Diffuse pruritic erythema as a clinical manifestation in anti-SAE antibody-associated dermatomyositis: a case report and literature review

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.

Clinical features of anti-SAE1 antibody-positive myositis and interstitial lung disease: a multicenter, retrospective study in Taiwan

Introduction

The clinical characteristics of patients positive for anti-small ubiquitin-like modifier 1-activating enzyme subunit 1 (SAE1) antibodies and diagnosed with idiopathic inflammatory myopathies (IIMs) vary across different cohorts and ethnicities, particularly concerning interstitial lung disease (ILD). We aimed to assess the clinical utility of the line immunoblot assay (LIA) in detecting anti-SAE1 autoantibodies and evaluate the clinical relevance and chronology of ILD development in relation to SAE1 autoantibody positivity among Taiwanese patients.

Methods

We retrospectively conducted a population-based cohort analysis involving 6,496 patients who visited Chang Gung Memorial Health System across Taiwan from May 2018 to December 2021. Patients were assayed for myositis-specific autoantibodies (MSAs) and myositis-associated autoantibodies (MAAs) using the LIA method, and the antinuclear antibody (ANA) indirect immunofluorescence (IIF) method was used to evaluate ANA patterns. Of these, 70 SAE1-positive patients (1.08%) were included and followed up until December 2023. Associations with clinical characteristics and final diagnosis, particularly ILD, were assessed.

Results

Among the 70 SAE1-positive patients, 10 (14.3%) were strongly positive and 60 (85.7%) were weakly positive. In the strong positive group, 70% (7/10) were diagnosed with IIM, with most (5/7) showing a concordant ANA IIF pattern (speckled type). Six patients presented ILD either before (1/6) or after (5/6) IIM diagnosis; the majority (4/6) were classified as organizing pneumonia. The remaining 30.0% (3/10) had connective tissue disease (CTD) other than IIM without detectable ILD during follow-up, and none demonstrated a concordant ANA IIF pattern. In the weakly positive group, only 5.0% (3/60) had IIM and 3.3% (2/60) had ILD. The positive predictive value for strong positive SAE1 autoantibodies in diagnosing IIM was significantly higher than for weak positives (70.0% vs. 5.0%; p < 0.001).

Conclusions

The study suggests that strong positive SAE1 autoantibodies detected via LIA are more closely associated with IIM compared to weak positive results. A high prevalence of ILD was observed among strong positive Taiwanese patients, indicating the need for prompt screening. Patients with weak positive or discordant ANA IIF results may represent false positives with a lower ILD risk.

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.

Adverse cutaneous reaction to hydroxychloroquine in a patient with anti-SAE-1-positive dermatomyositis and a history of diffuse large B-cell lymphoma

This case report details the cutaneous findings of a patient with a history of diffuse B-cell lymphoma and SAE-1-positive dermatomyositis who developed an adverse cutaneous reaction after initiation of treatment with hydroxychloroquine. This adds to the sparse literature available detailing the correlation between anti-SAE-1 autoantibodies in dermatomyositis and the unique adverse cutaneous reactions in patients taking hydroxychloroquine. Additionally, our patient developed dermatomyositis years after a diagnosis of lymphoma. This report highlights the utility of the myositis-specific antibody panel to guide diagnosis and management, as well as the potential for developing dermatomyositis years after a lymphoma diagnosis.

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.

Polymyositis and dermatomyositis biomarkers

Polymyositis (PM) and dermatomyositis (DM) are the two subtypes of idiopathic inflammatory myositis and are characterized as symmetrical progressive muscle weakness in the proximal extremities. PM/DM affect multiple organs and systems, including the cardiovascular, respiratory and digestive tract systems. An in-depth understanding of PM/DM biomarkers will facilitate development of simple and accurate strategies for diagnosis, treatment, and prognosis prediction. This review summarized the classic biomarkers of PM/DM, including anti-aminoacyl tRNA synthetases (ARS) antibody, anti-Mi-2 antibody, anti-melanoma differentiation-associated gene 5 (MDA5) antibody, anti-transcription intermediary factor 1-γ (TIF1-γ) antibody, anti-nuclear matrix protein 2 (NXP2) antibody, among others. Among them, anti-aminoacyl tRNA synthetases antibody is the most classic. In addition, many potential novel biomarkers were also discussed in this review, including anti-HSC70 antibody, YKL-40, interferons, myxovirus resistance protein 2, regenerating islet-derived protein 3-α, interleukin (IL)-17, IL-35, microRNA (miR)-1 and so on. Among the biomarkers of PM/DM described in this review, classic biomarkers have become the mainstream biomarkers to assist clinicians in diagnosis due to their early discovery, in-depth research, and widespread application. The novel biomarkers also have potential and broad research prospects, which will make immeasurable contributions to exploring biomarker-based classification standards and expanding their application value.

Autoantibodies and Cancer Association: the Case of Systemic Sclerosis and Dermatomyositis

Several rheumatic diseases have a perplexing association with cancer. Unraveling this mysterious connection is likely to provide deeper understanding regarding mechanisms governing the onset of both autoimmunity and cancer immunity, in addition to providing clinicians much needed guidance around whom and when to screen for occult malignancy. Systemic sclerosis (scleroderma) and dermatomyositis are two diseases in which the association with internal malignancy is well-described and can be considered as models from which to gain important insights that likely have broader applicability. The past 15 years have witnessed a striking acceleration in understanding how these two diseases are related to cancer emergence-an important crack in this inscrutable armor has been the discovery and characterization of disease-specific autoantigens that are closely tied with risk of cancer emergence. The best-described examples of this are antibodies against anti-RNA polymerase III (anti-POL3) and transcription intermediary factor 1-gamma (anti-TIF1γ). Patients with systemic sclerosis and cancer that are diagnosed within a short time interval of each other frequently have anti-POL3 antibodies. Antibodies against the minor spliceosome protein RNA-Binding Region Containing 3 (RNPC3) are also associated with increased cancer incidence in systemic sclerosis. Similarly, in the dermatomyositis spectrum, the majority of anti-TIF1γ-associated cancers are detected around the time of DM onset (most often within 1 year). Antibodies against Nuclear Matrix Protein 2 are also potentially associated with increased cancer emergence in dermatomyositis. The systemic sclerosis/anti-POL3 connection with close cancer onset led to the first experiments directly supporting the concept that rheumatic disease may in fact be a manifestation of cancer. It is now clear that studying these diseases through the lens of autoantibodies can reveal relationships and insights that would otherwise remain obscured. Extending these studies, new findings show that antibodies against RNA polymerase I large subunit are associated with protection against short interval cancers in anti-POL3-positive systemic sclerosis patients. These insights highlight the fact that autoantigen discovery related to cancer emergence remains an important priority; such new tools will enable the testing of specific hypotheses regarding mechanisms governing disease emergence and development of effective anti-tumor responses. Autoantibody phenotype will likely play an important role in the development of cancer screening guidelines that are critically needed by clinicians taking care of these patients. In this review, we will summarize the current state of knowledge regarding the different ways in which autoantibodies are connected with systemic sclerosis/dermatomyositis and malignancy and highlight potential paths forward.

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.

The chameleon rash: a review of the polyphenotypic dermatoses of dermatomyositis

Dermatomyositis (DM) is an autoimmune connective tissue disease that is included in the idiopathic inflammatory myopathies. Cutaneous manifestations are a prominent part of the condition: some skin signs in DM are common to most patients, while other signs are encountered infrequently. A number of features are pathognomic for DM. The demonstration of myositis-specific antibodies (MSAs) in DM has extended the ability to define phenotypic subgroups. It appears that the presence of certain MSAs confers susceptibility to specific clinical features, an association which reveals a serotype-phenotype relationship. In this review article we have provided a detailed summary of common and under-recognized cutaneous manifestations of DM.

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.

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.