Myxovirus resistance protein A (MxA) expression in myositides: Sarcoplasmic expression is common in both dermatomyositis and lupus myositis

INTRODUCTION/AIMS

Myxovirus resistance protein A (MxA) is a type I interferon (IFN1) pathway activation marker and MxA sarcoplasmic expression is currently recognized as a highly specific marker for dermatomyositis (DM). However, we have frequently observed endothelial tubuloreticular inclusions (TRI), another surrogate IFN1 activation marker, in a variety of overlap myositides. The aim of this study was to examine MxA expression in those myositides.

METHODS

We retrospectively performed MxA immunostaining on a wide range of myositides.

RESULTS

MxA sarcoplasmic expression was present in DM (94.4%, 17/18), active lupus myositis (LM, 80%,16/20), inactive LM (36%, 4/11), antisynthetase syndrome (ASyS, 20%, 2/10), systemic sclerosis (13%, 2/15), Sjogren's syndrome (7.7%, 1/13), and human immunodeficiency virus (HIV) myositis (5.6%, 1/18) and was absent in immune-mediated necrotizing myopathy (IMNM, 0/16) and hydroxychloroquine myopathy (0/5). The sensitivity and specificity of MxA sarcoplasmic expression for LM and DM combined compared with all other myositides were 84.6% (95% CI: 69.5-94.1) and 92.1 (95% CI: 83.6-97.0), respectively, and superior to TRIs. MxA capillary expression was nonspecific. Histologically, 35% of LM cases demonstrated a unique panfascicular necrotizing myopathy pattern. The remainder of the LM cases had significant morphological overlap with DM/ASyS (20%), IMNM (20%), or polymyositis (15%).

DISCUSSION

MxA sarcoplasmic expression is highly prevalent in LM and DM and is a useful marker in differentiating DM and LM from other myositides. LM can manifest in various pathology patterns that need to be differentiated from DM, IMNM, ASyS, and polymyositis.

A new proposal for phenotypic classification and outcome assessment of dermatomyositis based on clinical manifestations and serological testing

BACKGROUND

Dermatomyositis (DM) is an infrequent disease subgroup of idiopathic inflammatory myopathies characterized by distinct skin lesions. However, high heterogeneity makes clinical diagnosis and treatment of DM very challenging.

OBJECTIVES

Unsupervised classification in DM patients and analysis of key factors related to clinical outcomes.

METHODS

This retrospective study was conducted between 2017 and 2022 at the Department of Rheumatology, Xiangya Hospital, Central South University. 162 DM patients were enrolled for unsupervised hierarchical cluster analysis. In addition, we divided the clinical outcomes of DM patients into four subgroups: withdrawal, stabilization, aggravation, and death, and compared the clinical profiles amongst the subgroups.

RESULTS

Out of 162 DM patients, three clusters were defined. Cluster 1 (n = 40) was mainly grouped by patients with prominent muscular involvement and mild Interstitial Lung Disease (ILD). Cluster 2 (n = 72) grouped patients with skin rash, anti-Melanoma Differentiation Associated protein 5 positive (anti-MDA5+), and Rapid Progressive Interstitial Lung Disease (RP-ILD). Cluster 3 (n = 50) grouped patients with the mildest symptoms. The proportion of death increased across the three clusters (cluster 3 < cluster 1 < cluster 2).

STUDY LIMITATIONS

The number of cases was limited for the subsequent construction and validation of predictive models. We did not review all skin symptoms or pathological changes in detail.

CONCLUSIONS

We reclassified DM into three clusters with different risks for poor outcome based on diverse clinical profiles. Clinical serological testing and cluster analysis are necessary to help clinicians evaluate patients during follow-up and conduct phenotype-based personalized care in DM.

Disease spectrum of myopathies with elevated aldolase and normal creatine kinase

BACKGROUND AND PURPOSE

Elevation of serum creatine kinase (CK) or hyperCKemia is considered a biological marker of myopathies. However, selective elevation of serum aldolase with normal CK has been reported in a few myopathies, including dermatomyositis, immune-mediated myopathy with perimysial pathology and fasciitis with associated myopathy. The aim was to investigate the disease spectrum of myopathies with isolated aldolase elevation.

METHODS

Medical records were reviewed to identify patients >18 years old seen between December 1994 and June 2020 who had pathologically proven myopathies with elevated aldolase and normal CK level. Patients with alternative causes of aldolase elevation were excluded.

RESULTS

Thirty-four patients with various types of myopathies were identified. Myopathies were treatable in 27 patients. The three most common etiologies were dermatomyositis (n = 8), overlap myositis (n = 4) and nonspecific myopathy (n = 4). Perimysial pathology comprising inflammation, fragmentation, vasculitis, calcified perimysial vessels or extracellular amyloid deposition was found in 17/34 patients (50%). Eight dermatomyositis patients with selective elevated aldolase were compared to 24 sex- and age-matched patients with dermatomyositis and hyperCKemia. Dermatomyositis patients with normal CK significantly (p < 0.05) had less frequent cutaneous involvement (50.0% vs. 100.0%) and fibrillation potentials (50.0% vs. 90.5%) but higher median erythrocyte sedimentation rate (33.5 vs. 13.5 mm/h) and more common perifascicular mitochondrial pathology (37.5% vs. 4.2%).

CONCLUSION

Isolated aldolase elevation can be found in a greater variety of myopathies than initially thought and most were treatable. Dermatomyositis is the most common myopathy with selective elevation of aldolase in our cohort, which features some unique characteristics compared to dermatomyositis with hyperCKemia.

Causes and Clinical Presentation of Drug-Induced Dermatomyositis: A Systematic Review

Importance

While several medications are known to induce dermatomyositis (DM), most existing studies are case reports or small case series from a single institution. There is also limited information on DM induced by immune checkpoint inhibitors, which are increasingly used in oncologic therapy.

Objective

To characterize causes and clinical presentation of drug-induced DM based on the current literature.

Evidence Review

A systematic review was performed in PubMed according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guidelines, from inception to August 22, 2022. Articles meeting preestablished inclusion criteria (written in English and classified as original articles, case reports, literature reviews, and observation letters) were selected and data abstracted. Articles that met the scope of the review were also added from reference lists. When possible, study results were quantitatively combined.

Findings

In 134 studies (114 from the literature search and 20 additional studies pulled from reference lists) describing 165 cases, 88 patients (53.3%) were female, and the median (IQR) age was 61 (49-69) years. Among the cases of drug-induced DM, the most common associated medications were hydroxyurea (50 [30.3%]), immune checkpoint inhibitors (27 [16.4%]), statins (22 [13.3%]), penicillamine (10 [6.1%]), and tumor necrosis factor inhibitors (10 [6.1%]). Histopathologic testing, when undertaken, helped establish the diagnosis. There was a median (IQR) of 60 (21-288) days between drug initiation and drug-induced DM onset. History of cancer was reported in 85 cases (51.6%).

Conclusions and Relevance

In this systematic review, drug-induced DM was associated with multiple types of medications, including chemotherapies and immunotherapies. It is essential that dermatologists promptly recognize and diagnose drug-induced DM so that they can guide management to minimize interruption of therapy when possible.

Effect of type I interferon on engineered pediatric skeletal muscle: a promising model for juvenile dermatomyositis

OBJECTIVE

To investigate pathogenic mechanisms underlying JDM, we defined the effect of type I IFN, IFN-α and IFN-β, on pediatric skeletal muscle function and expression of myositis-related proteins using an in vitro engineered human skeletal muscle model (myobundle).

METHODS

Primary myoblasts were isolated from three healthy pediatric donors and used to create myobundles that mimic functioning skeletal muscle in structural architecture and physiologic function. Myobundles were exposed to 0, 5, 10 or 20 ng/ml IFN-α or IFN-β for 7 days and then functionally tested under electrical stimulation and analyzed immunohistochemically for structural and myositis-related proteins. Additionally, IFN-β-exposed myobundles were treated with Janus kinase inhibitors (JAKis) tofacitinib and baricitinib. These myobundles were also analyzed for contractile force and immunohistochemistry.

RESULTS

IFN-β, but not IFN-α, was associated with decreased contractile tetanus force and slowed twitch kinetics. These effects were reversed by tofacitinib and baricitinib. Type I IFN paradoxically reduced myobundle fatigue, which did not reverse after JAKi. Additionally, type I IFN correlated with MHC I upregulation, which normalized after JAKi treatment, but expression of myositis-specific autoantigens Mi-2, melanocyte differentiation-associated protein 5 and the endoplasmic reticulum stress marker GRP78 were variable and donor specific after type I IFN exposure.

CONCLUSION

IFN-α and IFN-β have distinct effects on pediatric skeletal muscle and these effects can partially be reversed by JAKi treatment. This is the first study illustrating effective use of a three-dimensional human skeletal muscle model to investigate JDM pathogenesis and test novel therapeutics.

Dermatomyositis presenting with diffuse calcinosis

We present the case of a woman in her early 50s who initially presented to an orthopedist for nodules located near the posterior knee. Imaging revealed diffuse subcutaneous calcifications and she was subsequently referred to rheumatology. Additional testing included myositis panel, electromyography (EMG) and muscle biopsy which indicated the presence of an inflammatory myopathy. It was determined that this patient had an uncommon presentation of dermatomyositis in which her primary complaint was calcinosis cutis. While rash and muscle weakness are often the symptoms most commonly associated with dermatomyositis, it is essential to have a wide differential for patients presenting with calcium deposition in soft tissues. This is particularly important in patients with certain antibodies, including the NXP-2 antibody, which can be associated with malignancy and should prompt an appropriate malignancy workup.

Single cell RNA sequencing sheds light on infiltrating T cells in idiopathic inflammatory myopathies

Idiopathic inflammatory myopathies (IIM), also referred to as "myositis," are a group of heterogeneous autoimmune disorders characterised by muscle weakness, atrophy and progressive reduced mobility (Lundberg et al, 2021). IIM represent a significant health burden in adult populations, affecting individuals at a mean age of 50 with an estimated prevalence of 2.9-34 per 100,000 (Dobloug et al, 2015; Svensson et al, 2017). IIM encompass several subtypes including dermatomyositis, immune-mediated necrotising myopathy, inclusion-body myositis, antisynthetase syndrome and polymyositis, which are characterised by specific clinical features, histopathological findings and autoantibody status (Pinal-Fernandez et al, 2020).

Anti-MDA5 antibody-positive dermatomyositis with mild encephalopathy with reversible splenial lesion: a possible rare association?

Central nervous system (CNS) involvement in dermatomyositis (DM) is seldom observed. However, there are very rare case reports of CNS involvement with juvenile dermatomyositis. Encephalopathy in DM may occur for a number of reasons, such as cerebral vasculitis and hypoperfusion/hypertensive encephalopathy, but mostly as a consequence of immunosuppressant treatment. We report here for the first time the case of a patient with two rare diseases, namely anti-MDA5 antibody-positive dermatomyositis and mild encephalopathy with reversible splenial lesion (MERS).

The Plasma Cell Infiltrate Populating the Muscle Tissue of Patients with Inclusion Body Myositis Features Distinct B Cell Receptor Repertoire Properties

Inclusion body myositis (IBM) is an autoimmune and degenerative disorder of skeletal muscle. The B cell infiltrates in IBM muscle tissue are predominantly fully differentiated Ab-secreting plasma cells, with scarce naive or memory B cells. The role of this infiltrate in the disease pathology is not well understood. To better define the humoral response in IBM, we used adaptive immune receptor repertoire sequencing, of human-derived specimens, to generate large BCR repertoire libraries from IBM muscle biopsies and compared them to those generated from dermatomyositis, polymyositis, and circulating CD27+ memory B cells, derived from healthy controls and Ab-secreting cells collected following vaccination. The repertoire properties of the IBM infiltrate included the following: clones that equaled or exceeded the highly clonal vaccine-associated Ab-secreting cell repertoire in size; reduced somatic mutation selection pressure in the CDRs and framework regions; and usage of class-switched IgG and IgA isotypes, with a minor population of IgM-expressing cells. The IBM IgM-expressing population revealed unique features, including an elevated somatic mutation frequency and distinct CDR3 physicochemical properties. These findings demonstrate that some of IBM muscle BCR repertoire characteristics are distinct from dermatomyositis and polymyositis and circulating Ag-experienced subsets, suggesting that it may form through selection by disease-specific Ags.

Potential role of type I interferon/IP-10 axis in the pathogenesis of anti-MDA5 antibody-positive dermatomyositis

OBJECTIVES

Dermatomyositis (DM) patients with anti-melanoma differentiation-associated protein 5 (MDA5) antibodies are known for poor prognosis. This study was designed to identify humoral factors that are readily detectable in the disease and may reflect its activity and pathophysiology.

METHODS

We first quantified the serum level expression of 28 cytokines in the serum of patients with collagen vascular diseases using bead-based multiplex immunoassays. We completed these evaluations at hospital admission and followed up with three DM patients with anti-MDA5 antibodies during hospitalisation. We also performed an immunohistochemical analysis of skin samples obtained from two patients.

RESULTS

The serum level of interferon gamma-induced protein 10 (IP-10) was significantly higher in DM patients with anti-MDA5 antibodies than in those without the antibody, decreasing drastically upon treatment. Interestingly, this time course paralleled not that of interferon (IFN)-γ, which was originally reported to be the inducer of IP-10, but that of IFN-α2. Immunohistochemical analysis revealed that most of the IP-10-positive cells were macrophages. Furthermore, monocytes stimulated with type I IFN in vitro produced IP-10 in a dose-dependent manner.

CONCLUSIONS

IP-10 is a potentially useful disease activity marker of DM with anti-MDA5 antibodies, correlating more with IFN-α2 then IFN-γ. IP-10 released from macrophages might prompt the infiltration of macrophages themselves. Thus, the type I IFN/IP-10 axis may play a pivotal role in the pathogenesis of this intractable disease.

Immunoproteasome subunit β5i promotes perifascicular muscle atrophy in dermatomyositis by upregulating RIG-I

BACKGROUND

Perifascicular atrophy is a unique pathological hallmark in dermatomyositis (DM)-affected muscles; however, the mechanism underlying this process remains unclear. In this study, we aimed to investigate the potential role of the immunoproteasome subunit β5i and retinoic acid-inducible gene-I (RIG-I) in DM-associated muscle atrophy.

METHODS

The expression of β5i and RIG-I in the muscles of 16 patients with DM was examined by PCR, western blotting and immunohistochemistry. The associations between β5i and RIG-I expression levels and muscle disease severity were evaluated. Lentivirus transduction was used to overexpress β5i in human skeletal muscle myoblasts (HSMMs) and consequent cell functional changes were studied in vitro.

RESULTS

β5i and RIG-I expression in the muscle of patients with DM was significantly increased and closely associated with muscle disease severity. Immunohistochemistry and immunofluorescence analyses showed the marked colocalised expression of β5i and RIG-I in perifascicular myofibres. β5i overexpression in HSMMs significantly upregulated RIG-I, the muscle atrophy marker MuRF1, type I IFN-related proteins (MxA and IFNβ) and NF-κB pathway-related proteins (pIκBα, pIRF3 and pNF-κBp65). In addition, the viability of HSMMs decreased significantly after β5i overexpression and was partly recovered by treatment with a β5i inhibitor (PR957). Moreover, activation of RIG-I by pppRNA upregulated IFNβ and MuRF1 and reduced the cell viability of HSMMs.

CONCLUSION

The immunoproteasome subunit β5i promotes perifascicular muscle atrophy in DM via RIG-I upregulation; our findings suggest a pathomechanistic role of β5i and RIG-I in DM-associated muscle damage, highlighting these components as potential therapeutic targets for the treatment of DM.

Increased Epidermal Nerve Growth Factor without Small-Fiber Neuropathy in Dermatomyositis

Small-fiber neuropathy (SFN) is suggested to be involved in the pathogenesis of some types of autoimmune connective tissue diseases. SFN with a reduction in epidermal nerve fibers might affect sensory fibers and cause neuropathic symptoms, such as pruritus and pain, which are common in both dermatomyositis (DM) and cutaneous lupus erythematosus (CLE). Nerve growth factor (NGF) has been recognized as important in nociception by regulating epidermal nerve fiber density and sensitizing the peripheral nervous system. The present study aimed to investigate whether SFN was associated with the cutaneous manifestations of DM and CLE. We also investigated the relationship between SFN and axon guidance molecules, such as NGF, amphiregulin (AREG), and semaphorin (Sema3A) in DM and CLE. To explore the molecular signaling, interleukin (IL)-18 and IL-31, which have been implicated in the cutaneous manifestation and neuropathic symptoms in DM, were examined in keratinocytes. Our results revealed that intraepidermal nerve fiber density (IENFD) was unchanged in patients with DM, but significantly reduced in IENFD in patients with CLE compared with healthy control. Increased epidermal expression of NGF and decreased expression of Sema3A were demonstrated in patients with DM. Furthermore, IL-18 and IL-31 both induced the production of NGF from keratinocytes. Taken together, IL-18 and IL-31 mediated epidermal NGF expression might contribute to the cutaneous neuropathic symptoms in DM, while SFN might be important for CLE.

[Treatment of Dermatomyositis and Immune-Mediated Necrotizing Myopathy with Poor Muscle Recovery with Steroids and IVIg: Intractable Dermatomyositis and Immune-Mediated Necrotizing Myopathy]

Among idiopathic inflammatory myopathies, dermatomyositis and immune-mediated necrotizing myopathy are distinguished by their different clinicopathological features. Corticosteroids are administered as the first-line treatment for both, and immunosuppressive agents and intravenous immunoglobulin important second-line treatments. Since some patients show resistance to these therapies, it is necessary to considering additional treatment based on muscle pathology, muscle imaging, and systemic complications such as malignancy and interstitial lung disease, in addition to the careful evaluation of muscle strength. However, more effective therapeutic strategies are not yet well-established for refractory cases because the available therapeutic agents are limited. Therefore, the development of novel therapies is required in the future.

Inflammatory myopathies: an update for neurologists

Idiopathic inflammatory myopathies (IIM) are a heterogenous group of treatable myopathies. Patients present mainly to the rheumatologist and neurologists, complaining of acute or subacute onset of proximal weakness. Extramuscular manifestations may occur, including involvement of the lungs, skin, and joints. Classically, the diagnosis used to be made based on the creatine kinase level increase, abnormalities in electroneuromyography and presence of inflammatory infiltrates in the muscle biopsy. Recently, the importance of autoantibodies has increased, and now they may be identified in more than half of IIM patients. The continuous clinicoseropathological improvement in IIM knowledge has changed the way we see these patients and how we classify them. In the past, only polymyositis, dermatomyositis and inclusion body myopathy were described. Currently, immune-mediated necrotizing myopathy, overlap myositis and antisynthetase syndrome have been considered the most common forms of IIM in clinical practice, increasing the spectrum of classification. Patients previously considered to have polymyositis, in fact have these other forms of seropositive IIM. In this article, we reviewed the new concepts of classification, a practical way to make the diagnosis and how to plan the treatment of patients suffering from IIM.

COVID-19 Disease and Dermatomyositis: A Mini-Review

The pandemic of coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 has caused a large number of deaths, and there is still no effective treatment. COVID-19 can induce a systemic inflammatory response, and its clinical manifestations are diverse. Recently, it has been reported that COVID-19 patients may develop myositis and interstitial pulmonary disease similar to dermatomyositis (DM). This condition is similar to the rapidly progressive interstitial lung disease associated with MDA5+ DM that has a poor prognosis and high mortality, and this poses a challenge for an early identification. Suppression of the immune system can protect COVID-19 patients by preventing the production of inflammatory cytokines. This article attempts to explore the possibility of a relationship between COVID-19 and DM in terms of the potential pathogenesis and clinical features and to analyze the therapeutic effect of the immunosuppressive drugs that are commonly used for the treatment of both DM and COVID-19.

Polymyositis: is there anything left? A retrospective diagnostic review from a tertiary myositis centre

OBJECTIVE

The current classification criteria for idiopathic inflammatory myopathy (IIM) retain PM as a major disease subgroup. However, evolution in the understanding of IIM has suggested that many of these patients could be better described as having an alternative diagnosis. In the present study, we apply the latest understanding of IIM subtyping to retrospectively review PM diagnoses in a large cohort of IIM patients.

METHODS

Within a previously reported cohort of 255 patients from a UK tertiary myositis clinic, 37 patients classified as PM according to both the EULAR/ACR IIM criteria and expert opinion were identified. Clinical data and complementary tests were reviewed, and consensus decisions regarding final classification were reached in each case.

RESULTS

Nine (9/37, 24.3%) patients remained classified as PM, 3.5% (9/255) of the original cohort; these PM patients were seronegative for myositis antibodies, responsive to immunosuppression, and in 4/7 (57.1%) patients where muscle biopsy was performed had HLA-1 upregulation and endomysial inflammatory infiltrates. Immune-mediated necrotizing myopathy (5/37, 13.5%) and connective tissue disease overlap myositis (7/37, 19%) were the main alternative diagnoses. The remaining patients were diagnosed as: unspecified myopathy (6/37, 16%), dermatomyositis (2/37, 5%), cancer-associated myopathy (3/37, 8.1%), and non-inflammatory myopathy (1/37, 3%, myofibrillar myopathy). Four patients (4/37, 10%) had insufficient data available to confidently reclassify.

CONCLUSION

Our study confirms that PM can now be considered a rare IIM subgroup. A thorough examination, complete myositis autoantibody panel, and careful interpretation of the biopsy results is recommended to confirm the correct IIM sub-type.

Recognition and Management of Cutaneous Connective Tissue Diseases

Connective tissue diseases (CTDs) encompass a broad spectrum of clinical presentations that involve multidisciplinary management. Cutaneous findings are common in CTD and careful examination of these features aids in appropriate diagnosis and subsequent evaluation. Thorough work-up of CTD is crucial to properly identify disease subtypes and systemic involvement. Management plans can be developed based on diagnosis and systemic manifestations of disease. Disease management often requires treatment with pharmacotherapies with potential for toxicities, further underscoring the importance of diagnostic accuracy in this patient population. Evolving research strives to better elucidate the pathogenic mechanisms of CTDs allowing for more targeted treatment modalities.

Anti-MDA-5 negative, anti-Ku positive clinically amyopathic dermatomyositis

We present a patient with anti-MDA5 negative, anti-Ku positive clinically amyopathic dermatomyositis (CADM). A 61-year-old woman presented with a chief complaint of a 20-year history of a pruritic rash that was active on her face, chest, hands, legs, and back. A mildly scaly, erythematous, photo-distributed eruption along with slightly violaceous, scaly papules accentuated on the wrist, metacarpophalangeal joints, proximal interphalangeal and distal interphalangeal joints. Antibody profile was significant for positive ANA and anti-dsDNA, elevated anti-TIF-1gamma (RDL)/p155, and weakly positive anti Ku. Biopsy was consistent with dermatomyositis. Melanoma differentiation-associated gene 5 antibody (anti-MDA-5) has been identified as the most commonly associated autoantibody found in CADM and is associated with poor prognosis and a biomarker for the diagnosis of rapidly progressive interstitial lung disease. To our knowledge, our patient is the first case of negative anti-MDA-5 and anti-Ku positive CADM.

Dermatomyositis associated with nivolumab therapy for melanoma: a case report and review of the literature

We present a rare case of dermatomyositis associated with nivolumab therapy for melanoma. Nivolumab is an immune checkpoint inhibitor that blocks the programmed death-1 (PD1) receptor and has a number of associated immunotherapy related adverse events. Although most are T-cell mediated, some are antibody mediated mimics of classical autoimmune diseases. We review the characteristics of other cases of anti-PD1 associated dermatomyositis and the recent literature to better understand how to classify and treat this challenging immunotherapy related adverse event.

Retrospective analysis of infliximab and adalimumab treatment in a large cohort of juvenile dermatomyositis patients

BACKGROUND

Anti-TNF treatment may be useful for the treatment of patients with refractory juvenile dermatomyositis (JDM). The aim of this study was to describe the use of infliximab and adalimumab therapy in juvenile dermatomyositis as an adjunctive treatment.

METHODS

Sixty children recruited to the UK JDM Cohort and Biomarker Study that had received at least 3 months of anti-TNF treatment (infliximab or adalimumab) were studied. Childhood Myositis Assessment Scale (CMAS), Manual Muscle Testing (MMT8) and physician's global assessment (PGA) were recorded. Skin disease was assessed using the modified skin disease activity score (DAS). Data were analysed using Friedman's test for repeated measures analysis of variance.

RESULTS

Compared to baseline, there were improvements at 6 and 12 months in skin disease (χ2(2) = 15.52, p = 0.00043), global disease (χ2(2) = 8.14, p = 0.017) and muscle disease (CMAS χ2(2) = 17.02, p = 0.0002 and MMT χ2(2) = 10.56, p = 0.005) in infliximab patients. For patients who switched from infliximab to adalimumab, there was improvement in global disease activity (χ2(2) = 6.73, p = 0.03), and trends towards improvement in CMAS, MMT8 and modified DAS. The median initial prednisolone dose was 6 [0-10] mg, and final was 2.5 [0-7.5] mg (p < 0.0001). Fifty-four per cent of patients had a reduction in the number and/or size of calcinosis lesions. Twenty-five per cent switched their anti-TNF treatment from infliximab to adalimumab. 66.7%of the switches were to improve disease control, 26.7% due to adverse events and 6.6% due to patient preference. A total of 13.9 adverse reactions occurred in 100 patient-years, of which 5.7 were considered serious.

CONCLUSION

Reductions in muscle and skin disease, including calcinosis, were seen following treatment with infliximab and adalimumab.

A case report of fulminant cytokine release syndrome complicated by dermatomyositis after the combination therapy with immune checkpoint inhibitors

INTRODUCTION

Immune-related adverse events (ir-AEs) are increasingly becoming a concern, as immune checkpoint inhibitors (ICIs) are used more frequently. Herein, we present a case of fulminant cytokine release syndrome (CRS) complicated by dermatomyositis after the combination therapy with ICIs.

PATIENT CONCERNS

A 70-year-old male developed dermatomyositis during the course of treatment with two ICIs, nivolumab and ipilimumab. He was treated by steroid pulse therapy, but the effect was limited. Afterwards, he had acute-onset high fever, hypotension, respiratory failure, impaired consciousness, renal failure, and coagulation abnormality at the same time. C reactive protein (CRP), creatinine kinase (CK), D-dimer, and ferritin levels were considerably elevated: CRP, 24 mg/dL; CK, 40,500 U/L; D-dimer, 290 μg/mL; ferritin, 329,000 ng/mL.

DIAGNOSIS

CRS induced by ICI combination therapy.

INTERVENTIONS

Given that high fever and elevated CRP level indicated potential sepsis, an antibiotic was used until the confirmation of negative blood cultures. All the simultaneous acute symptoms were supposed to be CRS. He was admitted to the intensive care unit (ICU), and temporary intubation and hemodialysis were needed. Immunosuppressive therapy was reinforced by mycophenolate mofetil together with steroid, and plasma exchange was performed for the elimination of abnormal proteins.

OUTCOMES

The patient's clinical symptoms and laboratory parameters gradually improved and he was discharged from the ICU in a month.

CONCLUSION

Fulminant CRS can be induced by ICI combination therapy. As the initial symptoms of CRS resemble sepsis, it is important to consider CRS as a differential diagnosis and to initiate immunosuppressive therapy early when needed. In steroid-resistant cases, early introduction of other immunosuppressive therapy and plasma exchange can be effective.

Paraneoplastic Dermatoses: A Brief General Review and an Extensive Analysis of Paraneoplastic Pemphigus and Paraneoplastic Dermatomyositis

Skin manifestations of systemic disease and malignancy are extremely polymorphous. Clinicians should be familiarized with paraneoplastic dermatoses in order to perform an early diagnosis of the underlying neoplasm. Lack of familiarity with cutaneous clues of internal malignancy may delay diagnosis and treatment of cancer. In this review, we described several paraneoplastic dermatoses and discussed extensively two paradigmatic ones, namely paraneoplastic pemphigus and paraneoplastic dermatomyositis.

Nuclear matrix protein 2 antibody-positive adult dermatomyositis: a case report and review of the literature

Dermatomyositis is a clinically heterogenous inflammatory myopathy with unique cutaneous features. Myositis-specific antibodies can aid in diagnosis and anticipation of patient prognosis. Herein, we report a 22-year-old man who presented with multifocal erythematous plaques with violaceous papules on his bilateral elbows, neck, and face. He was diagnosed with biopsy-proven dermatomyositis and determined to be seropositive for nuclear matrix protein 2 antibody (NXP-2). He was treated with systemic corticosteroids, then intravenous methylprednisolone and azathioprine, and ultimately achieved greatest treatment response with intravenous immune globulin therapy.

A patient with anti-NXP2-positive dermatomyositis and syphilis

Dermatomyositis is an auto-immune inflammatory myopathy that primarily affects the skin and muscle and can be triggered by exposure to various environmental factors. We present a patient with active syphilis infection who developed dermatomyositis and discuss the significance of anti-NXP2 autoantibody positivity.

A Study Based on the Correlation Between Slit2/Robo1 Signaling Pathway Proteins and Polymyositis/Dermatomyositis

AIMS

To investigate the role of Slit2 and Robo1 during the vascular disease of Polymyositis (PM) / dermatomyositis (DM).

BACKGROUND

PM and DM are nonsuppurative inflammatory myopathies that mainly invade the skeletal muscles.

OBJECTIVE

This study attempted to explore the specific mechanism of Slit2/Robo1 signaling pathway proteins during the vascular disease of PM/DM.

METHODS

The mRNA expressions of Slit2 and Robo1 in the muscle tissue were detected by RT-qPCR between newly-diagnosed PM/DM patients and healthy controls. The number of Slit2 and Robo1 positive cells in the serial sections of muscle paraffin tissues was measured by immunohistochemistry in 10 patients with PM, 10 patients with DM and 20 healthy controls.

RESULTS

The study results revealed that the mRNA expressions of Slit2 and Robo1 in muscle tissue in the PM and DM groups were higher than that in the control group (P<0.05). The positive expression rates of Slit2 and Robo1 in muscle tissue in the PM and DM groups were 80.0%, 80.0%, 70.0% and 70.0%, respectively. The difference was statistically significant (P<0.001), when compared to the control group (the positive expression rates were 0% and 10%, respectively).

CONCLUSION

The activation of the Slit2/Robo1 signaling pathway is an important mechanism leading to the development of PM/DM.

Juvenile Dermatomyositis-Clinical Phenotypes

PURPOSE OF REVIEW

Juvenile dermatomyositis is a heterogeneous disease with variable clinical outcomes. Here, we describe the recognised subtypes of idiopathic inflammatory myositis which occur in children, with particular reference to disease-associated autoantibodies.

RECENT FINDINGS

Large cohort studies have demonstrated that myositis autoantibodies are common in juvenile dermatomyositis and can be found in the majority of patients. They identify homogenous clinical subgroups and inform prognosis, particularly the risks of developing interstitial lung disease. Descriptions of immune-mediated necrotising myositis in juvenile patients have highlighted a rare but important clinical subset typically associated with severe muscle disease and treatment resistance. It is increasingly apparent that autoantibodies can provide detailed information on prognosis and the likely disease associations in those with juvenile dermatomyositis. Further work is needed to establish how this knowledge should influence our approach to treatment.

[Dermatomyositis associated with hepatitis B virus-related hepatocellular carcinoma: a case report in Peru]

Dermatomyositis is an idiopathic inflammatory myopathie characterized by proximal skeletal muscle weakness, typical skin manifestations and muscle inflammation. This disease has been associated with malignancies as a paraneoplastic syndrome. We present a patient of thirty-three years diagnosed with hepatitis B, chronic inactive HBV who presents papular, pruritic and desquamative lesions on the face, hands, inguinal area and feet. At the physical examination is evidentiated Gottron's papules, heliotrope sign and proximal symmetric muscular weakness. Findings compatible with DM were found in a skin biopsy. An abdominal ultrasound revealed a liver tumor whereby a biopsy was performed and the result was a moderately differentiated hepatocellular carcinoma. Subsequently, a segmentectomy has been made and consequently the DM symptoms decreased. This case is of great interest and rare reason why we decided to reported it.

Anti-MDA-5 Dermatomyositis Presenting with Rapidly Progressive Interstitial Lung Disease: A Cautionary Tale

A 68-year-old Indian man presented with a pruritic eruption on his neck, back, elbows, knees, and the dorsum of his hands. He was initially treated for possible Lyme's disease by his primary care physician, but without improvement. Then he developed daily chills and fevers up to 101 °F, as well as shortness of breath. A chest radiograph showed patchy airspace opacities suggestive of atypical pneumonia, and the patient was treated with levofloxacin and prednisone. Although prednisone diminished the eruption, the patient continued to experience fever, malaise, and generalized weakness, at which point he was hospitalized. Blood cultures and an antinuclear antibodies (ANA) were negative and extensive lab workup was only notable for an elevated erythrocyte sedimentation rate (ESR) (63 mm/hr, Reference Range 0-22), mild transaminitis (AST 77 U/L, Reference Range 10-40), hyponatremia (131 mEq/L, Reference Range 135-145) and elevated ferritin (440, Reference Range 20-500). The patient was discharged on 20 mg of prednisone, with referral to rheumatology and dermatology for possible autoimmune diseases.

Diagnostic potential of sarcoplasmic myxovirus resistance protein A expression in subsets of dermatomyositis

AIMS

To elucidate the diagnostic value of sarcoplasmic expression of myxovirus resistance protein A (MxA) for dermatomyositis (DM) specifically analysing different DM subforms, and to test the superiority of MxA to other markers.

METHODS

Immunohistochemistry for MxA and retinoic acid-inducible gene I (RIG-I) was performed on skeletal muscle samples and compared with the item presence of perifascicular atrophy (PFA) in 57 DM patients with anti-Mi-2 (n = 6), -transcription intermediary factor 1 gamma (n = 10), -nuclear matrix protein 2 (n = 13), -melanoma differentiation-associated gene 5 (MDA5) (n = 10) or -small ubiquitin-like modifier activating enzyme (n = 1) autoantibodies and with no detectable autoantibody (n = 17). Among the patients, nine suffered from cancer and 22 were juvenile-onset type. Disease controls included antisynthetase syndrome (ASS)-associated myositis (n = 30), immune-mediated necrotizing myopathy (n = 9) and inclusion body myositis (n = 5).

RESULTS

Sarcoplasmic MxA expression featured 77% sensitivity and 100% specificity for overall DM patients, while RIG-I staining and PFA reached respectively 14% and 59% sensitivity and 100% and 86% specificity. In any subset of DM, sarcoplasmic MxA expression showed higher sensitivity than RIG-I and PFA. Some anti-MDA5 antibody-positive DM samples distinctively showed a scattered staining pattern of MxA. No ASS samples had sarcoplasmic MxA expression even though six patients had DM skin rash.

CONCLUSIONS

Sarcoplasmic MxA expression is more sensitive than PFA and RIG-I expression for a pathological diagnosis of DM, regardless of the autoantibody-related subgroup. In light of its high sensitivity and specificity, it may be considered a pathological hallmark of DM per se. Also, lack of MxA expression in ASS supports the idea that ASS is a distinct entity from DM.

Correlation between quantitative and semiquantitative magnetic resonance imaging and histopathology findings in dermatomyositis

OBJECTIVES

The aim of this study was to compare muscle biopsy findings, as well as clinical and analytical features, with those of magnetic resonance imaging (MRI) studies of muscle in patients with dermatomyositis.

METHODS

All patients from the Longitudinal Myopathy Cohort of the Hospital Clínic de Barcelona were prospectively included in the study from 2009 to 2016. MRI images of muscle and fascial oedema were compared with muscle pathology results using both quantitative and semi-quantitative scores.

RESULTS

We found a statistically significant association between the inflammatory infiltrate and both muscle (r2=0.54, p=0.001) and fascial oedema (r2=0.54, p<0.001). In addition, muscle oedema was significantly associated with punched-out vacuoles (p=0.04) and muscle enzymes in serum (r2=0.34, p=<0.01 for CK and r2=0.22, p<0.05 for aldolase). The number of treatment drugs received at the time of MRI was inversely associated with the number of muscle inflammatory cells in the biopsy and with both muscle and fascial oedema (all p<0.05).

CONCLUSIONS

Key MRI findings correlate with the main features of dermatomyositis muscle biopsy results, suggesting that MRI findings could be used as a surrogate marker of disease activity.

Clinical value of a [18F]-FDG PET-CT muscle-to-muscle SUV ratio for the diagnosis of active dermatomyositis

OBJECTIVE

To study a muscle-to-muscle standardised uptake value (SUV) ratio with FDG-PET/CT (FDG-PET) as a marker for the detection of disease activity in dermatomyositis (DM).

METHODS

Patients with DM (n = 24) who met the European Neuro-Muscular Centre diagnostic criteria were retrospectively identified over a 3-year period through a national survey. Muscle biopsy was performed in all patients. Maximum SUV was measured in proximal muscles (SUV_PROX) that had the highest radiotracer uptake on visual grading as well as in the musculus longissimus thoracis (SUV_MLT), whereas mean SUV was measured for the liver (SUV_LIV). Muscle-to-liver SUV ratios for either muscle group were compared and a SUV_PROX/SUV_MLT ratio was calculated. SUV_PROX/SUV_MLT of DM patients were compared with age- and sex-matched control subjects (n = 24) with melanoma who had received FDG-PET scans.

RESULTS

DM patients presented with proximal and symmetrical muscle uptake. Differences in SUV_PROX/SUV_LIV and SUV_MLT/SUV_LIV ratios in DM subjects were significant (p < 0.001). SUV_PROX/SUV_MLT ratios in DM and their controls also differed significantly (p = 0.0012). The SUV_PROX/SUV_MLT ratio threshold between DM subjects and controls was 1.73 with a sensitivity of 50% (CI95%, 29.1 to 70.9%) and specificity at 83.3% (CI95%, 62.6 to 95.3%). When amyopathic DM patients were removed from the analysis, specificity was increased to 95% (CI95%, 75.1 to 99.9%) with a likelihood ratio of 10 and an AUC of 83.4% (CI95%, 71.4 to 95.4%).

CONCLUSION

A muscle-to-muscle SUV_PROX/SUV_MLT ratio with a cut-off value of 1.73 in FDG-PET imaging might serve as a non-invasive marker to determine disease activity in dermatomyositis.

KEY POINTS

• [18F]-FDG PET-scanner standardised uptake value (SUV) could reflect disease activity in dermatomyositis (DM). • A ratio of SUV in proximal muscles (SUV_PROX) to SUV in musculus longissimus thoracis (SUV_MLT) could be used to determine active DM. • Active disease is suspected for SUV _PROX /SUV _MLT ratios greater than 1.73.

Serum-soluble TRAIL: a potential biomarker for disease activity in myositis patients

OBJECTIVES

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a member of the TNF super-family, which is involved in the regulation of immune response and pathogenesis of autoimmune diseases, including polymyositis (PM) and dermatomyositis (DM). In this study, we examined the level and origin of serum-soluble TRAIL (sTRAIL) in patients with PM and DM and analyzed its association with disease activity and clinical features.

METHOD

11 PM patients, 33 DM patients, and 20 healthy controls were enrolled in this study. Clinical features were recorded when admitted, and disease activity was evaluated by myositis disease activity assessment visual analogue scale (MYOACT). TRAIL expression in muscle tissues was detected by immunohistochemistry. Serum sTRAIL levels were measured by enzyme-linked immunosorbent assay. The expression of membrane TRAIL (mTRAIL) and its receptors, including DR4 and DR5, on circulating T cells was analyzed by flow cytometry.

RESULTS

TRAIL was expressed in infiltrated inflammatory cells in muscle tissues from patients. The serum sTRAIL level was markedly increased in patients and was positively correlated with the disease activity. Serum sTRAIL was decreased after therapy in patients and was specifically higher in patients with dysphagia, but lower in patients with autoantibody Jo-1 positive. The frequency of mTRAIL and its receptors on circulating T cells from patients were significantly elevated than that from healthy controls.

CONCLUSIONS

The serum sTRAIL could be a biomarker for evaluating the disease activity of PM and DM, and targeting the generation of TRAIL in T cells might be a potential approach in the treatment of PM and DM.

Disseminated Cutaneous Mycobacterium chelonae Infection in a Patient with Dermatomyositis

A 39-year-old Caucasian man with a history of dermatomyositis and diabetes mellitus on a regimen of tacrolimus and methylprednisolone presented to our dermatology outpatient clinic with a painful eruption on his left lower leg. Three months before presentation, he had been admitted to the hospital for cellulitis of the left leg. During admission, a needle aspirate of the left leg cellulitis was performed to obtain fluid for culture to guide therapy. The patient was empirically started on vancomycin 1 g every 12 hours and managed by infectious diseases. The culture yielded no growth, however, and the patient was continued on vancomycin for 2 weeks, with resolution of his cellulitis. Two months later, the patient developed multiple painful nodules on his left leg and returned to the infectious disease physician who had managed him during his inpatient stay. He was initially treated with 2 weeks of clindamycin 300 mg twice daily (bid) without improvement. This was then followed by 2 weeks of erythromycin 500 mg every 6 hours, again without improvement. At this point, he was referred to our clinic.

Dermatomyositis Developing Post Neoadjuvant Chemotherapy and Lumpectomy

Dermatomyositis is an idiopathic inflammatory myopathy known to occur as a paraneoplastic syndrome. The course of dermatomyositis is commonly reported to mirror the course of the malignancy. Here, we report a case of dermatomyositis that developed in a patient after lump- ectomy and completed chemotherapeutic treatment.

Triggers of inflammatory myopathy: insights into pathogenesis

The inflammatory myopathies, which include dermatomyositis, polymyositis, and the immune-mediated necrotizing myopathies, are a heterogeneous group of autoimmune diseases that manifest with muscle, skin, or lung damage. Collectively, these autoimmune diseases result from loss of tolerance to a select group of self-antigens, although the precise mechanism through which this occurs is not known. Infection, malignancy, and certain medications including statins and the immune checkpoint inhibitors used in cancer therapy have been identified as potential immunologic triggers of the inflammatory myopathies. Some of these triggers are classically associated with specific myositis-specific autoantibodies (MSAs). The strong association between certain triggers and MSAs provides insights into how an immunologic event can lead to loss of tolerance to specific self-antigens, resulting in autoimmune disease. In this review, we discuss the proposed triggers of the inflammatory myopathies and their associations with MSAs, and provide insights into how these triggers may result in the inflammatory myopathies.

[Dermatomyositis associated with anti-MDA5 autoantibody]

Dematomyositis is an idiopathic inflammatory myopathy with a variable clinical spectrum. In recent years, a number of myositis-specific antibodies have been identified including anti-MDA5, which is us eful for diagnosis, prognosis and classification of the diverse clinical forms of the disease. This antibody is associated with cutaneous ulcers, rapidly progressive interstitial lung disease, early mortality and poor prognosis, so the detection of this antibody in a suitable clinical context, raises the need for an aggressive immunosuppressive treatment. We describe a case of dermatomyositis classified as hypomyopathic (i.e. involving mild muscle weakness), presenting specific skin lesions, interstitial lung disease, and presence of anti-MDA5 antibody that had a favorable response to combined treatment with cyclophosphamide, gamma globulin and corticosteroids.

Panniculitis associated with amyopathic dermatomyositis

Panniculitis is a rare clinical finding in dermatomyositis, with less than 30 cases reported and there is only one case associated with the amyopathic subtype described in the literature. The present report describes a 49-year-old female patient that one year after being diagnosed with amyopathic dermatomyositis, presented indurated, painful, erythematous to violaceous nodules located on the upper limbs, thighs and gluteal region. Skin biopsy revealed lobular panniculitis with a lymphocytic infiltrate. The patient was treated with prednisone and methotrexate, but remained unresponsive to treatment.