Serum autoantibody to the nucleolar antigen PM-Scl. Clinical and immunogenetic associations

Cumulative disease damage and anti-PM/Scl antibodies are associated with a heavy burden of calcinosis in systemic sclerosis

OBJECTIVES

Ectopic calcification (calcinosis) is a common complication of SSc, but a subset of SSc patients has a heavy burden of calcinosis. We examined whether there are unique risk factors for a heavy burden of calcinosis, as compared with a light burden or no calcinosis.

METHODS

We reviewed the medical records of all patients in the Johns Hopkins Scleroderma Center Research Registry with calcinosis to quantify calcinosis burden using pre-specified definitions. We performed latent class analysis to identify SSc phenotypic classes. We used multinomial logistic regression to determine whether latent phenotypic classes and autoantibodies were independent risk factors for calcinosis burden.

RESULTS

Of all patients, 29.4% (997/3388) had calcinosis, and 13.5% (130/963) of those with calcinosis had a heavy burden. The latent phenotypic class with predominantly diffuse skin disease and higher disease severity (characterized by pulmonary hypertension, interstitial lung disease, cardiomyopathy, severe RP, gastrointestinal involvement, renal crisis, myopathy and/or tendon friction rubs) was associated with an increased risk of both a heavy burden [odds ratio (OR) 6.92, 95% CI 3.66, 13.08; P < 0.001] and a light burden (OR 2.88, 95% CI 2.11, 3.95; P < 0.001) of calcinosis compared with the phenotypic class with predominantly limited skin disease. Autoantibodies to PM/Scl were strongly associated with a heavy burden of calcinosis (OR 17.31, 95% CI 7.72, 38.81; P < 0.001) and to a lesser degree a light burden of calcinosis (OR 3.59, 95% CI 1.84, 7.00; P < 0.001).

CONCLUSIONS

Calcinosis burden is associated with cumulative SSc-related tissue damage. Independent of disease severity, autoantibodies to PM/Scl are also associated with a heavy burden of calcinosis.

Joint and muscle inflammatory disease: A scoping review of the published evidence

OBJECTIVES

Polyarthritis is commonly reported in idiopathic inflammatory myositis patients, but few studies have focused on the overlap of myositis with rheumatoid arthritis which is a difficult diagnosis in the absence of well-defined diagnostic criteria. The primary objective of this scoping review was to map the field of research to explore the potential diagnoses in patients presenting with both myositis and polyarthritis.

METHODS

Two electronic databases (MEDLINE/PubMed® and Web of Science®) were systematically searched using the terms (myositis OR 'inflammatory idiopathic myopathies') AND (polyarthritis OR 'rheumatoid arthritis') without any publication date limit.

RESULTS

Among individual records, 280 reports met inclusion criteria after full-text review. There was heterogeneity in the definition of overlap myositis as well as the characteristics of rheumatoid arthritis. In many studies, key data were lacking; rheumatoid factor status was reported in 56.8% (n=151), anti-citrullinated proteins antibodies status in 18.8% (n=50), and presence or absence of bone erosions in 45.1% (n=120) of the studies. Thirteen different diagnoses were found to associate myositis with polyarthritis: antisynthetase syndrome (29.6%, n=83), overlap myositis with rheumatoid arthritis (16.1%, n=45), drug-induced myositis (20.0%, n=56), rheumatoid myositis (7.5%, n=21), inclusion body myositis (1.8%, n=5), overlap with connective tissue disease (20.0%, n=56), and others (5.0%, n=14).

CONCLUSION

The spectrum of joint and muscle inflammatory diseases encompasses many diagnoses including primitive and secondary myositis associated with RA or arthritis mimicking RA. This review highlights the need for a consensual definition of OM with RA to better individualise this entity from the numerous differential diagnoses.

Scleromyositis: A distinct novel entity within the systemic sclerosis and autoimmune myositis spectrum. Implications for care and pathogenesis

Systemic sclerosis and autoimmune myositis are both associated with decreased quality of life and increased mortality. Their prognosis and management largely depend on the disease subgroups. Indeed, systemic sclerosis is a heterogeneous disease, the two predominant forms of the disease being limited and diffuse scleroderma. Autoimmune myositis is also a heterogeneous group of myopathies that classically encompass necrotizing myopathy, antisynthetase syndrome, dermatomyositis and inclusion body myositis. Recent data revealed that an additional disease subset, denominated "scleromyositis", should be recognized within both the systemic sclerosis and the autoimmune myositis spectrum. We performed an in-depth review of the literature with the aim of better delineating scleromyositis. Our review highlights that this concept is supported by recent clinical, serological and histopathological findings that have important implications for patient management and understanding of the disease pathophysiology. As compared with other subsets of systemic sclerosis and autoimmune myositis, scleromyositis patients can present with a characteristic pattern of muscle involvement (i.e. distribution of muscle weakness) along with multisystemic involvement, and some of these extra-muscular complications are associated with poor prognosis. Several autoantibodies have been specifically associated with scleromyositis, but they are not currently integrated in diagnostic and classification criteria for systemic sclerosis and autoimmune myositis. Finally, striking vasculopathic lesions at muscle biopsy have been shown to be hallmarks of scleromyositis, providing a strong anatomopathological substratum for the concept of scleromyositis. These findings bring new insights into the pathogenesis of scleromyositis and help to diagnose this condition, in patients with subtle SSc features and/or no autoantibodies (i.e. "seronegative" scleromyositis). No guidelines are available for the management of these patients, but recent data are showing the way towards a new therapeutic approach dedicated to these patients.

Clinical Significance of Antinucleolar Antibodies: Biomarkers for Autoimmune Diseases, Malignancies, and others

Nucleolar staining is one of the standard patterns in immunofluorescence antinuclear antibodies (ANA), seen in 5-9% of ANA in various conditions. Antinucleolar antibodies (ANoA) are classified into 3 patterns in the International Consensus on ANA Patterns (ICAP) classification; AC-8 homogeneous pattern, AC-9 clumpy pattern, and AC-10 punctate pattern. Specificities known to show AC-8 include anti-Th/To, -PM-Scl, -nucleophosmin/B23, -nucleolin/C23, -No55, and others. AC-9 is seen by anti-fibrillarin/U3RNP and AC-10 by anti-RNA polymerase I and hUBF/NOR-90. ANoA has been classically known to be associated with scleroderma (SSc) and the characterization of nucleolar antigens identified several autoantigens recognized by SSc autoantibodies. The clinical association of anti-Th/To, PM-Scl, fibrillarin/U3RNP, and RNA polymerase I with SSc or SSc-overlap syndrome is well established, and commercial assays are developed. Anti-hUBF/NOR90, nucleophosmin/B23, and nucleolin/C23 are known for decades and reported in systemic autoimmune rheumatic diseases (SARDs), malignancies, graft versus host disease (GVHD), and others; however, their clinical significance remains to be established.

Anti-PM-Scl antibodies positive patients encompass three different groups with distinct prognosis

OBJECTIVE

To help identify homogeneous subgroups among patients with anti-polymyositis-scleroderma-antibodies (PM-Scl-Abs) positive auto-immune diseases regardless of diagnostic classifications.

METHODS

This multicentric (four hospitals) retrospective study collected all consecutive patients (from 2011 to 2021) with positive testing for anti-PM-Scl-Abs in a context of connective tissue disease. Subgroups of patients with similar clinico-biological phenotypes were defined using unsupervised multiple correspondence analysis and hierarchical clustering analysis of the features recorded in the first year of follow-up.

RESULTS

One hundred and forty-two patients with anti-PM-Scl-Abs were evaluated and 129 patients were included in the clustering analysis and divided into 3 clusters. Cluster n°1 (n = 47) included patients with frequent skin thickening, digestive involvement and interstitial lung disease (ILD) with Non Specific Interstitial Pneumonia (NSIP). They were more likely to develop progressive fibrosing ILD. Cluster n°2 (n = 36) included patients who all featured NSIP with frequent Organizing pneumonia associated pattern and mechanic's hands. This subgroup had increased risk of relapse and ILD was characterized by a good functional outcome. Cluster n°3 (n = 46) was characterized by predominant or isolated musculoskeletal involvement and frequently matched undifferentiated connective tissue disease (UCTD) criteria. Although very frequent among Anti PM-Scl-Abs positive patients, muscle involvement was less discriminating compared with skin thickening and ILD pattern to classify patients into subgroups.

CONCLUSION

Anti-PM-Scl-Abs associated auto-immune diseases are segregated into 3 subgroups with distinct clinical phenotype and outcomes. Skin thickening and NSIP are determinant predictors in segregation of theses populations.

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.

Autoantibodies versus Skin Fibrosis Extent in Systemic Sclerosis: A Case-Control Study of Inverted Phenotypes

Objective: to describe the prevalences, characteristics, and survivals of patients with anti-topoisomerase 1 antibodies (ATA) and limited cutaneous systemic sclerosis (lSSc) and anti-centromere antibodies (ACA) and diffuse cutaneous systemic sclerosis (dSSc). Methods: patients with ATA lSSc or with ACA dSSc were included in a case-control retrospective study. Results: In our cohort of scleroderma, the prevalence of ACA dSSc and ATA lSSc was 1.1% (12/1040) and 8.9% (93/1040), respectively. ACA dSSc patients had less interstitial lung disease (ILD) (5 (41.7) vs. 74 (79.6); p < 0.01), more cardiac involvement, and more muscle involvement (3 (25) vs. 4 (4.3); p = 0.03 and 4 (33.3) vs. 4 (7.5); p = 0.02,) than ATA dSSc patients. ATA lSSc patients had a higher modified Rodnan skin score than ACA lSSc patients (4 [2−7.5] vs. 2 [0−5]; p < 0.01) and less cardiac or muscle involvement than ATA dSSc patients (6 (6.5) vs. 19 (20.4%); p < 0.01 and 15 (16.1) vs. 54 (58.1); p < 0.0001, respectively). The cumulative 5-year survival rate was 71% in ACA dSSc patients, 95% in ATA lSSc patients, 84% in ACA lSSc patients, and 66% in ATA dSSc patients (p < 0.0001). Conclusion: ATA lSSc and ACA dSSc have specific characteristics when compared to ATA dSSc or ACA lSSc. ATA lSSc patients have more ILD than ACA lSSc patients, and ATA dSSc patients have the worst prognosis. Overall, inverted phenotypes show the value of a patient assessment combining antibody and skin subset and should be considered as a separate group.

High-Dimensional Analysis Reveals Distinct Endotypes in Patients With Idiopathic Inflammatory Myopathies

The idiopathic inflammatory myopathies (IIM) are a rare clinically heterogeneous group of conditions affecting the skin, muscle, joint, and lung in various combinations. While myositis specific autoantibodies are well described, we postulate that broader immune endotypes exist in IIM spanning B cell, T cell, and monocyte compartments. This study aims to identify immune endotypes through detailed immunophenotyping of peripheral blood mononuclear cells (PBMCs) in IIM patients compared to healthy controls. We collected PBMCs from 17 patients with a clinical diagnosis of inflammatory myositis and characterized the B, T, and myeloid cell subsets using mass cytometry by time of flight (CyTOF). Data were analyzed using a combination of the dimensionality reduction algorithm t-distributed stochastic neighbor embedding (t-SNE), cluster identification, characterization, and regression (CITRUS), and marker enrichment modeling (MEM); supervised biaxial gating validated populations identified by these methods to be differentially abundant between groups. Using these approaches, we identified shared immunologic features across all IIM patients, despite different clinical features, as well as two distinct immune endotypes. All IIM patients had decreased surface expression of RP105/CD180 on B cells and a reduction in circulating CD3+CXCR3+ subsets relative to healthy controls. One IIM endotype featured CXCR4 upregulation across all cellular compartments. The second endotype was hallmarked by an increased frequency of CD19+CD21loCD11c+ and CD3+CD4+PD1+ subsets. The experimental and analytical methods we describe here are broadly applicable to studying other immune-mediated diseases (e.g., autoimmunity, immunodeficiency) or protective immune responses (e.g., infection, vaccination).

Anti-Polymyositis/Scl Antibodies in Systemic Sclerosis: Clinical Associations in a Multicentric Spanish Cohort and Review of the Literature

OBJECTIVES

To assess the clinical profile of patients with anti-polymyositis/Scl (PM/Scl) antibodies in a cohort of Spanish patients with systemic sclerosis.

METHODS

From the Spanish Scleroderma Study Group database, we selected patients in whom PM/Scl antibodies had been tested. We compared demographic, clinical, laboratory, and survival data between patients with and without PM/Scl antibodies.

RESULTS

Seventy-two of 947 patients (7.6%) tested positive for PM/Scl antibodies. Patients with PM/Scl antibodies presented initially with more puffy fingers and arthralgias but less Raynaud phenomenon. Regarding cumulative manifestations, myositis and arthritis were more prevalent in patients with PM/Scl antibodies, as well as pulmonary fibrosis. On the contrary, patients with PM/Scl antibodies had less pulmonary hypertension. No difference in terms of survival at 5 and 10 years was noticed between the 2 groups.

CONCLUSIONS

In systemic sclerosis patients from Spain, PM/Scl antibodies are associated with a distinct clinical profile. However, PM/Scl antibodies did not influence survival.

A Japanese Patient with Anti-PM/Scl and Centromere Antibody-Positive Scleroderma-Amyopathic Dermatomyositis Overlap Syndrome Who Developed Renal Crisis

Anti-PM/Scl antibodies are associated with the overlap syndrome of systemic sclerosis and dermatomyositis/polymyositis (SSc-DM/PM), and are found in 50% of SSc-DM/PM cases in Europe and the United States, whereas they are rare in Japan. We report a case of an 80-year-old Japanese female with SSc-amyopathic dermatomyositis (ADM) overlap syndrome, who developed scleroderma renal crisis (SRC), a complication of SSc. She had positive antinuclear antibodies in a discrete-speckled and nucleolar pattern and anticentromere antibodies and anti-PM/Scl antibodies were confirmed by ELISA and immunoprecipitation, respectively. The incidence rate of SRC in SSc patients varies significantly depending on the specificity of autoantibodies, with the highest incidence of ~50% in anti-RNA polymerase III antibody positive patients, followed by ~10% in anti-PM/Scl and lower incidence of 0.45% in anticentromere antibody-positive cases. Anti-PM/Scl antibodies are uncommon in Japanese patients presumably due to its strong association with certain HLA haplotype that is rare in Japanese. Clinical significance of anti-PM/Scl antibodies in Japanese patients will need to be clarified with accumulation of cases in future studies.

The Association of Myositis Specific Antibodies in Patients with Inflammatory Myositis: Preliminary Data in Indian Patients

CONTEXT

Autoantibodies have a role in the diagnosis and prognosis in Autoimmune Inflammatory Myositis (AIM).

AIMS

The aim of this work was to study the prevalence and clinical correlation of myositis specific and associated antibodies (MSA and MAA) in AIM.

SETTING AND DESIGN

This was a cross-sectional observational study.

METHODS AND MATERIALS

Consecutive AIM patents were divided into groups as dermatomyositis (DM), polymyositis (PM), CTD-associated myositis (CTD-M), cancer-associated myositis (CAM) and juvenile myositis (JM). Their data along with serum samples were collected after obtaining informed consent. Sera was analyzed for IgG antibodies against Jo-1, PL-7, PL-12, EJ, SRP, Mi-2, MDA-5, TIF1γ, SAE1, SAE2, NXP2 and SSA/R052kD using the microELISA technique. The institutional ethics committee approved the study.

STATISTICAL ANALYSIS

SPSS software (version 24.0) was used. P value < 0.05 was considered statistically significant.

RESULTS

There were 48 patients (DM = 19, PM = 19, CTD-M = 5, CAM = 2, JM = 3) included. MSA were positive in 37.5% patients. Antibodies against Mi-2 were present in 6 (12.5%), Jo-1 in 5 (10.4%), 2 (4.1%) each had PL-7 and SRP antibodies. One patient (2%) each had MDA-5, NXP2 and TIf1g antibodies. Jo-1 antibody was associated with mechanic's hands and ILD. There was a significant association of rash in the Mi-2 group with none of the patients having ILD. Malignancy screening was negative in NXP2 and TIF1g antibody-positive patients. Ro52 was the most common MAA (33.3%) and was associated with mechanic's hand.

CONCLUSION

MSA was present in almost 40% of the cohort. Anti Jo-1 antibody was associated with mechanic's hands and ILD. None of the Mi-2 patients had ILD, which may point to a protective role of this antibody for ILD. The association of newer antibodies in Indian patients needs to be further studied in larger cohorts.

The clinical phenotype of Systemic Sclerosis patients with anti-PM/Scl antibodies: results from the EUSTAR cohort

OBJECTIVE

To evaluate clinical associations of anti-PM/Scl antibodies in patients with Systemic Sclerosis (SSc) in a multicentre international cohort, with particular focus on unresolved issues, including scleroderma renal crisis (SRC), malignancies, and functional outcome of interstitial lung disease (ILD).

METHODS

(1) Analysis of SSc patients from the EUSTAR database: 144 anti-PM/Scl+ without SSc-specific autoantibodies were compared to 7,202 anti-PM/Scl-, and then to 155 anti-Pm/Scl+ with SSc-specific antibodies. (2) Case-control study: additional data were collected for 165 anti-PM/Scl+ SSc (85 from the EUSTAR registry), and compared to 257 anti-PM/Scl- SSc controls, matched for sex, cutaneous subset, disease duration, and age at SSc onset.

RESULTS

Patients with isolated anti-PM/Scl positivity, as compared with anti-Pm/Scl-, had higher frequency of muscle involvement, ILD, calcinosis and cutaneous signs of dermatomyositis, but similar frequency of SRC and malignancies (either synchronous with SSc onset or not). The presence of muscle involvement was associated with a more severe disease phenotype. Although very frequent, ILD had a better functional outcome in cases than in controls.In patients with both anti-PM/Scl and SSc-specific antibodies, a higher frequency of typical SSc features than in those with isolated anti-PM/Scl was observed.

CONCLUSION

The analysis of the largest series of anti-PM/Scl+ SSc patients so far reported helps to delineate a specific clinical subset with muscle involvement, cutaneous dermatomyositis, calcinosis, and ILD characterized by a good functional outcome. SRC and malignancies do not seem to be part of this syndrome.

Molecular characteristics and functional differences of anti-PM/Scl autoantibodies and two other distinct and unique supramolecular structures known as "EXOSOMES"

The term "exosome" has been applied to three distinct supramolecular entities, namely the PM/Scl autoantibodies or "RNA exosomes", transforming DNA fragments termed "DNA exosomes", and small size extracellular vesicles knows as "exosomes". Some of the molecular components of the "PM/Scl exosome complex" or "RNA exosome" are recognized by specific autoantibodies present in the serum from some Systemic Sclerosis (SSc), polymyositis (PM) and polymyositis SSc (PM/Scl) overlap syndrome patients. On the other hand, one of the most active focuses of laboratory investigation in the last decade has been the biogenesis and role of extracellular vesicles known as "exosomes". The remarkable ability of these "exosome" vesicles to alter the cellular phenotype following fusion with target cells and the release of their macromolecular cargo has revealed a possible role in the pathogenesis of numerous diseases, including malignant, inflammatory, and autoimmune disorders and may allow them to serve as theranostic agents for personalized and precision medicine. The indiscriminate use of the term "exosome" to refer to these three distinct molecular entities has engendered great confusion in the scientific literature. Here, we review the molecular characteristics and functional differences between the three molecular structures identified as "exosomes". Given the rapidly growing scientific interest in extravesicular exosomes, unless a solution is found the confusion in the literature resulting from the use of the term "exosomes" will markedly increase.

Calcinosis Biomarkers in Adult and Juvenile Dermatomyositis

Dermatomyositis (DM) is a rare idiopathic inflammatory myopathy characterized by muscle weakness and cutaneous manifestations in adults and children. Calcinosis, a complication of DM, is the abnormal deposition of insoluble calcium salts in tissues, including skin, subcutaneous tissue, tendons, fascia, and muscle. Calcinosis is more commonly seen in juvenile DM (JDM), but also develops in adult DM. Although the mechanism of calcinosis remains unclear, several pathogenic hypotheses have been proposed, including intracellular accumulation of calcium secondary to an alteration of the cellular membrane by trauma and inflammation, local vascular ischemia, dysregulation of mechanisms controlling the deposition and solubility of calcium and phosphate, and mitochondrial damage of muscle cells. Identifying calcinosis biomarkers is important for early disease detection and risk assessment, and may lead to novel therapeutic targets for the prevention and treatment of DM-associated calcinosis. In this review, we summarize myositis autoantibodies associated with calcinosis in DM, histopathology and chemical composition of calcinosis, genetic and inflammatory markers that have been studied in adult DM and JDM-associated calcinosis, as well as potential novel biomarkers.

What Is in the Myopathy Literature?

We review the development of exon 51 skipping therapy with eteplirsen for Duchenne muscular dystrophy, including the recent report of long-term, sustained dystrophin production. Studies of the late-life health profile of patients with Duchenne muscular dystrophy, early detection of left ventricular systolic dysfunction, and caregiver burden are also covered. A study of skeletal muscle magnetic resonance imaging in dysferlinopathies provides an extensive, detailed map of the involved muscles and consistency across phenotypes. Regarding the category of autoimmune myopathies, we discuss an article on the clinical and laboratory features associated with PM/Scl antibodies in comparison with other autoimmune myopathy subgroups. Finally, the overall increase in mortality in inflammatory myopathies is highlighted in a recent report from Sweden.

Review of the "X chromosome-nucleolus nexus" hypothesis of autoimmune diseases with an update explaining disruption of the nucleolus

The "X chromosome-nucleolus nexus" hypothesis provides a comprehensive explanation of how autoantibodies can develop following cellular stress. The hypothesis connects autoimmune diseases with the impact of environmental factors, such as viruses, through epigenetic disruption. The inactive X chromosome, a major epigenetic structure in the female cell's nucleus, is a key component of the hypothesis. The inactive X is vulnerable to disruption due to the following: (1) its heavy requirements for methylation to suppress gene expression, (2) its peripheral location at the nuclear envelope, (3) its late replication timing, and (4) its frequently observed close association with the nucleolus. The dynamic nucleolus can expand dramatically in response to cellular stress and this could disrupt the neighboring inactive X, particularly during replication, leading to expression from previously suppressed chromatin. Especially vulnerable at the surface of the inactive X chromosome would be genes and elements from Xp22 to the terminus of the short arm of the X. Expression of these genes and elements could interfere with nucleolar integrity, nucleolar efficiency, and future nucleolar stress response, and even lead to fragmentation of the nucleolus. Ribonucleoprotein complexes assembled in the nucleolus could be left in incomplete states and inappropriate conformations, and/or contain viral components when the nucleolus is disrupted and these abnormal complexes could initiate an autoimmune response when exposed to the immune system. Epitope spreading could then lead to an autoimmune reaction to the more abundant normal complexes. Many autoantigens reported in lupus and other autoimmune diseases are, at least transiently, nucleolar components.

Nuclear mRNA Surveillance Mechanisms: Function and Links to Human Disease

Production of export-competent mRNAs involves transcription and a series of dynamic processing and modification events of pre-messenger RNAs in the nucleus. Mutations in the genes encoding the transcription and mRNP processing machinery and the complexities involved in the biogenesis events lead to the formation of aberrant messages. These faulty transcripts are promptly eliminated by the nuclear RNA exosome and its cofactors to safeguard the cells and organisms from genetic catastrophe. Mutations in the components of the core nuclear exosome and its cofactors lead to the tissue-specific dysfunction of exosomal activities, which are linked to diverse human diseases and disorders. In this article, we examine the structure and function of both the yeast and human RNA exosome complex and its cofactors, discuss the nature of the various altered amino acid residues implicated in these diseases with the speculative mechanisms of the mutation-induced disorders and project the frontier and prospective avenues of the future research in this field.

Muscular and extramuscular clinical features of patients with anti-PM/Scl autoantibodies

OBJECTIVE

To define the clinical features of myositis patients with anti-PM/Scl-75 and/or anti-PM/Scl-100 autoantibodies at disease onset and during the course of disease and compare them to patients with other forms of myositis.

METHODS

In this longitudinal cohort study, the prevalence and severity of clinical features at disease onset and during follow-up were compared between anti-PM/Scl-positive patients and those with the antisynthetase syndrome (AS), dermatomyositis (DM), and immune-mediated necrotizing myopathy (IMNM).

RESULTS

Forty-one anti-PM/Scl-positive, 132 AS, 178 DM, and 135 IMNM patients were included. Although muscle weakness was a presenting feature in just 37% of anti-PM/Scl-positive patients, 93% eventually developed weakness. Unlike the other groups, anti-PM-Scl-positive patients had more severe weakness in arm abductors than hip flexors. Interstitial lung disease was a presenting feature in just 10% of anti-PM/Scl-positive patients, but occurred in 61% during follow-up; fewer patients with DM (13%, p < 0.001) and IMNM (6%, p < 0.001) and more patients with AS (80%, p < 0.05) developed interstitial lung disease during the course of disease. Mechanic's hands (80%), Raynaud syndrome (78%), sclerodactyly (66%), telangiectasias (66%), esophageal reflux disease (61%), subcutaneous edema (46%), puffy hands (39%), and calcinosis (39%) occurred more frequently in anti-PM/Scl-positive patients than in the other groups. Although 30% of anti-PM/Scl-positive patients met criteria for systemic sclerosis, less than 5% had renal crisis or finger ulcerations. No differences were found between patients with only anti-PM/Scl-100 or only anti-PM/Scl-75 autoantibodies.

CONCLUSIONS

Unlike patients with DM, AS, or IMNM, anti-PM/Scl-positive patients have weaker arm abductors than hip flexors. Anti-PM/Scl-positive patients also have the most extensive extramuscular features.

Muscle involvement in systemic sclerosis: points to consider in clinical trials

SSc is clinically and pathogenetically heterogeneous. Consensus standards for trial design and outcome measures are needed. International experts experienced in SSc clinical trial design and a researcher experienced in systematic literature review screened the PubMed and Cochrane Central Register of Controlled Trials in order to develop points to consider when planning a clinical trial for muscle involvement in SSc. The experts conclude that SSc-associated muscle involvement is heterogeneous and lacks a universally accepted gold-standard for measuring therapeutic response. Although outcome studies are currently limited by the inability to clearly distinguish active, reversible muscle inflammation from irreversible muscle damage and extramuscular organ involvement, strong consideration should be given to enrolling patients with a myopathy that features several elements of likely reversibility such as muscle weakness, biopsy-proven active inflammation, an MRI indicating muscle inflammation and a baseline serum creatinine kinase above three times the upper limit of normal to prevent floor effect. Randomized controlled trials are preferred, with a duration of at least 24 weeks. Outcome measures should include a combination of elements that are likely to be reversible, such as muscle weakness, biopsy-proven active inflammation, creatinine kinase/aldolase and a quality of life questionnaire. The individual measurements might require a short pre-study for further validation. A biological sample repository is recommended.

Musculoskeletal Involvement in Systemic Sclerosis: An Unexplored Aspect of the Disease

Musculoskeletal (MSK) symptoms in patients with systemic sclerosis (SSc) include articular involvement (arthralgia, synovitis, contractures), which is often an early phenomenon and significantly contributes to the disability. Predominantly the hands are affected. Consensus in outcome measures of articular involvement is missing. Health Assessment Questionnaire Disability Index (HAQ-DI), Cochin Hand Function Scale (CHFS), Hand Mobility Index in Scleroderma (HAMIS), and Disease Activity Score of 28 Joints (DAS28) may be used for the assessment of different aspects of joint involvement. There is an unmet need for therapies confirmed by randomized controlled clinical trials (RCTs) to treat both synovitis and non-inflammatory joint involvement. The few rehabilitation studies that have been conducted have shown some promising efficacy.

Muscle involvement may be an early symptom. The presence of clinically meaningful muscle involvement often heralds an unfavourable prognosis. The histology of muscle biopsy shows a variable picture including inflammation and necrosis. Besides, signs of acute neurogenic atrophy have been recently described as a previously underestimated contributor to muscle weakness. Similar to articular involvement, the lack of classification criteria on inflammatory and non-inflammatory SSc-associated myopathies, and the lack of validated core set of outcome measures makes it difficult to perform RCTs.

The SSc-specific fibrinous tenosynovitis (tendon-friction rubs /TFRs/) is a frequent finding in SSc. Patients with TFR are at increased risk of developing renal, vascular, cardiac and gastrointestinal involvement and have reduced survival rates. Changes of fibrinous tenosynovitis can be objectively detected by ultrasound and may be used as an outcome measure in the treatment of MSK involvement.

Idiopathic inflammatory myopathies and the lung

Idiopathic inflammatory myositis (IIM) is a group of rare connective tissue diseases (CTDs) characterised by muscular and extramuscular signs, in which lung involvement is a challenging issue. Interstitial lung disease (ILD) is the hallmark of pulmonary involvement in IIM, and causes morbidity and mortality, resulting in an estimated excess mortality of 50% in some series. Except for inclusion body myositis, these extrapulmonary disorders are associated with the general and visceral involvement frequently found in other CTDs including fever, Raynaud's phenomenon, arthralgia, nonspecific cutaneous modifications and ILD, for which the prevalence is estimated to be up to 65%. Substantial heterogeneity exists within the spectrum of IIMs, and each condition is associated with various frequencies and subtypes of pulmonary involvement. This heterogeneity is partly related to the presence of various autoantibodies encompassing anti-synthetase, anti-MDA5 and anti-PM/Scl. ILD is present in all subsets of IIM including juvenile myositis, but is more frequent in dermatomyositis and overlap myositis. IIM can also be associated with other presentations of respiratory involvement, namely pulmonary arterial hypertension, pleural disease, infections, drug-induced toxicity, malignancy and respiratory muscle weakness. Here, we critically review the current knowledge about adult and juvenile myositis-associated lung disease with a detailed description of therapeutics for chronic and rapidly progressive ILD.

Clinical correlates of monospecific anti-PM75 and anti-PM100 antibodies in a tri-nation cohort of 1574 systemic sclerosis subjects

OBJECTIVE

Autoantibodies directed against the two principal antigens of the human exosome complex, PM75 and PM100, are present in systemic sclerosis (SSc) sera and have been associated with myositis and calcinosis. However, there is a paucity of data on the clinical correlates of these autoantibodies separately and in the absence of other SSc-specific antibodies. The aim of this study was to assess the clinical correlates of monospecific anti-PM75 and anti-PM100 in SSc.

METHODS

A tri-nation cohort of 1574 SSc subjects was formed, clinical variables were harmonized and sera were tested for anti-PM75 and anti-PM100 antibodies using a line immunoassay.

RESULTS

Forty-eight (3.0%) subjects had antibodies against PM75 and 18 (1.1%) against PM100. However, only 16 (1%) had monospecific anti-PM75 antibodies and 11 (0.7%) monospecific anti-PM100 antibodies (i.e. in isolation of each other and other SSc-specific antibodies). Monospecific profiles of each autoantibody included more calcinosis. An increased frequency of myositis was only seen in subjects positive for both anti-PM75 and anti-PM100 antibodies. Lung disease was only associated with anti-PM75 and subjects with anti-PM100 antibodies had better survival compared to other antibody subsets.

CONCLUSION

The prevalence of monospecific anti-PM75 and anti-PM100 antibodies in this large SSc cohort was low. Disease features associated with anti-PM/Scl antibodies may depend on particular and possibly multiple antigen specificities. However, due to the small samples, these results need to be interpreted with caution. International collaborations are key to understanding the clinical correlates of uncommon serological profiles in SSc.

A cross-sectional study of autoantibody profiles in the Waikato systemic sclerosis cohort, New Zealand

The autoantibody profiles in New Zealand systemic sclerosis patients have not previously been reported. The aim of this study was to evaluate the autoantibody profiles of patients in the Waikato Hospital Systemic Sclerosis Clinic cohort. The EUROLINE (IgG) Systemic Sclerosis panel test kit (which tests for Scl-70, CENP-A, CENP-B, RP11, RP155, Fib, NOR90, Th/To, PM100, PM75, Ku, PDGFR and Ro-52) was selected for the purpose of this study. All patients attending the Waikato Hospital Systemic Sclerosis clinic were invited to participate. These patients were categorised by systemic sclerosis subtypes [1]. Results were compared with previously published data, including the EUSTAR database. Sixty patients (56 female) were recruited, with a median age of 61 years (range 29-81 years). Forty-one had limited cutaneous systemic sclerosis (lcSSc). Of these lcSSc patients, 31 (75.6%) were positive for CENP-A and CENP-B (anti-centromere) antibodies, 12 (29.3%) for Ro-52 antibodies, 5 (12.2%) for RP11 and RP155, 4 (9.8%) for Scl-70 and 1 (2.4%) each for anti-Fib and Th/To antibodies. Fifteen patients had diffuse cutaneous systemic sclerosis (dcSSc), of which 7 patients (47.6%) were positive for RP11 and RP155, 4 (26.7%) for Scl-70. Three dcSSc patients did not have either of these two major antibodies, but of these 15 dcSSc patients, 4 patients (26.7%) were positive also for Ro-52, 2 (13.3%) for anti-Ku, and 1 (6.7%) each for anti-Fib and NOR90. Four patients had overlap syndrome (OLS), 1 had CENP-A and CENP-B antibodies, 1 had Ro-52 autoantibodies 1 had anti-Ku antibodies. Three patients had no autoantibodies. This is the first study to look at the autoantibody profile of SSc patients in New Zealand. A higher prevalence of antibodies against centromere and RNA polymerase III was demonstrated in our group compared with the EUSTAR database suggesting that antibody prevalence may vary geographically.

Update on etiopathogenesis of systemic sclerosis

Systemic Sclerosis (SSc) is an autoimmune disease of multifactorial etiology, triggered by a combination of genetic and environmental factors. Its varied clinical expression results from the complex physiopathogenic interaction of three main elements: proliferative vasculopathy, immune dysregulation and abnormal deposition and remodeling of the extracellular matrix (ECM), of which the characteristic disease fibrosis is the result. Early physiopathogenic events appear to be endothelial injury and imbalance in vascular repair with the activation of endothelial cells, the immune system and platelets, with the release of multiple mediators such as TH2 proinflammatory cytokines and growth factors, triggering a sequence of simultaneous or cascading events that involve several intracellular signaling pathways. The most important result of these events is the hyperactivation of fibroblasts, the main effector cells of fibrosis, which will then produce large amounts of ECM constituents and secrete multiple growth factors and cytokines that perpetuate the process. In this article we review the main factors potentially involved in the etiology of SSc and reexamine the current knowledge about the most important mechanisms involved in the development of lesions that are characteristic of the disease. A better understanding of these physiopathogenic mechanisms will help identify potential therapeutic targets, which may result in advances in the management of this complex and debilitating disease.

Good outcome of interstitial lung disease in patients with scleroderma associated to anti-PM/Scl antibody

OBJECTIVE

The objective of this article was to establish the clinical course of interstitial lung disease (ILD) in scleroderma related to the presence of anti-PM/Scl antibody compared with anti-Scl-70 in a Spanish cohort. Furthermore, no study has thoroughly investigated the outcome of pulmonary function test in the first group of patients.

METHODS

A total of 63 Spanish patients with scleroderma and ILD were selected in a retrospective observational study. Among them, 14 were positive for anti-PM/Scl antibodies and 49 for anti-Scl-70. Clinical assessments, including pulmonary function test, were collected. Variations equal or greater than 10% in forced vital capacity (FVC) were considered significant. Progression-free survival of disease was defined as the period of stable illness since pulmonary fibrosis diagnosis.

RESULTS

Anti-Scl-70 patients had a higher frequency of diffuse SSc subset, peripheral vasculopathy, and gastrointestinal involvement. Inflammatory myopathy was associated to anti-PM/Scl antibody. Anti-PM/Scl patients presented more improvement in FVC during follow-up, 30.8% compared to a 7.1% in Scl-70 group (P = 0.04), with less worsening of this parameter (15.4% vs 52.4% in Scl-70 patients, P = 0.01), and secondary less frequency of severe restrictive pattern (FVC < 50%) (7.7% compared to 42.9% in the other group, P = 0.02). Regarding treatment, more anticalcineurinics were used in anti-PM/Scl patients, while cyclophosphamide and mycophenolate were mainly used in anti-Scl-70 patients. The progression-free survival of disease was higher in anti-PM/Scl patients, with 76% at 10 years from diagnosis of ILD against a 29% in the Scl-70 group.

CONCLUSIONS

Several features and prognosis of ILD in SSc may be modified depending on the identified immunological profile.

Scleroderma-polymyositis overlap syndrome versus idiopathic polymyositis and systemic sclerosis: a descriptive study on clinical features and myopathology

INTRODUCTION

The objective was to characterize the clinical and myopathologic features of patients with scleroderma-polymyositis (SSc-PM) overlap compared with a population of patients with systemic sclerosis (SSc) and polymyositis (PM).

METHODS

A three-way comparison of patients with SSc-PM overlap (n = 25) with patients with SSc (n = 397) and PM (n = 40) on clinical and myopathologic features and causes of death. One neuropathologist blinded for the diagnosis evaluated all recent available muscle biopsies. Biopsies were scored for presence of inflammation, necrotic muscle fibers, rimmed vacuoles, fibrosis, and immunohistochemical staining. Clinical or myopathologic characteristics were compared by using the χ(2) test or one-way analysis of variance (ANOVA).

RESULTS

The prevalence of SSc-PM overlap in the Nijmegen Systemic Sclerosis cohort was 5.9%. The mortality was 32% (eight of 25) in SSc-PM, of which half was related to cardiac diseases. The prevalence of pulmonary fibrosis was significantly increased in SSc-PM (83%) (P = 0.04) compared with SSc (49%) and PM (53%). SSc or myositis-specific antibodies were nearly absent in the SSc-PM group. In almost all biopsies (96%) of SSc-PM patients, necrotic muscle fibers were present, which was significantly increased compared with PM patients (P = 0.02).

CONCLUSIONS

Patients with SSc-PM have increased prevalence of pulmonary fibrosis and cardiac disease as the cause of death compared with patients with SSc and PM . In addition, we found that necrotizing muscle fibers with inflammation characterize SSc-PM overlap in muscle biopsies. Further research should focus on underlying mechanisms causing necrosis, inflammation, and fibrosis and their relation to pulmonary involvement and mortality in patients with SSc-PM overlap.

Humoral aspects of polymyositis/dermatomyositis

Abstract Evidence of the involvement of systemic autoimmunity has been observed in polymyositis/dermatomyositis (PM/DM). Autoantibodies directed against various cellular constituents have been detected in most patients with PM/DM, and about one-third of patients have autoantibodies (myositis-specific antibodies: MSAs) that are found specifically in myositis patients. These autoantibodies are closely associated with a characteristic clinical subgroup, and therefore help in establishing the correct diagnosis, classifying the myositis patients in a homogeneous subset, and facilitating the clinical and treatment follow-up. Autoantibodies to six of the aminoacyl tRNA synthetases are each associated with a similar syndrome marked by myositis, interstitial lung disease, arthritis, and other features constituting an "antisynthetase syndrome." Antibodies to other cytoplasmic antigens that are involved in protein synthesis or translation factors are seen in a small proportion of patients. Antisignal recognition particles are associated with severe, refractory myositis that differs significantly from antisynthetase syndrome. Antibodies to the nuclear antigen are specifically seen in patietnts with DM. Several autoantibodies, including anti-U1 RNP, anti-U2 RNP, anti-Ku, and anti-PM-Scl, have been associated with scleroderma-PM overlap. In recent years, these MSAs and their antigens have been characterized using molecular biology approaches. It is not known if the MSAs are involved in tissue injury or the pathogenesis of PM/DM. However, an understanding of the production mechanisms of these autoantibodies can provide insight into the etiology of this disorder.

Disease progression in systemic sclerosis-overlap syndrome is significantly different from limited and diffuse cutaneous systemic sclerosis

BACKGROUND

Systemic sclerosis (SSc)-overlap syndromes are a very heterogeneous and remarkable subgroup of SSc-patients, who present at least two connective tissue diseases (CTD) at the same time, usually with a specific autoantibody status.

OBJECTIVES

To determine whether patients, classified as overlap syndromes, show a disease course different from patients with limited SSc (lcSSc) or diffuse cutaneous SSc (dcSSc).

METHODS

The data of 3240 prospectively included patients, registered in the database of the German Network for Systemic Scleroderma and followed between 2003 and 2013, were analysed.

RESULTS

Among 3240 registered patients, 10% were diagnosed as SSc-overlap syndrome. Of these, 82.5% were female. SSc-overlap patients had a mean age of 48±1.2 years and carried significantly more often 'other antibodies' (68.0%; p<0.0001), including anti-U1RNP, -PmScl, -Ro, -La, as well as anti-Jo-1 and -Ku antibodies. These patients developed musculoskeletal involvement earlier and more frequently (62.5%) than patients diagnosed as lcSSc (32.2%) or dcSSc (43.3%) (p<0.0001). The onset of lung fibrosis and heart involvement in SSc-overlap patients was significantly earlier than in patients with lcSSc and occurred later than in patients with dcSSc. Oesophagus, kidney and PH progression was similar to lcSSc patients, whereas dcSSc patients had a significantly earlier onset.

CONCLUSIONS

These data support the concept that SSc-overlap syndromes should be regarded as a separate SSc subset, distinct from lcSSc and dcSSc, due to a different progression of the disease, different proportional distribution of specific autoantibodies, and of different organ involvement.

Idiopathic inflammatory myopathies

Inflammatory myopathies are chronic, immune-mediated diseases characterised by progressive proximal muscle weakness. They encompass a variety of syndromes with protean manifestations. The diagnosis is based on Bohan and Peter's classification criteria, which nowadays seem to be obsolete. Our increasing knowledge about the risk factors, genetic susceptibility and immunological pathways in the disease mechanism leads to the establishment of a new, immunogenetically and serologically validated diagnostic criteria system. The treatment of idiopathic inflammatory myopathy is also a complex task requiring much experience. The aims of therapy are to increase muscle strength, prevent the development of contractures and manage the systemic manifestations of the disease. The most important one is the early detection of diseases and patients' immunological control in special centres. Using the basis therapeutic drugs temporary or permanent remission can be achieved, which improves patientsG' quality of life and functional ability. Rehabilitation and physiotherapy in the remission period may significantly improve the outcome of patients with functional disorders. The introduction of new biological therapies further allows us to control the myositis patients' state more effectively. The aim of this review is to summarise our knowledge about clinical symptoms, pathomechanism, as well as genetic, serologic and environmental risk factors. We would also like to present the way to diagnosis and the latest research about diagnostic criteria system, proposed outcome measures and therapeutic possibilities.

Overlap connective tissue disease syndromes

Overlap Syndromes (OSs) have been defined as entities satisfying classification criteria of at least two connective tissue diseases (CTDs) occurring at the same or at different times in the same patient. CTDs include systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), systemic sclerosis (SSc), polymyositis/dermatomyositis (PDM), and Sjögren syndrome (SS). Every combination between these disorders has been reported. In some OS a specific autoantibody has been indentified, supporting the hypothesis that these syndromes are not a mere association of two or more CTD in the same patient, but a well defined clinical entity with specific clinical characteristics. As an example, anti-t-RNA synthetase syndrome is characterized by the presence of anti-t-RNA synthetase antibodies. Notably, clinical manifestations observed in OS may be different from those observed in the single CTD. The treatment of OS is mainly based on the use of corticosteroids and immunosuppressants. Biologic drugs, i.e. anti-TNFα or anti-CD20 monoclonal antibodies, have been recently introduced as alternative treatments in refractory cases. Moreover, there are some concerns with the use of anti-TNF agents in patients with systemic autoimmune diseases due to the risk of triggering disease exacerbations. In this paper the most frequent OS are described with a special focus on the specific immunologic and clinical aspects. Furthermore, some personal data on anti-t-RNA synthetase syndrome and rhupus syndrome are reported.

Aldolase predicts subsequent myopathy occurrence in systemic sclerosis

Introduction

Myopathy related to systemic sclerosis (Myo-SSc) is a disabling and unpredictable complication of SSc. We assessed the predictive value of serum aldolase, creatine kinase (CK), alanine transaminase (ALT), aspartate transaminase (AST) and C-reactive protein (CRP) to estimate the risk of developing Myo-SSc.

Methods

We enrolled 137 SSc patients without proximal muscle weakness in a prospective monocentric study to follow them longitudinally over a four-year period. The risk of occurrence of Myo-SSc was ascertained according to the European NeuroMuscular Centre criteria and was analyzed according to levels of plasma aldolase, CK, transaminase enzymes and CRP at inclusion. Performance of each parameter to predict Myo-SSc occurrence was assessed and compared with the others.

Results

The area under the receiver operating characteristic curves (ROC) of plasma aldolase for Myo-SSc occurrence prediction was 0.80 (95% CI: 0.67 to 0.94, P < 0.001), which was higher than that of plasma CK (0.75, P = 0.01), and that of ALT (0.63, P = 0.04). AST and CRP had no predictive value for Myo-SSc occurrence. The best cut-off of aldolase for prediction of Myo-SSc occurrence within three years after inclusion was 9 U/L and higher than the upper normality limit (7 U/L), unlike that of CK and ALT. Myo-SSc occurred more frequently in patients whose plasma aldolase was higher than 9 U/L. Adjusted Hazard Ratio for patients with aldolase > 9 U/L was 10.3 (95% CI: 2.3 to 45.5), P < 0.001.

Conclusions

Increased plasma aldolase level accurately identified SSc patients with high risk to develop subsequent Myo-SSc. This could help initiate appropriate treatment when the disabling muscle damage is still in a reversible stage.

Frequency of disease-associated and other nuclear autoantibodies in patients of the German Network for Systemic Scleroderma: correlation with characteristic clinical features

Introduction

In the present study, we analysed in detail nuclear autoantibodies and their associations in systemic sclerosis (SSc) patients included in the German Network for Systemic Scleroderma Registry.

Methods

Sera of 863 patients were analysed according to a standardised protocol including immunofluorescence, immunoprecipitation, line immunoassay and immunodiffusion.

Results

Antinuclear antibodies (ANA) were detected in 94.2% of patients. In 81.6%, at least one of the autoantibodies highly associated with SSc or with overlap syndromes with scleroderma features was detected, that is, anti-centromere (35.9%) or anti-topoisomerase I (30.1%), followed in markedly lower frequency by antibodies to PM-Scl (4.9%), U1-ribonucleoprotein (U1-RNP) (4.8%), RNA polymerases (RNAPs) (3.8%), fibrillarin (1.4%), Ku (1.2%), aminoacyl-transfer RNA synthetases (0.5%), To (0.2%) and U11-RNP (0.1%). We found that the simultaneous presence of SSc-associated autoantibodies was rare (1.6%). Furthermore, additional autoantibodies were detected in 55.4% of the patients with SSc, of which anti-Ro/anti-La, anti-mitochondrial and anti-p25/p23 antibodies were most frequent. The coexistence of SSc-associated and other autoantibodies was common (43% of patients). SSc-associated autoantibodies disclosed characteristic associations with clinical features of patients, some of which were previously not acknowledged.

Conclusions

This study shows that five autoantigens (that is, centromere, topoisomerase I, PM-Scl, U1-RNP and RNAP) detected more than 95% of the known SSc-associated antibody responses in ANA-positive SSc patients and characterise around 79% of all SSc patients in a central European cohort. These data confirm and extend previous data underlining the central role of the determination of ANAs in defining the diagnosis, subset allocation and prognosis of SSc patients.

Recent advances in the immunogenetics of idiopathic inflammatory myopathy

This review summarizes the previous and current literature on the immunogenetics of idiopathic inflammatory myopathy (IIM) and updates the research progress that has been made over the past decade. A substantial part of the genetic risk for developing adult- and juvenile-onset IIM lies within the major histocompatibility complex (MHC), and a tight relationship exists between individual human leukocyte antigen alleles and specific serological subtypes, which in turn dictate clinical disease phenotypes. Multiple genetic regions outside of the MHC are increasingly being identified in conferring IIM disease susceptibility. We are still challenged with the task of studying a serologically and clinically heterogeneous disorder that is rarer by orders of magnitude than the likes of rheumatoid arthritis. An ongoing and internationally coordinated IIM genome-wide association study may provide further insights into IIM immunogenetics.

[Idiopathic inflammatory myopathies with anti-PM-Scl antibodies: case series and literature review]

PURPOSE

The objectives of this study were to evaluate: (1) the prevalence of anti-PM-Scl antibodies within the framework of antinuclear antibodies detection; and (2) the clinical features and outcome of patients with isolated polymyositis/dermatomyositis.

METHODS

Nine thousand and sixty-four consecutive antinuclear testing data allowed us to evaluate anti-PM-Scl antibody prevalence. Second, we also assessed the characteristics of patients with isolated dermatomyositis/polymyositis and associated anti-PM-Scl antibody.

RESULTS

Over 9064 consecutive antinuclear samples tested for antinuclear antibodies, 3263 (36%) were positive; anti-PM-Scl antibody were positive in nine patients: 0.1% of all sera, 0.2% of sera positive for antinuclear antibodies, 1.2% of sera positive for anti-ENA antibodies. Four of the nine patients with anti-PM-Scl antibody had dermatomyositis (n=3) and polymyositis (n=1). Patients with dermatomyositis/polymyositis and anti-PM-Scl antibody exhibited severe complications, as follows: ventilatory insufficiency (n=2) requiring mechanical ventilation in one case, esophageal involvement requiring enteral feeding (n=1); also, two of these patients had cancer.

CONCLUSION

Our case series suggests that the presence of anti-PM-Scl antibody is not a favorable prognostic factor in patients with dermatomyositis/polymyositis. This type of antibody appears to be associated with lung and esophageal involvement; in addition, anti-PM-Scl antibody may co-exist with malignancy in PM/DM patients. Taken together, we suggest that patients with dermatomyositis/polymyositis and anti-PM-Scl antibody require both initial evaluation for lung/digestive manifestations and cancer and close surveillance.

Interstitial Lung Disease in Idiopathic Inflammatory Myopathy

The lung is one of the most common extra-muscular targets in idiopathic inflammatory myopathies (IIM) and interstitial lung disease (ILD) is a prevalent and often devastating manifestation of IIM. IIM-associated ILD (IIM-ILD) contributes to nearly 80% of the mortality in IIM with a reported prevalence of 65% of newly diagnosed IIM cases. Although ILD frequently accompanies clinical and laboratory findings of myositis, overt signs of muscle disease may be absent in the setting of significant lung disease. Understanding the varied scope of presentation of these diseases is essential to providing optimal patient care. This review will provide an in depth examination of ILD in IIM both from a rheumatologic and pulmonary perspective and will discuss the scope of disease, presenting features, genetic associations, pathogenesis, diagnosis, radiographic and histopathologic findings, along with biomarker assessment and a rationale for therapeutic intervention.

Interstitial lung disease associated with anti-PM/Scl or anti-aminoacyl-tRNA synthetase autoantibodies: a similar condition?

OBJECTIVE

To compare anti-PM/Scl autoantibody-associated interstitial lung disease (ILD) with anti-aminoacyl-tRNA synthetases (anti-ARS) autoantibody-associated ILD.

METHODS

We retrospectively studied 21 patients with ILD from a department of respiratory medicine, including 9 with anti-PM/Scl autoantibodies (6 women, median age 55 yrs, followup 5.5 yrs) and 12 with anti-ARS autoantibodies (6 women, median age 59 yrs, followup 2.3 yrs).

RESULTS

Pulmonary manifestations in patients with anti-PM/Scl autoantibody-associated ILD usually followed the extrapulmonary manifestations of the connective tissue disease (CTD) (7/9 cases). The predominant imaging features on initial high resolution computed tomography were ground-glass attenuation and reticular opacities, and mainly suggested nonspecific interstitial pneumonia in both groups. CTD was classified as dermatomyositis (DM; 2), undifferentiated CTD (2), cutaneous limited systemic sclerosis (2), rheumatoid arthritis (RA; 1), and overlap syndrome (1) in the anti-PM/Scl group; and polymyositis (4), undifferentiated CTD (5), DM (1), amyopathic DM (1), and RA (1) in the anti-ARS group. Frequencies of arthralgia, Raynaud phenomenon, cutaneous rash, and mechanic's hands were comparable in both groups. Myalgia or muscle weakness was present in 0/9 PM/Scl and 5/12 ARS patients (p < 0.05). More than 1 autoantibody was present in 11 patients. ILD worsened despite treatment in 4 patients with anti-PM/Scl autoantibodies and 2 with anti-ARS autoantibodies, and included 1 death.

CONCLUSION

Anti-PM/Scl and anti-ARS antibodies are associated with similar clinical manifestations, with the exception only of more overt myositis in the latter, therefore challenging the clinical specificity of the antisynthetase syndrome.