Undifferentiated connective tissue disease at risk of systemic sclerosis: A weighted score to identify patients who will evolve

Progression from suspected to definite systemic sclerosis and the role of anti-topoisomerase I antibodies

INTRODUCTION

Early diagnosis of systemic sclerosis (SSc) is important to start therapeutic interventions timely. Important risk factors for progression to SSc are the SSc-specific autoantibodies, of whom anti-centromere antibodies (ACA) and anti-topoisomerase I antibodies (ATA) are the most frequent. ATA is associated with a severe disease course. A more detailed characterisation of the ATA-response in SSc might increase insights in preclinical disease stages and improve prognostication. To address this we identified all patients with suspected very early ATA-positive SSc, defined as all patients who are ATA-positive not fulfilling American College of Rheumatology (ACR)/European Alliance of Associations for Rheumatology (EULAR) 2013 criteria, in the Leiden Combined Care in Systemic Sclerosis (CCISS)-cohort and found very low numbers.

METHODS

This triggered us to search the literature on the ATA prevalence in patients with suspected very early SSc and contribution of the SSc-specific autoantibodies to progression from suspected very early to definite SSc. To increase insights on the ATA-response in suspected very early SSc, we then evaluated the association between the ATA-response and time between onset of Raynaud's phenomenon (RP) and first non-RP symptom, as a proxy for progressing to definite SSc, in all patients with ATA-positive SSc from the Leiden CCISS-cohort.

RESULTS

In short, included studies show that prevalence of ATA is much lower in suspected very early SSc than in populations fulfilling ACR/EULAR 2013 criteria. After 1-15 years of follow-up, only 52% of the patients with suspected very early SSc progress to definite SSc. ATA-IgG levels tend to be higher in patients with ATA-positive SSc with more rapid disease progression.

CONCLUSION

Although a role of ATA in disease progression is suggested, more studies on the ATA response in suspected very early SSc are warranted.

Predicting progression from undifferentiated connective tissue disease to definite connective tissue disease: A systematic review and meta-analysis

PURPOSE

Undifferentiated connective tissue disease (UCTD) encapsulates a broad range of conditions including incomplete forms of systemic lupus erythematosus (SLE) and systemic sclerosis (SSc), some of whom progress to a formal clinical diagnosis over time. This systematic review (SR) and meta-analysis aimed to identify clinical and laboratory features and biomarkers that can predict progression of UCTD.

METHODS

A systematic literature search was carried out on MEDLINE, EMBASE and the Cochrane Central Register of Randomized Controlled Trials. Abstracts and full-text manuscripts were screened by two reviewers. Publications were included if they included at least 20 UCTD patients, a minimum of six months of follow up, and provided data on at least one risk factor for developing a defined CTD. The QUIPS tool was used to assess risk of bias (RoB) and GRADE for grading the quality of the evidence. The study is registered with PROSPERO (ID: CRD42021237725).

RESULTS

Fifty-nine studies were included in the SR, and forty-one in the meta-analysis. The predictors for progression to SLE with the highest certainty of evidence included those with younger age (MD -5.96 [-11.05-0.87 years]), serositis (RR 2.69 [1.61-4.51]), or the presence of anti-dsDNA antibodies (RR 4.27 [1.92-9.51]). For SSc, the highest certainty of evidence included puffy fingers (RR [3.09 [1.48-6.43]), abnormal nailfold changes (NFC) (avascular areas [RR 5.71 (3.03-10.8)] or active or late SSc pattern [RR 2.24 (1.25-4.01)] and anti-topoisomerase-I (RR 1.83 [1.45-2.30]). No novel biomarkers were included in the meta-analysis; however HLA molecules, regulatory T cell shift, pro-inflammatory cytokines and complement activation products were identified as potential predictors for evolution of disease.

CONCLUSIONS

Clinical and immunological parameters may predict which patients with UCTD progress to definitive disease; however, the heterogeneous nature and RoB in most studies limits the ability to apply these results in routine clinical practice. Limited data suggest that some novel biomarkers may provide additional predictive value but these will need larger well designed studies to fully delineate their clinical utility.

Can Antinuclear Antibodies Have a Pathogenic Role in Systemic Sclerosis?

Systemic sclerosis (SSc) is a connective tissue disease characterized by extensive fibrosis of the skin and internal organs, associated with vasculopathy and autoimmune features. Antinuclear antibodies (ANA) are found in almost all SSc patients and constitute strong diagnosis and prognosis biomarkers. However, it remains unclear whether ANA are simple bystanders or if they can have a role in the pathophysiology of the disease. One might think that the nuclear nature of their targets prevents any accessibility to autoantibodies. Nevertheless, recent data suggest that ANA could be pathogenic or at least contribute to the perennation of the disease. We review here first the indirect clues of the contribution of ANA to SSc: they are associated to the disease subtypes, they may precede disease onset, their titer correlates with disease activity and severity, there is an association between molecular subsets, and some patients can respond to B-cell targeting therapy. Then, we describe in a second part the mechanisms of ANA production in SSc from individual genetic background to post-transcriptional modifications of neoantigens. Finally, we elaborate on the potential mechanisms of pathogenicity: ANA could be pathogenic through immune-complex-mediated mechanisms; other processes potentially involve molecular mimicry and ANA penetration into the target cell, with a focus on anti-topoisomerase-I antibodies, which are the most probable candidate to play a role in the pathophysiology of SSc. Finally, we outline some technical and conceptual ways to improve our understanding in this field.

Progression of patients with Raynaud's phenomenon to systemic sclerosis: a five-year analysis of the European Scleroderma Trial and Research group multicentre, longitudinal registry study for Very Early Diagnosis of Systemic Sclerosis (VEDOSS)

BACKGROUND

Preliminary criteria for the very early diagnosis of systemic sclerosis (VEDOSS) have been previously proposed to identify signs and symptoms in patients with Raynaud's phenomenon. Patients with all signs or symptoms of the VEDOSS criteria already fulfil the 2013 American College of Rheumatology-European League Against Rheumatism (ACR-EULAR) classification criteria for systemic sclerosis. However, prospective data for the evolution to fulfilling these criteria do not exist. We therefore aimed to determine the clinical value of the VEDOSS criteria to identify patients with Raynaud's phenomenon who progress to systemic sclerosis within 5 years.

METHODS

The VEDOSS project was a multicentre, longitudinal registry study done in 42 European Scleroderma Trial and Research group centres located in 20 countries in Europe, North America, and South America. Patients with Raynaud's phenomenon were eligible for enrolment. Those who had fulfilled the 1980 ACR or the 2013 ACR-EULAR classification criteria for systemic sclerosis, as well as of any other ACR or EULAR classification criteria for other definite connective tissue diseases at enrolment were excluded. Data were recorded each year during follow-up visits and included the four VEDOSS criteria (ie, positivity for antinuclear antibodies [ANAs], puffy fingers, systemic sclerosis-specific autoantibodies, and abnormal nailfold capillaroscopy). The primary endpoint was the fulfilment of the 2013 ACR-EULAR classification criteria for systemic sclerosis (ie, progression from enrolment to follow-up). Proportion of progressors and VEDOSS criteria interaction were reported descriptively. Predictors of progression of the distinct VEDOSS criteria interactions were determined based on the point prevalence at 5 years. To investigate the intermediate course of progression of the distinct VEDOSS criteria and their combinations, Kaplan-Meier analysis was done.

RESULTS

Between March 1, 2010, and Oct 4, 2018, we enrolled 1150 patients with Raynaud's phenomenon in the VEDOSS database. 764 (66·4%) of 1150 patients met the VEDOSS criteria for study inclusion. Of the 764 patients, 553 (72·4%) had at least one available follow-up visit and the median duration of follow-up was 3·6 years (IQR 1·7-5·8). The mean age was 45·9 years (SD 15·0), 507 (91·7%) of 553 participants were female, and the median time since the onset of Raynaud's phenomenon was 4·0 years (IQR 1·7-10·0). At baseline, 401 (73·7%) of 544 patients with Raynaud's phenomenon had detectable ANA, with 208 (39·5%) of 527 patients positive for systemic sclerosis-specific autoantibodies. Nailfold capillaroscopy abnormalities were present in 182 (36·0%) of 505 patients and puffy fingers were detected in 96 (17·8%) of 540 at baseline. 1885 follow-up visits were recorded. 254 (45·9%) of 553 patients completed the study with progression or a 5-year follow-up; of whom, 133 reached the primary endpoint, resulting in an overall progression rate of 52·4%. The absence of ANA at baseline was the factor most strongly associated with a lack of progression within 5 years, with only four (10·8%) of 37 ANA-negative patients progressing. Conversely, positivity at baseline for systemic sclerosis-specific autoantibodies and puffy fingers was the combination having the highest risk of progression (16 [94·1%] of 17).

INTERPRETATION

Our results from the VEDOSS project offers a useful tool for a stratified risk approach to patients with Raynaud's phenomenon. The absence of ANA is a strong protective factor that identifies patients with very low risk of developing systemic sclerosis whereas the presence of one or two VEDOSS criteria in patients with Raynaud's phenomenon confers a progressively higher risk for systemic sclerosis over time. This stratification tool can be used both for clinical management and to inform early interventional trials.

FUNDING

European Scleroderma Trial And Research and World Scleroderma Foundation.

Autoimmunity in 2019

Based on the PubMed data, we have been performing a yearly evaluation of the publications related to autoimmune diseases and immunology to ascertain the relative weight of the former in the scientific literature. It is particularly intriguing to observe that despite the numerous new avenues of immune-related mechanisms, such as cancer immunotherapy, the proportion of immunology manuscripts related to autoimmunity continues to increase and has been approaching 20% in 2019. As in the previous 13 years, we performed an arbitrary selection of the peer-reviewed articles published by the major dedicated Journals and discussed the common themes which continue to outnumber peculiarites in autoimmune diseases. The investigated areas included systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), psoriatic arthritis (PsA), autoantibodies (autoAbs), and common therapeutic avenues and novel pathogenic mechanisms for autoimmune conditions. Some examples include new pathogenetic evidence which is well represented by IL21 or P2X7 receptor (P2X7R) in SLE or the application of single-cell RNA sequencing (scRNA-seq), mass cytometry, bulk RNA sequencing (RNA-seq), and flow cytometry for the analysis of different cellular populations in RA. Cumulatively and of interest to the clinicians, a large number of findings continue to underline the importance of a strict relationship between basic and clinical science to define new pathogenetic and therapeutic developments. The therapeutic pipeline in autoimmunity continues to grow and maintain a constant flow of new molecules, as well illustrated in RA and PsA, and this is most certainly derived from the new basic evidence and the high-throughput tools applied to autoimmune diseases.

Undifferentiated connective tissue disease at risk for systemic sclerosis: Which patients might be labeled prescleroderma?

Undifferentiated Connective Tissue Disease at risk for Systemic Sclerosis (UCTD-risk-SSc), otherwise referred to as very early-early SSc (very early-early diagnosis of systemic sclerosis VEDOSS), is a condition characterized by Raynaud's phenomenon (RP) and either SSc serum marker autoantibodies or a capillaroscopic scleroderma pattern or both, but without satisfying classification criteria for SSc neither features consistent with SSc sine scleroderma. Approximately half the UCTD-risk-SSc patients develop definite SSc over 5-10 years of follow-up. Identifying patients who will undergo such evolution is an unmet need. Predicting at onset which patients with RP are going to develop SSc over time has long been a research objective and still is an unaccomplished task. The present review is devoted to the critical analysis of the nosographic boundaries of the condition and of items predictive of evolution including serological, capillaroscopic and circulating markers. A weighted score, based on serum antinuclear antibody titre, serum marker antibodies positivity and avascular areas has been developed and may identify in the meanwhile patients to be labeled prescleroderma i.e. those probably developing SSc over time. Future research should be directed to investigate unexplored features, validate and improve the performance of the score and highlight the involved pathways to be contrasted in order to identify a targeted therapy hampering the development of overt SSc.