Decoding the Intricacies of Statin-Associated Muscle Symptoms

PURPOSE OF REVIEW

Hyperlipidemia is the major cardiovascular morbidity and mortality risk factor. Statins are the first-line treatment for hyperlipidemia. Statin-associated muscle symptoms (SAMS) are the main reason for the discontinuation of statins among patients. The purpose of this review is to guide clinicians to recognize the difference between self-limited and autoimmune statin myopathy in addition to the factors that potentiate them. Finally, treatment strategies will be discussed. This review mostly focuses on new data in the past 3 years.

RECENT FINDINGS

Recent findings suggest that SAMS is a complex and multifactorial condition that involves mitochondrial dysfunction, oxidative stress, and immune-mediated mechanisms. Effective management of SAMS requires a thorough evaluation of the patient's symptoms, risk factors, and medication history, as well as consideration of alternative treatment options. While statins are effective in reducing the risk of cardiovascular events, their use is associated with a range of adverse effects, including SAMS.

Amyopathic dermatomyositis may be on the spectrum of autoinflammatory disease: A clinical review

Systemic autoinflammatory diseases (SAIDs) are distinct from autoimmune diseases. The former primarily results from abnormal innate immune response and genetic testing is crucial for disease diagnosis. Similar cutaneous involvement is a main feature for both SAID and dermatomyositis (DM), so they can be confused with each other. A literature search of PubMed and MEDLINE was conducted for relevant articles. The similarities and differences between these two types of diseases were analyzed. We found phenotypic similarities between these two types of disorders. Accumulating data supports a major role of the innate immune system and a similar cytokine profile. Molecular testing using an autoinflammatory disease gene panel may help identify SAID patients from the DM population and may offer therapeutic benefit using interleukin-1 (IL-1) inhibitors. A subset of DM, notably amyopathic dermatomyositis in the absence of autoantibodies may be on the spectrum of autoinflammatory disease.

Responsiveness and meaningful thresholds of PROMIS pain interference, fatigue, and physical function forms in adults with idiopathic inflammatory myopathies: Report from the OMERACT Myositis Working Group

BACKGROUND

A series of qualitative studies conducted by the OMERACT Myositis Working Group identified pain interference, fatigue, and physical function as highly important life impact domains for adults with idiopathic inflammatory myositis (IIM). In this study, our goal was to assess the responsiveness and minimal important difference of PROMIS pain interference (6a), fatigue (7a), and physical function (8b).

METHODS

Adults with IIM from USA, Netherlands, Korea, Sweden, and Australia with two "clinical" visits were enrolled in this prospective study. Anchor questions on a Likert scale were collected at baseline, and manual muscle testing (MMT), physician and patient reported global disease activity, and PROMIS instruments were collected at both visits. Responsiveness was assessed with i) ANOVA, ii) paired t-test, effect size and standardized response mean, and iii) Pearson correlation. Minimal important difference (MID), minimal important change (MIC) and minimal detectable change (MDC) values were calculated.

RESULTS

114 patients with IIM (median age 60, 60 % female) completed both visits. Changes in PROMIS instruments were significantly different among anchor categories. Patients who reported improvement had a significant improvement in their PROMIS scores with at least medium effect size, while patients who reported worsening and stability did not show a significant change with weak effect size. PROMIS instruments had weak to moderate correlations with MMT, patient and physician global disease activity. MID was approximately 2-3 points for Pain Interference and 3-4 points for Fatigue and Physical Function forms based on the method used. MIC was approximately 4-5 for improvement of all the instruments, while MDC was 1.7-2 points for Pain Interference and Physical Function and 3.2-3.9 for Fatigue.

CONCLUSION

This study provides evidence towards the responsiveness of the PROMIS instruments in a large international prospective cohort of adults with IIM supporting their use as PROMs in adult myositis.

Collaborative research in myositis-related disorders: MIHRA, a global shared community model

Myositis International Health and Research Collaborative Alliance (MIHRA) is a newly formed purpose-built non-profit charitable research organization dedicated to accelerating international clinical trial readiness, global professional and lay education, career development and rare disease advocacy in IIM-related disorders. In its long form, the name expresses the community's scope of engagement and intent. In its abbreviation, MIHRA, conveys linguistic roots across many languages, that reflects the IIM community's spirit with meanings such as kindness, community, goodness, and peace. MIHRA unites the global multi-disciplinary community of adult and pediatric healthcare professionals, researchers, patient advisors and networks focused on conducting research in and providing care for pediatric and adult IIM-related disorders to ultimately find a cure. MIHRA serves as a resourced platform for collaborative efforts in investigator-initiated projects, consensus guidelines for IIM assessment and treatment, and IIM-specific career development through connecting research networks.MIHRA's infrastructure, mission, programming and operations are designed to address challenges unique to rare disease communities and aspires to contribute toward transformative models of rare disease research such as global expansion and inclusivity, utilization of community resources, streamlining ethics and data-sharing policies to facilitate collaborative research. Herein, summarises MIHRA operational cores, missions, vision, programming and provision of community resources to sustain, accelerate and grow global collaborative research in myositis-related disorders.

Pathogenic autoantibody internalization in myositis

Objectives

Myositis is a heterogeneous family of autoimmune muscle diseases. As myositis autoantibodies recognize intracellular proteins, their role in disease pathogenesis has been unclear. This study aimed to determine whether myositis autoantibodies reach their autoantigen targets within muscle cells and disrupt the normal function of these proteins.

Methods

Confocal immunofluorescence microscopy was used to localize antibodies and other proteins of interest in myositis muscle biopsies. Bulk RNA sequencing was used to study the transcriptomic profiles of 668 samples from patients with myositis, disease controls, and healthy controls. Antibodies from myositis patients were introduced into cultured myoblasts by electroporation and the transcriptomic profiles of the treated myoblasts were studied by bulk RNA sequencing.

Results

In patients with myositis autoantibodies, antibodies accumulated inside myofibers in the same subcellular compartment as the autoantigen. Each autoantibody was associated with effects consistent with dysfunction of its autoantigen, such as the derepression of genes normally repressed by Mi2/NuRD in patients with anti-Mi2 autoantibodies, the accumulation of RNAs degraded by the nuclear RNA exosome complex in patients with anti-PM/Scl autoantibodies targeting this complex, and the accumulation of lipids within myofibers of anti-HMGCR-positive patients. Internalization of patient immunoglobulin into cultured myoblasts recapitulated the transcriptomic phenotypes observed in human disease, including the derepression of Mi2/NuRD-regulated genes in anti-Mi2-positive dermatomyositis and the increased expression of genes normally degraded by the nuclear RNA exosome complex in anti-PM/Scl-positive myositis.

Conclusions

In myositis, autoantibodies are internalized into muscle fibers, disrupt the biological function of their autoantigen, and mediate the pathophysiology of the disease.

Current myositis clinical trials and tribulations

With improved understanding of disease pathogenesis and availability of outcome measures, there has been a remarkable increase in the number of therapeutic clinical trials in idiopathic inflammatory myopathies (myositis) over the last three years reaching as many as five trials per site. These trials share similar design and inclusion/exclusion criteria resulting in a competitive clinical trial landscape in myositis. While these are exciting times for the myositis field, we have a number of concerns about the design and conduct of the myositis trials. These include competitive landscape, lengthy placebo arms, underrepresentation of minority groups among participants, use of patient reported outcome measures with limited/no data on validity in myositis, antiquated disease classification criteria, and unclear performance of the ACR/EULAR Myositis Response Criteria in skin-predominant patients despite inclusion of these patients in trials. In this viewpoint, we further discuss these concerns and offer potential solutions such as including patient perspectives in the trial design and adoption of innovative frameworks.

Diagnostic Yield of Computed Tomography for Cancer Detection in a Tertiary Referral Population of Idiopathic Inflammatory Myositis Patients

OBJECTIVE

To inform guidance for cancer detection in patients with idiopathic inflammatory myopathy (IIM), we evaluated the diagnostic yield of computed tomography (CT) imaging for cancer screening/surveillance within distinct IIM subtypes and myositis-specific autoantibody strata.

METHODS

We conducted a single-center, retrospective cohort study in IIM patients. Overall diagnostic yield (number of cancers diagnosed/number of tests performed), percentage of false positives (number of biopsies performed not leading to cancer diagnosis/number of tests performed), and test characteristics were determined on CT of the chest and abdomen/pelvis.

RESULTS

Within the first 3 years since IIM symptom onset, a total of 9 of 1,011 (0.9%) chest CT scans and 12 of 657 (1.8%) abdomen/pelvis CT scans detected cancer. Diagnostic yields for both CT of the chest and CT of the abdomen/pelvis were highest in dermatomyositis, specifically anti-transcription intermediary factor 1γ (2.9% and 2.4% for CT of the chest and abdomen/pelvis, respectively). The highest percentage of false positives was in patients with antisynthetase syndrome (ASyS) (4.4%) and immune-mediated necrotizing myopathy (4.4%) on CT of the chest, and ASyS (3.8%) on CT of the abdomen/pelvis. Patients ages <40 years old at IIM onset had both low diagnostic yields (0% and 0.5%) and high false-positive rates (1.9% and 4.4%) for CT of the chest and abdomen/pelvis, respectively.

CONCLUSION

In a tertiary referral cohort of IIM patients, CT imaging has a wide range of diagnostic yield and frequency of false positives for contemporaneous cancer. These findings suggest that cancer detection strategies targeted according to IIM subtype, autoantibody positivity, and age may maximize cancer detection while minimizing the harms and costs of over-screening.

Identification of Unique microRNA Profiles in Different Types of Idiopathic Inflammatory Myopathy

Dermatomyositis (DM), antisynthetase syndrome (AS), immune-mediated necrotizing myopathy (IMNM), and inclusion body myositis (IBM) are four major types of idiopathic inflammatory myopathy (IIM). Muscle biopsies from each type of IIM have unique transcriptomic profiles. MicroRNAs (miRNAs) target messenger RNAs (mRNAs), thereby regulating their expression and modulating transcriptomic profiles. In this study, 18 DM, 12 IMNM, 6 AS, 6 IBM, and 6 histologically normal muscle biopsies underwent miRNA profiling using the NanoString nCounter system. Eleven miRNAs were exclusively differentially expressed in DM compared to controls, seven miRNAs were only differentially expressed in AS, and nine miRNAs were specifically upregulated in IBM. No differentially expressed miRNAs were identified in IMNM. We also analyzed miRNA-mRNA associations to identify putative targets of differentially expressed miRNAs. In DM and AS, these were predominantly related to inflammation and cell cycle progression. Moreover, our analysis showed an association between miR-30a-3p, miR-30e-3p, and miR-199b-5p downregulation in DM and the upregulation of target genes induced by type I interferon. In conclusion, we show that muscle biopsies from DM, AS, and IBM patients have unique miRNA signatures and that these miRNAs might play a role in regulating the expression of genes known to be involved in IIM pathogenesis.

The pattern of MHC class I expression in muscle biopsies from patients with myositis and other neuromuscular disorders

OBJECTIVE

Diagnostic muscle biopsies are routinely immunostained for major histocompatibility complex class I (MHC-I) protein. In this study we analysed the prevalence and patterns of MHC-I immunostaining in biopsies from patients with different types of myopathies and neurogenic disorders.

METHODS

All 357 diagnostic muscle biopsies processed at the Johns Hopkins Neuromuscular Pathology Laboratory from August 2013 to January 2017 were immunostained for MHC-I. The prevalence and patterns of MHC-I immunostaining were compared between patients with histologically normal muscle biopsies (n = 31), idiopathic inflammatory myopathies (IIMs; n = 170), non-inflammatory myopathies (n = 60) and neurogenic disorders (n = 96).

RESULTS

MHC-I immunostaining was abnormal in most patients with DM (98%), sporadic IBM (sIBM; 100%), immune-mediated necrotizing myopathy (IMNM; 100%) and polymyositis (77%). In contrast, MHC-I immunostaining was less frequently present in non-inflammatory myopathies (32%) or neurogenic disorders (30%). Overall, abnormal MHC-I immunostaining had a sensitivity of 0.95 and a specificity of 0.82 for diagnosing IIMs. A focal MHC-I staining pattern was associated with IMNM, whereas a global pattern was more prevalent in sIBM and a perifascicular pattern was significantly more common in dermatomyositis. Among 18 DM biopsies without perifascicular atrophy, 50% had a perifascicular MHC-I staining pattern. Sarcoplasmic upregulation staining was more common than sarcolemmal staining across all groups.

CONCLUSION

MHC-I immunostaining was useful to distinguish IIMs from non-inflammatory myopathies or neurogenic disorders. Of note, a perifascicular MHC-I staining pattern was present only in those with DM, including half of those without perifascicular atrophy; many of these biopsies may not otherwise have been diagnostic for DM.

Myocarditis in Patients With Idiopathic Inflammatory Myopathies: Clinical Presentation and Outcomes

OBJECTIVE

To determine the clinical phenotype and outcomes of patients with idiopathic inflammatory myopathies (IIMs) and myocarditis.

METHODS

Using the Johns Hopkins Myositis Center Research Registry, we identified 31 adult patients with IIM-out of a total of 3082 with confirmed or suspected muscle disease-with an encounter code of myocarditis from 2004 to 2021. Of these, 14 adult patients with IIM were adjudicated to have clinical myocarditis. Information about demographics, autoantibodies, and clinical outcomes was retrospectively collected and analyzed.

RESULTS

Of 14 patients with IIM with clinical myocarditis, the median age at IIM diagnosis was 49 (IQR 35-56) years, and the median age at myocarditis diagnosis was 54 (IQR 36-61) years. The median duration between IIM diagnosis and myocarditis was 3 (IQR 2-9) years. The majority of patients were female (8/14, 57%) and Black (10/14, 71%). Antisynthetase syndrome was the most common IIM subtype (9/14, 64%). Anti-Jo1 (n = 4) and anti-PL12 (n = 3) were the most frequent autoantibodies. At myocarditis diagnosis, most patients (11/14, 79%) had active myositis, defined as elevated creatine kinase and/or muscle weakness; required hospitalization (13/14, 93%); and had reduced left ventricular ejection fraction (LVEF < 50%; 10/14, 71%). Despite intensification of immunosuppression, the 5-year overall survival rate from IIM diagnosis was 84%, and the 5-year overall survival rate from myocarditis diagnosis was 53%. Systolic dysfunction (LVEF < 40%) at final evaluation was observed in all expired patients (n = 6).

CONCLUSION

Clinical presentations of myocarditis in this select cohort of patients with IIM were severe and heterogeneous with poor outcomes despite intensification of immunosuppression, potentially reflecting late detection of myocarditis.

Transcriptional derepression of CHD4/NuRD-regulated genes in the muscle of patients with dermatomyositis and anti-Mi2 autoantibodies

OBJECTIVES

Myositis is a heterogeneous family of diseases including dermatomyositis (DM), immune-mediated necrotising myopathy (IMNM), antisynthetase syndrome (AS) and inclusion body myositis (IBM). Myositis-specific autoantibodies define different subtypes of myositis. For example, patients with anti-Mi2 autoantibodies targeting the chromodomain helicase DNA-binding protein 4 (CHD4)/NuRD complex (a transcriptional repressor) have more severe muscle disease than other DM patients. This study aimed to define the transcriptional profile of muscle biopsies from anti-Mi2-positive DM patients.

METHODS

RNA sequencing was performed on muscle biopsies (n=171) from patients with anti-Mi2-positive DM (n=18), DM without anti-Mi2 autoantibodies (n=32), AS (n=18), IMNM (n=54) and IBM (n=16) as well as 33 normal muscle biopsies. Genes specifically upregulated in anti-Mi2-positive DM were identified. Muscle biopsies were stained for human immunoglobulin and protein products corresponding to genes specifically upregulated in anti-Mi2-positive muscle biopsies.

RESULTS

A set of 135 genes, including SCRT1 and MADCAM1, was specifically overexpressed in anti-Mi2-positive DM muscle. This set was enriched for CHD4/NuRD-regulated genes and included genes that are not otherwise expressed in skeletal muscle. The expression levels of these genes correlated with anti-Mi2 autoantibody titres, markers of disease activity and with the other members of the gene set. In anti-Mi2-positive muscle biopsies, immunoglobulin was localised to the myonuclei, MAdCAM-1 protein was present in the cytoplasm of perifascicular fibres, and SCRT1 protein was localised to myofibre nuclei.

CONCLUSIONS

Based on these findings, we hypothesise that anti-Mi2 autoantibodies could exert a pathogenic effect by entering damaged myofibres, inhibiting the CHD4/NuRD complex, and subsequently derepressing the unique set of genes defined in this study.

Can IgG4-related disease present as isolated myositis?

IgG4-Related Disease (IgG4-RD)is a chronic fibroinflammatory disease typically characterized by inflammation or tumefaction of the organs involved. Skeletal muscle is not one of the typical organs involved in IgG4-RD. Isolated myositis related to IgG4-RD without common organ involvement such as lacrimal or salivary glands or retroperitoneal fibrosis is a controversial and debatable entity. Here we report a case of inflammatory myopathy in an elderly woman with several atypical clinical, lab, and histopathological findings suggestive of IgG4-related myositis. Two such case reports of IgG4-related myositis were reported in the literature review. This is a third case report of elevated IgG4 positive plasma cell infiltration in muscle with severe endomysial fibrosis and unusual myositis features (Figs. 1 and 2). This case-based review opens a possibility of a novel presentation of IgG4-RD and new pathogenesis in myositis.

Association of Anti-CCAR1 Autoantibodies With Decreased Cancer Risk Relative to the General Population in Patients With Anti-Transcriptional Intermediary Factor 1γ-Positive Dermatomyositis

OBJECTIVE

To describe the disease specificity, clinical phenotype, and risk of cancer in dermatomyositis (DM) patients with autoantibodies against cell division cycle and apoptosis regulator protein 1 (anti-CCAR1).

METHODS

The frequency of anti-CCAR1 autoantibodies was measured by enzyme-linked immunosorbent assay in the serum of DM patients from 2 independent cohorts (Johns Hopkins and Stanford), with patients with several other rheumatic diseases and healthy controls used as comparators. Clinical features and the risk of cancer incidence relative to that in the general population were determined in anti-CCAR1-positive DM patients.

RESULTS

Anti-CCAR1 antibodies were significantly associated with anti-transcriptional intermediary factor 1γ (anti-TIF1γ) antibodies present in the serum of patients with DM: 80 (32%) of 252 anti-TIF1γ-positive DM patients versus 14 (8%) of 186 anti-TIF1γ-negative DM patients were positive for anti-CCAR1 antibodies (P < 0.001). Anti-CCAR1 antibodies were not detected in any of the 32 serum samples from healthy controls, and were present at very low frequencies in the sera of patients with other rheumatic diseases: 1 (2.3%) of 44 patients with anti-hydroxymethylglutaryl-coenzyme A reductase-positive necrotizing myopathy, 1 (2.3%) of 44 patients with inclusion body myositis, and 3 (6.5%) of 46 patients with systemic lupus erythematosus were positive for anti-CCAR1 antibodies. Upon examining data on occurrence of cancer from the onset of DM onward, the observed number of cancers diagnosed in anti-TIF-1γ-positive DM patients was significantly greater than expected in both cohorts, with a standardized incidence ratio (SIR) of 3.49 (95% confidence interval [95% CI] 2.39-4.92) in the Johns Hopkins cohort and a SIR of 4.54 (95% CI 3.04-6.52) in the Stanford cohort (each P < 0.001). DM patients who were both anti-TIF1γ positive and anti-CCAR1 positive had lower SIRs for cancer, with a SIR of 1.78 (95% CI 0.77-3.51) (P = 0.172) in the Johns Hopkins cohort and a SIR of 1.61 (95% CI 0.44-4.13) (P = 0.48) in the Stanford cohort.

CONCLUSION

Anti-CCAR1 autoantibodies are specific for anti-TIF1γ-positive DM. Their presence in anti-TIF1γ-positive patients attenuates the risk of cancer to a level comparable to that seen in the general population.

Myositis interstitial lung disease and autoantibodies

The aim of this review is to examine and evaluate published literature associated with idiopathic inflammatory myopathies (IIM) and interstitial lung disease (ILD) based on myositis specific autoantibodies (MSA) and the potential clinical significance of each autoantibody subtype for the practicing clinician. The review is a comprehensive search of literature published in PubMed from the year 2005 and onward coinciding with the surge in the discovery of new MSAs. Additionally, we comment on recommended multidisciplinary longitudinal care practices for patients with IIM-ILD with regard to imaging and other testing. Treatment is not covered in this review.

Transcriptomic profiling reveals distinct subsets of immune checkpoint inhibitor induced myositis

OBJECTIVES

Inflammatory myopathy or myositis is a heterogeneous family of immune-mediated diseases including dermatomyositis (DM), antisynthetase syndrome (AS), immune-mediated necrotising myopathy (IMNM) and inclusion body myositis (IBM). Immune checkpoint inhibitors (ICIs) can also cause myositis (ICI-myositis). This study was designed to define gene expression patterns in muscle biopsies from patients with ICI-myositis.

METHODS

Bulk RNA sequencing was performed on 200 muscle biopsies (35 ICI-myositis, 44 DM, 18 AS, 54 IMNM, 16 IBM and 33 normal muscle biopsies) and single nuclei RNA sequencing was performed on 22 muscle biopsies (seven ICI-myositis, four DM, three AS, six IMNM and two IBM).

RESULTS

Unsupervised clustering defined three distinct transcriptomic subsets of ICI-myositis: ICI-DM, ICI-MYO1 and ICI-MYO2. ICI-DM included patients with DM and anti-TIF1γ autoantibodies who, like DM patients, overexpressed type 1 interferon-inducible genes. ICI-MYO1 patients had highly inflammatory muscle biopsies and included all patients that developed coexisting myocarditis. ICI-MYO2 was composed of patients with predominant necrotising pathology and low levels of muscle inflammation. The type 2 interferon pathway was activated both in ICI-DM and ICI-MYO1. Unlike the other types of myositis, all three subsets of ICI-myositis patients overexpressed genes involved in the IL6 pathway.

CONCLUSIONS

We identified three distinct types of ICI-myositis based on transcriptomic analyses. The IL6 pathway was overexpressed in all groups, the type I interferon pathway activation was specific for ICI-DM, the type 2 IFN pathway was overexpressed in both ICI-DM and ICI-MYO1 and only ICI-MYO1 patients developed myocarditis.

Subsets of Idiopathic Inflammatory Myositis Enriched for Contemporaneous Cancer Relative to the General Population

OBJECTIVE

This study investigates cancer risk in idiopathic inflammatory myopathy (IIM) relative to the general population.

METHODS

We conducted a single-center, retrospective cohort study of IIM patients and malignancy. Myositis-specific and -associated autoantibodies were determined by Euroimmun line blot, enzyme-linked immunosorbent assay, and immunoprecipitation. We calculated standardized prevalence ratios (SPRs) and adjusted for calendar year, age, sex, race, and ethnicity by comparing observed cancers in IIM patients versus expected cancers in the general population using the Surveillance, Epidemiology, and End Results registry.

RESULTS

Of 1,172 IIM patients, 203 (17%) patients with a cancer history were studied. Over a median follow-up of 5.2 years, the observed number of IIM patients diagnosed with cancer was increased 1.43-fold (SPR 1.43 [95% confidence interval (95% CI) 1.15-1.77]; P = 0.002). Within 3 years of IIM symptom onset, an increased SPR was observed for anti-transcription intermediary factor 1γ (anti-TIF1γ)-positive patients for ovarian and breast cancer (ovarian SPR 18.39 [95% CI 5.01-47.08], P < 0.001; breast SPR 3.84 [95% CI 1.99-6.71], P < 0.001). As expected, anti-TIF1γ positivity was associated with a significantly elevated SPR; however, only 55% (36 of 66) of all cancers within 3 years of dermatomyositis onset were observed in anti-TIF1γ-positive patients. Other myositis-specific autoantibodies, including anti-Mi-2, anti-small ubiquitin-like modifier activating enzyme (SAE), and anti-nuclear matrix protein 2 (NXP-2), accounted for 26% (17 of 66) of cancers diagnosed within 3 years of dermatomyositis onset. No cancer association, positive or negative, was observed for patients with antisynthetase, anti-melanoma differentiation-associated protein 5 (anti-MDA-5), or anti-hydroxymethylglutaryl-coenzyme A reductase (anti-HMGCR) antibodies.

CONCLUSION

In a tertiary referral center population, anti-TIF1γ was most strongly associated with breast and ovarian cancer. Patients with antisynthetase, anti-MDA-5, or anti-HMGCR antibodies had the same cancer risk as the general population.

Clinical Subgroups and Factors Associated With Progression in Patients With Inclusion Body Myositis

BACKGROUND AND OBJECTIVES

Sporadic inclusion body myositis (IBM) is the most common acquired myopathy in individuals older than 50 years. The disorder is slowly progressive, and although many therapies have been investigated, response has generally been poor. Clinical heterogeneity may influence treatment responsiveness; however, data regarding heterogeneity in IBM are limited and often conflicting. We aim to identify clinically distinct subgroups within a large IBM cohort and prognostic factors for disease progression.

METHODS

Clinical, histologic, radiologic, and electrophysiologic data were analyzed for all patients with IBM and other forms of myositis enrolled in a longitudinal cohort from The Johns Hopkins Myositis Center from 2003 to 2018. Patients with IBM were included if they met at least one of the following criteria: Griggs possible, European Neuromuscular Centre 2011 probable, or Lloyd-Greenberg data-derived criteria for IBM. Univariate, multivariate, and graphical analyses were used to identify prognostic factors in patients with IBM. Thus, linear and logistic regressions were used to adjust for potential confounding variables. The evolution of creatine kinase and muscle strength was studied using multilevel linear regression models. Nonmodifiable risk factors (sex, race, disease duration, and age at the onset of first symptoms) were used as adjusting covariates for the regression analyses.

RESULTS

Among the 335 patients meeting the inclusion criteria for IBM, 64% were male with an average age of disease onset of 58.7 years and delay to diagnosis of 5.2 years. Initial misdiagnosis (52%) and immunosuppressant treatment (42%) were common. Less than half (43%) of muscle biopsies demonstrated all 3 pathologic hallmarks: endomysial inflammation, mononuclear cell invasion, and rimmed vacuoles. Black patients had significantly weaker arm abductors, hip flexors, and knee flexors compared with non-Black patients. Female patients had stronger finger flexors and knee extensors compared with their male counterparts. Younger age (<50 years) at onset was not associated with increased weakness.

DISCUSSION

Our study demonstrates that female and Black patients have distinct clinical phenotypes and trajectories within the overarching IBM clinical phenotype. These subgroups may have different responses to therapies, which may influence the design of future clinical trials in IBM.

Anti-MDA5-positive dermatomyositis and remission in a single referral centre population

OBJECTIVES

To describe a single-centre North American adult cohort of anti-MDA5-positive dermatomyositis patients, with emphasis on drug-free long-term remission.

METHODS

We conducted an observational retrospective cohort study of anti-MDA5-positive DM patients. All consented patients seen in the Johns Hopkins Myositis Centre from 2003-2020 with suspected muscle disease were routinely screened for myositis-specific autoantibodies. All sera were screened for anti-MDA5 autoantibodies by line blot; positives were verified by enzyme-linked immunoassay. Patients whose sera were anti-MDA5 positive by both assays (n=52) were followed longitudinally. If clinical status was unavailable, structured telephone interviews were conducted. Clinical remission was defined as being off all immunosuppression >1 year while remaining asymptomatic.

RESULTS

38/52 (73%) of the patients were women with a median age at disease-onset of 47 (IQR 40-54). Twenty-five of the patients (48%) were White, 16 (30%) were Black and 3 (6%) were Asian. Most patients (42/52, 80%) had interstitial lung disease, defined by inflammatory or fibrotic changes on high resolution computed tomography (HRCT). 18/52 (35%) of patients required pulse-dose methylprednisolone, 4/52 (8%) experienced spontaneous pneumothorax/pneumomediastinum, 6/52 (12%) required intubation, and 5/52 (10%) died. Over longitudinal follow-up (median 3.5 years), 9 (18%) patients achieved clinical remission. The median time from symptom onset to clinical remission was 4 years, and the median duration of sustained remission was 3.5 years (range 1.4-7.8). No demographic or disease characteristics were significantly associated with remission.

CONCLUSIONS

In this single centre, tertiary referral population of anti-MDA5-positive dermatomyositis, ~20% of patients experienced long-term drug-free remission after a median disease duration of 4 years. No clinical or biologic factors were associated with clinical remission.

Use of Janus kinase inhibitors in dermatomyositis: a systematic literature review

Dermatomyositis (DM) is an idiopathic inflammatory myopathy that commonly manifests with proximal muscle weakness and is associated with extramuscular pathology, including characteristic skin lesions such as Gottron's papules and heliotrope rash, as well as lung, gastrointestinal, joint, and cardiac involvement. Systemic corticosteroids are a cornerstone of therapy, and more recently intravenous immunoglobulin (IVIG; OCTAGAM®) has been approved by the US Food and Drug Administration for the treatment of adults with DM. Both steroids and IVIG represent nonspecific anti-inflammatory therapy, and more targeted approaches are lacking. Transcriptomics has identified upregulation of interferon (IFN)-regulated genes as key features of both adult DM and juvenile DM (JDM). Accordingly, blocking IFN signalling through inhibition of the Janus kinase (JAK) pathway represents a potential treatment option for DM. Placebo-controlled trial data assessing the use of JAK inhibitors for the treatment of DM are limited; as such, a systematic literature review was undertaken to assess the evidence of JAK inhibitors in the treatment of patients with DM. Terms related to DM and JAK inhibitors were searched using PubMed, Embase, Web of Science, Scopus, and Dimensions to identify peer-reviewed publications reporting patients with DM who were treated with a JAK inhibitor. Baseline demographics, clinical characteristics, and treatment outcome data were extracted. A total of 48 publications reporting 145 unique patients (adult DM, n=84; JDM, n=61) were identified. Among cases of adult DM, 61 of 84 (73%) had refractory skin disease at baseline, and all (61 of 61) reported improvement in cutaneous symptoms. Of patients with adult DM, 16 of 84 (19%) had refractory muscle disease at baseline, and all (16 of 16) reported improvement in muscle symptoms. In patients with adult DM complicated by interstitial lung disease (ILD; n=33), 31 (94%) patients improved with JAK inhibitor treatment. Among cases of JDM with refractory skin disease at baseline (60 of 61), most patients (57 of 60; 95%) showed improvements in skin symptoms after JAK inhibitor treatment. Of patients with JDM with refractory muscle disease at baseline (36 of 61), most (30 of 36; 83%) reported improvement in muscle symptoms. Four patients with JDM and ILD experienced improvement in lung disease activity following treatment with a JAK inhibitor. Among both DM and JDM cases, all patients (17 with DM and 16 with JDM) who had elevated serum IFN and/or IFN-stimulated gene expression at baseline showed reduction in IFN or IFN gene expression. Although the conclusions that can be drawn from this analysis are limited because of the differences in assessments used across publications, overall treatment of patients with DM or JDM with a JAK inhibitor was associated with significant improvement of a wide range of DM manifestations, including skin lesions, muscle weakness, and ILD. Our systematic literature review suggests that JAK inhibitors may be a viable treatment option for DM/JDM, and randomised controlled trials are necessary to confirm these findings.

Coordinated local RNA overexpression of complement induced by interferon gamma in myositis

Complement proteins are deposited in the muscles of patients with myositis. However, the local expression and regulation of complement genes within myositis muscle have not been well characterized. In this study, bulk RNA sequencing (RNAseq) analyses of muscle biopsy specimens revealed that complement genes are locally overexpressed and correlate with markers of myositis disease activity, including the expression of interferon-gamma (IFNγ)-induced genes. Single cell and single nuclei RNAseq analyses showed that most local expression of complement genes occurs in macrophages, fibroblasts, and satellite cells, with each cell type expressing different sets of complement genes. Biopsies from immune-mediated necrotizing myopathy patients, who have the lowest levels of IFNγ-induced genes, also had the lowest complement gene expression levels. Furthermore, data from cultured human cells showed that IFNγ upregulates complement expression in macrophages, fibroblasts, and muscle cells. Taken together, our results suggest that in myositis muscle, IFNγ coordinates the local overexpression of complement genes that occurs in several cell types.

Coexisting autoantibodies against transcription factor Sp4 are associated with decreased cancer risk in patients with dermatomyositis with anti-TIF1γ autoantibodies

OBJECTIVES

In dermatomyositis (DM), autoantibodies are associated with unique clinical phenotypes. For example, anti-TIF1γ autoantibodies are associated with an increased risk of cancer. The purpose of this study was to discover novel DM autoantibodies.

METHODS

Phage ImmunoPrecipitation Sequencing using sera from 43 patients with DM suggested that transcription factor Sp4 is a novel autoantigen; this was confirmed by showing that patient sera immunoprecipitated full-length Sp4 protein. Sera from 371 Johns Hopkins patients with myositis (255 with DM, 28 with antisynthetase syndrome, 40 with immune-mediated necrotising myopathy, 29 with inclusion body myositis and 19 with polymyositis), 80 rheumatological disease controls (25 with Sjogren's syndrome, 25 with systemic lupus erythematosus and 30 with rheumatoid arthritis (RA)) and 200 healthy comparators were screened for anti-SP4 autoantibodies by ELISA. A validation cohort of 46 anti-TIF1γ-positive patient sera from the University of Pittsburgh was also screened for anti-Sp4 autoantibodies.

RESULTS

Anti-Sp4 autoantibodies were present in 27 (10.5%) patients with DM and 1 (3.3%) patient with RA but not in other clinical groups. In patients with DM, 96.3% of anti-Sp4 autoantibodies were detected in those with anti-TIF1γ autoantibodies. Among 26 TIF1γ-positive patients with anti-Sp4 autoantibodies, none (0%) had cancer. In contrast, among 35 TIF1γ-positive patients without anti-Sp4 autoantibodies, 5 (14%, p=0.04) had cancer. In the validation cohort, among 15 TIF1γ-positive patients with anti-Sp4 autoantibodies, 2 (13.3%) had cancer. By comparison, among 31 TIF1γ-positive patients without anti-Sp4 autoantibodies, 21 (67.7%, p<0.001) had cancer.

CONCLUSIONS

Anti-Sp4 autoantibodies appear to identify a subgroup of anti-TIF1γ-positive DM patients with lower cancer risk.

Reliability and validity of PROMIS physical function, pain interference, and fatigue as patient reported outcome measures in adult idiopathic inflammatory myopathies: International study from the OMERACT myositis working group

OBJECTIVE

Pain interference, fatigue, and impaired physical function are common features of idiopathic inflammatory myopathies (IIM). The objective of this study was to evaluate the construct validity and test-retest reliability of the Patient Reported Outcome Information System (PROMIS) Pain Interference 6av1.0, Fatigue 7av1.0, and Physical Function 8bv2.0 instruments.

METHODS

Patient-Reported Outcome Measures (PROMs) were deployed to adult IIM patients from OMERACT Myositis Working Group (MWG) international clinic sites via two online surveys (2019, 2021). Internal consistency of each PROM was analyzed by Cronbach's α. Construct validity was determined by a priori hypotheses generated by the MWG with >75% agreement for each hypothesis and calculated with Pearson correlations. Test-retest reliability was assessed using intraclass correlation coefficient with PROMIS instruments administered at time zero and 7 days.

RESULTS

Surveys were sent to 368 participants in total; participants who completed each questionnaire varied (n=65 to 263). For construct validity, 10 out of 13 a priori hypotheses were met supporting construct validity of PROMIS instruments (Pain Interference 3/4, fatigue 4/4, and Physical Function 3/5). Test-retest reliability was strong for all PROMIS instruments. All PROMIS instruments demonstrated excellent internal consistency. None of the measures demonstrated any ceiling or floor effects except for a ceiling effect in the Pain Interference instrument.

CONCLUSIONS

This study presents test-retest reliability and construct validity evidence supporting PROMIS Pain Interference (6a v1.0), Fatigue (7a v1.0), and Physical Function (8b v2.0) using a large international cohort of patients with IIM. Internal consistency of these instruments was excellent. A ceiling effect was noted in the Pain Interference instrument.

Rapidly progressive interstitial lung disease in patients with anti-melanoma differentiation-associated gene 5-positive dermatomyositis: serial changes on HRCT

BACKGROUND

Anti-melanoma differentiation-associated gene 5 (anti-MDA5) antibodies in patients with dermatomyositis are associated with rapidly progressive interstitial lung disease (RP-ILD). Computed tomography (CT) plays a central role in the diagnosis of RP-ILD and may help characterize the temporal changes.

METHODS

We report five anti-MDA5-positive dermatomyositis patients with serial CT scans spanning their acute RP-ILD disease course.

RESULTS

Our case series highlights the variable imaging pattern that can manifest in this setting, including diffuse alveolar damage and nonspecific interstitial pneumonia patterns. Three patients in our series died within 4 months of their disease onset, whereas the other two patients survived.

CONCLUSION

The serial CT changes in anti-MDA5 disease are dynamic and variable; therefore, it is imperative to maintain a broad differential when faced with these HRCT patterns to improve the diagnosis and management of this underrecognized entity.

Mushroom supplements triggering a flare of HMGCR immune mediated necrotising myopathy

Hydroxyl-methyl-glutaryl-Co-A reductase (HMGCR) immune mediated necrotising myopathy (IMNM) is a rare autoimmune myositis that is thought to be triggered by statins and responds to immunomodulation. We report a case of a woman in her 30s with HMGCR IMNM without a history of statin exposure who had a clear flare of her myositis after beginning mushroom supplements. Mushrooms are natural HMGCR inhibitors, and this is the first case to demonstrate a flare triggered by mushrooms in a patient with known HMGCR IMNM. This case highlights the importance of reviewing diet and supplements in patients with IMNM. It also emphasises the importance of strict statin avoidance for patients with IMNM even when the myositis is under good control.

IgM anti-ACE2 autoantibodies in severe COVID-19 activate complement and perturb vascular endothelial function

BackgroundSome clinical features of severe COVID-19 represent blood vessel damage induced by activation of host immune responses initiated by the coronavirus SARS-CoV-2. We hypothesized autoantibodies against angiotensin-converting enzyme 2 (ACE2), the SARS-CoV-2 receptor expressed on vascular endothelium, are generated during COVID-19 and are of mechanistic importance.MethodsIn an opportunity sample of 118 COVID-19 inpatients, autoantibodies recognizing ACE2 were detected by ELISA. Binding properties of anti-ACE2 IgM were analyzed via biolayer interferometry. Effects of anti-ACE2 IgM on complement activation and endothelial function were demonstrated in a tissue-engineered pulmonary microvessel model.ResultsAnti-ACE2 IgM (not IgG) autoantibodies were associated with severe COVID-19 and found in 18/66 (27.2%) patients with severe disease compared with 2/52 (3.8%) of patients with moderate disease (OR 9.38, 95% CI 2.38-42.0; P = 0.0009). Anti-ACE2 IgM autoantibodies were rare (2/50) in non-COVID-19 ventilated patients with acute respiratory distress syndrome. Unexpectedly, ACE2-reactive IgM autoantibodies in COVID-19 did not undergo class-switching to IgG and had apparent KD values of 5.6-21.7 nM, indicating they are T cell independent. Anti-ACE2 IgMs activated complement and initiated complement-binding and functional changes in endothelial cells in microvessels, suggesting they contribute to the angiocentric pathology of COVID-19.ConclusionWe identify anti-ACE2 IgM as a mechanism-based biomarker strongly associated with severe clinical outcomes in SARS-CoV-2 infection, which has therapeutic implications.FUNDINGBill & Melinda Gates Foundation, Gates Philanthropy Partners, Donald B. and Dorothy L. Stabler Foundation, and Jerome L. Greene Foundation; NIH R01 AR073208, R01 AR069569, Institutional Research and Academic Career Development Award (5K12GM123914-03), National Heart, Lung, and Blood Institute R21HL145216, and Division of Intramural Research, National Institute of Allergy and Infectious Diseases; National Science Foundation Graduate Research Fellowship (DGE1746891).

Myositis-specific Antibodies: Overview and Clinical Utilization

Purpose of review-To review autoantibodies associated with different subtypes of idiopathic inflammatory myopathy (IIM) and their clinical applications. IIM are a heterogenous group of autoimmune disorders characterized by muscle weakness, cutaneous features, and internal organ involvement. The diagnosis and classification, which is often challenging, is made using a combination of clinical features, muscle enzyme levels, imaging, and biopsy. The landmark discoveries of novel autoantibodies specific to IIM subtypes have been one of the greatest advancements in the field of myositis. The specificity of these autoantibodies has simplified the diagnostic algorithm of IIM with their heterogenous presentation and outdated the earlier diagnostic criteria. Myositis-specific antibodies (MSAs) have improved diagnostics, clinical phenotyping, and prognostic stratification of the subtypes of IIMs. Furthermore, the levels of certain MSAs correlate with disease activity and muscle enzyme levels such that titers may be able to be used to predict disease course and treatment response.

Performance of the 2017 European Alliance of Associations for Rheumatology/American College of Rheumatology Classification Criteria for Idiopathic Inflammatory Myopathies in Patients With Myositis-Specific Autoantibodies

OBJECTIVE

We undertook this study to 1) determine the sensitivity of the European Alliance of Associations for Rheumatology (EULAR)/American College of Rheumatology (ACR) classification criteria for idiopathic inflammatory myopathies (IIMs) to properly classify myositis-specific autoantibody (MSA)-positive myositis patients, 2) describe the phenotype and muscle involvement over time in different MSA-positive patients, and 3) compare MSA subgroups to EULAR/ACR criteria-defined myositis subgroups for their capacity to predict clinical phenotypes in patients with IIMs.

METHODS

The study included 524 MSA-positive myositis patients from the Johns Hopkins Myositis Center. Each patient was classified using the EULAR/ACR classification criteria. Patient phenotypes were summarized using factor analysis of mixed data (FAMD). We compared the ability of MSAs to that of the EULAR/ACR classification subgroups to predict the phenotype of patients by applying the Akaike information criterion (AIC) and the Bayesian information criteria (BIC) to the linear regression models.

RESULTS

Overall, 91% of MSA-positive patients met the EULAR/ACR criteria to be classified as having myositis. However, 20% of patients with anti-hydroxymethylglutaryl-coenzyme A reductase (anti-HMGCR) and 50% of patients with anti-PL-7 were incorrectly classified as not having myositis. Furthermore, ~10% of patients with anti-signal recognition particle (anti-SRP) and patients with anti-HMGCR were misclassified as having inclusion body myositis. FAMD demonstrated that patients within each MSA-defined subgroup had similar phenotypes. Application of both the AIC and BIC to the linear regression models revealed that MSAs were better predictors of myositis phenotypes than the subgroups defined by the EULAR/ACR criteria.

CONCLUSION

Although the EULAR/ACR criteria successfully classified 91% of MSA-positive myositis patients, certain MSA-defined subgroups, including those with autoantibodies against HMGCR, SRP, and PL-7, are frequently misclassified. In myositis patients with MSAs, autoantibodies outperform the EULAR/ACR-defined myositis subgroups in predicting the clinical phenotypes of patients. These findings underscore the need to include MSAs in a revised myositis classification scheme.

Risk Factors for Infection and Health Impacts of the Coronavirus Disease 2019 (COVID-19) Pandemic in People With Autoimmune Diseases

BACKGROUND

People with autoimmune or inflammatory conditions taking immunomodulatory/suppressive medications may have higher risk of novel coronavirus disease 2019 (COVID-19). Chronic disease care has also changed for many patients, with uncertain downstream consequences.

METHODS

We included participants with autoimmune or inflammatory conditions followed by specialists at Johns Hopkins. Participants completed periodic surveys querying comorbidities, disease-modifying medications, exposures, COVID-19 testing and outcomes, social behaviors, and disruptions to healthcare. We assessed whether COVID-19 risk is higher among those on immunomodulating or suppressive agents and characterized pandemic-associated changes to care and mental health.

RESULTS

In total, 265 (5.6%) developed COVID-19 over 9 months of follow-up (April-December 2020). Patient characteristics (age, race, comorbidity, medications) were associated with differences in social distancing behaviors during the pandemic. Glucocorticoid exposure was associated with higher odds of COVID-19 in models incorporating behavior and other potential confounders (odds ratio [OR]: 1.43; 95% confidence interval [CI]: 1.08, 1.89). Other medication classes were not associated with COVID-19 risk. Diabetes (OR: 1.72; 95% CI: 1.08, 2.73), cardiovascular disease (OR: 1.68; 95% CI: 1.24, 2.28), and kidney disease (OR: 1.76; 95% CI: 1.04, 2.97) were associated with higher odds of COVID-19. Of the 2156 reporting pre-pandemic utilization of infusion, mental health or rehabilitative services, 975 (45.2%) reported disruptions therein, which disproportionately affected individuals experiencing changes to employment or income.

CONCLUSIONS

Glucocorticoid exposure may increase risk of COVID-19 in people with autoimmune or inflammatory conditions. Disruption to healthcare and related services was common. Those with pandemic-related reduced income may be most vulnerable to care disruptions.

Anti-Cortactin Autoantibodies Are Associated With Key Clinical Features in Adult Myositis But Are Rarely Present in Juvenile Myositis

OBJECTIVE

To define the prevalence and clinical phenotype of anti-cortactin autoantibodies in adult and juvenile myositis.

METHODS

In this longitudinal cohort study, anti-cortactin autoantibody titers were assessed by enzyme-linked immunosorbent assay in 670 adult myositis patients and 343 juvenile myositis patients as well as in 202 adult healthy controls and 90 juvenile healthy controls. The prevalence of anti-cortactin autoantibodies was compared among groups. Clinical features of patients with and those without anti-cortactin autoantibodies were also compared.

RESULTS

Anti-cortactin autoantibodies were more common in adult dermatomyositis (DM) patients (15%; P = 0.005), particularly those with coexisting anti-Mi-2 autoantibodies (24%; P = 0.03) or anti-NXP-2 autoantibodies (23%; P = 0.04). In adult myositis, anti-cortactin was associated with DM skin involvement (62% of patients with anti-cortactin versus 38% of patients without anti-cortactin; P = 0.03), dysphagia (36% versus 17%; P = 0.02) and coexisting anti-Ro 52 autoantibodies (47% versus 26%; P = 0.001) or anti-NT5c1a autoantibodies (59% versus 33%; P = 0.001). Moreover, the titers of anti-cortactin antibodies were higher in patients with interstitial lung disease (0.15 versus 0.12 arbitrary units; P = 0.03). The prevalence of anti-cortactin autoantibodies was not different in juvenile myositis patients (2%) or in any juvenile myositis subgroup compared to juvenile healthy controls (4%). Nonetheless, juvenile myositis patients with these autoantibodies had a higher prevalence of "mechanic's hands" (25% versus 7%; P = 0.03), a higher number of hospitalizations (2.9 versus 1.3; P = 0.04), and lower peak creatine kinase values (368 versus 818 IU/liter; P = 0.02) than those without anti-cortactin.

CONCLUSION

The prevalence of anti-cortactin autoantibodies is increased in adult DM patients with coexisting anti-Mi-2 or anti-NXP-2 autoantibodies. In adults, anti-cortactin autoantibodies are associated with dysphagia and interstitial lung disease.

Immune responses to CCAR1 and other dermatomyositis autoantigens are associated with attenuated cancer emergence

BACKGROUND

The temporal clustering of a cancer diagnosis with dermatomyositis (DM) onset is strikingly associated with autoantibodies against transcriptional intermediary factor 1-γ (TIF1-γ). Nevertheless, many patients with anti–TIF1-γ antibodies never develop cancer. We investigated whether additional autoantibodies are found in anti–TIF1-γ–positive patients without cancer.

METHODS

Using a proteomic approach, we defined 10 previously undescribed autoantibody specificities in 5 index anti–TIF1-γ–positive DM patients without cancer. These were subsequently examined in discovery (n = 110) and validation (n = 142) cohorts of DM patients with anti–TIF1-γ autoantibodies.

RESULTS

We identified 10 potentially novel autoantibodies in anti–TIF1-γ–positive DM patients, 6 with frequencies ranging from 3% to 32% in 2 independent DM cohorts. Autoantibodies recognizing cell division cycle and apoptosis regulator protein 1 (CCAR1) were the most frequent, and were significantly negatively associated with contemporaneous cancer (discovery cohort OR 0.27 [95% CI 0.7–1.00], P = 0.050; validation cohort OR 0.13 [95% CI 0.03–0.59], P = 0.008). When cancer did emerge, it occurred significantly later in anti-CCAR1–positive compared with anti-CCAR1–negative patients (median time from DM onset 4.3 vs. 0.85 years, respectively; P = 0.006). Cancers that emerged were more likely to be localized (89% of anti-CCAR1–positive cancers presenting at stage 0 or 1 compared with 42% of patients without anti-CCAR1 antibodies, P = 0.02). As the number of additional autoantibody specificities increased in anti–TIF1-γ–positive DM patients, the frequency of cancer decreased (P < 0.001).

CONCLUSION

As the diversity of immune responses in anti–TIF1-γ DM patients increases, the likelihood of cancer emerging decreases. Our findings have important relevance for cancer risk stratification in DM patients and for understanding natural immune regulation of cancer in humans.

TRIAL REGISTRATION

Not applicable.

FUNDING SOURCES

The NIH, the Donald B. and Dorothy L. Stabler Foundation, and the Huayi and Siuling Zhang Discovery Fund.

On the Nose: Anti-MDA-5 Dermatomyositis Manifesting as Perinasal Swelling

The clinical presentation of dermatomyositis (DM) is diverse, with varied phenotypes that may be correlated with specific autoantibodies. The anti-melanoma differentiation-associated gene 5 (MDA5) antibody in DM is associated with an amyopathic phenotype of DM, with several unusual cutaneous manifestation and increased risk for rapidly progressive interstitial lung disease. Initial presentation may be subtle, but early diagnosis is key to initiation of proper immunosuppressive therapy. In this report, we describe perinasal edema and erythema as a presenting complaint of anti-MDA5 DM in an otherwise healthy 40-year-old woman. The edema began shortly after heavy sun exposure and was followed by painful papules in her hands and arthritis within a few weeks. She was found to have high titer of anti-CCP and anti-MDA5, and thus was diagnosed with DM and rheumatoid arthritis overlap. A CT chest, abdomen, and pelvis showed patchy ground-glass and interstitial opacities in bilateral lower lobes consistent with mild interstitial lung disease without evidence of malignancy. Perinasal cutaneous findings and arthralgias improved with initiation of prednisone. To our knowledge, this is the first report of perinasal edema as a presenting symptom for DM and should raise suspicion for MDA-5 disease.

Disease Flare and Reactogenicity in Patients With Rheumatic and Musculoskeletal Diseases Following Two-Dose SARS-CoV-2 Messenger RNA Vaccination

OBJECTIVE

To evaluate disease flare and postvaccination reactions (reactogenicity) in patients with rheumatic and musculoskeletal diseases (RMDs) following 2-dose SARS-CoV-2 messenger RNA (mRNA) vaccination.

METHODS

RMD patients (n = 1,377) who received 2-dose SARS-CoV-2 mRNA vaccination between December 16, 2020 and April 15, 2021 completed questionnaires detailing local and systemic reactions experienced within 7 days of each vaccine dose (dose 1 and dose 2), and 1 month after dose 2, detailing any flares of RMD. Associations between demographic/clinical characteristics and flares requiring treatment were evaluated using modified Poisson regression.

RESULTS

Among the patients, 11% reported flares requiring treatment; there were no reports of severe flares. Flares were associated with prior SARS-CoV-2 infection (incidence rate ratio [IRR] 2.09, P = 0.02), flares in the 6 months preceding vaccination (IRR 2.36, P < 0.001), and the use of combination immunomodulatory therapy (IRR 1.95, P < 0.001). The most frequently reported local and systemic reactions included injection site pain (87% after dose 1, 86% after dose 2) and fatigue (60% after dose 1, 80% after dose 2). Reactogenicity increased after dose 2, particularly for systemic reactions. No allergic reactions or SARS-CoV-2 diagnoses were reported.

CONCLUSION

Flares of underlying RMD following SARS-CoV-2 vaccination were uncommon. There were no reports of severe flares. Local and systemic reactions typically did not interfere with daily activity. These early safety data can help address vaccine hesitancy in RMD patients.

Idiopathic inflammatory myopathies

Idiopathic inflammatory myopathies (IIM), also known as myositis, are a heterogeneous group of autoimmune disorders with varying clinical manifestations, treatment responses and prognoses. Muscle weakness is usually the classical clinical manifestation but other organs can be affected, including the skin, joints, lungs, heart and gastrointestinal tract, and they can even result in the predominant manifestations, supporting that these are systemic inflammatory disorders. Different myositis-specific autoantibodies have been identified and, on the basis of clinical, histopathological and serological features, IIMs can be classified into several subgroups — dermatomyositis (including amyopathic dermatomyositis), antisynthetase syndrome, immune-mediated necrotizing myopathy, inclusion body myositis, polymyositis and overlap myositis. The prognoses, treatment responses and organ manifestations vary among these groups, implicating different pathophysiological mechanisms in each subtype. A deeper understanding of the molecular pathways underlying the pathogenesis and identifying the autoantigens of the immune reactions in these subgroups is crucial to improve outcomes. New, more homogeneous subgroups defined by autoantibodies may help define disease mechanisms, and will also be important in future clinical trials to develop targeted therapies and in identifying biomarkers to guide treatment decisions for the individual patient.

A network of core and subtype-specific gene expression programs in myositis

Myositis comprises a heterogeneous group of skeletal muscle disorders which converge on chronic muscle inflammation and weakness. Our understanding of myositis pathogenesis is limited, and many myositis patients lack effective therapies. Using muscle biopsy transcriptome profiles from 119 myositis patients (spanning major clinical and serological disease subtypes) and 20 normal controls, we generated a co-expression network of 8101 dynamically regulated transcripts. This network organized the myositis transcriptome into a map of gene expression modules representing interrelated biological processes and disease signatures. Universally myositis-upregulated network modules included muscle regeneration, specific cytokine signatures, the acute phase response, and neutrophil degranulation. Universally myositis-suppressed pathways included a specific subset of myofilaments, the mitochondrial envelope, and nuclear isoforms of the anti-apoptotic humanin protein. Myositis subtype-specific modules included type 1 interferon signaling and titin (dermatomyositis), RNA processing (antisynthetase syndrome), and vasculogenesis (inclusion body myositis). Importantly, therapies exist to target influential proteins in many myositis-dysregulated modules, and nearly all modules contained understudied proteins and non-coding RNAs - many of which were extraordinarily dysregulated in myositis and may represent novel therapeutic targets. Finally, we apply our network to patient classification, finding that a deep learning algorithm trained on patient-level network "images" successfully assigned patients to clinical groups and further into molecular subclusters. Altogether, we provide a global resource to probe and contextualize differential gene expression in myositis.

Racial Disparities in Skin Tone Representation of Dermatomyositis Rashes: A Systematic Review

OBJECTIVE

This systemic review assesses skin tone representation in images of dermatomyositis rashes in medical education literature.

METHODS

A review of 59 dermatology, 11 neurology, 10 neuromuscular, 7 rheumatology, and 6 internal medicine textbooks published between 2011 and 2021 and 3 online image databases (UpToDate, VisualDx, and DermNet NZ) that were available through an online medical school library was performed. After extracting images, images with poor lighting or unclear rashes were removed. Authors graded skin tone independently on the Massey and Martin Skin Colour Scale (MMSCS) from 1 (very light) to 10 (very dark). The median score was taken for a final score, grouped within MMSCS 1-2, 3-4, 5-7, or 8-10. Inter-rater reliability was assessed using Kendall's coefficient of concordance (W).

RESULTS

621 images were extracted after reviewing 93 textbooks and 3 online databases. Of the 561 images analyzed, 73.1% of images represented MMSCS 1-2, followed by 3-4 (13.4%), 5-7 (11.8%), and 8-10 (1.8%). Inter-rater reliability was high (W = 0.835). Of the images in MMSCS 5-10, 59.2% were in online databases and 80.6% of textbook images were in dermatology books.

CONCLUSIONS

Patients with lighter skin tones were represented in a higher number of dermatomyositis-related educational materials compared with patients with darker skin tones. Our findings add to current research implicating that darker skin tones are underrepresented in cutaneous educational materials, specifically for dermatomyositis. This leads to the inability to properly characterize skin involvement in dermatomyositis and may lead to inappropriate exclusion from clinical trials due to erroneous skin scoring.