Low prevalence of anti-small ubiquitin-like modifier activating enzyme antibodies in dermatomyositis patients

Longitudinal study of patients with anti-SAE antibody-positive dermatomyositis: a multicenter cohort study in China

OBJECTIVES

To describe the longitudinal study and long-term prognosis of a multicentre large inception cohort of patients with anti-SAE positive DM.

METHODS

We retrospectively recruited patients with anti-SAE+DM in four tertiary referral centres from China between March 2005 and December 2022. Long-term survival analysis was performed on the enrolled patients. The Myositis Damage Index and Cutaneous Disease Area and Severity Index were used to evaluate the degree of different organ damage and the extent of skin rashes. Longitudinal CT patterns were analysed. Phenotypes were characterized using unsupervised cluster analysis.

RESULTS

All-cause death occurred in 10.5% (4/38) of all patients, in which three patients succumbed to malignancies at 13, 18 and 36 months. Most patients had favourable long-term outcomes, 35.3% of them were in drug-free remission. Skin rashes showed significant improvement evaluated by Cutaneous Disease Area and Severity Index with time. However, damage to different systems was observed in 70.6% of the surviving patients using the Myositis Damage Index, which mainly consisted of skin damage, accounting for 47.1%. Nine patients with anti-SAE+DM-associated interstitial lung disease underwent repeat CT showed marked radiological improvement at 6 months or being stable after 12 months. In further, different characteristics and outcomes were also showed in three clusters identified by unsupervised analysis.

CONCLUSIONS

Anti-SAE+DM is characterized with a lower mortality rate and the development of malignancies being the primary cause of death. Patients who survived showed notable cutaneous damage, while the interstitial lung disease tends to stabilize. Clusters identified with unsupervised analysis could assist physicians in identifying a higher risk of mortality.

Patients with anti-small ubiquitin-like modifier activating enzyme-positive dermatomyositis resembling antisynthetase syndrome with poor prognosis: a bicentric international retrospective study and literature review

OBJECTIVE

This study aimed to describe adult Brazilian and Japanese patients with anti-small ubiquitin-like modifier activating enzyme (SEA)-positive dermatomyositis (DM), as there are few studies in the literature. A literature review was also conducted.

METHODS

This bicentric international retrospective study, conducted between 2012 and 2023, included patients with anti-SAE-positive DM (2017 European League Against Rheumatism/ American College of Rheumatology classification criteria). All demographic features and clinical, laboratory, therapeutic, and follow-up data were collected from Brazilian and Japanese centers using pre-standardized and parameterized information.

RESULTS

We included 17 adult patients with a median age of 65 years (56-76 years) and a predominance of females (82.4%). Constitutional symptoms at baseline were present in 58.8% of the patients. In addition to classical cutaneous DM lesions, one-third of the patients had myalgia and significant muscle weakness, whereas half presented with dysphagia, interstitial lung disease, and joint manifestations. The first-line treatment consisted of intravenous methylprednisolone and immunoglobulin pulse therapy in 41.2% and 28.6% of the patients, respectively. The median follow-up duration was 20 (13-74) months; at the last medical evaluation, half had active disease and were still using oral glucocorticoids (median dosage, 10.0 mg/day). Approximately one-fifth to one-third of the patients were diagnosed with different types of cancer, had severe infections, or died.

CONCLUSIONS

Patients with anti-SAE-positive DM not only resemble the phenotype of antisynthetase syndrome but are also associated with a poor prognosis.

A case of anti-SAE1/2 antibody-positive dermatomyositis with extensive panniculitis: A possible cutaneous manifestation of treatment resistance

Dermatomyositis constitutes a heterogeneous group of autoimmune inflammatory conditions with a wide variety of clinical outcomes. The symptomatic heterogeneity carries skin, muscle, and joint manifestations; pulmonary and cardiac involvements; and concomitant malignancy. Any of these symptoms often appear at different combinations and time courses, thus posing difficulty in early diagnosis and appropriate treatment choice. Recent progress in laboratory investigations explored the identification of several myositis-specific autoantibodies (MSAs) and myositis-associated autoantibodies, allowing precise characterization for a clinical perspective of the disease. MSAs can be detectable in approximately 80% of patients with whole dermatomyositis, some of which closely reflect unique clinical features in the particular disease subset(s), including the distribution and severity of organ involvement, treatment response, and prognosis. However, only limited evidence has been available in dermatomyositis-associated panniculitis, mostly that in anti- melanoma differentiation-associated protein 5 antibody-positive disease. We present a rare case of a patients with dermatomyositis with extensive panniculitis on the trunk whose serum IgG autoantibodies reacted with both subunits of small ubiquitin-like modifier activating enzymes (SAEs), SAE1 and SAE2. The onset of panniculitis coincided with increased disease activity, including disease-related skin manifestations, fever, dysphagia, and muscle weakness in the extremities. These symptoms responded well to a high dose of systemic steroid, but even upon receiving a high-dose intravenous immunoglobulin, the panniculitic lesions and pruritic erythema flared with tapering of steroid dose, further requiring tacrolimus and mycophenolate mofetil to achieve disease remission. To our knowledge, this is the third reported case of anti-SAE autoantibody-positive dermatomyositis with panniculitis. We aim to extend the understanding of the current limitation and further perspective in the clinical management of the extremely rare skin manifestation associated with dermatomyositis.

Antibodies against Small Ubiquitin-like Modifier Activating Enzyme May Be a Protective Factor from Rapid Progressive Interstitial Lung Disease in Patients Bearing Antibodies against Melanoma Differentiation Associated Gene 5

Background: Anti-MDA5 antibody-bearing (anti-MDA5+)-dermatomyositis (DM) or polymyositis (PM) is notorious for causing rapidly progressive interstitial lung disease (RPILD) and/or cancers with high mortality rate. However, anti-MDA5 antibodies (Abs) are also found in other connective tissue diseases and their link with RPILD, especially with regard to the mortality rate, are unknown. Methods: We retrospectively recruited 71 patients bearing anti-MDA5-Abs in serum, stratified them in terms of a presence or absence of RPILD, and evaluated their clinical features, laboratory findings, associated myositis antibodies, concurrent connective tissue disease (CTD) as well as newly developed malignancies. Results: In total, 39 (55%) patients presented with DM/PM, but 32 (45%) did not. In total, 22 of the former and 11 of the latter developed RPILD eventually, accounting for a total of 46% of all MDA-5 bearing patients. On the other hand, 15 of all 71 (21.1%) patients had cancers. Among the 32 patients who did not have DM/PM, 27 (38.0% of all 71) had other CTDs, indicating that only 5 (7.0% of 71) patients did not have CTDs. Senility (odds ratio (OR) = 1.816, p = 0.032), presence of anti-Ro-52 antibody (OR = 1.676, p = 0.018), elevated C-reactive protein (CRP, OR = 4.354, p < 0.001) and carcinoembryonic antigen (CEA, OR = 2.625, p = 0.005) posed risks for RPILD. High lactose dehydrogenase (LDH, p = 0.009), CRP (p = 0.001) and CEA (p = 0.001), ferritin (p ≤ 0.001) and low albumin (p ≤ 0.001) were significantly associated with mortality. Anti-SAE antibodies were negatively correlated with RPILD as analyzed by univariate (OR = 0.245, p = 0.017) and multivariate (OR = 0.058, p = 0.036) regressions, indicating that they may be a protective factor in relation to RPILD (OR = 0.543, p = 0.008) or fatality (OR = 0.707, p = 0.012), which was also demonstrated in subgroup analyses. Conclusions: In contrast to various risk factors for RPILD or mortality, anti-SAE antibodies might conversely be a protective factor in anti-MDA5+ patients.

Anti-SAE autoantibody in dermatomyositis: original comparative study and review of the literature

OBJECTIVE

Among specific autoantibodies in DM, the anti-small ubiquitin-like modifier activating enzyme (SAE) antibody is rare. We aim to describe the clinical characteristics, cancer prevalence, and muscle pathology of anti-SAE-positive DM.

METHODS

Patients with a diagnosis of DM and sera positive for the anti-SAE antibody were recruited from 19 centres in this retrospective observational study. The available muscular biopsies were reviewed. We conducted a comparison with anti-SAE-negative DM and a review of the literature.

RESULTS

Of the patients in the study (n = 49), 84% were women. Skin involvement was typical in 96% of patients, with 10% having calcinosis, 18% ulceration and 12% necrosis; 35% presented with a widespread skin rash. Muscular disease affected 84% of patients, with mild weakness [Medical Research Council (MRC) scale 4 (3, 5)], although 39% of patients had dysphagia. Muscular biopsies showed typical DM lesions. Interstitial lung disease was found in 21% of patients, mainly with organizing pneumonia pattern, and 26% of patients showed dyspnoea. Cancer-associated myositis was diagnosed in 16% of patients and was responsible for the majority of deaths, its prevalence being five times that of the general population. IVIG therapy was administered to 51% of the patients during the course of the disease. Comparison with anti-SAE-negative DM (n = 85) showed less and milder muscle weakness (P = 0.02 and P = 0.006, respectively), lower creatinine kinase levels (P < 0.0001) and less dyspnoea (P = 0.003).

CONCLUSION

Anti-SAE positive DM is a rare subgroup associated with typical skin features but a potentially diffuse rash, a mild myopathy. Interstitial lung disease defines an organizing pneumonia pattern. Cancer associated DM prevalence is five times that of the general population.

TRIAL REGISTRATION

ClinicalTrials.gov, http://clinicaltrials.gov, NCT04637672.

Profile of specific and associated autoantibodies in patients with idiopathic inflammatory myopathies in a Colombian population

Objectives

Idiopathic inflammatory myopathies (IIMs) are chronic, autoimmune diseases with several forms of presentation. Diagnosis is mostly clinical in our region. Our aim was to evaluate the autoantibody profile of patients with IIMs.

Methods

This study is a cross-sectional study with a prospective recollection of data, conducted between 2019–2021, in a single center in Cali, Colombia. Patients with a clinical diagnosis or suspicion of IIM were included. The presence of myositis-specific/associated antibodies was evaluated by immunoblotting in serum samples. Phenotypic characterization was performed.

Results

A total of 36 patients were included. The mean age was 50.6 (16.7) years, and 20 (55.6%) were female. Eighteen (50%) patients were seropositive, of which 11 (30.5%) presented one positive antibody, with anti-TIF1ɣbeing the most frequent (n = 4, 11.1%), followed by anti-Ro52 (n = 2, 5.6%). Seven patients (19.4%) showed >1 positive antibody. Dermatomyositis was the most frequent type of IIM in seropositive patients (n = 8, 44.4%), followed by anti-synthetase syndrome (n = 4, 22.2%). Weakness was symmetric and presented in the upper and lower extremities in 11 (61.1%) patients each. Both respiratory insufficiency and weight loss were seen in 7 (38.9%) patients, Gottron papules in six (33.3%) patients, and heliotrope rash, esophageal dysmotility, and myalgia in 5 (27.8%) patients. Pulmonary interstitial disease was seen in 4 (22.2%, with antibodies for anti-Ro52, anti-MDA5 + anti-Jo1 + anti-TIF1ɣ, anti-MDA5 + anti-SAE1 + anti-NXP2, and anti-cN1A + anti-Ro52) patients, and malignancy was seen in 2 (11.1%) patients (1 with anti-Mi2β and 1 with anti-TIF1ɣ + anti-Mi2α). In all, 7 (19.4%) patients required intensive care (2 seropositive, 1 with anti-PL7, 1 with anti-MDA5 + anti-Jo1 + anti-TIF1ɣ), and 1 (2.8%) (seronegative) patient died.

Conclusion

This study is the first study in the Southwest of Colombia that evaluates myositis-specific/associated antibodies in IIM. Half of the patients were seropositive. Anti-TIF1ɣwas the most frequent MSA and anti-Ro52 was the most frequent MAA. Several patients presented antibody combinations. Further studies are needed to fully associate phenotypes with antibodies.

Alarmins in autoimmune diseases

Alarmins are endogenous, constitutively expressed, chemotacting and immune activating proteins or peptides released because of non-programmed cell death (i.e. infections, trauma, etc). They are considered endogenous damage-associated molecular patterns (DAMPs), able to induce a sterile inflammation. In the last years, several studies highlighted a possible role of different alarmins in the pathogenesis of various autoimmune and immune-mediated diseases. We reviewed the relevant literature about this topic, for about 160 articles. Particularly, we focused on systemic autoimmune diseases (systemic lupus erythematosus, rheumatoid arthritis, idiopathic inflammatory myopathies, ANCA-associated vasculitides, Behçet's disease) and cutaneous organ-specific autoimmune diseases (vitiligo, psoriasis, alopecia, pemphigo). Finally, we discussed about future perspectives and potential therapeutic implications of alarmins in autoimmune diseases. In fact, identification of receptors and downstream signal transducers of alarmins may lead to the identification of antagonistic inhibitors and agonists, with the capacity to modulate alarmins-related pathways and potential therapeutic applicability.

Update on Cutaneous Signs to Assist in the Diagnosis of Dermatomyositis

PURPOSE OF REVIEW

Dermatomyositis (DM) is a heterogeneous idiopathic inflammatory myopathy that can be challenging to diagnose. Learning about the cutaneous manifestations in DM can assist with prompt diagnosis as well as subgroup classification. This review highlights recent data regarding cutaneous signs in DM and their associations with myositis-specific antibodies (MSAs).

RECENT FINDINGS

Several novel DM skin signs have recently been reported. Novel and confirmatory data have helped to define more clearly the associations between various cutaneous manifestations and MSAs. Awareness of the diverse cutaneous phenotypes can help with the timely diagnosis of DM. As some MSAs are associated with atypical skin features and/or characteristic patterns of clinical findings, knowledge of these associations can help clinicians to recognize DM patients. Understanding how the prevalence and presentation of various cutaneous signs differ among ethnically diverse patients is a high priority for further study.

A Case of Anti-SAE1 Dermatomyositis

Introduction

Anti-SAE1 antibodies have a low prevalence in dermatomyositis patients. Case Description. A 61-year-old woman presented with progressive shortness of breath, arthralgia, heliotrope rash, Gottron's papules, and erythematous rash. She had an interstitial lung disease (ILD) with a significant decrease in lung function. There was no muscle involvement. Immunological laboratory test results showed strongly positive anti-SAE1 antibodies. Glucocorticoid treatment resulted in remission of dermatomyositis.

Conclusion

Anti-SAE antibodies in dermatomyositis patients are closely linked to unique clinical features.

Myositis Antibodies and Interstitial Lung Disease

BACKGROUND

Interstitial lung disease (ILD) comprises a heterogeneous group of inflammatory and fibrotic conditions, often resulting in progressive lung function decline and increased mortality. Connective tissue disease (CTD) should be considered in all patients with ILD, as distinguishing between CTD-ILD and other forms of fibrotic lung disease has important therapeutic and prognostic implications. The idiopathic inflammatory myopathies (IIM) represent a CTD subtype of growing interest to ILD experts. The expansion and availability of myositis-specific and myositis-associated antibody testing has allowed for improved disease detection and characterization.

CONTENT

In this review, we highlight the relationship between myositis antibodies and ILD. Select forms of IIM, such as the antisynthetase syndrome and clinically amyopathic dermatomyositis can present with rapidly progressive ILD, warranting timely disease diagnosis and management. Disease phenotypes, prevalence, laboratory testing, prognosis, and management strategies are described according to select myositis antibodies.

SUMMARY

Myositis antibodies provide valuable information for clinicians managing patients with ILD. This review aims to increase awareness of their role in disease detection, pathophysiology, and possibly therapeutics.

A North American Cohort of Anti-SAE Dermatomyositis: Clinical Phenotype, Testing, and Review of Cases

Objective

Antibodies against the small ubiquitin‐like modifier (SUMO) activating enzyme (SAE) are one of the rarer specificities associated with dermatomyositis (DM). The purpose of this study is to describe the clinical characteristics of patients with anti‐SAE autoantibodies in a North American cohort and to ascertain cancer prevalence. We also describe the performance characteristics of the line blotting (Euroimmun) method for antibody detection compared with an immunoprecipitation‐based assay.

Methods

Sera from 2127 patients suspected of having myositis were assayed for myositis‐specific autoantibodies using the Euroimmun platform. Those positive for SAE autoantibodies were assayed by a second method (immunoprecipitation) for confirmation. Only those cases positive by both methods were taken as definite cases of anti‐SAE–positive DM. Chart reviews of these patients were completed to obtain information on clinical characteristics, cancer history, and treatment.

Results

Forty‐three of 2127 sera were anti‐SAE autoantibody positive by Euroimmun (≥15 units, +); of these, only 19 were confirmed positive by immunoprecipitation. All 19 cases had skin involvement and varying presentations of muscle, lung, and joint disease. Cancer occurred coincident with DM in two patients, and cancers were detected more than 5 years from symptom onset in three patients. In a population of suspected inflammatory myositis, a higher cutoff on line blot testing (≥36 units, ++) yielded better agreement with immunoprecipitation methods.

Conclusion

SAE autoantibodies associate with a clinical phenotype of DM, which most commonly presents with a rash first, followed by muscle involvement and varying extramuscular involvement. As coincident cancer was seen in anti‐SAE–positive DM, judicious malignancy screening may be warranted.

Anti-SAE autoantibody-positive Japanese patient with juvenile dermatomyositis complicated with interstitial lung disease - a case report

BACKGROUND

Clinical phenotypes and outcomes in juvenile dermatomyositis (JDM) have been defined by various myositis-specific autoantibodies (MSAs). One of the recently described MSAs associated with DM is targeted against the small ubiquitin-like modifier 1 activating enzyme (SAE). We report an anti-SAE autoantibody-positive JDM patient complicated with interstitial lung disease (ILD).

CASE PRESENTATION

An 8-year-8-month-old Japanese girl presented with bilateral eyelid edema and facial erythema. At 8 years 4 months, she had dry cough and papules with erythema on the dorsal side of the interphalangeal joints of both hands. Her facial erythema gradually worsened and did not improve with topical steroids. At the first visit to our department at 8 years 8 months of age, she had a typical heliotrope rash and Gottron's papules, with no fever or weight loss, and a chest computed tomography scan showed ground-glass opacity under visceral pleura. There was no clinical evidence of myositis, muscle weakness, myalgia, or muscle magnetic resonance imaging (MRI) findings. She had mild dry cough, without any signs of respiratory distress. Laboratory tests showed no elevated inflammatory markers. She had a normal serum creatine kinase level with a slightly elevated aldolase level, and serum anti-SAE autoantibody was detected by immunoprecipitation-western blotting. She was diagnosed with juvenile amyopathic DM complicated by ILD and received two courses of methylprednisolone pulse therapy followed by oral corticosteroid and cyclosporin A. We gradually reduced the corticosteroid dose as her skin rash improved after treatment initiation. There was no progression of muscle symptoms, dysphagia, or disease flare during a 24-month follow-up period.

CONCLUSIONS

We report a patient with anti-SAE autoantibody-positive JDM complicated by interstitial pneumonia. This patient had no progression of muscle symptoms and dysphagia during a 24-month follow-up period, which differs from previous reports in adult patients with MSAs. There have been no previous reports of pediatric patients with SAE presenting with ILD. However, ILD seen in this case was not rapidly progressive and did not require cytotoxic agents. To prevent overtreatment, appropriate treatment choices are required considering the type of ILD.

Dermatomyositis autoantibodies: how can we maximize utility?

The past 15 years has seen significant advances in the characterization of myositis-specific autoantibodies (MSAs) and their associated phenotypes in patients with dermatomyositis (DM). As more careful studies are performed, it is clear that unique combinations of clinical and pathological phenotypes are associated with each MSA, despite the fact that there is considerable heterogeneity within antibody classes as well as overlap across the groups. Because risk for interstitial lung disease (ILD), internal malignancy, adverse disease trajectory, and, potentially response to therapy differ by DM MSA group, a deeper understanding of MSAs and validation and standardization of assays used for detection are critical for optimizing diagnosis and treatment. Like any test, the diagnostic sensitivity and specificity of assays for various MSAs is not perfect. Currently tests for MSAs are helpful at minimum for a clinician to assess relative risk or contribute to diagnosis and perhaps counsel the appropriate patient about what to expect. With international standardization and larger studies it is likely that more antibody tests will make their way into formal schemata for diagnosis and actionable risk assessment in DM. In this review, we summarize key considerations for interpreting the clinical and pathologic associations with MSA in DM and identify critical gaps in knowledge and practice that will maximize their clinical utility and utility for understanding disease pathogenesis.

Human kidney stone matrix proteins alleviate hyperoxaluria induced renal stress by targeting cell-crystal interactions

Increased levels of urinary oxalate also known as hyperoxaluria, increase the likelihood of kidney stone formation through enhanced calcium oxalate (CaOx) crystallization. The management of lithiatic renal pathology requires investigations at the initial macromolecular stages. Hence, the current study was designed to unravel the protein make-up of human kidney stones and its impact on renal cells' altered proteome, induced as the consequence of CaOx injury. CaOx kidney stones were collected from patients; stones were pooled for entire cohort, followed by protein extraction. Immunocytochemistry, RT-PCR and flow-cytometric analysis revealed the promising antilithiatic activity of kidney stone matrix proteins. The iTRAQ analysis of renal cells showed up-regulation of 12 proteins and down-regulation of 41 proteins due to CaOx insult, however, this differential expression was normalized in the presence of kidney stone matrix proteins. Protein network analysis revealed involvement of up-regulated proteins in apoptosis, calcium-binding, inflammatory and stress response pathways. Moreover, seven novel antilithiatic proteins were identified from human kidney stones' matrix: Tenascin-X-isoform2, CCDC-144A, LIM domain kinase-1, Serine/Arginine receptor matrix protein-2, mitochondrial peptide methionine sulfoxide reductase, volume-regulated anion channel subunit-LRRC8A and BMPR2. In silico analysis concluded that these proteins exert antilithiatic potential through crystal binding, thereby inhibiting the crystal-cell interaction, a pre-requisite to initiate inflammatory response. Thus, the outcomes of this study provide insights into the molecular events of CaOx induced renal toxicity and subsequent progression into nephrolithiasis.

The association between myositis-specific autoantibodies and muscle pathologies in idiopathic inflammatory myopathies

OBJECTIVE

To investigate specific muscle pathologies of different kinds of myositis-specific autoantibodies (MSAs) in idiopathic inflammatory myopathy (IIM) patients.

METHODS

One hundred eleven Chinese patients from Xiangya Hospital, Central South University diagnosed with IIMs according to European Neuromuscular Centre (ENMC) criteria were included. Clinical manifestation, myositis-specific autoantibodies, and histologic findings were evaluated to explore the pattern of necrosis, regeneration, and perifascicular atrophy, inflammatory cells in IIM patients with different MSAs.

RESULTS

Anti-SRP group has the lowest muscle strength scores, the highest creatine kinase levels, the most severe degree of necrosis and regeneration (1.90[0.80-3.95], 1.00[0.30-1.71]), and the lowest positive rate of MHC-I staining (35.71%). The anti-MDA5 group demonstrates the mildest pathological changes, with the fewest necrotic and regenerated muscle fibers (0.00[0.00-0.50], 0.00[0.00-0.00]), and the fewest inflammatory cell infiltration, and the highest muscle strength scores. The anti-NXP2 group has the most frequent inflammatory infiltrates, especially CD4+ T cells (31.14[15.00-39.00]). The patients with anti-NXP2 and the anti-TIF1γ antibodies show higher frequency of punched-out fibers (1.50[0.00-3.70], 0.00[0.00-1.00]) and perifascicular atrophy (71.43%, 55.56%). As for anti-synthetase antibodies (ASAs), the anti-Jo-1 group shows the most frequent rate of perifascicular necrosis (60%), while other ASA groups do not show perifascicular necrosis.

CONCLUSIONS

Of the MSAs, the anti-SRP antibody leads to the most severe muscle involvement, while the anti-MAD5 antibody the mildest. The anti-NXP2 and anti-TIF1γ groups have the most typical "DM" pathology. Key Points • Anti-SRP group shows severe muscle pathology while anti-MDA5 group shows the mildest. • Anti-NXP2 group has the most frequent inflammatory infiltrates. Pouch-out fibers and perifascicular atrophy are more prevalent in anti-NXP2 and anti-TIF1γ groups. • Anti-Jo-1 group is often accompanied by perifascicular necrosis, while other anti-synthetase antibody groups are not.

Dermatomyositis: An Update on Diagnosis and Treatment

Dermatomyositis is a rare inflammatory disease with characteristic cutaneous findings and varying amounts of systemic involvement. Patients may present with skin disease alone, have concomitant muscle disease, or have extracutaneous manifestations such as pulmonary disease or an associated malignancy. Given such diverse presentations, dermatomyositis is both a diagnostic and therapeutic challenge. However, a prompt diagnosis is of utmost importance to institute adequate therapy and screen patients for an associated malignancy. Dermatologists should play a crucial role in the diagnosis and management of patients with dermatomyositis as cutaneous disease tends to be chronic, negatively impact quality of life, and be more recalcitrant to therapy. In this review, we discuss diagnosis, with a focus on myositis-specific antibodies and their associated phenotypes. We also review therapies available for this often refractory skin disease.

A rare form of dermatomyositis associated with muscle weakness and normal creatine kinase level

We present a case study of a 61-year-old Vietnamese woman who presents with features of dermatomyositis (DM), including Gottron’s papules, heliotrope rash, cutaneous ulcers, generalised weakness and pain, and weight loss with normal levels of creatine kinase (CK). She demonstrated features of interstitial lung disease and subsequently tested positive for anti-melanoma differentiation-associated gene 5 and anti-small ubiquitin-like modifier 1 activating enzyme antibodies, which belong to a DM subtype known as clinically amyopathic dermatomyositis and do not present with raised CK. She received standard treatment for DM, including oral prednisolone, hydroxychloroquine, mycopheonlate and topical betamethasone. The treatment successfully reversed skin changes; however, the patient remained generally weak and unable to carry out her activities of daily living.

Myositis Specific Autoantibodies: A Clinical Perspective

Dermatomyositis (DM) is an idiopathic inflammatory condition characterized by myositis and variable skin manifestation. The existence of myositis specific autoantibodies usually manifests with varying degrees of skin or muscle inflammations. The condition has a well-established association with most clinical phenotypes, and these autoantibodies are useful in informing the diagnosis, management and prognosis of the disease. DM-specific autoantibodies include anti-MDA5, anti-NXP2, anti-SAE, anti-Mi-2, anti-ARS, anti-TIF1-gamma. Anti-Mi-2 antibodies are widely associated with DM cases that exhibit mainly cutaneous symptoms, such as cuticular overgrowths, Gottron's papules while being less susceptible to complications like interstitial lung disease or malignancy. The most distinct clinical features of patients with anti-SAE antibodies are their high prevalence of dysphagia and cutaneous manifestations that antecede the development of myopathies. In addition, DM patients with positive anti-PL-7 antibodies tend to have milder myositis characterized by low levels of creatine kinase as compared to patients with positive anti-Jo-1 antibodies. The anti-NXP2 antibodies are associated with transcriptional regulation and production of various proteins targeted by other DM antibodies, while anti- TIF1-γ. facilitates the transcription of deoxyribonucleic acids and regulates the growth and subsequent differentiation of body cells by controlling the signaling of TGF-β. The present review targets DM specific autoantibodies, considering their association, significance, and clinical presentation.

Disease Specific Autoantibodies in Idiopathic Inflammatory Myopathies

Idiopathic inflammatory myopathies represent still a diagnostic and therapeutic challenge in different disciplines including neurology, rheumatology, and dermatology. In recent years, the spectrum of idiopathic inflammatory myopathies has been significantly extended and the different manifestations were described in more detail leading to new classification criteria. A major breakthrough has also occurred with respect to new biomarkers especially with the characterization of new autoantibody-antigen systems, which can be separated in myositis specific antibodies and myositis associated antibodies. These markers are detectable in approximately 80% of patients and facilitate not only the diagnostic procedures, but provide also important information on stratification of patients with respect to organ involvement, risk of cancer and overall prognosis of disease. Therefore, it is not only of importance to know the significance of these markers and to be familiar with the optimal diagnostic tests, but also with potential limitations in detection. This article focuses mainly on antibodies which are specific for myositis providing an overview on the targeted antigens, the available detection procedures and clinical association. As major tasks for the near future, the need of an international standardization is discussed for detection methods of autoantibodies in idiopathic inflammatory myopathies. Furthermore, additional investigations are required to improve stratification of patients with idiopathic inflammatory myopathies according to their antibody profile with respect to response to different treatment options.

Biomarkers in Adult Dermatomyositis: Tools to Help the Diagnosis and Predict the Clinical Outcome

Dermatomyositis pathophysiology is complex. In recent years, medical research has identified molecules associated with disease activity. Besides providing insights into the driving mechanisms of dermatomyositis, these findings could provide potential biomarkers. Activity markers can be used to monitor disease activity in clinical trials and may also be useful in daily practice. This article reviews molecules that could be used as biomarkers for diagnosis and monitoring dermatomyositis disease activity.

Advances in biomarkers for dermatomyositis

Dermatomyositis (DM) and polymyositis (PM) are heterogeneous complex autoimmune diseases involving muscle damage. Patients with DM and PM display a wide spectrum of clinical manifestations and serological biomarkers, which may mislead and delay the proper diagnosis. Therefore, specific biomarkers or indicators for diagnosing DM and PM and monitoring disease activity are essential. Significant progress has been made through identifying novel serological biomarkers for DM and PM in recent years. Our aim is to focus on novel biomarkers for diagnosing and monitoring disease activity in DM and PM to highlight their predictive value and applicability in clinical practice.

Autoantibodies Associated With Connective Tissue Diseases: What Meaning for Clinicians?

Connective tissue diseases (CTDs) such as systemic lupus erythematosus, systemic sclerosis, myositis, Sjögren's syndrome, and rheumatoid arthritis are systemic diseases which are often associated with a challenge in diagnosis. Autoantibodies (AAbs) can be detected in these diseases and help clinicians in their diagnosis. Actually, pathophysiology of these diseases is associated with the presence of antinuclear antibodies. In the last decades, many new antibodies were discovered, but their implication in pathogenesis of CTDs remains unclear. Furthermore, the classification of these AAbs is nowadays misused, as their targets can be localized outside of the nuclear compartment. Interestingly, in most cases, each antibody is associated with a specific phenotype in CTDs and therefore help in better defining either the disease subtypes or diseases activity and outcome. Because of recent progresses in their detection and in the comprehension of their pathogenesis implication in CTD-associated antibodies, clinicians should pay attention to the presence of these different AAbs to improve patient's management. In this review, we propose to focus on the different phenotypes and features associated with each autoantibody used in clinical practice in those CTDs.

Bench to bedside review of myositis autoantibodies

Idiopathic inflammatory myopathies represent a heterogeneous group of autoimmune diseases with systemic involvement. Even though numerous specific autoantibodies have been recognized, they have not been included, with the only exception of anti-Jo-1, into the 2017 Classification Criteria, thus perpetuating a clinical-serologic gap. The lack of homogeneous grouping based on the antibody profile deeply impacts the diagnostic approach, therapeutic choices and prognostic stratification of these patients. This review is intended to highlight the comprehensive scenario regarding myositis-related autoantibodies, from the molecular characterization and biological significance to target antigens, from the detection tools, with a special focus on immunofluorescence patterns on HEp-2 cells, to their relative prevalence and ethnic diversity, from the clinical presentation to prognosis. If, on the one hand, a notable body of literature is present, on the other data are fragmented, retrospectively based and collected from small case series, so that they do not sufficiently support the decision-making process (i.e. therapeutic approach) into the clinics.

Distinctive cutaneous and systemic features associated with specific antimyositis antibodies in adults with dermatomyositis: a prospective multicentric study of 117 patients

BACKGROUND

Identification of myositis-specific autoantibodies (MSAs) for dermatomyositis (DM) could allow the characterization of an antibody-associated clinical phenotype.

OBJECTIVE

We sought to define the clinical phenotype of DM and the risk of cancer, interstitial lung disease (ILD) and calcinosis based on MSA.

METHODS

A 3.5-year multicentre prospective study of adult DM patients was conducted to determine the clinical phenotype associated with MSAs and the presence of cancer, ILD and calcinosis.

RESULTS

MSAs were detected in 47.1% of 117 included patients. Patients with antimelanoma differentiation-associated protein-5 antibodies (13.7%) had significantly more palmar violaceous macules/papules [odds ratio (OR) 9.9], mechanic's hands (OR 8), cutaneous necrosis (OR 3.2), articular involvement (OR 15.2) and a higher risk of ILD (OR 25.3). Patients with antitranscriptional intermediary factor-1 antibodies (11.1%), antinuclear matrix protein-2 antibodies (6.8%) and antiaminoacyl-transfer RNA synthetase (5.1%) had, respectively, significantly more poikiloderma (OR 5.9), calcinosis (OR 9.8) and articular involvement (OR 15.2). Cutaneous necrosis was the only clinical manifestation significantly associated with cancer (OR 3.1).

CONCLUSION

Recognition of the adult DM phenotype associated with MSAs would allow more accurate appraisal of the risk of cancer, ILD and calcinosis.

Dermatomyositis and Immune-Mediated Necrotizing Myopathies: A Window on Autoimmunity and Cancer

Autoimmune myopathies (myositides) are strongly associated with malignancy. The link between myositis and cancer, originally noticed by Bohan and Peter in their classification in 1975 (1), has been evidenced by large population-based cohort studies and a recent meta-analysis. The numerous reports of cases in which the clinical course of myositis reflects that of cancer and the short delay between myositis and cancer onset support the notion that myositis may be an authentic paraneoplastic disorder. Thus, cancer-associated myositis raises the question of cancer as a cause rather than a consequence of autoimmunity. Among myositides, dermatomyositis and more recently, although to a lesser extent, immune-mediated necrotizing myopathies are the most documented forms associated with cancer. Interestingly, the current diagnostic approach for myositis is based on the identification of specific antibodies where each antibody determines specific clinical features and outcomes. Recent findings have shown that the autoantibodies anti-TIF1γ, anti-NXP2 and anti-HMGCR are associated with cancers in the course of myositis. Herein, we highlight the fact that the targets of these three autoantibodies involve cellular pathways that intervene in tumor promotion and we discuss the role of cancer mutations as autoimmunity triggers in adult myositis.

Clinical characteristics of anti-SAE antibodies in Chinese patients with dermatomyositis in comparison with different patient cohorts

This study aimed to analyze the clinical features of anti-SAE antibodies in Chinese myositis patients in comparison with different cohorts. The anti-SAE antibodies were tested in myositis patients and in control subjects. Long-term follow-up was conducted on the antibody-positive patients. Anti-SAE antibodies were exclusively present in 12 out of 394 (3.0%) adult dermatomyositis (DM) patients. Of the anti-SAE-positive DM patients, 75% had distinctive diffuse dark-red or pigment-like skin rashes, and 67% of these patients experienced mild muscle weakness. Muscular biopsies showed mild pathological manifestations. Compared with the antibody-negative group, the average age of dermatomyositis onset in the antibody-positive group was higher, and dysphagia occurred more frequently noted (p = 0.012). Only 9 patients received follow-up, 7 experienced improvement after treatment. The anti-SAE antibody levels correlated with improved disease condition. The anti-SAE antibody was found exclusively in adult DM patients, occurring infrequently in Chinese patients. In addition to a diffuse dark-red or pigment-like skin rash and mild muscular weakness, common symptoms included propensity for developing dysphagia. Serum levels of the anti-SAE antibody correlated with myositis disease activity, and anti-SAE-positive patients were responsive to treatment.

Cutaneous Manifestations in Dermatomyositis: Key Clinical and Serological Features-a Comprehensive Review

Dermatomyositis (DM) is a common idiopathic inflammatory myopathy. The pathogenesis is considered to be microangiopathy affecting skin and muscle. The cutaneous manifestations of DM are the most important aspect of this disease, and their correct evaluation is important for early diagnosis. The skin signs are various: Some are pathognomonic or highly characteristic, and others are compatible with DM. Recently, DM has been categorized into several disease subsets based on the various autoantibodies present in patients. Sometimes, characteristic cutaneous manifestations are strongly associated with the presence of specific autoantibodies. For example, anti-Mi-2 antibody is associated with the classic features of DM, including heliotrope rash, Gottron's papules, the V-neck sign, the shawl sign, cuticular overgrowth, and photosensitivity. Frequent cutaneous features in anti-transcriptional intermediary factor 1 gamma (TIF1γ)-positive patients are diffuse photoerythema, including "dusky red face," while skin ulcerations, palmar papules (inverse Gottron), diffuse hair loss, panniculitis, and oral pain and/or ulcers are sometimes associated with anti-melanoma differentiation-associated gene 5 product (MDA5) antibody. Here, we review important cutaneous manifestations seen in patients with DM, and we examine the relationship between the skin changes and myositis-associated autoantibodies. Correct evaluation of cutaneous manifestations and myositis-associated autoantibodies should help the clinician in the early diagnosis of DM, for a quick recognition of cutaneous signs that may be the symptom of onset before muscle inflammation.

A Comprehensive Overview on Myositis-Specific Antibodies: New and Old Biomarkers in Idiopathic Inflammatory Myopathy

Autoantibodies specific for idiopathic inflammatory myopathy (myositis-specific autoantibodies (MSAs)) are clinically useful biomarkers to help the diagnosis of polymyositis/dermatomyositis (PM/DM). Many of these are also associated with a unique clinical subset of PM/DM, making them useful in predicting and monitoring certain clinical manifestations. Classic MSAs known for over 30 years include antibodies to Jo-1 (histidyl transfer RNA (tRNA) synthetase) and other aminoacyl tRNA synthetases (ARS), anti-Mi-2, and anti-signal recognition particle (SRP). Anti-Jo-1 is the first autoantibodies to ARS detected in 15-25 % of patients. In addition to anti-Jo-1, antibodies to seven other aminoacyl tRNA synthetases (ARS) have been reported with prevalence, usually 1-5 % or lower. Patients with any anti-ARS antibodies are associated with anti-synthetase syndrome characterized by myositis, interstitial lung disease (ILD), arthritis, Raynaud's phenomenon, and others. Several recent studies suggested heterogeneity in clinical features among different anti-ARS antibody-positive patients and anti-ARS may also be found in idiopathic ILD without myositis. Anti-Mi-2 is a classic marker for DM and associated with good response to steroid treatment and good prognosis. Anti-SRP is specific for PM and associated with treatment-resistant myopathy histologically characterized as necrotizing myopathy. In addition to classic MSAs, several new autoantibodies with strong clinical significance have been described in DM. Antibodies to transcription intermediary factor 1γ/α (TIF1γ/α, p155/140) are frequently found in DM associated with malignancy while anti-melanoma differentiation-associated gene 5 (MDA5; CADM140) are associated with clinically amyopathic DM (CADM) complicated by rapidly progressive ILD. Also, anti-MJ/nuclear matrix protein 2 (NXP-2) and anti-small ubiquitin-like modifier-1 (SUMO-1) activating enzyme (SAE) are recognized as new DM-specific autoantibodies. Addition of these new antibodies to clinical practice in the future will help in making earlier and more accurate diagnoses and better management for patients.

Pulmonary arterial hypertension in idiopathic inflammatory myopathies: Data from the French pulmonary hypertension registry and review of the literature

Occurrence of pulmonary arterial hypertension (PAH) in idiopathic inflammatory myopathies (IIMs) without extensive interstitial lung disease (ILD) has rarely been described in the medical literature. This study aimed to report all cases with association of PAH and IIM in the French Pulmonary Hypertension (PH) Registry, to identify IIM features associated with the presence of PAH, and to describe treatment modalities of these patients.All cases of IIM-PAH were retrieved from the French PH Registry, which gathers PH patients prospectively enrolled by 27 referral hospital centers across France. Patients were excluded if they had an extensive ILD or overlap syndrome. Characteristics of IIM-PAH patients were compared with a control group of IIM patients without PH.Among the 5223 PH patients in the Registry, 34 had a diagnosis of IIM. Among them, 3 IIM-PAH patients (2 females and 1 male) had no evidence of extensive ILD or overlap syndrome, and were included in this study. In these 3 patients, dermatomyositis (DM) was the only identified IIM. One patient had autoantibodies classically associated with IIM (anti-Ku). PAH had always developed after IIM onset, was severe in all cases, and led to a marked functional impairment.By pooling our cases with 6 patients previously reported in the literature, and comparing them with a control cohort of 35 IIM patients without PH, we identify several IIM characteristics possibly associated with PAH occurrence, including DM subtype (78% vs 46%; P = 0.02), skin involvement (P = 0.04), anti-SSA antibodies (P = 0.05), and peripheral microangiopathy (P = 0.06).Overall, IIM-PAH patients were managed by corticosteroids and/or immunosuppressants, either alone or combined with PAH therapy. Patients did not seem to respond to IIM treatment alone.Our study reports for the first time the rare but possible association of PAH and IIM in a large prospective PH Registry. In that setting, PAH seems associated with DM, skin involvement, peripheral microangiopathy, and anti-SSA positivity. The best therapeutic strategy for IIM-PAH remains to be defined.

Comparing and contrasting clinical and serological features of juvenile and adult-onset myositis: implications for pathogenesis and outcomes

PURPOSE OF REVIEW

To explore the different characteristics of the serological phenotypes identified in juvenile and adult myositis, consider how differences between the two groups might be explained and discuss how this enhances our understanding of disease pathogenesis.

RECENT FINDINGS

Current research has focussed on two main areas: first, defining the autoantibody associated disease phenotype in greater detail, particularly with regard to cutaneous disease and within specified populations such as juvenile-onset disease and different ethnic groups, and second, we have gained new insights into disease pathogenesis through studies analysing genetic associations and autoantigen expression.

SUMMARY

Although there are many clinically important differences between adult and juvenile-onset myositis, recent work has highlighted many of the similarities at least within autoantibody-defined subgroups. Viewing age at disease onset as a continuum with its own influence on disease phenotype strengthens the ability of autoantibodies to define homogenous disease groups, and may be important in understanding the relationship between autoantibodies and disease pathogenesis.

Myositis-specific autoantibodies: an important tool to support diagnosis of myositis

The idiopathic inflammatory myopathies are characterized by muscle weakness, skin disease and internal organ involvement. Autoimmunity is known to have a role in myositis pathogenesis, and myositis-specific autoantibodies, targeting important intracellular proteins, are regarded as key biomarkers aiding in the diagnosis of patients. In recent years, a number of novel myositis autoantibodies including anti-TIF1, anti-NXP2, anti-MDA5, anti-SAE, anti-HMGCR and anti-cN1A have been identified in both adult and juvenile patients. These autoantibodies correlate with distinct clinical manifestations and importantly are found in inclusion body, statin-induced, clinically amyopathic and juvenile groups of myositis patients, previously believed to be mainly autoantibody negative. In this review, we will describe the main myositis-specific and myositis-associated autoantibodies and their frequencies and clinical associations across different ages and ethnic groups. We will also discuss preliminary studies investigating correlations between specific myositis autoantibody titres and clinical markers of disease course, collectively demonstrating the utility of myositis autoantibodies as both diagnostic and prognostic markers of disease.

Autoimmune Myopathies: Where Do We Stand?

Autoimmune diseases (AIDs) as a whole represent a major health concern and remain a medical and scientific challenge. Some of them, such as multiple sclerosis or type 1 diabetes, have been actively investigated for many decades. Autoimmune myopathies (AIMs), also referred to as idiopathic inflammatory myopathies or myositis, represent a group of very severe AID for which we have a more limited pathophysiological knowledge. AIM encompass a group of, individually rare but collectively not so uncommon, diseases characterized by symmetrical proximal muscle weakness, increased serum muscle enzymes such as creatine kinase, myopathic changes on electromyography, and several typical histological patterns on muscle biopsy, including the presence of inflammatory cell infiltrates in muscle tissue. Importantly, some AIMs are strongly related to cancer. Here, we review the current knowledge on the most prevalent forms of AIM and, notably, the diagnostic contribution of autoantibodies.

Clinical significance and new detection system of autoantibodies in myositis with interstitial lung disease

Anti-aminoacyl-tRNA synthetase (ARS) and anti-melanoma differentiation-associated gene 5 ( MDA5) antibodies are closely associated with interstitial lung disease in polymyositis and dermatomyositis. Anti-ARS-positive patients develop common clinical characteristics termed anti-synthetase syndrome and share a common clinical course, in which they respond well to initial treatment with glucocorticoids but in which disease tends to recur when glucocorticoids are tapered. Anti- MDA5 antibody is associated with rapidly progressive interstitial lung disease and poor prognosis, particularly in Asia. Therefore, intensive immunosuppressive therapy is required for anti- MDA5-positive patients from the early phase of the disease. New enzyme-linked immunosorbent assays to detect anti-ARS and anti- MDA5 antibodies have recently been established and are suggested to be efficient and useful. These assays are expected to be widely applied in daily practice.

Autoimmunity in 2013

The peer-reviewed publications in the field of autoimmunity published in 2013 represented a significant proportion of immunology articles and grew since the previous year to indicate that more immune-mediated phenomena may recognize an autoimmune mechanism and illustrated by osteoarthritis and atherosclerosis. As a result, our understanding of the mechanisms of autoimmunity is becoming the paradigm for translational research in which the progress in disease pathogenesis for both tolerance breakdown and inflammation perpetuation is rapidly followed by new treatment approaches and clinical management changes. The similarities across the autoimmune disease spectrum outnumber differences, particularly when treatments are compared. Indeed, the therapeutics of autoimmune diseases are based on a growing armamentarium that currently includes monoclonal antibodies and small molecules which act by targeting molecular markers or intracellular mediators with high specificity. Among the over 100 conditions considered as autoimmune, the common grounds are well illustrated by the data reported for systemic lupus erythematosus and rheumatoid arthritis or by the plethora of studies on Th17 cells and biomarkers, particularly serum autoantibodies. Further, we are particularly intrigued by studies on the genomics, epigenetics, and microRNA at different stages of disease development or on the safe and effective use of abatacept acting on the costimulation of T and B cells in rheumatoid arthritis. We are convinced that the data published in 2013 represent a promising background for future developments that will exponentially impact the work of laboratory and clinical scientists over the next years.

The evolving spectrum of polymyositis and dermatomyositis--moving towards clinicoserological syndromes: a critical review

The idiopathic inflammatory myopathies: polymyositis (PM) and dermatomyositis (DM) have been historically defined by broad clinical and pathological criteria. These conditions affect both adults and children with clinical features including muscle weakness, skin disease and internal organ involvement. Over the last few years, it has become increasingly apparent that using a clinico-serological approach, both DM and PM can be defined into more homogeneous subsets. A large number of antibodies are directed against cytoplasmic or nuclear components involved in key regulatory intra-cellular processes including protein synthesis, translocation and gene transcription within this disease spectrum. In addition, these autoantibodies are found in patients with clinical features other than myositis, in particular 'idiopathic' interstitial pneumonia emphasizing that these patients may in fact be a formes-frustes of autoimmune connective tissue disease. Other important findings are the identification of specific autoantibodies in both cancer-associated dermatomyositis, clinically amyopathic dermatomyositis and juvenile dermatomyositis, which previously were classically described as antibody-negative clinical subsets. Finally, work has highlighted how target autoantigens identified in the myositis-connective tissue disease overlap share common cellular mechanisms, which provides us with further insights into disease pathogenesis.