Anti-U11/U12 RNP antibodies in systemic sclerosis: a new serologic marker associated with pulmonary fibrosis

Acute Exacerbations of Interstitial Lung Diseases: Focus on Biomarkers

Interstitial lung diseases (ILDs) are a large group of pulmonary disorders characterized histologically by the cardinal involvement of the pulmonary interstitium. The prototype of ILDs is idiopathic pulmonary fibrosis (IPF), an incurable disease characterized by progressive distortion and loss of normal lung architecture through unchecked collagen deposition. Acute exacerbations are dramatic events during the clinical course of ILDs, associated with high morbidity and mortality. Infections, microaspiration, and advanced lung disease might be involved in the pathogenesis of acute exacerbations. Despite clinical scores, the prediction of the onset and outcome of acute exacerbations is still inaccurate. Biomarkers are necessary to characterize acute exacerbations better. We review the evidence for alveolar epithelial cell, fibropoliferation, and immunity molecules as potential biomarkers for acute exacerbations of interstitial lung disease.

Training the Next Generation of Rheumatologists: What Is the Best Way to Teach Fellows About Scleroderma?

Rheumatology is rich in educational opportunities, learning about a variety of diseases. Rheumatology subspecialty training is a time of unparalleled learning, and within the curriculum of a training program, the connective tissue diseases (CTDs) represent a unique challenge to the fellows. The challenge therein lies in the multisystem presentations they are faced with mastering. Scleroderma, as a rare and life-threatening CTD, remains one of the most difficult conditions to manage and treat. In this article, the authors focus on an approach to training the next generation of rheumatologists to take care of patients with scleroderma.

Anti-U11/U12 Antibodies as a Rare but Important Biomarker in Patients with Systemic Sclerosis: A Narrative Review

Anti-nuclear (ANA) are present in approximately 90% of systemic sclerosis (SSc) patients and are key biomarkers in supporting the diagnosis and determining the prognosis of this disease. In addition to the classification criteria autoantibodies for SSc [i.e., anti-centromere, anti-topoisomerase I (Scl-70), anti-RNA polymerase III], other autoantibodies have been associated with important SSc phenotypes. Among them, anti-U11/U12 ribonucleoprotein (RNP) antibodies, also known as anti-RNPC-3, were first reported in a patient with SSc, but very little is known about their association and clinical utility. The U11/U12 RNP macromolecular complex consists of several proteins involved in alternative mRNA splicing. More recent studies demonstrated associations of anti-anti-U11/U12 antibodies with SSc and severe pulmonary fibrosis as well as with moderate to severe gastrointestinal dysmotility. Lastly, anti-U11/U12 autoantibodies have been strongly associated with malignancy in SSc patients. Here, we aimed to summarize the knowledge of anti-U11/U12/RNPC-3 antibodies in SSc, including their seroclinical associations in a narrative literature review.

Advanced Autoantibody Testing in Systemic Sclerosis

Systemic sclerosis is a systemic autoimmune rheumatic disease characterized by immune abnormalities, leading to vasculopathy and fibrosis. Autoantibody testing has become an increasingly important part of diagnosis and prognostication. Clinicians have been limited to antinuclear antibody (ANA), antitopoisomerase I (also known as anti-Scl-70) antibody, and anticentromere antibody testing. Many clinicians now have improved access to an expanded profile of autoantibody testing. In this narrative review article, we review the epidemiology, clinical associations, and prognostic value of advanced autoantibody testing in people with systemic sclerosis.

The Role of Autoantibody Testing in Modern Personalized Medicine

Personalized medicine (PM) aims individualized approach to prevention, diagnosis, and treatment. Precision Medicine applies the paradigm of PM by defining groups of individuals with akin characteristics. Often the two terms have been used interchangeably. The quest for PM has been advancing for centuries as traditional nosology classification defines groups of clinical conditions with relatively similar prognoses and treatment options. However, any individual is characterized by a unique set of multiple characteristics and therefore the achievement of PM implies the determination of myriad demographic, epidemiological, clinical, laboratory, and imaging parameters. The accelerated identification of numerous biological variables associated with diverse health conditions contributes to the fulfillment of one of the pre-requisites for PM. The advent of multiplex analytical platforms contributes to the determination of thousands of biological parameters using minute amounts of serum or other biological matrixes. Finally, big data analysis and machine learning contribute to the processing and integration of the multiplexed data at the individual level, allowing for the personalized definition of susceptibility, diagnosis, prognosis, prevention, and treatment. Autoantibodies are traditional biomarkers for autoimmune diseases and can contribute to PM in many aspects, including identification of individuals at risk, early diagnosis, disease sub-phenotyping, definition of prognosis, and treatment, as well as monitoring disease activity. Herein we address how autoantibodies can promote PM in autoimmune diseases using the examples of systemic lupus erythematosus, antiphospholipid syndrome, rheumatoid arthritis, Sjögren syndrome, systemic sclerosis, idiopathic inflammatory myopathies, autoimmune hepatitis, primary biliary cholangitis, and autoimmune neurologic diseases.

Predicting the Progression of Very Early Systemic Sclerosis: Current Insights

Systemic sclerosis (SSc) is a complex autoimmune connective tissue disease with distinct pathological hallmarks (ie, inflammation, vasculopathy, fibrosis) that may predominate at different stages in the disease course with varying severity. Initial efforts to classify patients with SSc identified a subset of patients with very early SSc. These patients possessed signs of SSc (eg, Raynaud phenomenon, SSc specific autoantibodies and/or nailfold capillary abnormalities) without fulfilling complete SSc classification criteria. Recognizing the inherent value in early diagnosis and intervention in SSc, researchers have endeavored to identify risk factors for progression from very early SSc to definite SSc. The present review summarizes the clinical phenotype of patients with very early and early SSc. Through a scoping review of recent literature, this review also describes risk factors for progression to definite SSc with a focus on the specific clinical features that arise early in the SSc disease course (eg, diffuse cutaneous sclerosis, interstitial lung disease, esophageal dysfunction, renal crisis, cardiac involvement). In addition to clinical risk factors, this review provides evidence for how biological data (ie, serological, genomic, proteomic profiles, skin bioengineering methods) can be integrated into risk assessment models in the future. Furthering our understanding of biological features of very early SSc will undoubtedly provide novel insights into SSc pathogenesis and may illuminate new therapeutic targets to prevent progression of SSc.

Systemic Sclerosis-Specific Antibodies: Novel and Classical Biomarkers

Disease-specific autoantibodies are considered the most important biomarkers for systemic sclerosis (SSc), due to their ability to stratify patients with different severity and prognosis. Anti-nuclear antibodies (ANA), occurring in subjects with isolated Raynuad's phenomenon, are considered the strongest independent predictors of definite SSc and digital microvascular damage, as observed by nailfold videocapillaroscopy. ANA are present in more than 90% of SSc, but ANA negativity does not exclude SSc diagnosis: a little rate of SSc ANA negative exists and shows a distinct subtype of disease, with less vasculopathy, but more frequent lower gastrointestinal involvement and severe disease course. Anti-centromere, anti-Th/To, and anti-Topoisomerase I antibodies could be considered as classical biomarkers, covering about 60% of SSc and defining patients with well-described cardio-pulmonary complications. In particular, anti-Topoisomerase I represent a risk factor for development of diffuse cutaneous involvement and digital ulcers in the first 3 years of disease, as well as severe interstitial lung disease (ILD). Anti-RNA polymerase III is a biomarker with new clinical implications: very rapid skin thickness progression, gastric antral vascular ectasia, the occurrence of synchronous cancers, and possible association with silicone breast implants rupture. Moreover, novel SSc specific autoantibodies have been globally described in about 10% of "seronegative" SSc patients: anti-elF2B, anti-RuvBL1/2 complex, anti-U11/U12 RNP, and anti-BICD2 depict specific SSc subtypes with severe organ complications. Many autoantibodies could be considered markers of overlap syndromes, including SSc. Anti-Ku are found in 2-7% of SSc, strictly defining the PM/SSc overlap. They are associated with synovitis, joint contractures, myositis, and negatively associated with vascular manifestation of disease. Anti-U3RNP are associated with a well-defined clinical phenotype: Afro-Caribbean male patients, younger at diagnosis, and higher risk of pulmonary hypertension and gastrointestinal involvement. Anti-PM/Scl define SSc patients with high frequency of ILD, calcinosis, dermatomyositis skin changes, and severe myositis. The accurate detection of autoantibodies SSc specific and associated with overlap syndromes is crucial for patients' stratification. ANA should be correctly identified using indirect immunofluorescent assay and a standardized way of patterns' interpretation. The gold-standard technique for autoantibodies' identification in SSc is still considered immunoprecipitation, for its high sensitivity and specificity, but other assays have been widely used in routine practice. The identification of SSc autoantibodies with high diagnostic specificity and high predictive value is mandatory for early diagnosis, a specific follow-up and the possible definition of the best therapy for every SSc subsets. In addition, the validation of novel autoantibodies is mandatory in wider cohorts in order to restrict the gap of so-called seronegative SSc patients.

Targeting Systemic Sclerosis from Pathogenic Mechanisms to Clinical Manifestations: Why IL-6?

Systemic sclerosis (SS) is a chronic autoimmune disorder, which has both cutaneous and systemic clinical manifestations. The disease pathogenesis includes a triad of manifestations, such as vasculopathy, autoimmunity, and fibrosis. Interleukin-6 (IL-6) has a special role in SS development, both in vascular damage and in the development of fibrosis. In the early stages, IL-6 participates in vascular endothelial activation and apoptosis, leading to the release of damage-associated molecular patterns (DAMPs), which maintain inflammation and autoimmunity. Moreover, IL-6 plays an important role in the development of fibrotic changes by mediating the transformation of fibroblasts into myofibroblasts. All of these are associated with disabling clinical manifestations, such as skin thickening, pulmonary fibrosis, pulmonary arterial hypertension (PAH), heart failure, and dysphagia. Tocilizumab is a humanized monoclonal antibody that inhibits IL-6 by binding to the specific receptor, thus preventing its proinflammatory and fibrotic actions. Anti-IL-6 therapy with Tocilizumab is a new hope for SS patients, with data from clinical trials supporting the favorable effect, especially on skin and lung damage.

Systematic Analysis of the Literature in Search of Defining Systemic Sclerosis Subsets

OBJECTIVE

Systemic sclerosis (SSc) is a multisystem disease with heterogeneity in presentation and prognosis.An international collaboration to develop new SSc subset criteria is underway. Our objectives were to identify systems of SSc subset classification and synthesize novel concepts to inform development of new criteria.

METHODS

Medline, Cochrane MEDLINE, the Cumulative Index to Nursing and Allied Health Literature, EMBASE, and Web of Science were searched from their inceptions to December 2019 for studies related to SSc subclassification, limited to humans and without language or sample size restrictions.

RESULTS

Of 5686 citations, 102 studies reported original data on SSc subsets. Subset classification systems relied on extent of skin involvement and/or SSc-specific autoantibodies (n = 61), nailfold capillary patterns (n = 29), and molecular, genomic, and cellular patterns (n = 12). While some systems of subset classification confer prognostic value for clinical phenotype, severity, and mortality, only subsetting by gene expression signatures in tissue samples has been associated with response to therapy.

CONCLUSION

Subsetting on extent of skin involvement remains important. Novel disease attributes including SSc-specific autoantibodies, nailfold capillary patterns, and tissue gene expression signatures have been proposed as innovative means of SSc subsetting.

Nintedanib in patients with systemic sclerosis-associated interstitial lung disease: subgroup analyses by autoantibody status and skin score

Objective

Using data from the SENSCIS trial, these analyses were undertaken to assess the effects of nintedanib versus placebo in subgroups of patients with systemic sclerosis–associated interstitial lung disease (SSc‐ILD), based on characteristics previously identified as being associated with the progression of SSc‐ILD.

Methods

Patients with SSc‐ILD were randomized to receive either nintedanib or placebo, stratified by anti–topoisomerase I antibody (ATA) status. We assessed the rate of decline in forced vital capacity (FVC) (expressed in ml/year) over 52 weeks in subgroups based on baseline ATA status, modified Rodnan skin thickness score (MRSS) (<18 versus ≥18), and SSc subtype (limited cutaneous SSc [lcSSc] versus diffuse cutaneous SSc [dcSSc]).

Results

At baseline, 60.8% of 576 patients who received treatment with either nintedanib or placebo were positive for ATA, 51.9% had dcSSc, and 77.5% of 574 patients with MRSS data available had an MRSS of <18. The effect of nintedanib versus placebo on reducing the rate of decline in FVC (ml/year) was numerically more pronounced in ATA‐negative patients compared to ATA‐positive patients (adjusted difference in the rate of FVC decline, 57.2 ml/year [95% confidence interval (95% CI) –3.5, 118.0] versus 29.9 ml/year [95% CI –19.1, 78.8]), in patients with a baseline MRSS ≥18 compared to those with a baseline MRSS of <18 (adjusted difference in the rate of FVC decline, 88.7 ml/year [95% CI 7.7, 169.8] versus 26.4 ml/year [95% CI –16.8, 69.6]), and in patients with dcSSc compared to those with lcSSc (adjusted difference in the rate of FVC decline, 56.6 ml/year [95% CI 3.2, 110.0] versus 25.3 ml/year [95% CI –28.9, 79.6]). However, all exploratory interaction P values were nonsignificant (all P > 0.05), indicating that there was no heterogeneity in the effect of nintedanib versus placebo between these subgroups of patients.

Conclusion

In patients with SSc‐ILD, reduction in the annual rate of decline in FVC among patients receiving nintedanib compared to those receiving placebo was not found to be heterogenous across subgroups based on ATA status, MRSS, or SSc subtype.

Video Abstract

Exercise as a multi-modal disease-modifying medicine in systemic sclerosis: An introduction by The Global Fellowship on Rehabilitation and Exercise in Systemic Sclerosis (G-FoRSS)

Systemic sclerosis (SSc) is a heterogeneous multisystem autoimmune disease whereby its main pathological drivers of disability and damage are vascular injury, inflammatory cell infiltration, and fibrosis. These mechanisms result in diffuse and diverse impairments arising from ischemic circulatory dysfunction leading to painful skin ulceration and calcinosis, neurovascular aberrations hindering gastrointestinal (GI) motility, progressive painful, incapacitating or immobilizing effects of inflammatory and fibrotic effects on the lungs, skin, articular and periarticular structures, and muscle. SSc-related impairments impede routine activities of daily living (ADLs) and disrupt three critical life areas: work, family, social/leisure, and also impact on psychological well-being. Physical activity and exercise are globally recommended; however, for connective tissue diseases, this guidance carries greater impact on inflammatory disease manifestations, recovery, and cardiovascular health. Exercise, through myogenic and vascular phenomena, naturally targets key pathogenic drivers by downregulating multiple inflammatory and fibrotic pathways in serum and tissue, while increasing circulation and vascular repair. G-FoRSS, The Global Fellowship on Rehabilitation and Exercise in Systemic Sclerosis recognizes the scientific basis of and advocates for education and research of exercise as a systemic and targeted SSc disease-modifying treatment. An overview of biophysiological mechanisms of physical activity and exercise are herein imparted for patients, clinicians, and researchers, and applied to SSc disease mechanisms, manifestations, and impairment. A preliminary guidance on exercise in SSc, a research agenda, and the current state of research and outcome measures are set forth.

Role of autoantibodies in the diagnosis and prognosis of interstitial lung disease in autoimmune rheumatic disorders

Interstitial lung disease (ILD) has been recognized as a frequent manifestation associated with a substantial morbidity and mortality burden in patients with autoimmune rheumatic disorders. Serum autoantibodies are considered good biomarkers for identifying several subsets or specific phenotypes of ILD involvement in these patients. This review features the role of several autoantibodies as a diagnostic and prognostic biomarker linked to the presence ILD and specific ILD phenotypes in autoimmune rheumatic disorders. The case of the diverse antisynthetase antibodies in the antisynthease syndrome or the anti-melanoma differentiation-associated 5 protein (MDA5) antibodies as a marker of a severe condition such as rapidly progressive ILD in patients with clinically amyopathic dermatomyositis are some of the associations herein reported in the group of myositis spectrum disorders. Specific autoantibodies such as the well-known anti-topoisomerase I (anti-Scl70) or the anti-Th/To, anti-U11/U12 ribonucleoprotein, and anti-eukaryotic initiation factor 2B (eIF2B) antibodies seems to be specifically linked to ILD in patients with systemic sclerosis. Overlap syndromes between systemic sclerosis and myositis, also have good ILD biomarkers, which are the anti-PM/Scl and anti-Ku autoantibodies. Lastly, other not so often reported disorders as being associated with ILD but recently most recognized as is the case of rheumatoid arthritis associated ILD or entities herein included in the miscellaneous disorders section, which include anti-neutrophil cytoplasmic antibody-associated interstitial lung disease, Sjögren's syndrome or the mixed connective tissue disease, are also discussed.

Recognising the spectrum of scleromyositis: HEp-2 ANA patterns allow identification of a novel clinical subset with anti-SMN autoantibodies

Objective

To describe systemic sclerosis (SSc) with myopathy in patients without classic SSc-specific and SSc-overlap autoantibodies (aAbs), referred to as seronegative scleromyositis.

Methods

Twenty patients with seronegative scleromyositis diagnosed by expert opinion were analysed retrospectively for SSc features at myositis diagnosis and follow-up, and stratified based on HEp-2 nuclear patterns by indirect immunofluorescence (IIF) according to International Consensus of Autoantibody Patterns. Specificities were analysed by protein A−assisted immunoprecipitation. Myopathy was considered an organ involvement of SSc.

Results

SSc sine scleroderma was a frequent presentation (45%) at myositis diagnosis. Myositis was the most common first non-Raynaud manifestation of SSc (55%). Lower oesophagal dysmotility was present in 10 of 11 (91%) investigated patients. At follow-up, 80% of the patients met the American College of Rheumatology/EULAR SSc classification criteria. Two-thirds of patients had a positive HEp-2 IIF nuclear pattern (all with titers ≥1/320), defining three novel scleromyositis subsets. First, antinuclear antibody (ANA)-negative scleromyositis was associated with interstitial lung disease (ILD) and renal crisis. Second, a speckled pattern uncovered multiple rare SSc-specific aAbs. Third, the nuclear dots pattern was associated with aAbs to survival of motor neuron (SMN) complex and a novel scleromyositis subset characteriszed by calcinosis but infrequent ILD and renal crisis.

Conclusions

SSc skin involvement is often absent in early seronegative scleromyositis. ANA positivity, Raynaud phenomenon, SSc-type capillaroscopy and/or lower oesophagal dysmotility may be clues for scleromyositis. Using HEp-2 IIF patterns, three novel clinicoserological subsets of scleromyositis emerged, notably (1) ANA-negative, (2) ANA-positive with a speckled pattern and (3) ANA-positive with nuclear dots and anti-SMN aAbs.

Autoantibody Discovery, Assay Development and Adoption: Death Valley, the Sea of Survival and Beyond

Dating to the discovery of the Lupus Erythematosus (LE) cell in 1948, there has been a dramatic growth in the discovery of unique autoantibodies and their cognate targets, all of which has led to the availability and use of autoantibody testing for a broad spectrum of autoimmune diseases. Most studies of the sensitivity, specificity, commutability, and harmonization of autoantibody testing have focused on widely available, commercially developed and agency-certified autoantibody kits. However, this is only a small part of the spectrum of autoantibody tests that are provided through laboratories world-wide. This manuscript will review the wider spectrum of testing by exploring the innovation pathway that begins with autoantibody discovery followed by assessment of clinical relevance, accuracy, validation, and then consideration of regulatory requirements as an approved diagnostic test. Some tests are offered as "Research Use Only (RUO)", some as "Laboratory Developed Tests (LDT)", some enter Health Technology Assessment (HTA) pathways, while others are relegated to a "death valley" of autoantibody discovery and become "orphan" autoantibodies. Those that achieve regulatory approval are further threatened by the business world's "Darwinian Sea of Survival". As one example of the trappings of autoantibody progression or failure, it is reported that more than 200 different autoantibodies have been described in systemic lupus erythematosus (SLE), a small handful (~10%) of these have achieved regulatory approval and are widely available as commercial diagnostic kits, while a few others may be available as RUO or LDT assays. However, the vast majority (90%) are orphaned and languish in an autoantibody 'death valley'. This review proposes that it is important to keep an inventory of these "orphan autoantibodies" in 'death valley' because, with the increasing availability of multi-analyte arrays and artificial intelligence (MAAI), some can be rescued to achieve a useful role in clinical diagnostic especially in light of patient stratification and precision medicine.

Disruption of exon-bridging interactions between the minor and major spliceosomes results in alternative splicing around minor introns

Vertebrate genomes contain major (>99.5%) and minor (<0.5%) introns that are spliced by the major and minor spliceosomes, respectively. Major intron splicing follows the exon-definition model, whereby major spliceosome components first assemble across exons. However, since most genes with minor introns predominately consist of major introns, formation of exon-definition complexes in these genes would require interaction between the major and minor spliceosomes. Here, we report that minor spliceosome protein U11-59K binds to the major spliceosome U2AF complex, thereby supporting a model in which the minor spliceosome interacts with the major spliceosome across an exon to regulate the splicing of minor introns. Inhibition of minor spliceosome snRNAs and U11-59K disrupted exon-bridging interactions, leading to exon skipping by the major spliceosome. The resulting aberrant isoforms contained a premature stop codon, yet were not subjected to nonsense-mediated decay, but rather bound to polysomes. Importantly, we detected elevated levels of these alternatively spliced transcripts in individuals with minor spliceosome-related diseases such as Roifman syndrome, Lowry–Wood syndrome and early-onset cerebellar ataxia. In all, we report that the minor spliceosome informs splicing by the major spliceosome through exon-definition interactions and show that minor spliceosome inhibition results in aberrant alternative splicing in disease.

Anti-RNPC-3 antibody predicts poor prognosis in patients with Interstitial Lung Disease associated to Systemic Sclerosis

OBJECTIVE

To analyse the prevalence, the clinical characteristics, the overall survival and the event-free survival (EFS) of Systemic Sclerosis (SSc) patients who express anti- U11/U12 RNP (RNPC-3) antibodies.

METHODS

A total of 447 SSc patients from Barcelona (n = 286) and Milan (n = 161) were selected. All samples were tested using a particle-based multi-analyte technology. We compared anti-RNPC-3 positive and negative patients. Epidemiological, clinical features and survival were analyzed. End-stage lung disease (ESLD) was defined if the patient developed FVC < 50% of predicted, needed oxygen therapy or lung transplantation. EFS was defined as the period of time free of either ESLD or death.

RESULTS

Nineteen of 447 (4.3%) patients had anti-RNPC-3 antibodies and interstitial lung disease (ILD) was more frequent (11, 57.9% vs. 144, 33.6%, p = 0.030) in individuals with anti-RNPC-3 antibodies. More patients reached ESLD in the positive group (7, 36.8% vs. 74, 17.3%, p = 0.006), and a higher use of non-glucocorticoid immunosuppressive drugs was observed (11, 57.9% vs. 130, 30.4%, p = 0.012). Anti-RNPC-3 positive patients had lower EFS, both in the total cohort (log-rank p=0.001), as well as in patients with ILD (log-rank p=0.002). In multivariate Cox regression analysis diffuse cutaneous subtype, age at onset, the presence of ILD or pulmonary arterial hypertension, and the expression of anti-RNPC-3 positivity or anti-topoisomerase I were independently associated with worse EFS.

CONCLUSIONS

The presence of anti-RNPC-3 was associated with higher frequency of ILD and either ESLD or death. These data suggest anti-RNPC-3 is an independent poor prognosis antibody in SSc, especially if ILD is also present.

The Autoantigen Repertoire and the Microbial RNP World

Although autoimmunity and autoimmune disease (AID) are relatively common, the repertoire of autoantigens is paradoxically very limited. Highly enriched in this autoantigen repertoire are nucleic acids and their binding proteins, which together form large macromolecular structures. Most of these complexes are of ancient evolutionary origin, with homologs throughout multiple kingdoms of life. Why and if these nucleic acid-protein particles drive the development of autoimmunity remains unresolved. Recent advances in our understanding of the microbiome may provide clues about the origins of autoimmunity - and the particular puzzle of why the autoantigen repertoire is so particularly enriched in ribonucleoprotein particles (RNPs). We discuss the possibility that autoimmunity to some RNPs may arise from molecular mimicry to microbial orthologs.

Antinuclear Antibodies in Systemic Sclerosis: an Update

Systemic sclerosis is an autoimmune disease characterized by fibrosis of skin and internal organs, vasculopathy, and dysregulation of immune system. A diagnostically important feature of immunological abnormalities in systemic sclerosis is the presence of circulating antinuclear antibodies, which may be detected in 90-95% of patients with either of the four main laboratory methods: immunofluorescence, enzyme-linked immunosorbent assay, immunodiffusion, and immunoblotting. There are several antinuclear antibodies specific for systemic sclerosis. These include antibodies against topoisomerase (anti-TOPO I), kinetochore proteins (ACA), RNA polymerase enzyme (anti-RNAP III), ribonuclear proteins (anti-U11/U12 RNP, anti-U1 RNP, anti-U3 RNP) and nucleolar antigens (anti-Th/To, anti-NOR 90, anti-Ku, antiRuvBL1/2, and anti-PM/Scl). Autoantibodies specific for systemic sclerosis have been linked to distinct clinical features. Therefore, detecting a particular antibody type is important in predicting a possible organ involvement and prognosis and may have an impact on monitoring and treatment.

Clinical features of Japanese systemic sclerosis (SSc) patients negative for SSc-related autoantibodies: A single-center retrospective study

OBJECTIVE

To examine the clinical features of systemic sclerosis (SSc) patients negative for SSc-related autoantibodies (autoAbs).

METHODS

Serum samples were collected from 546 SSc patients. The presence of antinuclear antibody (ANA) was screened by indirect immunofluorescence (IIF) staining using HEp-2 cells. SSc-related autoantibodies were identified by specific IIF staining, enzyme-linked immunosorbent assay, or immunoprecipitation assay. Clinical features were analyzed among patients negative for ANA/SSc-related autoAbs, anticentromere Abs (ACA), anti-topoisomerase I (anti-topo I) Abs, and anti-RNA polymerase (anti-RNAP) Abs.

RESULTS

Of the 546 SSc patients, 26 (4.8%) were negative for ANA and 29 (5.3%) were ANA-positive but negative for SSc-related autoAbs. Regarding clinical features, patients negative for ANA/SSc-related autoAbs (n = 55) had a significantly shorter disease duration, higher proportion of the diffuse type, contracture of phalanges, diffuse pigmentation, higher modified Rodnan total skin thickness score (mRSS), and lower incidence of telangiectasia than those with ACA (n = 224). On the other hand, younger disease onset, lower mRSS, and lower incidence of scleroderma renal crisis were observed in patients negative for ANA/SSc-related autoAbs than in those with anti-RNAP Abs (n = 52). Although pitting scars were less common in patients negative for ANA/SSc-related autoAbs than in those with anti-topo I Abs (n = 144), their clinical features were similar.

CONCLUSION

Patients negative for ANA/SSc-related autoAbs form a clinically distinct subset among SSc patients.

Autoantibodies to stratify systemic sclerosis patients into clinically actionable subsets

Systemic sclerosis (SSc) is a rare chronic disease of unknown etiology characterized by vascular abnormalities and fibrosis involving the skin and internal organs, especially the gastrointestinal tract, lung, heart and kidneys. Although the disease was historically stratified according to the extent of skin involvement, more recent approaches place more emphasis on patterns and extent of internal organ involvement. Despite numerous clinical trials, disease-modifying treatment options are still limited resulting in persistent poor quality of life and high mortality. This review provides an overview of autoantibodies in SSc and novel approaches to stratify the disease into clinically actionable subsets.

Pathogenic Roles of Autoantibodies and Aberrant Epigenetic Regulation of Immune and Connective Tissue Cells in the Tissue Fibrosis of Patients with Systemic Sclerosis

Systemic sclerosis (SSc) is a multi-system autoimmune disease with tissue fibrosis prominent in the skin and lung. In this review, we briefly describe the autoimmune features (mainly autoantibody production and cytokine profiles) and the potential pathogenic contributors including genetic/epigenetic predisposition, and environmental factors. We look in detail at the cellular and molecular bases underlying tissue-fibrosis which include trans-differentiation of fibroblasts (FBs) to myofibroblasts (MFBs). We also state comprehensively the pro-inflammatory and pro-fibrotic cytokines relevant to MFB trans-differentiation, vasculopathy-associated autoantibodies, and fibrosis-regulating microRNAs in SSc. It is conceivable that tissue fibrosis is mainly mediated by an excessive production of TGF-β, the master regulator, from the skewed Th2 cells, macrophages, fibroblasts, myofibroblasts, and keratinocytes. After binding with TGF-β receptors on MFB, the downstream Wnt/β-catenin triggers canonical Smad 2/3 and non-canonical Smad 4 signaling pathways to transcribe collagen genes. Subsequently, excessive collagen fiber synthesis and accumulation as well as tissue fibrosis ensue. In the later part of this review, we discuss limited data relevant to the role of long non-coding RNAs (lncRNAs) in tissue-fibrosis in SSc. It is expected that these lncRNAs may become the useful biomarkers and therapeutic targets for SSc in the future. The prospective investigations in the development of novel epigenetic modifiers are also suggested.

Autoantibody Biomarkers in Rheumatic Diseases

Autoantibodies encountered in patients with systemic rheumatic diseases bear clinical significance as a biomarker to help or predict diagnosis, clinical phenotypes, prognosis, and treatment decision-making. Furthermore, evidence has accumulated regarding the active involvement of disease-specific or disease-associated autoantibodies in the pathogenic process beyond simple association with the disease, and such knowledge has become essential for us to better understand the clinical value of autoantibodies as a biomarker. This review will focus on the current update on the autoantibodies of four rheumatic diseases (rheumatoid arthritis, myositis, systemic sclerosis, and anti-neutrophil cytoplasmic antibody associated vasculitis) where there has been a tremendous progress in our understanding on their biological effects and clinical use.

Using Autoantibodies and Cutaneous Subset to Develop Outcome-Based Disease Classification in Systemic Sclerosis

OBJECTIVE

To describe the associations between autoantibodies, clinical presentation, and outcomes among patients with systemic sclerosis (SSc) in order to develop a novel SSc classification scheme that would incorporate both antibodies and the cutaneous disease subset as criteria.

METHODS

Demographic and clinical characteristics, including cutaneous subset, time of disease and organ complication onset, and autoantibody specificities, were determined in a cohort of SSc subjects. Survival analysis was used to assess the effect of the autoantibodies on organ disease and death.

RESULTS

The study included 1,325 subjects. Among the antibody/skin disease subsets, anticentromere antibody-positive patients with limited cutaneous SSc (lcSSc) (n = 374) had the highest 20-year survival (65.3%), lowest incidence of clinically significant pulmonary fibrosis (PF) (8.5%) and scleroderma renal crisis (SRC) (0.3%), and lowest incidence of cardiac SSc (4.9%), whereas the frequency of pulmonary hypertension (PH) was similar to the mean value in the SSc cohort overall. The anti-Scl-70+ groups of patients with lcSSc (n = 138) and patients with diffuse cutaneous SSc (dcSSc) (n = 149) had the highest incidence of clinically significant PF (86.1% and 84%, respectively, at 15 years). Anti-Scl-70+ patients with dcSSc had the lowest survival (32.4%) and the second highest incidence of cardiac SSc (12.9%) at 20 years. In contrast, in anti-Scl-70+ patients with lcSSc, other complications were rare, and these patients demonstrated the lowest incidence of PH (6.9%) and second highest survival (61.8%) at 20 years. Anti-RNA polymerase antibody-positive SSc patients (n = 147) had the highest incidence of SRC (28.1%) at 20 years. The anti-U3 RNP+ SSc group (n = 56) had the highest incidence of PH (33.8%) and cardiac SSc (13.2%) at 20 years. Among lcSSc patients with other autoantibodies (n = 295), the risk of SRC and cardiac SSc was low at 20 years (2.7% and 2.4%, respectively), while the frequencies of other outcomes were similar to the mean values in the full SSc cohort. Patients with dcSSc who were positive for other autoantibodies (n = 166) had a poor prognosis, demonstrating the second lowest survival (33.6%) and frequent organ complications.

CONCLUSION

These findings highlight the importance of autoantibodies, cutaneous subset, and disease duration when assessing morbidity and mortality in patients with SSc. Our novel classification scheme may improve disease monitoring and benefit future clinical trial designs in SSc.

The nosology of systemic sclerosis: how lessons from the past offer new challenges in reframing an idiopathic rheumatological disorder

Systemic sclerosis is a rare connective tissue disease characterised by a wide range of clinical manifestations. Compared with previous sets of criteria, the 2013 American College of Rheumatology and European League Against Rheumatism (ACR/EULAR) classification of systemic sclerosis encompasses a broader and more relevant spectrum of the condition. Nonetheless, clinical and prognostic heterogeneity persists among patients fulfilling these criteria. The next task in the classification of systemic sclerosis is the development of new subset criteria that can successfully identify subgroups of patients with distinct prognostic or pathophysiological features. In this Viewpoint we describe the history of systemic sclerosis over the past century with the objective of highlighting the effect of previous nosological debates on efforts to understand and manage this disorder. Rather than seeking to present a systematic review of possible subgrouping for systemic sclerosis in relation to prognosis, we aim to clarify how nosological considerations have influenced our understanding of the cause and prognosis of this so-called idiopathic rheumatological disorder and how aetiological, prognostic, and pathophysiological hypotheses have helped to describe clusters within the disease. By reflecting on past nosological debates and endeavours, we identify challenges for the current initiative to develop a new subgrouping of systemic sclerosis.

Does Systemic Sclerosis-associated Interstitial Lung Disease Burn Out? Specific Phenotypes of Disease Progression

RATIONALE

Previous studies have suggested that interstitial lung disease (ILD) progresses most rapidly early in the course of systemic sclerosis-associated (SSc)-ILD, and that SSc-ILD is often more stable or even "burned out" after the first 4 years following diagnosis.

OBJECTIVES

Our objectives were to determine whether an apparent plateau in pulmonary function decline is due to survival bias and to identify distinct prognostic phenotypes of ILD progression.

METHODS

Consecutive patients with SSc-ILD from a single center were included. Pulmonary function measurements were typically performed every 6 months. Study participants were categorized into long-term survivors (>8 yr survival from diagnosis), and those with medium-term and short-term mortality (4-8 and <4 yr survival, respectively). We excluded those censored with less than 8 years of follow-up. Subject-specific slopes for change in forced vital capacity (FVC) and diffusing capacity of the lung for carbon monoxide (Dl_CO) were calculated using generalized linear models with mixed effects. The rate of decline in FVC was compared across prognostic groups.

RESULTS

The cohort included 171 study participants with SSc-ILD. A plateau in the progression of FVC was apparent in the full cohort analysis but disappeared with stratification into prognostic subgroups to account for survival bias. Those with short-term mortality had a higher annual rate of decline in FVC (-4.10 [95% confidence interval (CI), -7.92 to -0.28] vs. -2.14 [95% CI, -3.31 to -0.97] and -0.94 [-1.46 to -0.42]; P = 0.003) and Dl_CO (-5.28 [95% CI, -9.58 to -0.99] vs. -3.13 [95% CI, -4.35 to -1.92] and -1.32 [95% CI, -2.01 to -0.63]; P < 0.001) than those with medium-term mortality and long-term survival with adjustment for age, sex, and pack-years. Change in FVC in the previous year did not predict FVC change in the subsequent year.

CONCLUSIONS

Adults with SSc-ILD have distinct patterns of physiological progression that remain relatively consistent during long-term follow-up; however, recent change in FVC cannot be used to predict future change in FVC within shorter follow-up intervals. The findings of this study provide important information on the course of disease in SSc-ILD and identify specific phenotypes of progression that may improve clinical decision-making and design of future therapeutic trials.

Anti-RNPC-3 (U11/U12) Antibodies in Systemic Sclerosis in Patients With Moderate-to-Severe Gastrointestinal Dysmotility

OBJECTIVE

To examine the association of anti-RNPC-3 antibodies in patients with systemic sclerosis (scleroderma or SSc) with selected gastrointestinal (GI) tract complications.

METHODS

Sera from patients with SSc with or without severe GI dysfunction (total parenteral nutrition dependence) from the Johns Hopkins Scleroderma Center were screened for anti-RNPC-3 antibodies. We then examined anti-RNPC-3-positive cases and negative SSc controls from the University of Pittsburgh and the University of Pittsburgh Medical Center (UPMC) scleroderma cohort to confirm our findings and to examine whether specific GI features were associated with anti-RNPC-3 antibodies.

RESULTS

In the discovery cohort, patients with SSc with severe GI dysfunction (n = 37) and without GI dysfunction (n = 38) were screened for anti-RNPC-3 antibodies. The former were more likely to have anti-RNPC-3 antibodies (14% versus 3%; P = 0.11). In the Pittsburgh cohort, moderate-to-severe GI dysfunction (Medsger GI score ≥2) was present in 36% of anti-RNPC-3-positive patients versus 15% of anti-RNPC-3-negative patients (P ≤ 0.01). Anti-RNPC-3-positive patients were more likely to be male (31% versus 15%; P = 0.04), African American (18% versus 6%; P = 0.02), have esophageal dysmotility (93% versus 62%; P < 0.01), and interstitial lung disease (ILD) (77% versus 35%; P < 0.01). After adjusting for relevant covariates and potential confounders, moderate-to-severe GI disease was associated with anti-RNPC-3 antibodies (odds ratio [OR] 3.8 [95% confidence interval (95% CI) 1.0-14.3]), and ILD trended toward significance (OR 2.8 [95% CI 1.0-8.2]).

CONCLUSION

Patients with SSc and anti-RNPC-3 antibodies are more likely to be male and African American and to have moderate-to-severe GI disease and ILD. Further studies on larger patient cohorts may be helpful in further defining subsets of patients with SSc at risk for severe GI involvement.

Autoantibodies to a novel Rpp38 (Th/To) derived B-cell epitope are specific for systemic sclerosis and associate with a distinct clinical phenotype

Objective

Detection of antinuclear antibodies and specific autoantibodies is important in the diagnosis and classification of SSc. Several proteins of the Th/To complex, including Rpp25, Rpp38 and hPop1 are the target of autoantibodies in SSc patients. However, very little is known about the epitope distribution of this autoantigen. Consequently, we screened Rpp25, Rpp38 and hPop1 for B cell epitopes and evaluated their clinical relevance.

Methods

Serum pools with (n = 2) and without (n = 1) anti-Th/To autoantibodies were generated and used for epitope discovery. Identified biomarker candidate sequences were then utilized to synthesize synthetic, biotinylated, soluble peptides. The peptides were tested to determine reactivity with sera from SSc cohorts (n = 202) and controls (n = 159) using a chemiluminescence immunoassay. Additionally, samples were also tested for antibodies to full-length recombinant Rpp25 antibodies by chemiluminescence immunoassay.

Results

Several immunodominant regions were found on the three proteins. The strongest reactivity was observed with an Rpp38 peptide (aa 229–243). Autoantibodies to the Rpp38 peptide were detected in 8/149 (5.4%) limited cutaneous SSc patients, but not in any of 159 controls (P = 0.003 by two-sided Fisher's exact probability test). Although reactivity to the novel antigenic peptide was correlated with the binding to Rpp25 (rho = 0.44; P < 0.0001), subsets of patient sera either reacted strongly with Rpp25 or with the novel Rpp38-derived peptide.

Conclusion

A novel Rpp38 epitope holds promise to increase the sensitivity in the detection of anti-Th/To autoantibodies, thus enhancing the serological diagnosis of SSc.

Estradiol levels are elevated in older men with diffuse cutaneous SSc and are associated with decreased survival

BACKGROUND

Systemic sclerosis (SSc) is a female-predominant disease, characterized by excessive extracellular matrix deposition (ECM) with dermal and internal organ fibrosis. Considering the sex-based disparity in disease incidence, estradiol (E2), an estrogen form with pro-fibrotic effects, may play a role in SSc. We reported that post-menopausal women with diffuse cutaneous (dc)SSc have higher serum E2 levels compared to similar aged, healthy controls. Since males with SSc tend to have more severe disease, we examined serum E2 in dcSSc males in relation to disease characteristics and survival.

METHODS

We measured serum E2 in 83 dcSSc men > 50 years old from the University of Pittsburgh Scleroderma Center and similar aged healthy controls. Using statistical modeling, we examined the associations between serum E2, internal organ involvement, autoantibody profiles, and survival.

RESULTS

Male dcSSc patients had significantly higher serum E2 levels compared to healthy males and similar aged dcSSc post-menopausal women. Male dcSSc patients with high serum E2 had significantly more heart involvement, a trend for higher skin thickness progression rate, and worse survival. Using Cox regression modeling, increased serum E2 levels in anti-Scl-70 antibody-positive dcSSc males were associated with an increased risk of death.

CONCLUSIONS

dcSSc males > 50 years old have higher levels of serum E2 compared to healthy controls and dcSSc post-menopausal women. Elevated serum E2 levels in dcSSc males are associated with heart involvement, trend to progression of dermal fibrosis, and, if anti-Scl-70 antibody positive, worse survival. Our study expands on previous work implicating E2 in dermal fibrosis in SSc and associates E2 levels with internal organ involvement and survival. These data suggest a role for estrogen imbalance in dcSSc.

Recent Advances in Research Regarding Autoantibodies in Connective Tissue Diseases and Related Disorders

Connective tissue diseases (CTDs), also known as systemic autoimmune diseases, involve a variety of autoantibodies against cellular components. An important factor regarding these autoantibodies is that each antibody is exclusively related to a certain clinical feature of the disease type, which may prove useful in clinical practice. Thus far, more than 100 types of autoantibodies have been found in CTDs, and most of their target antigens have been identified. Many of these autoantigens are enzymes or regulators involved in important cellular functions, such as gene replication, transcription, repair/recombination, RNA processing, and protein synthesis, as well as proteins that form complexes with RNA and DNA. This article reviews the autoantibodies for each CTD, along with an assessment of their clinical significance, and provides suggestions regarding their utilization for clinical practice.

Anti-RNA binding protein positivity in idiopathic interstitial pneumonia

INTRODUCTION

Idiopathic interstitial pneumonias (IIP) are diffuse lung diseases whose cause is unknown and often present with features of autoimmunity despite not meeting criteria for a connective tissue disease (CTD). Recent studies suggest that anti-RNA binding protein (anti-RBP) antibodies, which include anti-SSA, anti-SSB, anti-Sm, and anti-RNP, play a role in the loss of immune tolerance and severity of pulmonary hypertension (PH) in CTDs. We hypothesized that anti-RBP positive (RBP+) subjects would have worse measures of lung function, radiographic findings, PH, and survival than anti-RBP negative (RBP-) subjects.

METHODS

Subjects with both IIP and serologies for review were identified retrospectively and stratified based on anti-RBP antibody seropositivity. Baseline cohort characteristics, pulmonary function tests (PFT), ambulatory oxygen requirement, radiographic characteristics, markers of PH, and transplant-free survival were compared between anti-RBP positive and negative groups.

RESULTS

Five hundred twenty patients with IIP were identified, of which ten percent (n = 53) were anti-RBP positive. RBP+ as compared to RBP- subjects had significantly worse PFTs as indicated by FEV1 (59.6 vs. 64.9, p = 0.046) and FVC (71.6 vs. 78.8, p = 0.018). There was a higher prevalence of radiographic honeycombing (49.1% vs. 38.3%, p = 0.006) and emphysema (22.6% vs. 5.1%, p < 0.001) in the RBP+ group despite no difference in smoking history. The Pulmonary Artery-Aorta ratio was also larger in the RBP+ group (0.93 vs. 0.88, p = 0.040). There was no difference in transplant-free survival between groups (log rank = 0.912).

CONCLUSION

Anti-RBP+ IIP patients may have worse lung function, increased chest radiographic abnormalities, and PH compared with those without these antibodies.

Anti-nuclear autoantibodies in systemic sclerosis : News and perspectives

Systemic sclerosis is a connective tissue disorder characterized by microvascular damage and excessive fibrosis of the skin and internal organs. One hallmark of the immunological abnormalities in systemic sclerosis is the presence of anti-nuclear antibodies, which are detected in more than 90% of patients with systemic sclerosis. Anti-centromere antibodies, anti-DNA topoisomerase I antibodies, and anti-RNA polymerase III antibodies are the predominant anti-nuclear antibodies found in systemic sclerosis patients. Other systemic sclerosis-related anti-nuclear antibodies include those targeted against U3 ribonucleoprotein, Th/To, U11/U12 ribonucleoprotein, and eukaryotic initiation factor 2B. Anti-U1 ribonucleoprotein, anti-Ku antibodies, anti-PM-Scl, and anti-RuvBL1/2 antibodies are associated with systemic sclerosis overlap syndrome. Anti-human upstream binding factor, anti-Ro52/TRIM21, anti-B23, and anti-centriole antibodies do not have specificity to systemic sclerosis, but are sometimes detected in sera from patients with systemic sclerosis. Identification of each systemic sclerosis-related antibody is useful to diagnose and predict organ involvement, since the particular type of systemic sclerosis-related antibodies is often predictive of clinical features, severity, and prognosis. The clinical phenotypes are largely influenced by ethnicity. Currently, an immunoprecipitation assay is necessary to detect most systemic sclerosis-related antibodies; therefore, the establishment of an easy, reliable, and simple screening system is warranted.

Diagnostic criteria, severity classification and guidelines of systemic sclerosis

Several effective drugs have been identified for the treatment of systemic sclerosis (SSc). However, in advanced cases, not only their effectiveness is reduced but they may be also harmful due to their side-effects. Therefore, early diagnosis and early treatment is most important for the treatment of SSc. We established diagnostic criteria for SSc in 2003 and early diagnostic criteria for SSc in 2011, for the purpose of developing evaluation of each organ in SSc. Moreover, in November 2013, the American College of Rheumatology and the European Rheumatology Association jointly developed new diagnostic criteria for increasing their sensitivity and specificity, so we revised our diagnostic criteria and severity classification of SSc. Furthermore, we have revised the clinical guideline based on the newest evidence. In particular, the clinical guideline was established by clinical questions based on evidence-based medicine according to the New Minds Clinical Practice Guideline Creation Manual (version 1.0). We aimed to make the guideline easy to use and reliable based on the newest evidence, and to present guidance as specific as possible for various clinical problems in treatment of SSc.

Biomarkers in connective tissue diseases

Autoimmune connective tissue diseases are clinically variable, making biomarkers desirable for assessing future disease risk, supporting early and accurate diagnosis, monitoring disease activity and progression, selecting therapeutics, and assessing treatment response. Because of their correlations with specific clinical characteristics and often with disease progression, autoantibodies and other soluble mediators are considered potential biomarkers. Additional biomarkers might reflect downstream pathologic processes or appear because of ongoing inflammation and damage. Because of overlap between diseases, some biomarkers have limited specificity for a single autoimmune connective tissue disease. This review describes select current biomarkers that aid in the diagnosis and treatment of several major systemic autoimmune connective tissue disorders: systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis, and anti-neutrophil cytoplasmic antibody-associated vasculitides. Newly proposed biomarkers that target various stages in disease onset or progression are also discussed. Newer approaches to overcome the diversity observed in patients with these diseases and to facilitate personalized disease monitoring and treatment are also addressed.

Circulating Anti-Nuclear Antibodies in Systemic Sclerosis: Utility in Diagnosis and Disease Subsetting

The presence of circulating anti-nuclear antibodies (ANAs) is a hallmark of immune dysregulation in patients with systemic sclerosis (SSc). Currently, a variety of SSc-specific ANAs, including anticentromere, anti-topoisomerase I, and anti-RNA polymerase III antibodies, have been well characterized, and their commercial kits are available worldwide. Since these autoantibodies are specifically detected in SSc patients and are associated with unique sets of disease manifestations, they are widely used in routine clinical practice for diagnosis, clinical subgrouping, and prediction of future organ involvements and prognosis. In addition, SSc-specific ANAs are also useful in predicting future development of SSc in patients with Raynaud's phenomenon without any scleroderma skin changes, because their production often precedes onset of SSc symptoms. Application of circulating SSc-specific ANA measurement to clinical practice has greatly improved patient care, but utility of the autoantibody testing could be maximized by combining other clinical information, such as degree and extent of skin thickness and disease duration.

The utility of comprehensive autoantibody testing to differentiate connective tissue disease associated and idiopathic interstitial lung disease subgroup cases

Interstitial lung disease (ILD) comprises many heterogeneous disease groups, the largest being CTD-associated and those labelled as idiopathic out of necessity. The mechanisms causing ILD are poorly understood, but most CTD- and idiopathic-ILD cases can respond to immunosuppression, clearly suggesting a pathological role for inflammation. By contrast, corticosteroid immunosuppression causes harm without benefit in the feared idiopathic pulmonary fibrosis, suggesting that inflammation plays little pathological role, and where ILD progresses rapidly to lethal outcome even with anti-fibrotic drug use. Given the treatment response differences apparent between ILD subgroups, and the dangers and costs of corticosteroid and anti-fibrotic drug use, respectively, it has become vital in every ILD patient to make an accurate subgroup diagnosis, to optimize treatment selections. This review discusses why differentiating CTD- and idiopathic-ILD subgroup cases remains so problematic, and why existing comprehensive CTD-specific serology would, if generally available, represent an ideal biomarker tool to enhance ILD subgroup diagnostic accuracy.

Brief Report: Anti-RNPC-3 Antibodies As a Marker of Cancer-Associated Scleroderma

OBJECTIVE

Prior studies have demonstrated an increased risk of cancer-associated scleroderma in patients with anti-RNA polymerase III (anti-RNAP III) autoantibodies as well as in patients who are triple-negative for anticentromere (anti-CENP), anti-topoisomerase I (anti-topo I), and anti-RNAP III (also known as anti-POL) autoantibodies (referred to as CTP negative). In a recent study of 16 CTP-negative scleroderma patients with coincident cancer, 25% of the patients were found to have autoantibodies to RNPC-3, a member of the minor spliceosome complex. This investigation was undertaken to validate the relationship between anti-RNPC-3 antibodies and cancer and examine the associated clinical phenotype in a large sample of scleroderma patients.

METHODS

Scleroderma patients with cancer were assayed for anti-CENP, anti-topo I, anti-RNAP III, and anti-RNPC-3 autoantibodies. Disease characteristics and the cancer-scleroderma interval were compared across autoantibody groups. The relationship between autoantibody status and cancer-associated scleroderma was assessed by logistic regression.

RESULTS

Of 318 patients with scleroderma and cancer, 70 (22.0%) were positive for anti-RNAP III, 54 (17.0%) were positive for anti-topo I, and 96 (30.2%) were positive for anti-CENP. Twelve patients (3.8% of the overall group or 12.2% of CTP-negative patients) were positive for anti-RNPC-3. Patients with anti-RNPC-3 had a short cancer-scleroderma interval (median 0.9 years). Relative to patients with anti-CENP, patients with anti-RNPC-3 and those with anti-RNAP III had a >4-fold increased risk of cancer within 2 years of scleroderma onset (for anti-RNPC-3-positive patients, odds ratio [OR] 4.3, 95% confidence interval [95% CI] 1.10-16.9 [P = 0.037]; for anti-RNAP III-positive patients, OR 4.49, 95% CI 1.98-10.2 [P < 0.001]). Patients with anti-RNPC-3 had severe restrictive lung disease, gastrointestinal disease, Raynaud's phenomenon, and myopathy.

CONCLUSION

Anti-RNPC-3 autoantibodies, similar to anti-RNAP III autoantibodies, are associated with an increased risk of cancer at the onset of scleroderma. These data suggest the possibility of cancer-induced autoimmunity in this subset of patients with scleroderma.

Personalized medicine in rheumatology: the paradigm of serum autoantibodies

The sequencing of the human genome is now well recognized as the starting point of personalized medicine. Nonetheless, everyone is unique and can develop different phenotypes of the same disease, despite identical genotypes, as well illustrated by discordant monozygotic twins. To recognize these differences, one of the easiest and most familiar examples of biomarkers capable of identifying and predicting the outcome of patients is represented by serum autoantibodies. In this review, we will describe the concept of personalized medicine and discuss the predictive, prognostic and preventive role of antinuclear antibodies (ANA), anti-citrullinated peptide antibodies (ACPA), rare autoantibodies and anti-drug antibodies (ADA), to evaluate how these can help to identify different disease immune phenotypes and to choose the best option for treating and monitoring rheumatic patients in everyday practice. The importance of ANA resides in the prediction of clinical manifestations in systemic sclerosis and systemic lupus erythematosus and their association with malignancies. ACPA have a predictive role in rheumatoid arthritis, they are associated with the development of a more aggressive disease, extra-articular manifestations and premature mortality in RA patients; moreover, they are capable of predicting therapeutic response. Rare autoantibodies are associated with different disease manifestations and also with a greater incidence of cancer. The determination of ADA levels may be useful in patients where the clinical efficacy of TNF-α inhibitor has dropped, for the assessment of a right management. The resulting scenario supports serum autoantibodies as the cornerstone of personalized medicine in autoimmune diseases.

Mortality Risk Prediction in Scleroderma-Related Interstitial Lung Disease: The SADL Model

BACKGROUND

Interstitial lung disease (ILD) is an important cause of morbidity and mortality in patients with scleroderma (Scl). Risk prediction and prognostication in patients with Scl-ILD are challenging because of heterogeneity in the disease course.

METHODS

We aimed to develop a clinical mortality risk prediction model for Scl-ILD. Patients with Scl-ILD were identified from two ongoing longitudinal cohorts: 135 patients at the University of California, San Francisco (derivation cohort) and 90 patients at the Mayo Clinic (validation cohort). Using these two separate cohorts, a mortality risk prediction model was developed and validated by testing every potential candidate Cox model, each including three or four variables of a possible 19 clinical predictors, for time to death. Model discrimination was assessed using the C-index.

RESULTS

Three variables were included in the final risk prediction model (SADL): ever smoking history, age, and diffusing capacity of the lung for carbon monoxide (% predicted). This continuous model had similar performance in the derivation (C-index, 0.88) and validation (C-index, 0.84) cohorts. We created a point scoring system using the combined cohort (C-index, 0.82) and used it to identify a classification with low, moderate, and high mortality risk at 3 years.

CONCLUSIONS

The SADL model uses simple, readily accessible clinical variables to predict all-cause mortality in Scl-ILD.

Recent advances in connective tissue disease related interstitial lung disease

INTRODUCTION

Interstitial lung disease (ILD) is a common manifestation of connective tissue disease (CTD). Although the majority of patients with CTD-ILD are stable or slowly progressive, a significant group exhibits a more severe and progressive decline. Interstitial pneumonia with autoimmune features (IPAF) describes the subset of patients with interstitial pneumonia who have features suggesting underlying autoimmunity, but whose features fall short of a clear diagnosis of CTD. Areas covered: In this focused review, we discuss recent advances in early detection, prognostic evaluation, and management of autoimmune forms of ILD. Expert commentary: Early detection of ILD and a better understanding of factors that impact prognostication may be helpful when making decisions regarding therapeutic interventions. The treatment of CTD-ILD should be comprehensive, is often fraught with challenges and can be complicated by comorbid conditions and extra-thoracic disease activities. Several large randomized studies have examined the impact of immunosuppressive therapy for CTD-ILD, however, additional studies are needed to determine the optimal treatment strategies. Future studies may provide additional information about the best treatments in patients with IPAF.

Role of Autoantibodies in the Diagnosis of Connective-Tissue Disease ILD (CTD-ILD) and Interstitial Pneumonia with Autoimmune Features (IPAF)

The diagnosis of interstitial lung disease (ILD) requires meticulous evaluation for an underlying connective tissue disease (CTD), with major implications for prognosis and management. CTD associated ILD (CTD-ILD) occurs most commonly in the context of an established CTD, but can be the first and/or only manifestation of an occult CTD or occur in patients who have features suggestive of an autoimmune process, but not meeting diagnostic criteria for a defined CTD—recently defined as “interstitial pneumonia with autoimmune features” (IPAF). The detection of specific autoantibodies serves a critical role in the diagnosis of CTD-ILD, but there remains a lack of data to guide clinical practice including which autoantibodies should be tested on initial assessment and when or in whom serial testing should be performed. The implications of detecting autoantibodies in patients with IPAF on disease behaviour and management remain unknown. The evaluation of CTD-ILD is challenging due to the heterogeneity of presentations and types of CTD and ILD that may be encountered, and thus it is imperative that immunologic tests are interpreted in conjunction with a detailed rheumatologic history and examination and multidisciplinary collaboration between respiratory physicians, rheumatologists, immunologists, radiologists and pathologists.

Autoantibody to scaffold attachment factor B (SAFB): A novel connective tissue disease-related autoantibody associated with interstitial lung disease

OBJECTIVE

To identify and characterize a novel connective tissue disease (CTD)-related autoantibody (autoAb) directed against scaffold attachment factor B (SAFB).

METHODS

AutoAb specificity was analyzed using RNA and protein-immunoprecipitation assays. Autoimmune targets were affinity purified using patients' sera and subjected to liquid chromatography mass spectrometry.

RESULTS

By immunoprecipitation assay, 10 sera reacted with a protein with a molecular weight of approximately 160 kDa. Liquid chromatography mass spectrometry of the partially purified autoantigen and additional immunoblot-based analyses revealed that the Ab specifically recognized SAFB. Anti-SAFB Abs were detected in 2 of 646 patients with systemic sclerosis (SSc) (0.3%), 1 of 1570 patients with polymyositis/dermatomyositis (0.06%), 4 of 270 patients with interstitial lung disease (ILD) (1.5%), 1 of 43 patients with overlap syndrome (2.3%) and 2 patients with other diseases including primary Raynaud's disease and eosinophilic pneumonia. Five patients with anti-SAFB Abs had Raynaud's phenomenon and 3 had nail fold punctate hemorrhage. Of note, 8 of the 10 patients (80%) suffered from ILD. None of the patients with anti-SAFB Abs had pulmonary arterial hypertension, heart disease, or renal involvement.

CONCLUSIONS

Anti-SAFB Ab is a novel CTD-related autoAb possibly associated with ILD.