Myositis autoantibodies in Korean patients with inflammatory myositis: anti-140-kDa polypeptide antibody is primarily associated with rapidly progressive interstitial lung disease independent of clinically amyopathic dermatomyositis

Diagnosis and Management of Myositis-Associated Lung Disease

Although interstitial lung disease (ILD) is a leading cause of morbidity and mortality in patients with inflammatory myopathies, the current definition and diagnostic criteria of autoimmune myositis remain inadequate to capture the large proportion of patients with lung-dominant disease. As a result, these patients present unique diagnostic and treatment challenges for even the most experienced clinicians. This article highlights the emerging role of autoantibodies in the diagnosis, classification, and management of patients with ILD. We propose alternative nomenclature to facilitate research on this unique patient population. Additionally, evidence supporting the various therapies used in the treatment of myositis-associated ILD is reviewed. The classification and treatment of patients with myositis-associated ILD remains challenging. A standardized therapeutic approach to these patients is lacking, and prospective studies in the field are needed to determine optimal treatment regimens.

A systematic review and meta-analysis to inform cancer screening guidelines in idiopathic inflammatory myopathies

Objectives

To identify clinical factors associated with cancer risk in the idiopathic inflammatory myopathies (IIMs) and to systematically review the existing evidence related to cancer screening.

Methods

A systematic literature search was carried out on Medline, Embase and Scopus. Cancer risk within the IIM population (i.e. not compared with the general population) was expressed as risk ratios (RR) for binary variables and weighted mean differences (WMD) for continuous variables. Evidence relating to cancer screening practices in the IIMs were synthesized via narrative review.

Results

Sixty-nine studies were included in the meta-analysis. DM subtype (RR 2.21), older age (WMD 11.19), male sex (RR 1.53), dysphagia (RR 2.09), cutaneous ulceration (RR 2.73) and anti-transcriptional intermediary factor-1 gamma positivity (RR 4.66) were identified as being associated with significantly increased risk of cancer. PM (RR 0.49) and clinically amyopathic DM (RR 0.44) subtypes, Raynaud’s phenomenon (RR 0.61), interstitial lung disease (RR 0.49), very high serum creatine kinase (WMD −1189.96) or lactate dehydrogenase (WMD −336.52) levels, and anti-Jo1 (RR 0.45) or anti-EJ (RR 0.17) positivity were identified as being associated with significantly reduced risk of cancer. Nine studies relating to IIM-specific cancer screening were included. CT scanning of the thorax, abdomen and pelvis appeared to be effective in identifying underlying asymptomatic cancers.

Conclusion

Cancer risk factors should be evaluated in patients with IIM for risk stratification. Screening evidence is limited but CT scanning could be useful. Prospective studies and consensus guidelines are needed to establish cancer screening strategies in IIM patients.

Geographical Latitude Remains as an Important Factor for the Prevalence of Some Myositis Autoantibodies: A Systematic Review

The idiopathic inflammatory myopathies (IIM) are characterized by muscular weakness, cutaneous manifestations, muscle damage revealed by increase of muscular enzymes, muscle biopsy, electromyography and changes on magnetic resonance imaging. However, the hallmark of these IIM, is the development of myositis specific antibodies (MSA) or myositis associated antibodies (MAA). The theories about their presence in the serum of IIM is not known. Some studies have suggested that some of these MSA, such as anti-Mi-2 increases according to the intensity of UV radiation. There is scarce information about the environmental factors that might contribute in order to be considered as triggering factors as UV radiation might be. In this review, we analyzed the reported prevalence of MSAs and MAAs regarding to their geographical location and the possible relation with UV radiation. We collected the prevalence data of fifteen MSA and thirteen MAA from 22 countries around the world and we were able to observe a difference in prevalence between countries and continents. We found differences in anti-PL7, anti-Ro52, anti-La and anti-Ku prevalence according to UV radiation level. Otherwise, we observed that anti-Mi-2 prevalence increases near to the Equator meanwhile anti-MJ/NXP2 and anti-ARS prevalence had an opposite behavior increasing their prevalence in the geographical locations farther to the Equator. Our results highlighted the importance to include the UV radiation and other environmental factors in IIM studies, in order to clarify its association with MSA and MAA prevalence as well as its possible role in the immunopathogenesis of these diseases.

Understanding and managing anti-MDA 5 dermatomyositis, including potential COVID-19 mimicry

Anti-Melanoma Differentiation-Associated gene 5 (MDA-5) Dermatomyositis (MDA5, DM) is a recently identified subtype of myositis characteristically associated with Rapidly Progressive Interstitial Lung Disease (RP-ILD) and unique cutaneous features. We reviewed PubMed, SCOPUS and Web of Science databases and selected 87 relevant articles after screening 1485 search results, aiming to gain a better understanding of the pathophysiology, clinical features, diagnosis, and treatment approaches of anti-MDA-5 DM described in the literature. The etiopathogenesis is speculatively linked to an unidentified viral trigger on the background of genetic predisposition culminating in an acquired type I interferonopathy. The clinical phenotype is highly varied in different ethnicities, with new clinical features having been recently described, expanding the spectrum of cases that should raise the suspicion of anti-MDA-5 DM. Unfortunately, the diagnosis is frequently missed despite excessive mortality, calling for wider awareness of suspect symptoms. RP ILD is the major determinant of survival, treatment being largely based on observational studies with recent insights into aggressive combined immunosuppression at the outset.

Pharmacological Interventions for Pulmonary Involvement in Rheumatic Diseases

Among the diverse forms of lung involvement, interstitial lung disease (ILD) and pulmonary arterial hypertension (PAH) are two important conditions in patients with rheumatic diseases that are associated with significant morbidity and mortality. The management of ILD and PAH is challenging because the current treatment often provides only limited patient survival benefits. Such challenges derive from their common pathogenic mechanisms, where not only the inflammatory processes of immune cells but also the fibrotic and proliferative processes of nonimmune cells play critical roles in disease progression, making immunosuppressive therapy less effective. Recently, updated treatment strategies adopting targeted agents have been introduced with promising results in clinical trials for ILD ad PAH. This review discusses the epidemiologic features of ILD and PAH among patients with rheumatic diseases (rheumatoid arthritis, myositis, and systemic sclerosis) and the state-of-the-art treatment options, focusing on targeted agents including biologics, antifibrotic agents, and vasodilatory drugs.

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.

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.

Analysis of myositis autoantibodies in Chinese patients with cancer-associated myositis

Background

Cancer‐associated myositis (CAM) has poor prognosis and causes higher mortality. In general, myositis‐specific autoantibodies (MSAs) and myositis‐associated autoantibodies (MAAs) have been shown to be useful biomarkers for its diagnosis.

Methods

In the present study, focus was given in assessing the presence, prevalence, and diagnostic values of myositis autoantibodies in Chinese patients diagnosed with CAM. The sera collected from 49 CAM patients, 108 dermatomyositis/polymyositis (DM/PM) patients without cancer, 105 disease controls, and 60 healthy controls were detected for the presence of 16 autoantigens (Jo‐1, OJ, EJ, PL‐7, PL‐12, MDA5, TIF1γ, Mi‐2α, Mi‐2β, SAE1, NXP2, SRP, Ku, PM‐Scl75, PM‐Scl100, and Ro‐52) using a commercial Euroline assay.

Results

The frequency of anti‐TIF1γ was significantly higher in CAM patients than in DM/PM patients without cancer (46.9% vs 14.8%, P < .001). Importantly, the sensitivity and specificity for this MSA were 46.9% and 85.2%, respectively. These helped to differentiate CAM patients from DM/PM patients without cancer. However, there was no difference in other MSAs and MAAs between CAM and DM/PM patients without cancer.

Conclusion

The present study indicates that anti‐TIF1γ levels can serve as important biomarkers for CAM diagnosis and help in distinguishing between CAM and DM/PM patients without cancer.

Autoantibody Biomarkers in Rheumatic Diseases

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

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.

Novel susceptibility alleles in HLA region for myositis and myositis specific autoantibodies in Korean patients

OBJECTIVES

HLA genes are a major genetic risk factor for myositis and myositis specific antibodies (MSAs), exhibiting unique HLA backgrounds for myositis in different ethnic groups. This is the first large scale Korean study to genotype the HLA-DRB1 and -DPB1 alleles and to examine their association with myositis and MSAs.

METHODS

HLA-DRB1 and HLA-DPB1 alleles and MSAs were examined in 179 patients with dermatomyositis (DM, n = 129) or polymyositis (PM, n = 50) and healthy controls (n = 800 for HLA-DRB1, n = 548 for HLA-DPB1). Associations between individual HLA alleles and myositis/MSA were examined. Bonferroni correction was applied for multiple testing comparing patients and controls.

RESULTS

A total of 33 HLA-DRB1 and 24 HLA-DPB1 alleles were genotyped in patients and controls. MSAs were found in 67.0% of patients. Anti-MDA5 (26.8%) and anti-aminoacyl-tRNA synthetase antibodies (15.6%) were most common, followed by anti-Mi2 (9.5%) and anti-TIF1γ antibodies (8.9%). HLA-DRB1*12:02 and HLA-DRB1*14:03 were associated with DM and PM, respectively. HLA-DRB1*12:02 was associated with anti-MDA5, HLA-DRB1*08:03 with anti-ARS, HLA-DRB1*14:03 with anti-SRP, and HLA-DRB1*07:01 with anti-Mi2 antibodies. Although HLA-DRB1*13:01 was associated with anti-TIF1γ antibodies, the frequency of HLA-DRB1*13:01 was rare. HLA-DPB1*02:01 was negatively associated with myositis and PM while HLA-DPB1*17:01 was associated with anti-Mi2 positive DM.

CONCLUSIONS

Unique immunogenetic background was observed for Korean patients with myositis. Novel myositis susceptibility alleles, HLA-DRB1*12:02 and HLA-DRB1*14:03, were identified, together with MSA-associated HLA alleles unique to Korean patients with myositis.

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.

Juvenile Clinically Amyopathic Dermatomyositis: A Case Report and Review of Literature

Juvenile clinically amyopathic dermatomyositis (juvenile CADM) is a rare rheumatologic disease in children defined as the presence of the hallmark cutaneous features of dermatomyositis in absence of muscle involvement. In this article, we report an Iranian 14.5-year-old girl presented to Rheumatology Clinic of Mofid Children's Hospital, Tehran, Iran in Jan 2016 with cutaneous complaints diagnosed with juvenile CADM. Finally, we provide a literature review of previous studies on juvenile CADM.

Myositis-specific autoantibodies in dermatomyositis/polymyositis with interstitial lung disease

AIM

The prevalence and diagnostic values of myositis-specific autoantibodies (MSAs) and myositis-associated autoantibodies (MAAs) in dermatomyositis/polymyositis (DM/PM) were studied.

METHOD

A commercial immunoblot assay with 16 autoantigens was used to detect MSAs and MAAs in serum samples from 130 DM/PM patients, 100 disease controls, and 50 healthy subjects.

RESULTS

The prevalence of anti-Jo-1, anti-MDA5, anti-TIF1γ, anti-Mi-2α, and anti-Mi-2β was significantly higher in DM/PM than in other connective-tissue diseases (CTDs). Moreover, anti-MDA5 and anti-Ro-52 were significantly higher in DM/PM with interstitial lung disease (ILD) than in DM/PM without ILD, while that of anti-TIF1γ and anti-NXP2 were significantly lower in DM/PM with ILD than in DM/PM without ILD. For distinguishing DM/PM from other CTDs, the sensitivity, specificity, and positive predictive value (PPV) for anti-MDA5 were 28.46, 99.00, and 97.37%, respectively, with a positive likelihood ratio (LR+) of 28.46; they were 46.15, 58.00, and 58.82%, respectively, for anti-Ro-52 with an LR+ of 1.10. For distinguishing DM/PM with ILD from DM/PM without ILD, the sensitivity, specificity, and PPV for anti-MDA5 were 45.57, 100.00, and 100.00%, respectively, and for anti-Ro-52 were 60.76, 73.91, and 80.00%, respectively.

CONCLUSION

MSAs and MAAs serve as biomarkers for differentiating DM/PM from other CTDs as well as distinguishing DM/PM with ILD from DM/PM without ILD.

Recurrence of anti-MDA5 antibody-positive clinically amyopathic dermatomyositis after long-term remission: A case report

RATIONALE

Among all dermatomyositis (DM) patients, antimelanoma differentiation-associated gene 5 antibody (anti-MDA5 Ab) positive patients have significantly poor short-term mortality, whereas they experience less relapses over the long term after the remission. We report the case of a patient with anti-MDA5 Ab-positive clinically amyopathic dermatomyositis (CADM) with the recurrence of interstitial lung disease (ILD) after 7 years of remission. There has been no case report of an anti-MDA5 Ab-positive DM patient with the recurrence of ILD after 7 years of long-term remission.

PATIENT CONCERNS

A 70-year-old Japanese woman was diagnosed with anti-MDA5 Ab-positive CADM and ILD. After achieving 7 years long-term remission, she was admitted to our department with erythema on the fingers and interstitial pneumonia. Her anti-MDA5 Ab titer was elevated.

DIAGNOSES

We diagnosed recurrent CADM complicated with ILD.

INTERVENTIONS

We successfully treated her with 1,000 mg of methyl-prednisolone pulse and intravenous cyclophosphamide therapy followed by prednisolone 50 mg/day and an increase of cyclosporine.

OUTCOMES

After that treatment, the patient's skin symptoms and interstitial pneumonia were relieved. All laboratory investigations such as ferritin, the serum markers of interstitial pneumonia (i.e., SP-A, SP-D), and the titer of anti-MDA5 Ab showed signs of improvement.

LESSONS

Her case suggests that careful physical examinations and monitoring the serum markers are important even after long-term remission is achieved.

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.

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.

Anti-melanoma differentiation-associated gene 5 (MDA5) dermatomyositis: A concise review with an emphasis on distinctive clinical features

Melanoma differentiation-associated gene 5 (MDA5) is a recently described autoantigen target in a subset of patients with dermatomyositis. Anti-MDA5 dermatomyositis is characterized by a unique mucocutaneous and systemic phenotype that includes cutaneous and oral ulceration, painful palmar papules, alopecia, panniculitis, arthritis, a lower incidence of myositis, and, importantly, an elevated risk of interstitial lung disease with a potentially fatal course. Because the clinical features can differ substantially from those typically observed in cutaneous dermatomyositis, the diagnosis is often overlooked, which might negatively affect patient outcomes. This review aims to familiarize the clinician with the distinctive clinical features of anti-MDA5 dermatomyositis in order to enhance its recognition and to facilitate an appropriate screening and management strategy.

Assessment of anti-MDA5 antibody as a diagnostic biomarker in patients with dermatomyositis-associated interstitial lung disease or rapidly progressive interstitial lung disease

Anti-melanoma differentiation-associated protein 5 (MDA5) antibody have been found in dermatomyositis (DM)-associated interstitial lung disease (DM-ILD) and DM-associated rapidly progressive ILD (DM-RPILD). Due to the conflicting results regarding the association between anti-MDA5 antibody and DM-ILD or DM-RPILD and the diagnostic value of this antibody for DM-ILD and DM-RPILD, we performed this meta-analysis. A systematic search was performed to identify studies published to January 14, 2017. Sixteen publications with 491 DM with ILD versus 605 DM without ILD, as well as eighteen publications with 186 DM with RPILD and 790 DM without RPILD were included. The pooled sensitivity, specificity, and area under the curve (AUC) values of anti-MDA5 antibody for DM-ILD were 0.47 (95% CI: 0.37-0.57), 0.96 (95% CI, 0.92-0.97), and 0.90 (95% CI: 0.88-0.93), respectively, with a low sensitivity value. The pooled sensitivity, specificity, and AUC values were 0.83 (95% CI: 0.77-0.88), 0.86 (95% CI: 0.80-0.91), and 0.87 (95% CI: 0.84-0.90) for DM with RPILD versus without RPILD with good sensitivity and specificity values. Trial sequential analysis showed sufficient evidence to support that anti-MDA5 antibody was associated with DM-ILD and DM-RPILD. The statistical power of this study calculated using G*Power version 3.1.9.2 was more than 99% (α = 0.05). Taken together, these findings suggest that anti-MDA5 antibody has a potential useful ability as a noninvasive biomarker in the diagnosis of RPILD in patients with DM.

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.

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.

Temporal relationship between cancer and myositis identifies two distinctive subgroups of cancers: impact on cancer risk and survival in patients with myositis

OBJECTIVES

The aim was to compare standardized incidence ratios (SIRs) of cancers temporally related and unrelated to active myositis in patients with myositis.

METHODS

Fifty-two cancer cases were identified in 281 myositis patients. SIRs of cancers having temporal overlap with the active phase of myositis [cancers concurrent with active myositis (CAM), n = 30] and cancers not having such temporal overlap [cancers non-concurrent with active myositis (CNM), n = 22] were compared in 281 patients.

RESULTS

Patients with CAM were older at diagnosis of myositis, had a greater tendency to be male, more frequent dysphagia and less frequent interstitial lung disease than patients with CNM. CAM SIR (95% CI) was 1.78 (1.19, 2.56) and CNM SIR 1.23 (0.75, 1.90). The peak SIR was observed in the seventh decade of life for CAM and in the third decade for CNM. When stratified by myositis-cancer intervals, CAM SIR was 9.94 (6.43, 14.67) within 1 year of myositis diagnosis, whereas no temporal relationship was found for CNM. Elevated SIRs were observed for oesophageal cancer [57.77 (11.91, 168.82)], non-Hodgkin's lymphoma [41.43 (13.45, 96.69)], adenocarcinoma of unknown primary origin [67.6 (18.42, 173.07]), lung cancer [7.27 (1.98, 18.61)] and ovarian cancer [19.15 (2.32, 69.17)] within 3 years of CAM diagnosis. The cancer stage at the time of diagnosis was more advanced in CAM than CNM (P < 0.001), with a correspondingly increased hazard ratio of mortality [4.3 (1.5, 12.7)] in patients with CAM vs CNM.

CONCLUSION

A significantly elevated SIR was found for CAM, whereas there was a comparable SIR for CNM relative to the general population. Multiple types of cancers showed elevated SIRs among CAM, but none among CNM. Given that cancer stages in CAM were far advanced at diagnosis, mortality risk was greater in patients with CAM.

Factors Associated with Interstitial Lung Disease in Patients with Polymyositis and Dermatomyositis: A Systematic Review and Meta-Analysis

OBJECTIVES

Interstitial lung disease (ILD) is an extramuscular manifestation that results in increased morbidity and mortality from polymyositis (PM) and dermatomyositis (DM). The aim of this study was to systematically evaluate risk factors associated with the development of ILD in PM/DM.

METHODS

Observational studies were identified from searching PubMed, Medline, Embase, and the Cochrane Library. Pooled odds ratios (ORs) or standardized mean differences (SMDs) and corresponding 95% confidence intervals (CIs) were obtained for the relationships between risk factors and ILD in PM/DM using either fixed- or random-effects models, whichever were appropriate. Heterogeneity tests, sensitivity analyses, and publication bias assessments were also performed.

RESULTS

Twenty-three studies were selected for a meta-analysis that included 834 patients and 1245 control subjects. Risk factors that may have increased the risk of developing ILD in PM/DM patients included older age at diagnosis (SMD, 0.35; 95% CI, 0.18-0.52; P < 0.0001), arthritis/arthralgia (OR, 3.17; 95% CI, 1.99-5.04; P < 0.00001), fever (OR, 2.31; 95% CI, 1.42-3.76; P = 0.0007), presence of anti-Jo-1 antibodies (OR, 3.34; 95% CI, 2.16-5.16; P < 0.00001), elevated erythrocyte sedimentation rate (ESR; SMD, 0.48; 95% CI, 0.32-0.64; P < 0.00001), presence of anti-MDA5 antibodies (OR, 18.26; 95% CI, 9.66-34.51; P < 0.00001), and elevated C-reactive protein level (CRP; OR, 3.50; 95% CI, 1.48-8.28; P = 0.004). Meanwhile, malignancy (OR, 0.36; 95% CI, 0.18-0.72; P = 0.004) reduced the risk of developing ILD in PM/DM patients.

CONCLUSION

Our meta-analysis results suggest that the association between PM/DM and ILD may be due to such risk factors as older age at diagnosis, arthritis/arthralgia, fever, presence of anti-Jo-1 antibodies, elevated ESR, presence of anti-MDA5 antibodies, and elevated CRP level, while malignancy was associated with a reduced risk of developing ILD. Thus, these variables may be used to guide screening processes for ILD in patients with PM/DM.

Recent Treatment of Interstitial Lung Disease with Idiopathic Inflammatory Myopathies

Interstitial lung disease (ILD) is a prognostic factor for poor outcome in polymyositis (PM)/dermatomyositis (DM). The appropriate management of ILD is very important to improve the prognosis of patients with PM/DM. ILD activity and severity depend on the disease subtype. Therefore, clinicians should determine therapeutic strategies according to the disease subtype in each patient with PM/DM. Anti-melanoma differentiation-associated gene 5 antibody and hyperferritinemia predict the development and severity of rapidly progressive (RP) ILD, particularly in East Asian patients. Combination therapy with corticosteroids, intravenous cyclophosphamide pulse, and calcineurin inhibitors should be administered in RP-ILD. In contrast, patients with anti-aminoacyl-tRNA synthetase (ARS) show better responses to corticosteroids alone. However, ILDs with anti-ARS often display disease recurrence or become refractory to corticosteroid monotherapy. Recent studies have demonstrated that the administration of tacrolimus or rituximab in addition to corticosteroids may be considered in ILD patients with anti-ARS. Large-scale, multicenter randomized clinical trials should be conducted in the future to confirm that the aforementioned agents exhibit efficacy in ILD patients with PM/DM. The pathophysiology of ILD with PM/DM should also be elucidated in greater detail to develop effective therapeutic strategies for patients with ILD in PM/DM.

Diagnosis and treatment of clinically amyopathic dermatomyositis (CADM): a case series and literature review

The objective of this study was to report the clinical course of a cohort of patients with clinically amyopathic dermatomyositis (CADM) in correlation to the presence or absence of anti-melanoma differentiation-associated gene 5 (MDA-5) antibody. Five patients with CADM presented to our rheumatology unit between September 1, 2011 and March 31, 2014. We hereby present their clinical course, laboratory findings, imaging modalities, functional tests, and treatments regimens. Our cohort included five patients, with a mean age of 41.8 ± 17.7. Three patients, all anti-MDA-5 antibody positive, developed rapidly progressive interstitial lung disease (ILD) within 4.3 ± 4.5 months of presentation. Two of these patients succumbed to their disease within 30 months of diagnosis despite intensive immunosuppressive therapy. The third anti-MDA-5-positive patient with ILD is still stable, 20 months from disease onset, on massive combination therapy. One patient developed CADM associated with the anti-p155/140 antibody, a year after completing chemotherapy for non-seminomatous germ cell tumor. He presented with a benign clinical course with no evidence of ILD and no recurrence of malignancy after 20 months of follow-up. The fifth patient in our cohort, who is anti-MDA-5 negative and has no evidence of malignancy, also enjoys a benign clinical course. The presence of anti-MDA-5 antibodies in CADM patients is associated with rapidly progressive ILD and a poor prognosis. The serologic profile of patients with CADM should be routinely evaluated and integrated with clinical data in the management of these patients.

Distinctive cutaneous and systemic features associated with antitranscriptional intermediary factor-1γ antibodies in adults with dermatomyositis

BACKGROUND

Antibodies against transcriptional intermediary factor (TIF)-1γ are associated with malignancy in dermatomyositis (DM). Identification of clinical findings associated with anti-TIF-1γ antibodies in DM is a high priority for both patient diagnosis and risk assessment.

OBJECTIVE

We sought to define the clinical phenotype of patients with anti-TIF-1γ DM.

METHODS

Using a novel, sensitive, and specific assay for anti-TIF-1γ antibodies, we retrospectively tested plasma from 134 adult patients with DM and examined associations between anti-TIF-1γ antibodies and particular clinical and laboratory features.

RESULTS

In all, 55 (41%) patients had autoantibodies to TIF-1γ. Anti-TIF-1γ positive patients were less likely to have systemic features including interstitial lung disease, Raynaud phenomenon, and arthritis/arthralgia. Patients with TIF-1γ autoantibodies had more extensive skin involvement, and some patients manifested characteristic findings including palmar hyperkeratotic papules, psoriasis-like lesions and a novel finding of hypopigmented and telangiectatic ("red on white") patches.

LIMITATIONS

This was a retrospective study from a single tertiary referral center.

CONCLUSION

TIF-1γ is the most commonly targeted DM-specific autoantigen in adults in a large US cohort. Although these patients tend to have less systemic involvement, their skin disease is often extensive and characteristic. Recognition of cutaneous findings in anti-TIF-1γ positive patients may allow more accurate and timely diagnosis and effective treatment of patients with DM.

A case of sarcoidosis with interstitial lung disease mimicking clinically amyopathic dermatomyositis and rapidly progressive interstitial lung disease

Here, we report a patient with sarcoidosis who developed edematous erythema and interstitial lung disease. At the initial visit, clinically amyopathic dermatomyositis (CADM) with rapidly progressive interstitial lung disease (RP-ILD) was suspected because he had progressive dyspnea but no muscle weakness. The presence of anti-CADM-140/MDA5 autoantibodies was immediately assessed to facilitate a precise diagnosis, with negative results. Thereafter, skin and transbronchial lung biopsies revealed noncaseating granuloma with Langhans giant cells in both specimens, leading to a diagnosis of sarcoidosis. In this case, clinical features of skin and lung were unable to distinguish DM (including CADM) from sarcoidosis, but the lack of anti-CADM-140/MDA5 antibody was useful for differentiating CADM with RP-ILD mimicking sarcoidosis from bona fide sarcoidosis.

Clinical and laboratory features of fatal rapidly progressive interstitial lung disease associated with juvenile dermatomyositis

OBJECTIVE

Rapidly progressive interstitial lung disease (RP-ILD) is a rare but potentially fatal complication of JDM. The aim of this study was to establish markers for the prediction and early diagnosis of RP-ILD associated with JDM.

METHODS

The clinical records of 54 patients with JDM were retrospectively reviewed: 10 had RP-ILD (7 died, 3 survived), 19 had chronic ILD and 24 were without ILD. Routine tests included a high-resolution CT (HRCT) scan of the chest and measurement of serum levels of creatine phosphokinase, ferritin and Krebs von den Lungen-6 (KL-6). Anti-melanoma differentiation-associated gene 5 (MDA5) antibodies and IL-18 levels were measured by ELISA.

RESULTS

No differences were found in the ratio of juvenile clinically amyopathic DM between the three groups. Initial chest HRCT scan findings were variable and could not distinguish between RP-ILD and chronic ILD. Anti-MDA5 antibodies were positive in all 8 patients with RP-ILD and 10 of 14 with chronic ILD, but none of the patients without ILD. Serum levels of anti-MDA5 antibody, ferritin, KL-6 and IL-18 were significantly higher in the RP-ILD group than in the chronic ILD and non-ILD groups. Serum levels of IL-18 positively correlated with serum KL-6 (R = 0.66, P < 0.001).

CONCLUSION

High serum levels of IL-18, KL-6, ferritin and anti-MDA5 antibodies (e.g. >200 units by ELISA) are associated with RP-ILD. These can be used as an indication for early intensive treatment. Both alveolar macrophages and autoimmunity to MDA5 are possibly involved in the development of RP-ILD associated with JDM.

Identification of clinical features and autoantibodies associated with calcinosis in dermatomyositis

IMPORTANCE

Prior studies have estimated that up to 20% of adults with dermatomyositis (DM) have calcinosis, which can lead to significant morbidity. Identification of risk factors may provide a better understanding of the pathogenesis and ultimately therapy for this difficult clinical problem. Risk factors for calcinosis in adults with DM have not been extensively studied.

OBJECTIVES

To determine the prevalence of calcinosis and to identify associated clinical features in a cohort of extensively phenotyped adults with DM.

DESIGN, SETTING, AND PARTICIPANTS

A cross-sectional study of 126 patients diagnosed as having DM from January 1, 2006, through January 1, 2013, was performed. Patients were adults (≥18 years of age) attending the Stanford University Medical Center clinic.

MAIN OUTCOMES AND MEASURES

Calcinosis, defined as the presence of calcium deposition in the skin and subcutaneous tissues on physical examination.

RESULTS

Fourteen patients (11.1%) had calcinosis, with the extremities most commonly involved. Patients with vs those without calcinosis had a longer disease duration (median, 6.9 years; range, 2.4-18.1; vs median, 3.9 years; range, 0.2-19.2 years; P = .003) and more fingertip ulcers (50.0% vs 9.3%, P < .001). An association between calcinosis and both interstitial lung disease and anti-MDA-5 autoantibodies was identified, but this association did not persist in multivariate models that adjusted for fingertip ulcers. Fingertip ulcers and disease duration were strongly associated with calcinosis in all multivariate models, independent of the underlying autoantibody present. Autoantibodies to NXP-2 were associated with calcinosis (odds ratio, 15.52; 95% CI, 2.01-119.90), whereas anti-transcriptional intermediary factor 1-γ antibodies were protective (odds ratio, 0.2; 95% CI, 0.01-0.99) in multivariate analyses that adjusted for fingertip ulcers and other covariates.

CONCLUSIONS AND RELEVANCE

Calcinosis was a relatively uncommon clinical feature in our cohort of adults with DM. Our data suggest that calcinosis is positively associated with longer disease duration, fingertip ulcers, and NXP-2 autoantibodies and negatively associated with transcriptional intermediary factor 1-γ antibodies. A common vascular mechanism may underlie the development of both calcinosis and fingertip ulcers in patients with DM.

[Anti-NXP2-positive dermatomyositis associated with ulcerative colitis and celiac disease]

The authors discuss a rare case of a 25-year-old female patient having dermatomyositis associated with celiac disease and ulcerative colitis. The idiopathic inflammatory myopathies are systemic, chronic, immune-mediated diseases characterized by proximal, symmetrical muscle weakness. Many examples from the literature refer that celiac disease occurs more often in patients with myositis than in the general population, but its association with ulcerative colitis is a real rarity in the international literature.

Autoantibodies against TIF-1-γ and CADM-140 in Spanish patients with clinically amyopathic dermatomyositis (CADM): clinical significance and diagnostic utility

BACKGROUND

Patients with clinically amyopathic dermatomyositis (CADM) appear to be at risk for developing cancer and interstitial lung diseases, but population data to confirm this hypothesis are limited. Moreover, CADM presents cutaneous and histological findings that may overlap with subacute cutaneous lupus erythematosus (SCLE).

OBJECTIVES

To determine the association between myositis-specific autoantibodies, myositis-associated autoantibodies and CADM in Spanish patients. In addition, to study the usefulness of these autoantibodies in the differential diagnosis between CADM and SCLE.

METHODS

Serum samples were tested for myositis-specific autoantibodies and myositis-associated autoantibodies through immunoprecipitation and other standardized methods.

RESULTS

Anti-CADM-p140 and anti-p155 antibodies were the only myositis-specific autoantibodies found and were associated with interstitial lung diseases and cancer respectively. No myositis-associated autoantibodies were found in CADM. Moreover, clinical subsets and proportions seemed to differ from Asian cohorts, where anti-CADM-p140 is considered a CADM hallmark antibody and a risk factor for the development of interstitial lung disease. Interestingly, anti-SSA was highly associated with SCLE, whereas no myositis-specific autoantibodies were found in this entity.

LIMITATIONS OF THE STUDY

Association between CADM and myositis-specific autoantibodies and differences between CADM and SCLE were tested on a relatively small cohort of patients.

CONCLUSION

There is an association between cancer-associated myositis and interstitial lung diseases and their hallmark autoantibodies in our cohort. In addition, the combined determination of myositis-specific autoantibodies and SSA autoantibodies may help to accurately discriminate SCLE from CADM.

Factors predicting malignancy in patients with polymyositis and dermatomyostis: a systematic review and meta-analysis

Objective

To define potential factors that could predict concomitant neoplastic diseases in patients diagnosed with PM/DM, which could inform screening decisions.

Methods

Two researchers independently reviewed articles from Pubmed (MEDLINE), EMBASE, Cochrane Plus Library and ISI Web of Knowledge with no restrictions on study design or language. Given that some of the studies combined PM and DM patients as research subjects while others included only DM patients, data were subjected to meta-analyses for all combined PM/DM studies and studies that included only DM patients to obtain informative results.

Results

For PM/DM patients, the following factors are all associated with an increased risk of malignancy: older age, age greater than 45, male sex, dysphagia, cutaneous necrosis, cutaneous vasculitis, rapid onset of myostis (<4 weeks), elevated CK, higher ESR, higher CRP levels. Several factors were associated with lower-than-average risk, including the presence of ILD, arthritis/arthralgia, Raynaud's syndrome, or anti-Jo-1 antibody. For DM patients, results indicated an increased risk of malignancy with older age, male sex, the presence of cutaneous necrosis, elevated ESR (>35 mm/hr), higher CRP levels, or anti-p155 antibody. In addition, the presence of anti-ENA antibodies seem to be related to reduced risk of malignancy.

Conclusion

Awareness and implementation of early-stage cancer screening in PM/DM patients who have these identified factors – such as being older than 45, male sex, cutaneous necrosis, cutaneous vasculitis – are of crucial importance from public health and clinical perspectives and provide insight into the etiopathogenesis of CAM.

Anti-MDA5 antibodies in a large Mediterranean population of adults with dermatomyositis

A new myositis-specific autoantibody directed against melanoma differentiation-associated gene 5 (anti-MDA5) has been described in patients with dermatomyositis (DM). We report the clinical characteristics of patients with anti-MDA5 in a large Mediterranean cohort of DM patients from a single center, and analyze the feasibility of detecting this autoantibody in patient sera using new assays with commercially available recombinant MDA5. The study included 117 white adult patients with DM, 15 (13%) of them classified as clinically amyopathic dermatomyositis (CADM). Clinical manifestations were analyzed, with special focus on interstitial lung disease and its severity. Determination of anti-MDA5 antibodies was performed by a new ELISA and immunoblot technique. In sera, from 14 (12%) DM patients (8 CADM), MDA5 was recognized by ELISA, and confirmed by immunoblot. Eight of the 14 anti-MDA5-positive patients (57.14%) presented rapidly-progressive interstitial lung disease (RP-ILD) versus 3 of 103 anti-MDA5-negative patients (2.91%) (P < 0.05; OR: 44.4, 95% CI 9.3–212). The cumulative survival rate was significantly lower in anti-MDA5-positive patients than in the remainder of the series (P < 0.05). Patients with anti-MDA5-associated ILD presented significantly lower 70-month cumulative survival than antisynthetase-associated ILD patients. Among the cutaneous manifestations, only panniculitis was significantly associated with the presence of anti-MDA5 antibodies (P < 0.05; OR: 3.85, 95% CI 1.11–13.27). These findings support the reliability of using commercially available recombinant MDA5 for detecting anti-MDA5 antibodies and confirm the association of these antibodies with RP-ILD in a large series of Mediterranean patients with DM.

Most patients with cancer-associated dermatomyositis have antibodies to nuclear matrix protein NXP-2 or transcription intermediary factor 1γ

OBJECTIVE

Since dermatomyositis (DM) is associated with an increased risk of malignancy, accurate identification of patients likely to harbor cancers is important. Using immunoprecipitations from radiolabeled cell lysates, several groups recently showed that anti-transcription intermediary factor 1γ (anti-TIF-1γ) antibodies are associated with malignancy in DM. We undertook this study to develop sensitive, specific assays to detect antibodies against TIF-1γ and nuclear matrix protein NXP-2 and to evaluate their association with malignancy in DM.

METHODS

To detect anti-TIF-1γ antibodies, immunoprecipitations were performed using lysates made from HeLa cells overexpressing TIF-1γ, with detection by immunoblotting. Anti-NXP-2 antibodies were assayed by immunoprecipitation using (35) S-methionine-labeled NXP-2 generated by in vitro transcription/translation. We analyzed patient sera from DM cohorts seen at the Stanford University Dermatology Clinic (n = 111) and the Johns Hopkins Myositis Center (n = 102).

RESULTS

A total of 17% and 38% of patients had antibodies against NXP-2 and TIF-1γ, respectively. Reactivity against either NXP-2 or TIF-1γ identified 83% of patients with cancer-associated DM. In addition to older age and male sex, cancer was associated with antibodies to NXP-2 or TIF-1γ on multivariate analysis (odds ratio 3.78 [95% confidence interval 1.33-10.8]). Stratification by sex revealed that anti-NXP-2 was specifically associated with cancer in males (odds ratio 5.78 [95% confidence interval 1.35-24.7]).

CONCLUSION

These studies demonstrate that anti-NXP-2 and anti-TIF-1γ antibodies are frequent DM specificities (found in 55% of patients) and are present in most patients with cancer-associated DM.

Utility of anti-melanoma differentiation-associated gene 5 antibody measurement in identifying patients with dermatomyositis and a high risk for developing rapidly progressive interstitial lung disease: a review of the literature and a meta-analysis

OBJECTIVE

To assess the utility of anti-melanoma differentiation-associated gene 5 (anti-MDA5) antibody measurement for predicting a risk for developing rapidly progressive interstitial lung disease (RP-ILD) in patients with polymyositis/dermatomyositis (PM/DM).

METHODS

A single-center cohort of 64 consecutive Chinese patients with PM/DM was examined. Serum anti-MDA5 antibody was measured by enzyme-linked immunosorbent assay. For meta-analysis, we searched PubMed and the Institute for Scientific Information Web of Knowledge for original studies that measured anti-MDA5 antibodies in patients with PM/DM. We calculated pooled sensitivity, specificity, diagnostic odds ratio (DOR), and the summary receiver operating characteristic (sROC) curve.

RESULTS

In Chinese patients, anti-MDA5 antibodies were detected in 26 patients with classic DM or clinically amyopathic DM (CADM). Compared with anti-MDA5-negative patients, anti-MDA5-positive patients showed a higher prevalence of RP-ILD (P = 0.001). In a total of 233 patients with anti-MDA5 antibody, derived from 16 studies, a higher frequency of CADM was found in Japanese than in non-Japanese patients (74.7% versus 39.2%; P = 1.2 × 10(-7) ). Meta-analysis revealed that the pooled sensitivity and specificity of anti-MDA5 antibody for RP-ILD was 77% (95% confidence interval [95% CI] 64-87%) and 86% (95% CI 79-90%), respectively. The pooled DOR was 20.41 (95% CI 9.02-46.20) with a favorable area under the sROC curve of 0.89 (95% CI 0.63-0.98).

CONCLUSION

Detection of anti-MDA5 antibody is a valuable tool for identifying DM patients with a high risk for developing RP-ILD, but the distribution of classic DM and CADM in patients with this antibody varies among ethnic groups.

Anti-melanoma differentiation-associated protein 5-associated dermatomyositis: expanding the clinical spectrum

OBJECTIVE

Autoantibodies against melanoma differentiation-associated protein 5 (MDA-5) have been described in several Asian dermatomyositis (DM) cohorts, often associated with amyopathic DM and rapidly progressive interstitial lung disease (ILD). A recent study of a DM cohort seen at a US dermatology clinic reports that MDA-5 autoantibodies are associated with a unique cutaneous phenotype. Given the widening spectrum of clinical findings, we evaluated the clinical features of anti-MDA-5-positive patients seen at a US myositis referral center.

METHODS

One hundred sixty DM patients were screened for MDA-5 autoantibodies by immunoprecipitation and antibody titers were analyzed in longitudinal serum samples. Anti-MDA-5-positive patients were evaluated for the presence of additional myositis autoantibodies. Patient clinical characteristics were compared by retrospective chart review.

RESULTS

MDA-5 was targeted in 11 (6.9%) of 160 patients with DM. Of these, 9 presented with a symmetric polyarthropathy, 6 demonstrated overt clinical myopathy, and 8 had ILD. Eight anti-MDA-5-positive patients exhibited the clinical attributes of the antisynthetase syndrome in the absence of Jo-1 or other antisynthetase autoantibodies. MDA-5 autoantibody titers did not correlate with clinical course.

CONCLUSION

MDA-5 autoantibodies are found in DM patients presenting with a symmetric polyarthritis, clinically similar to rheumatoid arthritis. These patients often have features of the antisynthetase syndrome, but in the absence of antisynthetase autoantibodies. Most anti-MDA-5-positive patients had overt clinical myopathy and ILD. The latter, while occasionally severe, typically resolved with immunosuppressive therapy. In this cohort, the MDA-5 phenotype is frequently a clinical mimic of the antisynthetase syndrome and is not associated with rapidly progressive ILD.

A novel dermato-pulmonary syndrome associated with MDA-5 antibodies: report of 2 cases and review of the literature

Melanoma differentiation-associated protein 5 (MDA-5) is a novel autoantibody frequently characterized by interstitial lung disease and a distinct cutaneous phenotype with palmar papules, ulceration, and rash. Virtually all patients have underlying dermatomyositis, but many lack the characteristic clinical myopathy associated with it. In the setting of amyopathic disease, the absence of clinically available biomarkers or clear pathologic diagnosis can complicate effective prognostic and therapeutic intervention. Until recently the presence of MDA-5 antibody associated dermato-pulmonary syndrome was described only in Asian populations. We present 2 cases of MDA-5-associated dermato-pulmonary syndrome and provide a comprehensive review of available literature.