Analysis of anti-melanoma differentiation-associated gene 5 antibody in Hong Kong Chinese patients with idiopathic inflammatory myopathies: diagnostic utility and clinical correlations

A New Predictive Model for the Prognosis of MDA5+ DM-ILD

Purpose

The purpose of this study is to analyze clinical information and combine significant parameters to generate a predictive model and achieve a better prognosis prediction of dermatomyositis-associated interstitial lung disease with positive melanoma differentiation-associated gene 5 antibody (MDA5⁺ DM-ILD) and stratify patients according to prognostic risk factors appropriately.

Methods

We retrospectively reviewed 63 patients MDA5⁺ DM-ILD who were treated in our hospital from January 2018 to January 2021. Our study incorporated most clinical characteristics in clinical practice to explore the associations and predictive functions of clinical characteristics and prognosis. Student's t-test, Mann-Whitney U-test, chi-squared test, Pearson correlation analysis, Cox regression analysis, R, receiver operating characteristic curves (ROC curves), and Kaplan-Meier survival curves were performed to identify independent predictors for the prognosis of MDA5⁺DM-ILD.

Results

In all the 63 patients with MDA5⁺DM-ILD, 44 improved but 19 did not. Poor prognosis was found more frequently in patients who were older, clinically amyopathic variant of dermatomyositis (CADM), and/or with short duration, short interval of DM and ILD, long length of stay, fever, dyspnea, non-arthralgia, pulmonary infection, pleural effusion (PE), high total computed tomography scores (TCTs), ground-glass opacity (GGO), consolidation score, reticular score and fibrosis score, decreased forced vital capacity (FVC), forced expiratory volume in 1s (FEV1), albumin, A/G, glomerular filtration rate (GFR) and tumor necrosis factor α (TNFα), high titer of anti-MDA5, proteinuria, high levels of monocyte, lactate dehydrogenase (LDH), ferritin (FER), neuron specific enolase (NSE) and glucocorticoid, antibiotic, antiviral, and non-invasive positive pressure ventilation (NPPV). The multivariate Cox regression analysis demonstrated that duration, fever, PE, TCTs and aspartate transaminase (AST) were independent predictors of poor prognosis in patients with MDA5⁺DM-ILD. The nomogram model quantified the risk of 400-day death as: duration ≤ 4 months (5 points), fever (88 points), PE (21 points), TCTs ≥10 points (22 points), and AST ≥200 U/L (100 points) with high predictive accuracy and convenience. The ROC curves possessed good discriminative ability for combination of fever, PE, TCTs, and AST, as reflected by the area under curve (AUC) being.954, 95% CI 0.902–1.000, and sensitivity and specificity being 84.2 and 94.6%, respectively.

Conclusion

We demonstrated that duration, fever, PE, TCTs, and AST could be integrated together to be independent predictors of poor prognosis in MDA5⁺ DM-ILD with highly predictive accuracy.

Performance of the 2017 EULAR/ACR classification criteria in anti-MDA5 associated idiopathic inflammatory myopathy

OBJECTIVE

To evaluate the performance of the 2017 EULAR/ACR classification criteria in a cohort of anti-MDA5 associated IIM patients.

METHODOLOGY

Consecutive adult patients with a clinical diagnosis of anti-MDA5 associated IIM from 10 hospitals in Hong Kong were recruited retrospectively. Clinical characteristics were collected by reviewing the electronic medical records. A commercial line-blot immunoassay was used to detect the myositis specific antibodies (MSA). Performance of the 2017 EULAR/ACR classification criteria was examined. Incorporation of the anti-MDA5 antibody in the EULAR/ACR criteria and the MSA-based criteria recently proposed by Casal-Dominguez et al. were also evaluated. Lastly, a new set of phenotypic-serological classification criteria specific for anti-MDA5 was proposed.

RESULTS

A hundred and twenty patients with anti-MDA5 associated IIM were recruited. The subgroups were exclusively DM (31.7%) and CADM (68.3%). Eight-six (71.7%) and 49 (40.8%) patients fulfilled the EULAR/ACR classification criteria and the Bohan/Peter criteria respectively. With the addition of Sontheimer's criteria for CADM, 76.7% the patients could be classified by the Bohan and Peter criteria. The sensitivity of the EULAR/ACR criteria could be improved to 98.3% if anti-MDA5 antibody was considered one of the criteria. The criteria by Casal-Dominguez et al. had 100% sensitivity in this cohort. Our newly proposed criteria for "anti-MDA5 syndrome" could also classify 97.5% of the patients.

CONCLUSIONS

Almost 30% of patients with clinical anti-MDA5 associated IIM could not be classified by the EULAR/ACR criteria. Modification of the existing criteria incorporating anti-MDA5 antibody or development of a new specific set of criteria for "anti-MDA5 syndrome" are suggested.

Seasonal Effect on Disease Onset and Presentation in Anti-MDA5 Positive Dermatomyositis

Objective

To investigate the seasonal variation of disease onset and presentation in an ethno-geographically homogeneous cohort of patients with anti-MDA5 positive dermatomyositis (DM).

Methods

This was a multi-centered, retrospective cohort study. Adult Chinese anti-MDA5 positive DM patients were identified from the Hong Kong Myositis Registry and the Clinical Data Analysis and Reporting System from 2015 to 2020. Equal number of IIM patients without anti-MDA5 antibody were selected as controls. Line blot immunoassay was used to detect the autoantibodies. The onset of disease, presenting clinical features and subsequent complications were analyzed for any seasonality.

Results

A total of 110 patients with anti-MDA5 positive DM were studied. The mean age at diagnosis was 53.0 ± 12.3 years and the mean follow-up duration was 20.6 ± 23.1 months. Two third of the patients (66%) had the clinically amyopathic phenotype. Most patients (86%) had interstitial lung disease (ILD) and 42% developed rapidly progressive ILD (RP-ILD). The mortality was 40% and the commonest cause was RP-ILD. Chi-square test showed significantly less patients had symptom onset in July to September. However, no particular seasonal pattern was observed in the anti-MDA5 negative IIM controls. RP-ILD occurred more frequently in patients with disease onset in October to December. Anti-MDA5 positive DM patients with disease onset in warmer months (April to September) were more likely to have clinical muscle involvement.

Conclusion

Apparent seasonal patterns were noted in our ethno-geographically identical anti-MDA5 positive DM patients, but not in IIM patients in general. Certain environmental factors, particularly infection, might be implicated.

Dermatomyositis With Anti-MDA5 Antibodies: Bioclinical Features, Pathogenesis and Emerging Therapies

Anti-MDA5 dermatomyositis is a rare systemic autoimmune disease, historically described in Japanese patients with clinically amyopathic dermatomyositis and life-threatening rapidly progressive interstitial lung disease. Subsequently, the complete clinical spectrum of the disease was enriched by skin, articular and vascular manifestations. Depending on the predominance of these symptoms, three distinct clinical phenotypes with different prognosis are now defined. To date, the only known molecular component shared by the three entities are specific antibodies targeting MDA5, a cytosolic protein essential for antiviral host immune responses. Several biological tools have emerged to detect these antibodies, with drawbacks and limitations for each of them. However, the identification of this highly specific serological marker of the disease raises the question of its role in the pathogenesis. Although current knowledge on the pathogenic mechanisms that take place in the disease are still in their enfancy, several lines of evidence support a central role of interferon-mediated vasculopathy in the development of skin and lung lesions, as well as a possible pathogenic involvement of anti-MDA5 antibodies. Here, we review the clinical and biological evidences in favor of these hypothesis, and we discuss the contribution of emerging therapies that shed some light on the pathogenesis of the disease.

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

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

Fast-Onset Diffuse Interstitial Lung Disease in Anti-MDA5 Antibodies-Associated Amyopathic Dermatomyositis

Anti-MDA5 antibodies-associated amyopathic dermatomyositisis a rare autoimmune disease that involve polyarthritis, cutaneous and pulmonary manifestations. The development of rapidly progressing interstitial lung disease is a life-threatening complication. We report the case of a 45-year-old woman without medical history, who was addressed to the Pulmonary Department for a polyarthritis with dry cough and hypoxemic dyspnea. Initially there was neither cutaneous manifestation nor interstitial lung disease on chest CT scan. After a few days, the patient developed fatal acute respiratory failure with diffuse ground glass opacities. Identification of anti-MDA5 antibodies allowed establishing diagnosis, despite the fact that the first immunological assessment was negative. Corticosteroid bolus of 1 g for three days and immunosuppressive treatment by cyclophosphamide was only initiated at the acute respiratory distress syndrome stage. Given the rapidly unfavorable prognosis of this entity of amyopathic dermatomyositis, the testing for anti-MDA5 antibodies should be recommended in case of progressive pulmonary symptoms associated with joint signs in order to identify this disease at an early stage and to begin rapid and adequate management.

Juvenile Dermatomyositis: New Clues to Diagnosis and Therapy

PURPOSE OF REVIEW

To identify clues to disease activity and discuss therapy options.

RECENT FINDINGS

The diagnostic evaluation includes documenting symmetrical proximal muscle damage by exam and MRI, as well as elevated muscle enzymes-aldolase, creatine phosphokinase, LDH, and SGOT-which often normalize with a longer duration of untreated disease. Ultrasound identifies persistent, occult muscle inflammation. The myositis-specific antibodies (MSA) and myositis-associated antibodies (MAA) are associated with specific disease course variations. Anti-NXP-2 is found in younger children and is associated with calcinosis; anti-TIF-1γ+ juvenile dermatomyositis has a longer disease course. The diagnostic rash-involving the eyelids, hands, knees, face, and upper chest-is the most persistent symptom and is associated with microvascular compromise, reflected by loss of nailfold (periungual) end row capillaries. This loss is associated with decreased bioavailability of oral prednisone; the bioavailability of other orally administered medications should also be considered. At diagnosis, at least 3 days of intravenous methyl prednisolone may help control the HLA-restricted and type 1/2 interferon-driven inflammatory process. The requirement for avoidance of ultraviolet light exposure mandates vitamin D supplementation.

SUMMARY

This often chronic illness targets the cardiovascular system; mortality has decreased from 30 to 1-2% with corticosteroids. New serological biomarkers indicate occult inflammation: ↑CXCL-10 predicts a longer disease course. Some biologic therapies appear promising.

Myositis-specific autoantibodies and their clinical associations in idiopathic inflammatory myopathies

BACKGROUND

Myositis-specific autoantibodies (MSAs) have been found to be present predominantly in patients with idiopathic inflammatory myopathies (IIMs). This study aimed to investigate the prevalence of MSAs and their associated complications in a cohort of patients with IIMs.

METHODS

This was a multicentered prospective study. Consecutive adult Chinese patients with IIMs in the regional hospitals in Hong Kong were followed up from July 2016 to January 2018. Clinical characteristics, treatment history, and disease complications were documented. A commercially available immunoblot assay was used to detect the MSAs.

RESULTS

Out of the 201 patients studied, at least one MSA was found in 63.2% of patients. The most common among the identified MSAs were the anti-melanoma differentiation-associated gene 5 antibody (anti-MDA5 Ab) and the anti-transcriptional intermediary factor 1-gamma antibody (anti-TIF1-γ Ab) (both 13.9%), followed by anti-Jo-1 antibody (12.4%). Anti-MDA5 was present exclusively in dermatomyositis (DM) and was strongly associated with digital ulcers, amyopathy, and rapidly progressive interstitial lung disease (RP-ILD). Anti-TIF1γ was strongly associated with refractory rash and malignancy. Independent risk factors of RP-ILD included anti-MDA5 (OR 14.5), clinically amyopathic DM (OR 13.9), and history of pulmonary tuberculosis (OR 12.2). Cox regression analysis showed that anti-TIF1γ (HR 3.55), DM (HR 3.82), and family history of cancer (HR 3.40) were independent predictors of malignancy.

CONCLUSIONS

MSA testing enables dividing of patients with IIMs into phenotypically homogeneous subgroups and prediction of potentially life-threatening complications.

Interstitial Lung Disease in Anti-MDA5 Positive Dermatomyositis

Anti-melanoma differentiation-associated gene 5-positive dermatomyositis (MDA5⁺ DM) is a rare autoimmune disease predominantly reported in East Asia. MDA5⁺ DM is an intractable disease with impressively high mortality due to rapid-progressive interstitial lung disease (RPILD). Other typical clinical manifestations comprise DM-specific rash (Gottron's papules, heliotrope rash) and amyopathic/hypomyopathic muscle involvement. Multiple prognostic factors have been identified. Baseline forced vital capacity (FVC) %-based staging could serve as a simplified risk stratification system. Serum biomarkers including MDA5 Ab titers, ferritin, KL-6 levels, and CD4⁺CXCR4⁺ T cell percentage could provide additional surrogate value of ILD severity and treatment response, as well as potential predictive value for survival. Spontaneous pneumomediastinum (PNM), ground-glass opacity (GGO), and consolidation were demonstrated to be the most significant features in pulmonary high-resolution computed tomography (HRCT) findings of MDA5⁺ DM-ILD. The semi-quantitative assessment of lesions in HRCT has also been demonstrated relevant to the outcome. The current treatment of this disease is still largely empirical. Immunosuppressive treatments, i.e., "triple therapy" (combination of high-dose glucocorticoids, tacrolimus, and intravenous cyclophosphamide) and JAK inhibitor-based therapy, are the mainstream regimens for MDA5⁺ DM-ILD, supported by the recently published trials. However, more efficacious regimen with favorable safety profile and high-level evidence is still urgently demanded for patients with MDA5⁺ DM-ILD, especially those at advanced-stage. We will summarize the terminology, etiology and pathogenesis, clinical features and outcome, prognostic factors, and treatment of MDA5⁺ DM-ILD in this review.

Cyclophosphamide Versus Obinutuzumab for the Treatment of Anti-MDA5 Positive Inflammatory Myopathy with Interstitial Lung Disease: A Study Protocol and Literature Review

In patients with idiopathic inflammatory myopathy, the presence of the melanoma differentiation-associated gene 5 (MDA5) antibody carries an extremely poor prognosis as a result of the associated interstitial lung disease (ILD) that is often rapidly progressive and refractory to therapies. Management of anti-MDA5 associated ILD is a challenging task as there is a paucity of clinical data and treatment guidelines in the literature. We hereby describe a proposed protocol for a multicenter randomized controlled trial to compare the efficacy of intravenous cyclophosphamide and obinutuzumab in combination with high-dose glucocorticoids and tacrolimus in terms of mortality at six months (primary outcome). The epidemiology, pathogenesis and treatment options of anti-MDA5 associated ILD are briefly reviewed.

The spectrum and clinical significance of myositis-specific autoantibodies in Chinese patients with idiopathic inflammatory myopathies

OBJECTIVES

The aim of this study is to analyze the prevalence of myositis-specific autoantibodies (MSAs) and to elucidate their associations with clinical features in Chinese patients with polymyositis (PM) and dermatomyositis (DM).

METHODS

Twelve subsets of MSAs including anti-Mi-2, anti-TIF1-γ, anti-MDA5, anti-NXP2, anti-SAE1, anti-SRP, anti-Jo-1, anti-PL-7, anti-PL-12, anti-EJ, anti-OJ, and anti-HMGCR antibodies were tested. Four hundred and ninety-seven PM/DM patients were enrolled. Clinical features and laboratory data were collected. The frequency of MSAs and the correlations with clinical phenotypes were calculated by SPSS 21.0.

RESULTS

MSAs were present in 65.4% in PM/DM patients. Anti-TIF1-γ (14.3%), anti-MDA5 (12.5%), and anti-Jo-1 (10.1%) were the three commonest MSAs. Anti-SAE1 (OR 14.877, 95% CI 1.427-155.074), anti-SRP (OR 4.339, 95% CI 1.529-12.312) and anti-TIF1-γ (OR 2.790, 95% CI 1.578-4.935) were associated with dysphagia. In contrast, anti-MDA5 (OR 0.356, 95% CI 0.148-0.856) might decrease the frequency of this manifestation. Interstitial lung disease (ILD) was observed more frequently in patients carrying anti-EJ (OR 14.202, 95% CI 1.696-118.902), anti-Jo-1 (OR 11.111, 95% CI 3.306-37.335), and anti-MDA5 (OR 3.109, 95% CI 1.578-6.128). On the contrary, anti-Mi-2 (OR 0.180, 95% CI 0.055-0.589), anti-TIF1-γ (OR 0.163, 95% CI 0.080-0.333), and anti-HMGCR (OR 0.058, 95% CI 0.007-0.451) were protective factors against developing ILD. Anti-TIF1-γ was an independent risk factor for cancer-associated myositis (OR 4.237, 95% CI 1.712-10.487).

CONCLUSIONS

PM/DM patients had high frequencies of MSAs. Several MSAs were independent factors in determining unique clinical phenotypes.