremental increase in pathway scores related to the severity of fibrosis. Ctrl vs SSc-ILD comparison demonstrated 24 differentially expressed genes, two of which had the most pronounced p-values. Cyclin-dependent kinase inhibitor (cdkn2c) was overexpressed (P = 0.00052) in SSc-ILD compared to ctrl, while expression of Pellino E3 ubiquitin-protein ligase 1 (peli1) showed lower expression (P = 0.0012). Additionally, in all four groups, cdkn2c and peli1 gene expression showed an incremental increase and decrease, respectively. Immunohistochemistry of cdkn2c showed consistent results with the nS analysis.

CONCLUSION

More cdkn2c and less peli1 expression were associated with more advanced stages of SSc-ILD on histologic assessment. We report the potential of the cell cycle inhibitor and senescence marker, cdkn2c (p18) to be associated with fibrosis progression.

Systemic sclerosis, silica exposure and cellular therapies: The sand in the gears?

Systemic sclerosis (SSc) is a chronic orphan autoimmune disease with the highest mortality rate among rheumatic diseases. SSc-related interstitial-lung disease (ILD) remains among the leading causes of SSc-related mortality with still few therapeutic effective strategies. In patients with crystallin silica exposure, SSc is recognized as an occupational disease according to the French social security system (Table 25A of the general insurance regimen). Lympho-ablative or myeloablative immunosuppression followed by autologous hematopoietic stem-cell transplantation (aHSCT) is the only therapeutic approach with demonstrated efficacy, improved survival with disease modifying effects on SSc-fibrotic manifestations (skin disease and ILD) and quality of life. A documented past and/or present occupational silica exposure, with extensive exposure and/or silica-related ILD and/or with persistent silica content in the broncho-alveolar lavage fluid are contra-indications to aHSCT in SSc patients, due to the risk of silica-related malignancy or of SSc relapse. This article aims to discuss alternative options in SSc patients with a history of silica exposure, and how innovative cellular therapies (mesenchymal stromal cells, CAR cells) could represent new therapeutic options for these patients.