Toward Molecular Stratification and Precision Medicine in Systemic Sclerosis

Systemic sclerosis (SSc), a complex multi-systemic disease characterized by immune dysregulation, vasculopathy and fibrosis, is associated with high mortality. Its pathogenesis is only partially understood. The heterogenous pathological processes that define SSc and its stages present a challenge to targeting appropriate treatment, with differing treatment outcomes of SSc patients despite similar initial clinical presentations. Timing of the appropriate treatments targeted at the underlying disease process is critical. For example, immunomodulatory treatments may be used for patients in a predominantly inflammatory phase, anti-fibrotic treatments for those in the fibrotic phase, or combination therapies for those in the fibro-inflammatory phase. In advancing personalized care through precision medicine, groups of patients with similar disease characteristics and shared pathological processes may be identified through molecular stratification. This would improve current clinical sub-setting systems and guide personalization of therapies. In this review, we will provide updates in SSc clinical and molecular stratification in relation to patient outcomes and treatment responses. Promises of molecular stratification through advances in high-dimensional tools, including omic-based stratification (transcriptomics, genomics, epigenomics, proteomics, cytomics, microbiomics) and machine learning will be discussed. Innovative and more granular stratification systems that integrate molecular characteristics to clinical phenotypes would potentially improve therapeutic approaches through personalized medicine and lead to better patient outcomes.

Umbilical Cord Mesenchymal Stem Cells for Inhibiting the Fibrosis and Autoimmune Development in HOCl-Induced Systemic Scleroderma Mouse Model

Background and Objectives

Systemic scleroderma (SSc) is a rare and serious connective tissue disease, an autoimmune disease, and a rare refractory disease. In this study, preventive effect of single systemic human umbilical cord mesenchymal stem cells (UC-MSCs) transfusion on SSc was preliminarily explored.

Methods and Results

SSc mouse model was established by daily intradermal injection of Hypochlorite (HOCl). SSc mice were treated by single transfusion of UC-MSCs at 0.625×10⁵, 2.5×10⁵ and 1×10⁶ respectively. At the 42nd day of intradermal injection of HOCl, the symptoms showed up by skin and alveolar wall thickening, lymphocytic infiltration, increased collagen in skin/lung, and the increased proportion of CD3^＋CD4^＋CD25^＋FoxP3^＋ cells (a Treg subset) in spleen. After UC-MSCs transfusion, the degree of skin thickening, alveolar wall thickening and lymphocyte infiltration were decreased, the collagen sedimentation in skin/lung was decreased, and the proportion of CD3^＋CD4^＋CD25^＋FoxP3^＋ cells was decreased.

Conclusions

UC-MSC can achieve a preventive effect in SSc mice by fibrosis attenuation and immunoregulation.

Autoantibody profiles in systemic sclerosis; a comparison of diagnostic tests

OBJECTIVES

Autoimmune antibody profiling plays a prominent role in both classification and prognosis of systemic sclerosis (SSc). In the last years novel autoantibodies have been discovered and have become available in diagnostic assays. However, standardization in autoimmune serology is lacking, which may have a negative impact on the added value of autoantibodies in diagnosis and prognosis of SSc. In this paper we describe the comparison of commercially available diagnostic assays for the detection of SSc-associated autoantibodies and explored the coexistence of multiple SSc-associated autoantibodies within patients.

METHODS

Serum samples of 347 patients from the Nijmegen Systemic Sclerosis Cohort were included in this study. All patients fulfilled the ACR/EULAR 2013 classification criteria for SSc and were classified as DcSSc or LcSSc according to the Leroy and Medsger criteria. All samples were evaluated on standard laboratory diagnostic tests for detection of SSc-specific autoantibodies CENPA and CENPB (ACA), Scl-70 (ATA), RNA Polymerase III (rp11/155) (ARA), and SSc-associated autoantibodies Fibrillarin, Th-To, PM-scl75, PM-Scl100, RNP68/A/C, Ku, NOR90, and PDGFR from suppliers EUROIMMUN, D-tek and Thermo Fisher Scientific.

RESULTS

We found that 79% of the patients was positive for one or more of the SSc autoantibodies. Overall, a high agreement was observed between the diagnostic methods for the SSC-specific autoantibodies listed in the ACR/EULAR criteria (ATA, ACA, and ARA) (Cohen's kappa 0.53-0.97). However, a lower agreement was found for SSc-associated autoantibodies PM-Scl, and Ku, as well as for the SSc-specific autoantibodies fibrillarin and Th-To. Furthermore, the data revealed that the presence of ATA, ARA and ACA is predominantly mutually exclusive, with only a fraction of the patients testing positive for both ATA and ARA.

CONCLUSION

Our data showed high concordance of prevalent SSc-specific autoantibodies between different diagnostic assays. Further standardisation for low prevalent SSc-specific and SSc-associated autoantibodies is needed.

Current and Future Outlook on Disease Modification and Defining Low Disease Activity in Systemic Sclerosis

Systemic sclerosis (SSc) is an autoimmune rheumatic disease with heterogeneous clinical manifestations and a variable course in which the severity of the pathology dictates the disease prognosis and course. Among autoimmune rheumatic diseases, SSc has the highest mortality rate among all rheumatic diseases, though there are exciting new therapeutic targets that appear to halt the progression of SSc manifestations such as skin or lung fibrosis. In selected patients, high-intensity regimens with autologous stem cell transplantation can favorably modify the course. In what was once thought to be an untreatable disease, targeted therapies have now changed the outlook of SSc to a treatable disorder. Herein, we discuss the targeted therapies modifying the outlook on selected organ involvement and creating opportunities for future treatment. We also present a framework for defining low disease activity in SSc.

Spanish scleroderma risk score (RESCLESCORE) to predict 15-year all-cause mortality in scleroderma patients at the time of diagnosis based on the RESCLE cohort: Derivation and internal validation

A few scores predicting the short-term risk of mortality in Systemic sclerosis (SSc) have been reported to date. Our study aimed to create a predictive 15-year all-cause mortality score at the time of the diagnosis of SSc. The study was based on the Spanish Scleroderma Registry (RESCLE). The cohort was split up in derivation (DC) and validation cohort (VC). A multivariate analysis to detect variables related to all-cause mortality within the first 15 years from SSc diagnosis was performed, assigning points to the rounded beta values to create the score (RESCLESCORE). 1935 SSc patients were included. The variables in the final model were as follows: age at diagnosis (+2 points > 65 years-old), male gender (+1 point), lcSSc subset (-1 point), mode of onset other than Raynaud's (+1 point), cancer (+1 point) and visceral involvement, such as ILD (+1 point), PAH (+1 point), heart (+1 point) and renal involvement (+2 points). Autoantibodies did not achieve statistical significance in the multivariate analysis. The 3 categories of risk to predict 15-year all-cause mortality at the time of diagnosis were as follows: low risk (5% vs. 7%, p = .189), intermediate risk (26.5% vs. 25.5%, p = .911) and high risk (47.8% vs. 59%, p = .316). The AUC was 0.799 (DC) vs. 0.778 (VC) (p = .530). In conclusion, the RESCLESCORE demonstrated an excellent ability to categorize SSc patients at the time of diagnosis in separate 15-year all-cause mortality risk strata at the time of diagnosis.

Unmet Needs in Systemic Sclerosis Understanding and Treatment: the Knowledge Gaps from a Scientist's, Clinician's, and Patient's Perspective

Systemic sclerosis (SSc) is a highly heterogeneous disease caused by a complex molecular circuitry. For decades, clinical and molecular research focused on understanding the primary process of fibrosis. More recently, the inflammatory, immunological and vascular components that precede the actual onset of fibrosis, have become a matter of increasing scientific scrutiny. As a consequence, the field has started to realize that the early identification of this syndrome is crucial for optimal clinical care as well as for understanding its pathology. The cause of SSc cannot be appointed to a single molecular pathway but to a multitude of molecular aberrances in a spatial and temporal matter and on the backbone of the patient's genetic predisposition. These alterations underlie the plethora of signs and symptoms which patients experience and clinicians look for, ultimately culminating in fibrotic features. To solve this complexity, a close interaction among the patient throughout its "journey," the clinician through its clinical assessments and the researcher with its experimental design, seems to be required. In this review, we aimed to highlight the features of SSc through the eyes of these three professionals, all with their own expertise and opinions. With this unique setup, we underscore the importance of investigating the role of environmental factors in the onset and perpetuation of SSc, of focusing on the earliest signs and symptoms preceding fibrosis and on the application of holistic research approaches that include a multitude of potential molecular alterations in time in an unbiased fashion, in the search for a patient-tailored cure.

Systemic sclerosis

Systemic sclerosis, also called scleroderma, is an immune-mediated rheumatic disease that is characterised by fibrosis of the skin and internal organs and vasculopathy. Although systemic sclerosis is uncommon, it has a high morbidity and mortality. Improved understanding of systemic sclerosis has allowed better management of the disease, including improved classification and more systematic assessment and follow-up. Additionally, treatments for specific complications have emerged and a growing evidence base supports the use of immune suppression for the treatment of skin and lung fibrosis. Some manifestations of the disease, such as scleroderma renal crisis, pulmonary arterial hypertension, digital ulceration, and gastro-oesophageal reflux, are now treatable. However, the burden of non-lethal complications associated with systemic sclerosis is substantial and is likely to become more of a challenge. Here, we review the clinical features of systemic sclerosis and describe the best practice approaches for its management. Furthermore, we identify future areas for development.