RNA helicase encoded by melanoma differentiation-associated gene 5 is a major autoantigen in patients with clinically amyopathic dermatomyositis: Association with rapidly progressive interstitial lung disease

Soluble CXCL16 is a prognostic biomarker associated with rapidly progressive interstitial lung disease complicated with dermatomyositis

OBJECTIVES

Rapidly progressive interstitial lung disease (RPILD) in patients with dermatomyositis (DM) significantly impacts prognosis, leading to high mortality rates. Although several indicators have been demonstrated to strongly correlate with the risk of developing RPILD, their clinical utility still needs to be investigated. The objective of this study was to investigate the clinical significance of soluble CXCL16 (sCXCL16) in DM patients complicated with RPILD.

METHODS

Serum sCXCL16 was measured by enzyme-linked immunosorbent assay in 96 patients with DM and 55 matching healthy donors. Correlations between sCXCL16 levels and clinical features, laboratory examinations and the predictive value of baseline sCXCL16 level for RPILD were analysed.

RESULTS

The serum sCXCL16 levels were significantly higher in patients with DM (n = 96, 3.264 ± 1.516 ng/mL) compared with healthy donors (n = 55, 1.781 ± 0.318 ng/mL), especially in DM complicated with RPILD (n = 31, 4.441 ± 1.706 ng/mL). The sCXCL16 levels were positively correlated with levels of serum ferritin, C reactive protein, erythrocyte sedimentation rate, lactate dehydrogenase, hydroxybutyrate dehydrogenase, and negatively correlated with peripheral lymphocytes percentage, but showed no correlation with levels of anti-melanoma differentiation-associated gene 5 antibody, Krebs von den Lungen-6 or creatine kinase. Multivariable analysis showed that elevated sCXCL16 was an independent prognostic factor for poor prognosis of RPILD in patients with DM. The 2-year survival rate was significantly lower in patients with high sCXCL16 level than in those with low sCXCL16 level.

CONCLUSION

A higher serum sCXCL16 level was identified as a predictive biomarker of RPILD in patients with DM, and closely associated with poor prognosis.

Phage Immunoprecipitation-Sequencing Reveals CDHR5 Autoantibodies in Select Patients With Interstitial Lung Disease

OBJECTIVE

Interstitial lung diseases (ILDs) are a heterogeneous group of disorders that can develop in patients with connective tissue diseases. Establishing autoimmunity in ILD impacts prognosis and treatment. Patients with ILD are screened for autoimmunity by measuring antinuclear autoantibodies, rheumatoid factors, and other nonspecific tests. However, this approach may miss autoimmunity that manifests as autoantibodies to tissue antigens not previously defined in ILD.

METHODS

We use Phage Immunoprecipitation-Sequencing (PhIP-Seq) to conduct an autoantibody discovery screen of patients with ILD and controls. We screened for novel autoantigen candidates using PhIP-Seq. We next developed a radio-labeled binding assay and validated the leading candidate in 398 patients with ILD recruited from two academic medical centers and 138 blood bank individuals that formed our reference cohort.

RESULTS

PhIP-Seq identified 17 novel autoreactive targets, and machine learning classifiers derived from these targets discriminated ILD serum from controls. Among the 17 candidates, we validated CDHR5 and found CDHR5 autoantibodies in patients with rheumatologic disorders and importantly, patients not previously diagnosed with autoimmunity. Using survival and transplant free-survival data available from one of the two centers, patients with CDHR5 autoantibodies showed worse survival compared with other patients with connective tissue disease ILD.

CONCLUSION

We used PhIP-Seq to define a novel CDHR5 autoantibody in a subset of select patients with ILD. Our data complement a recent study showing polymorphisms in the CDHR5-IRF7 gene locus strongly associated with titer of anticentromere antibodies in systemic sclerosis, creating a growing body of evidence suggesting a link between CDHR5 and autoimmunity.

MDA5-autoimmunity and interstitial pneumonitis contemporaneous with the COVID-19 pandemic (MIP-C)

BACKGROUND

Anti-MDA5 (Melanoma differentiation-associated protein-5) positive dermatomyositis (MDA5+-DM) is characterised by rapidly progressive interstitial lung disease (ILD) and high mortality. MDA5 is an RNA sensor and a key pattern recognition receptor for the SARS-CoV-2 virus.

METHODS

This is a retrospective observational study of a surge in MDA5 autoimmunity, as determined using a 15 muscle-specific autoantibodies (MSAs) panel, between Janurary 2018 and December 2022 in Yorkshire, UK. MDA5-positivity was correlated with clinical features and outcome, and regional SARS-CoV-2 positivity and vaccination rates. Gene expression patterns in COVID-19 were compared with autoimmune lung disease and idiopathic pulmonary fibrosis (IPF) to gain clues into the genesis of the observed MDA5+-DM outbreak.

FINDINGS

Sixty new anti-MDA5+, but not other MSAs surged between 2020 and 2022, increasing from 0.4% in 2019 to 2.1% (2020), 4.8% (2021) and 1.7% (2022). Few (8/60) had a prior history of confirmed COVID-19, peak rates overlapped with regional SARS-COV-2 community positivity rates in 2021, and 58% (35/60) had received anti-SARS-CoV-2 vaccines. 25/60 cases developed ILD which rapidly progression with death in 8 cases. Among the 35/60 non-ILD cases, 14 had myositis, 17 Raynaud phenomena and 10 had dermatomyositis spectrum rashes. Transcriptomic studies showed strong IFIH1 (gene encoding for MDA5) induction in COVID-19 and autoimmune-ILD, but not IPF, and IFIH1 strongly correlated with an IL-15-centric type-1 interferon response and an activated CD8+ T cell signature that is an immunologic hallmark of progressive ILD in the setting of systemic autoimmune rheumatic diseases. The IFIH1 rs1990760TT variant blunted such response.

INTERPRETATION

A distinct pattern of MDA5-autoimmunity cases surged contemporaneously with circulation of the SARS-COV-2 virus during COVID-19. Bioinformatic insights suggest a shared immunopathology with known autoimmune lung disease mechanisms.

FUNDING

This work was supported in part by the National Institute for Health Research (NIHR) Leeds Biomedical Research Centre (BRC), and in part by the National Institutes of Health (NIH) grant R01-AI155696 and pilot awards from the UC Office of the President (UCOP)-RGPO (R00RG2628, R00RG2642 and R01RG3780) to P.G. S.S was supported in part by R01-AI141630 (to P.G) and in part through funds from the American Association of Immunologists (AAI) Intersect Fellowship Program for Computational Scientists and Immunologists.

Liver Involvement is Associated with Higher Risk of Rapidly Progressive Interstitial Lung Disease and Mortality in Anti-Melanoma Differentiation-Associated Gene 5 Antibody- Positive Dermatomyositis

Purpose

This study aimed to assess liver involvement and investigate its correlation with rapidly progressive interstitial lung disease (RP-ILD) and mortality in anti-melanoma differentiation-associated gene 5 antibody-positive (anti-MDA5 positive) DM patients.

Patients and Methods

This retrospective study included 159 patients diagnosed with anti-MDA5 positive DM or anti-synthetase syndrome (ASyS). Clinical features and laboratory findings were compared between patients with anti-MDA5 positive DM and patients with ASyS. In the anti-MDA5 positive DM cohort, clinical features and laboratory findings between patients with liver involvement and without liver involvement were further compared. The effects of liver involvement on the overall survival (OS) and development of RP-ILD were also analyzed using Kaplan-Meier method and Cox regression analysis.

Results

Levels of serum aspartate aminotransferase (AST), alanine transaminase (ALT), γ-glutamyl transferase (γGT) and alkaline phosphatase (ALP) were all significantly higher in patients with anti-MDA5 positive DM than those in patients with ASyS. In our cohort of anti-MDA5 positive DM patents, 31 patients (34.4%) were complicated with liver involvement. Survival analysis revealed that serum ferritin >1030.0 ng/mL (p<0.001), ALT >103.0 U/l (p<0.001), AST >49.0 U/l (p<0.001), γGT >82.0 U/l (p<0.001), ALP >133.0 U/l (p<0.001), lactate dehydrogenase (LDH)>474.0 U/l (p<0.001), plasma albumin (ALB) <35.7 g/l (p<0.001) and direct bilirubin (DBIL) >2.80 μmol/l (p=0.002) predicted poor prognosis. The incidence of RP-ILD increased remarkably in patients with liver involvement compared to patients without liver involvement (58.1% vs 22.0%, p=0.001). Multivariate analysis revealed that elevated serum ALT level was an independent risk factor for mortality (HR 6.0, 95% CI 2.3, 16.2, p<0.001) and RP-ILD (HR 5.9, 95% CI 2.2, 15.9, p<0.001) in anti-MDA5 positive DM patents.

Conclusion

Liver involvement is common in patients with anti-MDA5 positive DM. Elevated serum ALT level was an independent risk factor for RP-ILD and mortality in patients with anti-MDA5 positive DM.

The central helicase domain holds the major conformational epitopes of melanoma differentiation-associated gene 5 autoantibodies

OBJECTIVE

Autoantibodies against MDA5 (melanoma differentiation-associated protein 5) serve as a biomarker for DM (dermatomyositis) and indicate a risk factor for interstitial lung disease (ILD). MDA5 is a protein responsible for sensing RNA virus infection and activating signalling pathways against it. However, little is known about the antigen epitopes on MDA5 autoantibodies. We aimed to determine the interaction of the MDA5 autoantibody-antigen epitope.

METHODS

Cell-based assays (CBAs), immunoprecipitation-immunoblot assays, and various immunoblotting techniques were used in the study.

RESULTS

We demonstrated that DM patient autoantibodies recognize MDA5 epitopes in a native conformation-dependent manner. Furthermore, we identified the central helicase domain （3Hel） formed by Hel1, Hel2i, Hel2, and pincer as the major epitopes. As proof of principle, the purified 3Hel efficiently absorbed MDA5 autoantibodies from patient sera through immunoprecipitation-immunoblot assay.

CONCLUSION

Our study uncovered the nature of the antigen epitopes on MDA5 and can provide guidance for diagnosis and a targeted therapeutic approach development.

Autoantibodies against the melanoma differentiation-associated protein 5 in patients with dermatomyositis target the helicase domains

OBJECTIVES

Clinical observations in patients with dermatomyositis (DM) and autoantibodies against the melanoma differentiation-associated protein 5 (MDA5) suggest that the autoantibodies contribute to the pathogenesis of MDA5(+) DM. To gain insight into the role of the anti-MDA5 autoantibodies, we aimed to identify their binding sites on the different domains of the MDA5 protein.

METHODS

We developed an in-house ELISA to assess the reactivity against the MDA5 domains (conformational epitopes) in plasma (n = 8) and serum (n = 24) samples from MDA5(+) patients with varying clinical manifestations and disease outcomes. The reactivities were also assessed using western blot (linearized epitopes). An ELISA-based depletion assay was developed to assess cross-reactivity among the different MDA5 domains.

RESULTS

All eight plasma samples consistently showed reactivity towards conformational and linearized epitopes on the helicase domains of the MDA5 protein. The ELISA-based depletion assay suggests that anti-MDA5 autoantibodies specifically target each of the three helicase domains. Twenty-two of the 24 serum samples showed reactivity in the in-house ELISA and all 22 displayed reactivity towards the helicase domains of the MDA5 protein.

CONCLUSIONS

Our data revealed that the main immunogenic targets of anti-MDA5 autoantibodies from MDA5(+) patients are the helicase domains. Considering that the helicase domains are responsible for the enzymatic activity and subsequent triggering of an inflammatory response, our findings suggest that binding of anti-MDA5 autoantibodies could alter the canonical activity of the MDA5 protein and potentially affect the downstream induction of a pro-inflammatory cascade.

Elevated serum B-cell activator factor levels predict rapid progressive interstitial lung disease in anti-melanoma differentiation associated protein 5 antibody positive dermatomyositis

BACKGROUND

Rapid progressive interstitial lung disease (RP-ILD) is the leading cause of anti-melanoma differentiation associated protein 5 antibody positive dermatomyositis (anti-MDA5+DM) related death. Elevated serum B-cell activating factor (BAFF) levels have been implicated in connective tissue diseases associated ILD. Here, we evaluate whether BAFF could be a prognostic biomarker for predicting RP-ILD in anti-MDA5+DM patients.

METHODS

Serums were collected from 39 patients with anti-MDA5+DM (20 with RP-ILD and 19 with non-RP-ILD), 20 antisynthase syndrome (ASS) patients and 20 healthy controls (HC). BAFF concentration was measured by an enzyme-linked immunosorbent assay.

RESULTS

Serum BAFF level was higher in anti-MDA5+DM patients than those in ASS patients and HC (3882.32 ± 1880.09 vs. 2540.89 ± 1403.04 and 2486.28 ± 767.97 pg/mL, p = 0.0056 and 0.0038, respectively). Within anti-MDA5+DM groups, RP-ILD patients exhibited higher BAFF concentration than non-RP-ILD group (4549.78 ± 1839.97 vs. 3297.28 ± 1794.69 pg/mL, p = 0.04). The BAFF concentration was positively correlated with levels of C-reactive protein (CRP), dehydrogenase (LDH) and cytokeratin (CK) in anti-MDA5+DM patients (r = 0.350, p = 0.035; r = 0.393, p = 0.016; r = 0.518, p = 0.001; respectively). The best cut-off value of BAFF concentration was 2971.5 pg/mL by ROC curve (AUC area = 0.690, p = 0.045) and BAFF > 2971.5 pg/mL was an independent risk factor for RP-ILD using multivariate analysis (OR = 9.389, 95% CI = 1.609-54.769; p = 0.013).

CONCLUSIONS

Serum BAFF could be a useful prognostic biomarker for early detecting RP-ILD risk in anti-MDA5+DM patients.

Autoimmunity against melanoma differentiation-associated gene 5 induces interstitial lung disease mimicking dermatomyositis in mice

Anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive dermatomyositis (DM) is characterized by amyopathic DM with interstitial lung disease (ILD). Patients with anti-MDA5 antibody-associated ILD frequently develop rapidly progression and present high mortality rate in the acute phase. Here, we established a murine model of ILD mediated by autoimmunity against MDA5. Mice immunized with recombinant murine MDA5 whole protein, accompanied with complete Freund's adjuvant once a week for four times, developed MDA5-reactive T cells and anti-MDA5 antibodies. After acute lung injury induced by intranasal administration of polyinosinic-polycytidylic acid [poly (I:C)] mimicking viral infection, the MDA5-immunized mice developed fibrotic ILD representing prolonged respiratory inflammation accompanied by fibrotic changes 2 wk after poly (I:C)-administration, while the control mice had quickly and completely recovered from the respiratory inflammation. Treatment with anti-CD4 depleting antibody, but not anti-CD8 depleting antibody, suppressed the severity of MDA5-induced fibrotic ILD. Upregulation of interleukin (IL)-6 mRNA, which was temporarily observed in poly (I:C)-treated mice, was prolonged in MDA5-immunized mice. Treatment with anti-IL-6 receptor antibody ameliorated the MDA5-induced fibrotic ILD. These results suggested that autoimmunity against MDA5 exacerbates toll-like receptor 3-mediated acute lung injury, and prolongs inflammation resulting in the development of fibrotic ILD. IL-6 may play a key role initiating ILD in this model.

Spontaneous pneumomediastinum in anti-MDA5-positive dermatomyositis: Prevalence, risk factors, and prognosis

OBJECTIVE

To depict the clinical panorama of spontaneous pneumomediastinum (SPM) in anti-MDA5 antibody-positive dermatomyositis (anti-MDA5+ DM).

METHODS

A total of 1352 patients with idiopathic inflammatory myopathy (IIM), including 384 anti-MDA5+ DM patients were retrospectively enrolled. The clinical profiles of anti-MDA5+ DM-associated SPM were analyzed.

RESULTS

We identified that 9.4 % (36/384) of anti-MDA5+ DM patients were complicated with SPM, which was significantly higher than that of non-anti-MDA5+ DM and other IIM subtypes (P all <0.001). SPM developed at a median of 5.5 (3.0, 12.0) months after anti-MDA5+ DM onset. Anti-MDA5+ DM patients complicated with SPM showed a significantly higher frequency of fever, dyspnea, and pulmonary infection including viral and fungal infections compared to those without SPM (P all < 0.05). Cytomegalovirus (CMV) and fungal infections were identified to be independent risk factors for SPM development in the anti-MDA5+ DM. SPM and non-SPM patients in our anti-MDA5+ DM cohort showed comparable short-term and long-term survival (P = 0.236). Furthermore, in the SPM group, we found that the non-survivors had a lower peripheral lymphocyte count, higher LDH level, and higher frequency of intensification of immunosuppressive treatment (IST) than survivors. The elevated LDH level and intensification of IST were independent risk factors for increased mortality in anti-MDA5+ DM-associated SPM patients.

CONCLUSIONS

Nearly one-tenth of patients with anti-MDA5+ DM develop SPM. Both CMV and fungal infections are risk factors for SPM occurrence. The development of SPM does not worsen the prognosis of anti-MDA5+ DM patients, and the intensification of IST does harm to the SPM prognosis.

"Amyopathic" MDA5-positive dermatomyositis with severe lung involvement presenting with net myositic morphological features - insights from an autopsy study

Anti-MDA5-positive dermatomyositis (MDA5-DM) often presents with extramuscular, especially pulmonary and skin manifestations, and apparent clinical signs of frank myositis can be missing (so called amyopathic DM). We hereby present two male patients who died from respiratory failure during the course of MDA5-DM. While overt signs of myositis or any skin involvement were absent at admission to hospital we noticed conspicuous inflammatory alterations in various skeletal muscles morphologically, showing different degrees of affection. Furthermore, pathological changes of the lungs compatible with rapid progressive interstitial lung disease and characteristic cutaneous vasculoocclusive features were identified at autopsy. This observation shows that muscles and skin are subclinically affected in a widespread fashion, hence subtle signs of muscle involvement should be sought after in anti-MDA5-positive patients with predominant lung affection to ensure adequate treatment.

Rapidly progressive interstitial lung disease with positive anti-MDA5 antibody as an immune-related complication of nivolumab: A case report

Clinically amyopathic dermatomyositis (CADM) with a positive anti-MDA5 antibody titer is often associated with lethal rapidly progressive interstitial lung disease (RP-ILD). Despite the widespread use of immune checkpoint inhibitors (ICIs) in practice, there is no report of CADM with positive anti-MDA5 antibodies as their immune-related complication. We present a case of malignant mesothelioma who developed RP-ILD accompanied by distinct skin manifestations following the administration of nivolumab. Postmortem assessment of stored samples revealed a pre-existing positive titer of anti-MDA5 antibody, further augmented following ICI use, suggesting the possible value of serum screening for better risk stratification of this lethal complication.

[Pulmonary involvement in idiopathic inflammatory myopathies]

Idiopathic inflammatory myopathies are rare systemic diseases with different types of pulmonary manifestations depending on the underlying aetiology; here, interstitial lung diseases (ILD) are the most frequently found patterns depending on the underlying disorder. There is a lack of sufficient prospective studies on this heterogeneous group of patients, particularly in case of ILD being involved. The diagnosis is based upon guideline recommendations for ILD and requires a multidisciplinary discussion within a team with specific expertise in this field. Myositis specific antibodies and myositis associated antibodies form an essential part of the diagnostic tools and may also be associated with a certain phenotype or disease progression. Anti-t-RNA-synthetase antibodies (Anti-ARS) and anti-melanoma differentiation-associated gene 5 antibodies (MDA5) play an important clinical role for treatment the estimation of response and prognosis. The most common ILD patterns are nonspecific interstitial pneumonia (NSIP) and organising pneumonia (OP) or a mixed pattern of both. Treatment is based on systemic steroids and early initiation of other immunosuppressant drugs. Evidence for this is, however, sparse, since most of the studies having investigated treatment modalities are of retrospective nature, even though some new prospective data may be useful for the establishment of treatment pathways in the future.

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.

Extracellular Vesicles in the Pathogenesis, Clinical Characterization, and Management of Dermatomyositis: A Narrative Review

Extracellular vesicles (EVs) are lipid-bilayer particles secreted from cells that primarily assist in cell-to-cell communication through the content of their cargo, such as proteins and RNA. EVs have been implicated in the pathogenesis of various autoimmune diseases, including dermatomyositis (DM), an inflammatory autoimmune disease characterized by distinct cutaneous manifestations, myopathy, and lung disease. We sought to review the role of EVs in DM and understand how they contribute to the pathogenesis and clinical characterization of the disease. We summarized the research progress on EVs in dermatomyositis based on recent publications. EV cargoes, such as double-stranded DNA, microRNA, and proteins, contribute to DM pathogenesis and mediate the proinflammatory response and cytokine release through signaling pathways such as the stimulator of interferon genes (STING) pathway. These nucleic acids and proteins have been proposed as disease-specific, stable biomarkers to monitor disease activity and responses to therapy. They also correlate with clinical parameters, inflammatory markers, and disease severity scores. Furthermore, some markers show an association with morbidities of DM, such as muscle weakness and interstitial lung disease. The continued study of EVs will help us to further elucidate our understanding of dermatomyositis.

A bibliometric analysis of the research status and trends in studies on polymyositis and dermatomyositis with interstitial lung disease from 2000 to 2022 using Web of Science

BACKGROUND

The main subtypes of idiopathic inflammatory myopathies (IIMs)-polymyositis (PM) and dermatomyositis (DM)-are often presented as interstitial lung disease (ILD) in clinical practice; therefore, many researchers have combined the three studies into PM/DM with ILD.

METHODS

Using bibliometrics, the research status, progress, and hotspots of PM/DM with ILD between 2000 and 2022 were studied. Literature data on PM/DM with ILD were retrieved from the Web of Science (WoS) database for the research period. Visualization software, including VOSviewer, Pajek, CiteSpace, and Scimago Graphica were used for bibliometric analysis.

RESULTS

A total of 1555 relevant articles were obtained, and the overall research in this field showed an increasing trend. Regarding contributing countries and venues, Japan published the most articles while Rheumatology was the most prolific journal. Regarding authors, the most published article was by Wang Guochun from Changchun University of Technology in China. Keyword analysis and cocited literature cluster analysis showed that diagnosis, classification, autoantibodies, antibodies, prognosis, complications, and treatment of PM/DM with ILD have been hot topics in this field recently. Moreover, our study shows that anti-mda5 antibody, mortality, gene 5 antibody, IIMs, double-blind, and prognostic factors, among others, may be new hot topics.

CONCLUSION

This study found that research on PM/DM with ILD has increased over time, and scholars are paying more attention to this field. The development of new drugs for the management, treatment, and prevention of PM/DM with ILD is the primary task of researchers and a direction for future research in this field.

Early Initiation of Plasma Exchange Therapy for Anti-MDA5+Dermatomyositis with Refractory Rapidly Progressive Interstitial Lung Disease

Objectives Dermatomyositis (DM) is often associated with fatal anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive rapidly progressive interstitial lung disease (RP-ILD). RP-ILD often fails to respond to intensive treatment and has a poor prognosis. We examined the effectiveness of early plasma exchange therapy plus intensive treatment with high-dose corticosteroids and multiple immunosuppressants. Methods Autoantibodies were identified by an immunoprecipitation assay and enzyme-linked immunosorbent assay. All clinical and immunological data were collected retrospectively from medical charts. We divided patients into two groups based on treatment regimen: intensive immunosuppressive therapy alone as initial treatment (IS group) and early initiation of plasma exchange (PE) plus intensive immunosuppressive therapy (ePE group). Early PE therapy was designated if PE therapy was initiated within two weeks of starting treatment. Comparisons of the treatment response and prognosis between groups were performed. Patients Anti-MDA5-positive DM with RP-ILD was screened. Results Forty-four RP-ILD and DM patients had anti-MDA5 antibodies. Four patients were excluded because they died before receiving sufficient combined immunosuppressive therapy or before the evaluation of the immunosuppressive treatment effectiveness (IS, n=31; ePE, n=9). All 9 patients in the ePE group had improved respiratory symptoms and were alive, whereas 12 of 31 patients in the IS group died (100 vs. 61%, p=0.037). Of the 8 patients who had 2 values for a poor prognosis, indicating the highest risk for death using the MCK model, 3 of 3 patients in the ePE group and 2 of 5 in the IS group were alive (100 vs. 40%, p=0.20). Conclusion The early initiation of ePE therapy plus intensive immunosuppressive therapy was effective for patients with DM and refractory RP-ILD.

Anti-MDA5 antibody-positive dermatomyositis: pathogenesis and clinical progress

Anti-melanoma differentiation-associated protein 5 (MDA5) antibody-positive dermatomyositis (MDA5-DM) is a subtype of dermatomyositis. Although the aetiology and pathology remain unclear, increasing evidence suggests that viral infection is a potential trigger of MDA5-DM. Multiple factors, including T cells, B cells, neutrophils and macrophages, are implicated in the pathophysiology of MDA5-DM. Distinctive skin rashes, rapidly progressive interstitial lung disease, peripheral lymphopenia and elevated serum ferritin levels are the most prominent clinical and laboratory features of MDA5-DM. Concomitant infection is a common complication of MDA5-DM. The proper evaluation of patients with MDA5-DM requires knowledge of the disease heterogeneity and clinical course variability. Several biomarkers, including serum levels of anti-MDA5 antibodies and biomarkers related to macrophage activation, have been identified as useful tools for monitoring disease activity and prognosis. MDA5-DM shows a poor response to conventional glucocorticoid and immunosuppressant therapy and has a poor overall prognosis. Therefore, there is an urgent need to explore the key pathogenic mechanisms of MDA5-DM and develop novel therapeutic options for patients. This Review discusses recent clinical progress and pathogenic findings of MDA5-DM.

Gender differences in patients with anti-MDA5-positive dermatomyositis: a cohort study of 251 cases

OBJECTIVE

To investigate the impact of sex differences on the clinical characteristics and prognosis of patients with anti-melanoma differentiation-associated gene 5-positive dermatomyositis (MDA5+ DM).

METHODS

We retrospectively analyzed a cohort of 251 patients with MDA5+ DM, including 71 in the male group and 180 in the female group. A multivariate logistic regression model was built to analyze independent risk factors for RPILD in each group. An ROC curve was drawn to evaluate the predictive value of independent risk factors. Kaplan‒Meier analysis was used to compare the cumulative survival rates, while the log-rank test was used to test for significant differences between the two groups.

RESULTS

Patients in the male group had a significantly higher prevalence of heliotrope rash, V sign, severe interstitial lung disease (ILD), and rapidly progressive interstitial lung disease (RPILD) than those in the female group. Anti-Ro52 positivity, high CRP level and short disease were identified as independent risk factors for RPILD in both male and female groups by multivariate logistic regression analysis. The mortality rates of males and females were 33.8% and 22.0%, respectively, and the survival time of patients in the male group was shorter than that in the female group.

CONCLUSION

Male patients with MDA5+ DM exhibit an increased risk of RPILD, elevated mortality rates and reduced overall survival time compared to their female counterparts, and anti-Ro52 positivity may be an unfavorable prognostic factor for these patients. Key Points • The prevalence of solar rash, V sign, severe interstitial lung disease (ILD) and rapidly progressive interstitial lung disease (RPILD) in anti-MDA5-positive female patients was significantly lower than that in male patients. • Positive Anti-Ro52, high CRP level, and short course of disease were independent risk factors for RPILD in both men and women. • Female patients exhibited a lower mortality rate than male patients (22.0% vs 33.8%) and demonstrated longer survival time.

Dissociating Autoantibody Responses against Ro52 Antigen in Patients with Anti-Synthetase or Anti-MDA5 Antibodies

We aimed to dissociate the autoantibody response against the Ro52 protein in patients with anti-synthetase or anti-melanoma differentiation-associated gene 5 (MDA5) antibodies to explore the potential roles of different anti-Ro52 autoantibody responses in disease subclassification. This study used a single-center, prospective myositis cohort involving 122 consecutive patients with anti-synthetase antibodies identified by RNA immunoprecipitation (RNA-IP) and 34 patients with anti-MDA5 antibodies detected using enzyme immunoassay (EIA). Anti-Ro52 antibodies were measured using commercial EIA kits, while anti-Ro/SSA antibodies were identified using RNA-IP. Clinical features and outcomes were stratified according to two different patterns of autoantibody responses against Ro52, including "isolated anti-Ro52", defined by positive anti-Ro52 and negative anti-Ro/SSA antibodies, and "anti-SSA-Ro52", defined by positive anti-Ro52 and anti-Ro/SSA antibodies. Isolated anti-Ro52 positivity was the most prevalent autoantibody response in patients with both anti-synthetase (40/122; 32.8%) and anti-MDA5 antibodies (8/34; 23.5%). Isolated anti-Ro52 or anti-SSA-Ro52 positivity was associated with Gottron's sign in patients with anti-synthetase antibodies, while in patients with anti-MDA5 antibodies, isolated anti-Ro52 positivity was associated with respiratory insufficiency at initial presentation and poor overall survival. Isolated anti-Ro52 positivity could be a potential biomarker for patient stratification; however, the clinical significance of dissociating isolated anti-Ro52 positivity from overall anti-Ro52 positivity was not evident.

MDA5-autoimmunity and Interstitial Pneumonitis Contemporaneous with the COVID-19 Pandemic (MIP-C)

Background

Anti-MDA5 (Melanoma differentiation-associated protein-5) positive dermatomyositis (MDA5 + -DM) is characterised by rapidly progressive interstitial lung disease (ILD) and high mortality. MDA5 senses single-stranded RNA and is a key pattern recognition receptor for the SARS-CoV-2 virus.

Methods

This is a retrospective observational study of a surge in MDA5 autoimmunity, as determined using a 15 muscle-specific autoantibodies (MSAs) panel, between Janurary 2018-December 2022 in Yorkshire, UK. MDA5-positivity was correlated with clinical features and outcome, and regional SARS-CoV-2 positivity and vaccination rates. Gene expression patterns in COVID-19 were compared with autoimmune lung disease and idiopathic pulmonary fibrosis (IPF) to gain clues into the genesis of the observed MDA5 + -DM outbreak.

Results

Sixty new anti-MDA5+, but not other MSAs surged between 2020-2022, increasing from 0.4% in 2019 to 2.1% (2020), 4.8% (2021) and 1.7% (2022). Few (8/60) had a prior history of confirmed COVID-19, peak rates overlapped with regional SARS-COV-2 community positivity rates in 2021, and 58% (35/60) had received anti-SARS-CoV-2 RNA vaccines. Few (8/60) had a prior history of COVID-19, whereas 58% (35/60) had received anti-SARS-CoV-2 RNA vaccines. 25/60 cases developed ILD which rapidly progression with death in 8 cases. Among the 35/60 non-ILD cases, 14 had myositis, 17 Raynaud phenomena and 10 had dermatomyositis spectrum rashes. Transcriptomic studies showed strong IFIH1 (gene encoding for MDA5) induction in COVID-19 and autoimmune-ILD, but not IPF, and IFIH1 strongly correlated with an IL-15-centric type-1 interferon response and an activated CD8+ T cell signature that is an immunologic hallmark of progressive ILD in the setting of systemic autoimmune rheumatic diseases. The IFIH1 rs1990760TT variant blunted such response.

Conclusions

A distinct pattern of MDA5-autoimmunity cases surged contemporaneously with circulation of the SARS-COV-2 virus during COVID-19. Bioinformatic insights suggest a shared immunopathology with known autoimmune lung disease mechanisms.

Compounded sulfamethoxazole improved the prognosis of dermatomyositis patients positive with anti-melanoma differentiation-associated gene 5

OBJECTIVES

Mortality of dermatomyositis patients positive with anti-melanoma differentiation-related gene 5 antibody (anti-MDA5-DM) is alarming, especially during the first several months. Infection is an important cause of early death. As there are no reports regarding the effect of prophylactic use of compounded sulfamethoxazole (coSMZ; each tablet contains 400 mg of sulfamethoxazole and 80 mg of trimethoprim) in anti-MDA5-DM patients, we conducted this study to evaluate the efficacy of coSMZ in reducing the incidence of Pneumocystis jirovecii pneumonia (PJP).

METHODS

Consecutive patients with new-onset anti-MDA5-DM from June 2018 to October 2021 in our centre were retrospectively reviewed for >12 months. They were divided into two groups-coSMZ and non-coSMZ-based on the initial use of prophylactic coSMZ. Mortality and the incidence of severe infection within 12 months were compared between two groups.

RESULTS

Compared with the non-coSMZ group (n = 93), the coSMZ group (n = 121) had lower mortality (18.8% vs 51.1%; P < 0.001) and a lower incidence of PJP (6.8% vs 15.2%; P = 0.040) and fatal infection (16.1% vs 3.3%; P = 0.001) during the first 12 months from diagnosis. After adjusting for age, gender, disease duration, peripheral blood lymphocyte count, anti-MDA5 antibody titres, ground-glass opacity scores and treatments, an inverse association was revealed between the prophylactic use of coSMZ and incidence of PJP [adjusted odds ratio 0.299 (95% CI 0.102-0.878), P = 0.028].

CONCLUSION

Prophylactic use of coSMZ is an effective and safe way to improve the prognosis of anti-MDA5-DM patients by preventing the incidence of PJP.

Transcriptomic profiling and longitudinal study reveal the relationship of anti-MDA5 titer and type I IFN signature in MDA5+ dermatomyositis

Objective

This study aimed to investigate the relationship between anti-MDA5 titer and type I IFN signature in patients with MDA5+ DM.

Methods

We explored the transcriptome profiling of PBMCs in MDA5+ DM patients with high-titer of antibody at disease onset or relapse and normal low-titer after treatment and healthy donors. Subsequently, we revealed the dynamic relationship between serum type I IFN scores and antibody titers.

Result

Differentially expressed genes in MDA5+ DM patients were enriched for related pathways and biological functions linked to viruses and cytokines compared to healthy donors. Similar differences remained pooled between the high-titer and low-titer group, and type I-specific interferon response genes showed upregulation in high-titer group. Significant correlations were found between anti-MDA5 titers and type I IFN scores (r = 0.50, P< 0.001). Contemporaneous anti-MDA5 titers revealed to be significantly higher in the group with ultra-high type I IFN scores (vs. high group, P = 0.027; vs. low group, P< 0.001). Longitudinal assessment of type I IFN scores and anti-MDA5 titers, including pre- and post-treatment changes at initial diagnosis and dynamic changes during treatment, presented an asynchrony between the two parameters in response to treatment.

Conclusion

Anti-MDA5 antibody titers correlated with type I IFN signature in patients with MDA5+ DM and they both changed dynamically but not synchronously over the course of treatment.

Differences in sex- and age-associated mortality in patients with anti-MDA5-positive dermatomyositis

OBJECTIVES

The effect of sex and age on the outcomes of patients with anti-melanoma differentiation-associated gene 5 (MDA5)-positive dermatomyositis (MDA5+ DM) remains unclear. This study aimed to investigate the impact of sex and age on the prognosis of patients with MDA5+ DM.

METHODS

We included 251 patients (women, 156; men, 95), who were newly diagnosed with MDA5+ DM between 2014 and 2021. The outcome was 6-month all-cause mortality after the diagnosis of interstitial lung disease. Cox regression analysis was used to assess the mortality. Adjusted restricted cubic spline analysis was performed to explore the non-linear relationship between age and outcomes.

RESULTS

The 6-month mortality rates of women and men were 36.5% and 46.3%, respectively. Multivariate Cox regression revealed that ≥60 years of age was significantly associated with the risk of death (hazard ratio, 2.43; 95% confidence interval, 1.02-5.78). The trend of the risk of 6-month mortality in men was relatively flat until 54 years and increased rapidly afterwards (hazard ratio, 1.14; 95% confidence interval, 1.01-1.29). In contrast, the 6-month mortality rate showed a low linear increasing trend with age among females.

CONCLUSIONS

Patients with MDA5+ DM, who received contemporary treatment, had unfavourable outcomes. The 6-month mortality risk increased with age, particularly in male patients aged >54 years.

Predictors of rapidly progressive interstitial lung disease and prognosis in Chinese patients with anti-melanoma differentiation-associated gene 5-positive dermatomyositis

Background

Rapidly progressive interstitial lung disease (RP-ILD) is the most serious complication of anti-melanoma differentiation-associated gene 5-positive dermatomyositis (anti-MDA5+ DM). This study was performed to assess the prognostic factors of patients with anti-MDA5+ DM and the clinical characteristics and predictors of anti-MDA5+ DM in combination with RP-ILD.

Methods

In total, 73 MDA5+ DM patients were enrolled in this study from March 2017 to December 2021. They were divided into survival and non-survival subgroups and non-RP-ILD and RP-ILD subgroups.

Results

The lactate dehydrogenase (LDH) concentration and prognostic nutritional index (PNI) were independent prognostic factors in patients with anti-MDA5+ DM: the elevated LDH was associated with increased mortality (p = 0.01), whereas the elevated PNI was associated with reduced mortality (p < 0.001). The elevated LDH was independent risk prognostic factor for patients with anti-MDA5+ DM (HR 2.42, 95% CI: 1.02-4.83, p = 0.039), and the elevated PNI was independent protective prognostic factor (HR, 0.27; 95% CI, 0.08 - 0.94; p = 0.039). Patients who had anti-MDA5+ DM with RP-ILD had a significantly higher white blood cell count and LDH concentration than those without RP-ILD (p = 0.007 and p = 0.019, respectively). In contrast, PNI was significantly lower in patients with RP-ILD than those without RP-ILD (p < 0.001). The white blood cell count and elevated LDH were independent and significant risk factors for RP-ILD (OR 1.54, 95% CI: 1.12 - 2.13, p = 0.009 and OR 8.68, 95% CI: 1.28 - 58.83, p = 0.027, respectively), whereas the lymphocyte was an independent protective factor (OR, 0.11; 95% CI, 0.01 - 0.81; p = 0.03).

Conclusion

The elevated LDH and elevated PNI were independent prognostic factors for patients with anti-MDA5+ DM. The elevated LDH was independent risk factor for RP-ILD. Patients with anti-MDA5+ DM could benefit from the measurement of LDH and PNI, which are inexpensive and simple parameters that could be used for diagnosis as well as prediction of the extent of lung involvement and prognosis.

Treatment of refractory anti-melanoma differentiation-associated gene 5 anbibody-positive dermatomyositis complicated by rapidly progressing interstitial pulmonary disease: Two case reports

BACKGROUND

Anti-melanoma differentiation-associated gene 5 antibody-positive (anti-MDA5 Ab⁺) dermatomyositis complicated with rapidly progressive interstitial lung disease (anti-MDA5 Ab⁺ DM-RP-ILD) has an unclear underlying mechanism with no recommended unified treatment plan. Herein, one of the cases that we report (Case 2) was successfully treated with tocilizumab despite having lung infection.

CASE SUMMARY

Case 1 was a 30-year-old woman who was admitted due to recurrent rash for 5 mo, fever and cough for 1 mo, and chest tightness for 3 d. She was diagnosed with non-myopathic dermatomyositis (anti-MDA5 Ab⁺) and interstitial pneumonia, and was treated with the combination of hormone therapy and cyclophosphamide followed by oral tacrolimus. Case 2 was a 31-year-old man admitted due to systemic rash accompanied by muscle weakness of limbs for more than 1 mo, and chest tightness and dry cough for 4 d. He was diagnosed with dermatomyositis (anti-MDA5 Ab⁺) and acute interstitial pneumonia with Pneumocystis jirovecii and Aspergillus fumigatus infections and was treated with hormone therapy (without cyclophosphamide) and the combination of tocilizumab and tacrolimus. The condition of both patients eventually improved and they were discharged and showed clinically stable condition at the latest follow-up.

CONCLUSION

Tocilizumab could be a salvage treatment for patients with anti-MDA5 Ab⁺ DM-RP-ILD who are refractory to intensive immunosuppression.

Treatment of refractory anti-melanoma differentiation-associated gene 5 anbibody-positive dermatomyositis complicated by rapidly progressing interstitial pulmonary disease: Two case reports

BACKGROUND

Anti-melanoma differentiation-associated gene 5 antibody-positive (anti-MDA5 Ab+) dermatomyositis complicated with rapidly progressive interstitial lung disease (anti-MDA5 Ab+ DM-RP-ILD) has an unclear underlying mechanism with no recommended unified treatment plan. Herein, one of the cases that we report (Case 2) was successfully treated with tocilizumab despite having lung infection.

CASE SUMMARY

Case 1 was a 30-year-old woman who was admitted due to recurrent rash for 5 mo, fever and cough for 1 mo, and chest tightness for 3 d. She was diagnosed with non-myopathic dermatomyositis (anti-MDA5 Ab+) and interstitial pneumonia, and was treated with the combination of hormone therapy and cyclophosphamide followed by oral tacrolimus. Case 2 was a 31-year-old man admitted due to systemic rash accompanied by muscle weakness of limbs for more than 1 mo, and chest tightness and dry cough for 4 d. He was diagnosed with dermatomyositis (anti-MDA5 Ab+) and acute interstitial pneumonia with Pneumocystis jirovecii and Aspergillus fumigatus infections and was treated with hormone therapy (without cyclophosphamide) and the combination of tocilizumab and tacrolimus. The condition of both patients eventually improved and they were discharged and showed clinically stable condition at the latest follow-up.

CONCLUSION

Tocilizumab could be a salvage treatment for patients with anti-MDA5 Ab+ DM-RP-ILD who are refractory to intensive immunosuppression.

Intramuscular lesions in musculoskeletal MRI as a favourable prognostic sign in patients with anti-MDA5 antibody-positive dermatomyositis

OBJECTIVES

Anti-differentiation-associated gene 5 (MDA5) antibody-positive dermatomyositis, which has been described as clinically amyopathic dermatomyositis, complicates rapidly progressive interstitial lung disease (ILD). Owing to the absence of significant muscle symptoms, musculoskeletal MRI is often not performed. In this study, we aimed to devise a simple evaluation method using musculoskeletal MRI findings to elucidate the relationship between MRI findings and ILD prognosis and development.

METHODS

The medical records and MRI scans of the proximal muscles at the time of diagnosis were retrospectively reviewed for 28 patients with anti-MDA5 antibody-positive dermatomyositis who were admitted to The Jikei University Hospital and The Jikei University Kashiwa Hospital between January 2008 and March 2022. Three observers evaluated nine proximal muscles for high signals on either short-tau inversion recovery images and/or fat-saturated gadolinium-enhanced T1-weighted images in the fascia and/or in the margins of the muscles in contact with the fascia (fascial pattern), and/or high signals in the muscles away from the fascia (intramuscular pattern), and a consensus was reached.

RESULTS

Of the 28 patients, 15 presented with 'radiological myositis', where an intramuscular pattern was observed at any site. Patients with radiological myositis had significantly higher survival rates than those without radiological myositis, despite the lower rate of triple therapy with prednisolone, calcineurin inhibitors and cyclophosphamide. The spread of ILD on chest CT negatively and significantly correlated with the proportion of intramuscular lesions.

CONCLUSION

The detection of intramuscular lesions on musculoskeletal MRI using our novel evaluation method could be clinically useful as a favourable prognostic marker.

Age distribution and prevalence in different age groups of four myositis-specific autoantibodies, including anti-ARS, anti-MDA5, anti-Mi-2, and anti-TIF1γ antibodies

We accumulated the demographic information and analyzed the prevalence of myositis-specific antibodies (MSAs) in a large cohort across Japan as standard testing for MSAs becomes more widely available. This retrospective, observational, cohort study analyzed the records of individuals aged 0-99 years who are tested for serum MSAs at SRL Incorporation from January 2014 to April 2020 across Japan. An enzyme-linked immunosorbent assay testing was applied to determine the presence of anti-aminoacyl tRNA synthetase (anti-ARS), anti-Mi-2, anti-melanoma differentiation-associated gene 5 (anti-MDA5), or anti-transcriptional intermediary factor 1-γ (anti-TIF1γ) (Medical and Biological Laboratories). Anti-TIF1γ antibody was detected more in male patients than female patients. In contrast, women were predominant in patients with other MSAs. More than half of the anti-ARS or anti-TIF1γ antibody-positive patients were over 60 years old, although anti-MDA5 or anti-Mi-2-positive patients were mostly under <60 years old. Anti-MDA5 antibody-positive patients were mostly aged 40-59 years, while other MSA groups were mostly 60-79 years. Anti-MDA5 antibody was detected most frequently in the age range of 0-29 years. Anti-TIF1γ antibody was the second most commonly detected autoantibody in the age range of 0-19 years. Anti-ARS antibody was the most frequently detected autoantibody after the age of 30 years, and the frequency of anti-ARS gradually increased at more advanced ages. The second and third most detected autoantibodies were anti-MDA5 and anti-TIF1γ, respectively, in ages 30-79 years. We performed a nationwide >3-year evaluation of MSA detection in a routine diagnostic setting. This paper provides clinical images concerning the relationship between four MSA types and the distribution of sex and age in a large population.

Ground-glass opacity score predicts the prognosis of anti-MDA5 positive dermatomyositis: a single-centre cohort study

OBJECTIVE

Dermatomyositis (DM) positive with anti-melanoma differentiation-associated gene 5 (anti-MDA5-DM) is a systemic autoimmune disease with high mortality. This study aimed to explore the risk factors of death in anti-MDA5-DM and validate a prediction model for all-cause mortality in anti-MDA5-DM.

METHOD

We conducted a retrospective study using a single-centre cohort of patients with newly onset anti-MDA5-DM from June 1, 2018 to August 31, 2021. Patients were divided into four groups according to baseline ground-glass opacity (GGO) score: Group A, GGO ≤ 1; Group B, 1 < GGO ≤ 2; Group C, 2 < GGO ≤ 3; Group D, GGO > 3. The primary outcome was death during the follow-up. Secondary outcomes included death within 3, 6, 12 months, severe infection, and remission during the first 12 months.

RESULTS

A total of 200 patients were included in the study. Based on multivariable Cox regression, the prognostic factors at baseline were identified as CRP > 5 mg/L, serum ferritin (SF) > 600ng/ml, positive anti-Ro52 antibody, prophylactic use of compound sulfamethoxazole (SMZ Co), four-category GGO score: GGO ≤ 1, 1 < GGO ≤ 2, 2 < GGO ≤ 3, GGO > 3. The final mortality of four groups was 16.4, 22.2, 48.5, 92.0%, respectively. Compared with Group A, the Hazards Ratio (HR) of Group B was 1.408, (p = 0.408), HR of Group C was 3.433 (p = 0.005), HR of Group D was 4.376 (p = 0.001).

CONCLUSIONS

GGO score is a reliable predictor for risk stratification in anti-MDA5-DM and may provide guidance for individualized managements of patients.

Clinical characteristics of myositis patients with isolated anti-U1 ribonucleoprotein antibody resemble immune-mediated necrotizing myopathy

Background

Anti-U1 ribonucleoprotein (U1RNP) antibodies were associated with connective tissue diseases (CTDs), but the clinical characteristics of this antibody in Chinese myositis patients have not been studied.

Objective

We aim to analyze the clinical features of myositis patients who test positive for anti-U1RNP antibodies and delineate a subgroup of myositis.

Design

This is a retrospective cohort study.

Methods

We reviewed the clinical data of myositis patients with anti-U1RNP antibodies and compared them to those with anti-signal recognition particle (SRP) and hydroxy-3-methylglutaryl-CoA reductase (HMGCR) antibody-associated immune-mediated necrotizing myopathy (IMNM).

Results

A total of 30 adult cases were identified; median age was 47.5 years and 24 (80%) were females, and 12 patients did not coexist with myositis-specific antibodies (MSAs) (isolated anti-U1RNP). The serum creatine kinase (CK) was significantly higher in patients with isolated anti-U1RNP (2182.5 U/L versus 289 U/L, p = 0.01), and the number of patients with CK > 2000 U/L was higher compared to that in anti-U1RNP antibody patients coexisting with MSAs (66.7% versus 16.7%, p = 0.009). The prevalence of IMNM in patients' muscle pathology with isolated anti-U1RNP was significantly higher (75%, p = 0.003). Skin rashes were less common in isolated anti-U1RNP group (p < 0.05). Of the 25 individuals with available pulmonary high-resolution CT (HRCT), 14 (56%) were diagnosed with interstitial lung disease (ILD). The incidence of muscular weakness, dysphagia, or levels of CK was not different between the isolated anti-U1RNP antibody individuals and the anti-HMGCR or SRP-IMNM groups (p > 0.05). But the frequency of Raynaud's phenomenon, arthritis, and membrane attack complex (MAC) deposits in myositis patients with isolated anti-U1RNP antibodies were higher than in anti-HMGCR and SRP-IMNM (all p < 0.005). There was no difference between anti-U1RNP patients with and without Ro-52 (p > 0.05). Isolated anti-U1RNP individuals showed marked improvements in muscle strength, and the remission rate in 1 and 2 years was significantly higher than that in anti-HMGCR and SRP-IMNM (p < 0.05).

Conclusions

The clinical and pathological features of myositis patients with isolated anti-U1RNP antibodies were similar to IMNM. Arthritis and ILD are the most common extramuscular clinical features. Most respond well to treatment and have a good prognosis.

Changes in anti-MDA5 antibody titres and serum cytokine levels before and after diagnosis of anti-MDA5 antibody-positive dermatomyositis

OBJECTIVES

Anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive DM is characterized by rapidly progressive interstitial lung disease and has a poor prognosis. We aimed to investigate whether anti-MDA5 antibody titres and cytokine levels predict clinical course, and evaluate changes in both parameters before and after diagnosis.

METHODS

This was a retrospective, single-centre study in 38 patients with anti-MDA5 antibody-positive DM. We compared clinical characteristics and laboratory data at diagnosis between patients in the treatment response (n = 23) and non-response (n = 15) groups, and between those in the relapse (n = 5) and non-relapse (n = 24) groups. We also measured serum anti-MDA5 antibody titres and cytokine levels before and after diagnosis.

RESULTS

The non-response group was older, had a higher ground-glass opacity score, lower PaO2/FiO2, higher CRP level, and higher anti-MDA5 antibody titre than the response group. No cytokines significantly differed between groups at diagnosis. The relapse group had a significantly higher anti-MDA5 antibody titre than the non-relapse group. In the survivor group, the anti-MDA5 antibody titre and levels of IFN-α, IFN-γ, monocyte chemotactic protein-1 (MCP-1), IL-6, IL-33, CRP, and ferritin were significantly lower 6 months post-treatment than at diagnosis. Macrophage-associated cytokines such as IL-6, IL-8, IL-18 and MCP-1 increased after anti-MDA5 antibody positivity in three patients who were anti-MDA5 antibody-positive before diagnosis.

CONCLUSION

The anti-MDA5 antibody titre at diagnosis may predict the clinical course. Levels of macrophage-associated cytokines significantly declined at 6 months post-treatment, and they may have increased after anti-MDA5 antibody titre positivity.

Serum metabolomic analysis reveals disorder of steroid hormone biosynthesis in patients with idiopathic inflammatory myopathy

Idiopathic inflammatory myopathy (IIM) is a heterogeneous group of autoimmune diseases with various clinical manifestations, treatment responses, and prognoses. According to the clinical manifestations and presence of different myositis-specific autoantibodies (MSAs), IIM is classified into several major subgroups, including PM, DM, IBM, ASS, IMNM, and CADM. However, the pathogenic mechanisms of these subgroups remain unclear and need to be investigated. Here, we applied MALDI-TOF-MS to examine the serum metabolome of 144 patients with IIM and analyze differentially expressed metabolites among IIM subgroups or MSA groups. The results showed that the DM subgroup had lower activation of the steroid hormone biosynthesis pathway, while the non-MDA5 MSA group had higher activation of the arachidonic acid metabolism pathway. Our study may provide some insights into the heterogeneous mechanisms of IIM subgroups, potential biomarkers, and management of IIM.

Serum IgA levels for predicting the development of rapidly progressive interstitial lung disease in dermatomyositis

BACKGROUND

Some patients with dermatomyositis (DM) can develop rapidly progressive interstitial lung disease (RPILD) that is resistant to treatment and life-threatening. Convenient and practical predictive factors for the development of RPILD are currently lacking. We aimed to identify independent risk factors for RPILD in patients with DM.

METHODS

A total of 71 patients with DM admitted to our hospital between July 2018 and July 2022 were retrospectively reviewed. Risk factors to predict RPILD were identified by univariate and multivariate regression analyses, and significant variates for RPILD were included to establish a risk model.

RESULTS

Multivariate regression analysis revealed that the risk of RPILD was significantly associated with serum IgA levels. The area under the risk model curve, established by IgA levels combined with other independent predictors including the anti-melanoma differentiation-associated gene 5 (MDA5) antibody, fever, and C-reactive protein, was 0.935 (P < 0.001).

CONCLUSION

A higher serum IgA level was identified as an independent risk factor for RPILD in patients with DM.

Retinal microvascular and microstructural alterations in the diagnosis of dermatomyositis: a new approach

Purpose

To study the relationship between fundus alterations, including retinal thickness and microvascular changes, and dermatomyositis (DM) using optical coherence tomography angiography (OCTA).

Methods

A total of 16 patients with DM (32 eyes) and 16 healthy controls (HCs; 32 eyes) participated in this study. Based on the Early Treatment Diabetic Retinopathy Study subzones, OCTA fundus data were divided into different layers and regions for comparison.

Results

The full retinal thickness (RT) in the inner nasal (IN), outer nasal (ON), inner inferior (II), and outer inferior (OI) regions of patients with DM was significantly lower than that of HCs (P < 0.001). The inner layer RT was also significantly lower in the IN, ON, II, and OI regions in patients with DM (P < 0.001). The outer layer RT was lower only in the II region in patients with DM compared to HCs (P < 0.001). The full RT of the II region was more sensitive to the pathological changes of disease since its ROC curve had an AUC of 0.9028, 95% CI: 0.8159-0.9898. Meanwhile, the superficial vessel density (SVD) of patients with DM was significantly lower in the IN, ON, II, and OI regions compared to HCs (P < 0.001). The AUC for region II was 0.9634 (95% CI: 0.9034-1.0), which indicated good diagnostic sensitivity.

Conclusion

Optical coherence tomography angiography can be used to evaluate relevant ocular lesions and monitor disease progression in patients with DM and interstitial lung disease.

Type 1 interferon signature in peripheral blood mononuclear cells and monocytes of idiopathic inflammatory myopathy patients with different myositis-specific autoantibodies

Background

Myositis-specific autoantibodies (MSAs) are clinically used to diagnose and define idiopathic inflammatory myopathy (IIM) subsets. However, the underlying pathogenic mechanisms of patients with different MSAs remain unclear.

Methods

A total of 158 Chinese patients with IIM and 167 gender- and age-matched healthy controls (HCs) were enrolled. Transcriptome sequencing (RNA-Seq) was performed with peripheral blood mononuclear cells (PBMCs), followed by the identification of differentially expressed genes (DEGs) and analysis of gene set enrichment analysis, immune cell infiltration, and WGCNA. Monocyte subsets and related cytokines/chemokines were quantified. The expressions of interferon (IFN)-related genes were validated using qRT-PCR and Western blot in both PBMCs and monocytes. We also performed correlation analysis and ROC analysis to explore the potential clinical significance of the IFN-related genes.

Results

There were 1,364 genes altered in patients with IIM, including 952 upregulated and 412 downregulated genes. The type I interferon (IFN-I) pathway was remarkably activated in patients with IIM. Compared with patients with other MSAs, IFN-I signatures were significantly activated in patients with anti-melanoma differentiation-associated gene 5 (MDA5) antibodies. In total, 1,288 hub genes associated with IIM onset were identified using WGCNA, including 29 key DEGs associated with IFN signaling. The patients had more CD14brightCD16- classical, CD14brightCD16+ intermediate, and fewer CD14dimCD16+ non-classical monocyte subsets. Plasma cytokines like IL-6 and TNF and chemokines including CCL3 and MCPs increased. The validation of IFN-I-related gene expressions was consistent with the findings from RNA-Seq. The IFN-related genes were correlated with laboratory parameters and helpful for IIM diagnosis.

Conclusion

Gene expressions were remarkably altered in the PBMCs of IIM patients. Anti-MDA5+ IIM patients had a more pronounced activated IFN signature than others. Monocytes exhibited a proinflammatory feature and contributed to the IFN signature of IIM patients.

Interferon and autoantigens: intersection in autoimmunity

Interferon (IFN) is a key component of the innate immune response. For reasons that remain incompletely understood, the IFN system is upregulated in several rheumatic diseases, particularly those that feature autoantibody production, such as SLE, Sjögren's syndrome, myositis and systemic sclerosis. Interestingly, many of the autoantigens targeted in these diseases are components of the IFN system, representing IFN-stimulated genes (ISGs), pattern recognition receptors (PRRs), and modulators of the IFN response. In this review, we describe features of these IFN-linked proteins that may underlie their status as autoantigens. Note is also made of anti-IFN autoantibodies that have been described in immunodeficiency states.

Longitudinal study of patients with antimelanoma differentiation-associated gene 5 antibody-positive dermatomyositis-associated interstitial lung disease

OBJECTIVES

To describe the 8-year longitudinal study and long-term prognosis of a large inception cohort of anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive (MDA5+) DM-interstitial lung disease (ILD) patients.

METHODS

In total, 216 patients diagnosed with MDA5+ DM-ILD were enrolled and followed up to analyse long-term survival rate. Demographic and clinical variables were collected at baseline and each temporal end point. Seventy patients who survived the first year were analysed for the long-term serological and respiratory outcomes.

RESULTS

A total of 85 patients (39.3%) died during the follow-up period up to 96 months, with 89% of the deaths occurring in the first year after diagnosis. Long-term outcome was reported in 70 patients. Serological markers including anti-MDA5 antibody showed significant improvement with time. Radiographic findings and pulmonary function also improved notably in the follow-up period, especially in rapidly progressive ILD group, as measured by high-resolution computed tomography imaging scores, the estimated forced vital capacity, estimated diffusing capacity of lung carbon monoxide and dyspnoea scores. Early application of anti-fibrosis therapy helped to improve long-term pulmonary function.

CONCLUSIONS

MDA5+ DM-ILD patients had a high mortality rate despite aggressive treatment. Patients who survived the first year usually showed a significant improvement in serological markers and pulmonary function during the long-term follow-up.

PhIP-Seq uncovers novel autoantibodies and unique endotypes in interstitial lung disease

Interstitial lung diseases (ILDs) are a heterogeneous group of disorders that can develop in patients with connective tissue diseases (CTD). Establishing autoimmunity in ILD impacts prognosis and treatment. ILD patients are screened for autoimmunity by assaying for anti-nuclear autoantibodies, rheumatoid factors and other non-specific tests. However, this approach has not been rigorously validated and may miss autoimmunity that manifests as autoantibodies to tissue antigens not previously defined in ILD. Here, we use Phage Immunoprecipitation-Sequencing (PhIP-Seq) to conduct a large, multi-center unbiased autoantibody discovery screen of ILD patients and controls. PhIP-Seq identified 17 novel autoreactive targets, and machine learning classifiers derived from these targets discriminated ILD serum from controls. Among these 17 candidates, we validated Cadherin Related Family Member 5 (CDHR5) as an autoantigen and found CDHR5 autoantibodies in patients with rheumatologic disorders and importantly, subjects not previously diagnosed with autoimmunity. Lung tissue of CDHR5 autoreactive patients showed transcriptional profiles consistent with activation of NFκB signaling and upregulation of chitotriosidase (CHIT1), a molecular pathway linked to fibrosis. Our study shows PhIP-Seq uncovers novel autoantibodies in ILD patients not revealed by standard clinical tests. Furthermore, CDHR5 autoantibodies may define a novel molecular endotype of ILD characterized by inflammation and fibrosis.

Identification of Three Different Phenotypes in Anti-Melanoma Differentiation-Associated Gene 5 Antibody-Positive Dermatomyositis Patients: Implications for Prediction of Rapidly Progressive Interstitial Lung Disease

OBJECTIVE

There is substantial heterogeneity among the phenotypes of patients with anti-melanoma differentiation-associated gene 5 antibody-positive (anti-MDA5+) dermatomyositis (DM), hindering disease assessment and management. This study aimed to identify distinct phenotype groups in patients with anti-MDA5+ DM and to determine the utility of these phenotypes in predicting patient outcomes.

METHODS

A total of 265 patients with anti-MDA5+ DM were retrospectively enrolled in the study. An unsupervised hierarchical cluster analysis was performed to characterize the different phenotypes.

RESULTS

Patients were stratified into 3 clusters characterized by markedly different features and outcomes. Cluster 1 (n = 108 patients) was characterized by mild risk of rapidly progressive interstitial lung disease (RPILD), with the cumulative incidence of non-RPILD being 85.2%. Cluster 2 (n = 72 patients) was characterized by moderate risk of RPILD, with the cumulative incidence of non-RPILPD being 73.6%. Patients in cluster 3 (n = 85 patients), which was characterized by a high risk of RPILD and a cumulative non-RPILD incidence of 32.9%, were more likely than patients in the other 2 subgroups to have anti-Ro 52 antibodies in conjunction with high titers of anti-MDA5 antibodies. All-cause mortality rates of 60%, 9.7%, and 3.7% were determined for clusters 3, 2, and 1, respectively (P < 0.0001). Decision tree analysis led to the development of a simple algorithm for anti-MDA5+ DM patient classification that included the following 8 variables: age >50 years, disease course of <3 months, myasthenia (proximal muscle weakness), arthritis, C-reactive protein level, creatine kinase level, anti-Ro 52 antibody titer, and anti-MDA5 antibody titer. This algorithm placed patients in the appropriate cluster with 78.5% accuracy in the development cohort and 70.0% accuracy in the external validation cohort.

CONCLUSION

Cluster analysis identified 3 distinct clinical patterns and outcomes in our large cohort of anti-MDA5+ DM patients. Classification of DM patients into phenotype subgroups with prognostic values may help physicians improve the efficacy of clinical decision-making.

Clinical Outcomes With and Without Plasma Exchange in the Treatment of Rapidly Progressive Interstitial Lung Disease Associated With Idiopathic Inflammatory Myopathy

BACKGROUND/OBJECTIVE

A subset of patients with idiopathic inflammatory myopathy (IIM) develops highly fatal, rapidly progressive interstitial lung disease (RP-ILD). Treatment strategies consist of glucocorticoid and adjunctive immunosuppressive therapies. Plasma exchange (PE) is an alternative therapy, but its benefit is unclear. In this study, we aimed to determine whether PE benefited outcomes for patients with RP-ILD.

METHODS

In this medical records review study, we compared baseline characteristics and clinical outcomes for 2 groups of patients with IIM-related RP-ILD: those who received and did not receive PE.

RESULTS

Our cohort consisted of 15 patients, 9 of whom received PE. Baseline demographic characteristics and severity of lung, skin, and musculoskeletal disease between the 2 groups of patients were not significantly different. Five patients required mechanical ventilation (2, PE; 3, no PE). Plasma exchange was generally a third-line adjunctive treatment option. The PE group had a longer median (interquartile range) hospitalization (27.0 [23.0-36.0] days) than the non-PE group (12.0 [8.0-14.0] days) ( p = 0.02). There was a potential benefit in 30-day mortality improvement in those receiving PE (0% vs 33%, p = 0.14), with a statistically significant improvement in 2 important composite end points including 30-day mortality or need for lung transplant (0% vs 50%, p = 0.04) and 1-year mortality or need for lung transplant or hospital readmission for RP-ILD in those receiving PE (22% vs 83%, p = 0.04).

CONCLUSIONS

Plasma exchange may be an underutilized, safe salvage therapy for patients with IIM-related RP-ILD when other immunosuppressive therapies fail.

COVID-19 infection with complicated fulminant myocarditis: a case report

Herein, we report the case of a young female patient who suffered from myositis and heart failure due to fulminant myocarditis induced by the 2019 coronavirus disease (COVID-19). After receiving intra-aortic balloon pump (IABP) and immunomodulatory treatment, her vital signs gradually stabilized and the IABP was removed. Cardiac and muscle magnetic resonance imaging confirmed extensive myocardial and skeletal muscle edema. Though it is not uncommon for COVID-19 infection to be complicated by myocarditis and myositis, such serious muscle injury warrants clinical vigilance.

Evaluating the value of superoxide dismutase in anti-MDA5-positive dermatomyositis associated with interstitial lung disease

OBJECTIVE

This study aimed to investigate the relationship between serum superoxide dismutase (SOD) and interstitial lung disease (ILD) among patients with anti-melanoma differentiation-associated gene 5 antibody (MDA5)-positive DM.

METHOD

In this retrospective study, serum SOD of 90 health check-ups were tested in our hospital. A total of 94 hospitalized patients with anti-MDA5-positive DM had ILD. Their serum SOD, serum ferritin and autoantibody levels were determined and lung high-resolution CT was performed.

RESULTS

The serum SOD level was significantly lower in the anti-MDA5-positive DM group compared with the control group. The SOD level was significantly lower in patients positive for both anti-MDA5 antibodies and anti-Ro-52 antibodies than in those positive for only anti-MDA5 antibodies before treatment. The SOD level was significantly lower in the higher serum ferritin group compared with the lower serum ferritin group before treatment. After treatment, the serum SOD level decreased in patients with exacerbation of ILD, while it increased in those with alleviated ILD. The SOD level was significantly lower in the death group than in the survival group before treatment.

CONCLUSIONS

In patients with anti-MDA5-positive DM, the low SOD level before treatment indicated the presence of oxidative stress in the disease; the serum SOD level was affected by anti-Ro-52 antibodies and ferritin; there is a close relationship between serum SOD level and ILD among patients with anti-MDA5-positive DM, suggesting that SOD might serve as an effective indicator to evaluate the changes in ILD in these patients; and the low SOD level is an important indicator of poor prognosis in these patients, which deserves attention from rheumatologists.

Antibodies against Serum Anti-Melanoma Differentiation-Associated Gene 5 in Rheumatoid Arthritis Patients with Chronic Lung Diseases

Chronic lung diseases (CLD), including interstitial lung disease (ILD) and airway diseases (ADs), are common complications of rheumatoid arthritis (RA). Rheumatoid factor (RF) and anti-citrullinated peptide antibodies are reported to be associated with CLD in RA patients. The presence of anti-melanoma differentiation-associated gene 5 (MDA5) antibodies (Abs) is associated with clinically amyopathic dermatomyositis developing into rapidly progressive ILD. However, few studies on anti-MDA5 Abs in RA have been published. Here, we analyzed the association of anti-MDA5 Abs with CLD complications in RA. Anti-MDA5 Abs were quantified in sera from RA patients with or without CLD. Anti-MDA5 Ab levels were higher in RA patients with ADs than without (mean ± SDM, 4.4 ± 2.4 vs. 4.0 ± 4.2, p = 0.0001). AUC values of anti-MDA5 Ab and RF ROC curves were similar in RA patients with or without CLD (0.578, 95%CI 0.530-0.627 and 0.579, 95%CI 0.530-0.627, respectively, p = 0.9411). Multiple logistic regression analysis of anti-MDA5 Abs and clinical characteristics yielded an MDA5-index with a higher AUC value than anti-MDA5 Ab alone (0.694, 95%CI 0.648-0.740, p = 5.08 × 10^-5). Anti-MDA5 Abs were associated with ADs in RA patients and could represent a biomarker for CLD, similar to RF. The involvement of anti-MDA5 Abs in the pathogenesis of ADs in RA is proposed.

Elevated platelet-to-lymphocyte ratio and neutrophil-to-lymphocyte ratio in patients with polymyositis/dermatomyositis: a retrospective study

OBJECTIVES

This study aimed to examine the diagnostic and prognostic value of the platelet-to-lymphocyte ratio (PLR) and neutrophil-to-lymphocyte ratio (NLR) in patients with polymyositis/dermatomyositis (PM/DM).

METHOD

Clinical data of 200 patients with PM/DM and 204 healthy controls were retrospectively reviewed. We examined whether the PLR and NLR were associated with PM/DM.

RESULTS

The PLR and NLR were higher in patients with PM/DM than in controls (both P < 0.001). The PLR and NLR were higher in patients with DM than in those with PM (both P < 0.01). The PLR was higher in the anti-melanoma differentiation-associated protein-5 (anti-MDA5) ⁺ PM/DM group than in the anti-MDA5^- PM/DM group (P = 0.002). The NLR in non-survivors was higher than that in survivors (P = 0.01). The NLR was positively correlated with the occurrence of interstitial lung disease (ILD). The PLR and NLR were independent predictors of PM/DM, as well as risk factors (both P < 0.001). Moreover, the NLR had a predictive value for PM/DM-ILD and was closely related to mortality (P = 0.033, P = 0.003, respectively).

CONCLUSIONS

Patients with PM/DM have a higher NLR and PLR than healthy controls, especially in those with anti-MDA5⁺. The PLR and NLR are independent risk factors for PM/DM and have some predictive value. The NLR is correlated with ILD and associated with an increased risk of mortality in patients with PM/DM. The NLR and PLR may be simple, economical, and accurate diagnostic and prognostic markers for patients with PM/DM. Key points • The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have been studied in numerous inflammatory diseases as potential markers, but their clinical significance in polymyositis/dermatomyositis (PM/DM) remains unclear. • We examined the changes in the NLR and PLR between patients with PM/DM and healthy controls, as well as their association with mortality, interstitial lung disease, and anti-melanoma differentiation-associated protein-5. • Patients with PM/DM may benefit from using the NLR and PLR as simple, economical, and accurate diagnostic and prognostic markers.

Machine learning for screening and predicting the risk of anti-MDA5 antibody in juvenile dermatomyositis children

Objective

The anti-MDA5 (anti-melanoma differentiation associated gene 5) antibody is often associated with a poor prognosis in juvenile dermatomyositis (JDM) patients. In many developing countries, there is limited ability to access myositis- specific antibodies due to financial and technological issues, especially in remote regions. This study was performed to develop a prediction model for screening anti-MDA5 antibodies in JDM patients with commonly available clinical findings.

Methods

A cross-sectional study was undertaken with 152 patients enrolled from the inpatient wards of Beijing Children's Hospital between June 2018 and September 2021. Stepwise logistic regression, least absolute shrinkage and selection operator (LASSO) regression, and the random forest (RF) method were used to fit the model. Model discrimination, calibration, and decision curve analysis were performed for validation.

Results

The final prediction model included eight clinical variables (gender, fever, alopecia, periungual telangiectasia, digital ulcer, interstitial lung disease, arthritis/arthralgia, and Gottron sign) and four auxiliary results (WBC, CK, CKMB, and ALB). An anti-MDA5 antibody risk probability-predictive nomogram was established with an AUC of 0.975 predicted by the random forest algorithm. The model was internally validated by Harrell's concordance index (0.904), the Brier score (0.052), and a 500 bootstrapped satisfactory calibration curve. According to the net benefit and predicted probability thresholds of decision curve analysis, the established model showed a significantly higher net benefit than the traditional logistic regression model.

Conclusion

We developed a prediction model using routine clinical assessments to screen for JDM patients likely to be anti-MDA5 positive. This new tool may effectively predict the detection of anti-MDA5 in these patients using a non-invasive and efficient way.

Four cases of dermatomyositis with abnormally high anti-MDA-5 antibody titres and not high levels of serum ferritin

Anti-melanoma differentiation-associated gene 5 (MDA-5) antibody-positive dermatomyositis is a fatal disease presenting with rapidly progressive interstitial lung disease. High ferritin levels are a well-known poor prognostic factor. A high anti-MDA-5 antibody titre was also recently identified as a poor prognostic factor. We encountered four cases that had extremely high anti-MDA-5 antibody titres without high levels of ferritin in the initial examination. All cases were female with ages ranging between 29 and 54 years (mean age, 44 years). In the initial examination, anti-MDA-5 antibody titres were 2060-3040 (normal range, <32 index), ferritin levels were 87-480 ng/ml (normal range, 2.6-129.4 ng/ml), KL-6 level was 186-1806 U/ml (normal range, <500 U/ml), and creatine kinase level was normal in all patients. One patient had respiratory distress on exertion. Computed Tomography (CT) images showed mild ground-glass attenuation/reticular shadows near the pleura in all patients. Three patients were treated with a combination of high-dose glucocorticoids, intermittent intravenous cyclophosphamide, and calcineurin inhibitors, and two required plasma exchange due to the worsening of lung lesion. In these patients, ferritin and KL-6 levels tended to elevate after the beginning of treatment. Very mild pulmonary lesions disappeared in one patient treated with moderate doses of a glucocorticoid and calcineurin inhibitor. All patients survived, and one required oxygen on exertion at discharge. The condition of patients with abnormally high anti-MDA-5 antibody titres may deteriorate even though ferritin levels were not high and lung shadows are minimal at presentation. Therefore, intensive treatment needs to be considered early in the course of the disease regardless of the serum ferritin level.