An Autopsy Case of Anti-melanoma Differentiation-associated Gene-5 Antibody-positive Clinical Amyopathic Dermatomyositis Complicated by Rapidly Progressive Interstitial Lung Disease

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.

An autopsy case of anti-MDA5 antibody-positive amyopathic dermatomyositis with an initial manifestation of panniculitis on the left upper arm

A 53-year-old man was presented with refractory panniculitis on the left upper arm that had persisted for 10 months. The patient was diagnosed with lupus profundus, wherein oral glucocorticoid therapy was initiated. Four months prior, ulceration was observed in the same area. Dapson was administered instead, scarring the ulcer but enlarging the panniculitis. Five weeks earlier, he developed a fever, productive cough, and dyspnoea. Three weeks earlier, a skin rash was observed on the forehead, left auricle posterior to the neck, and extensor aspect of the left elbow. Chest computed tomography showed pneumonia in the right lung, after which the patient's dyspnoea worsened. The patient was admitted and diagnosed with anti-MDA5 antibody-positive amyopathic dermatomyositis (ADM) based on skin findings, hyperferritinaemia, and rapidly progressive diffuse lung shadows. Glucocorticoid pulse therapy, intravenous cyclophosphamide, and tacrolimus were initiated, and later, plasma exchange therapy was combined. However, his condition worsened and required management with extracorporeal membrane oxygenation. The patient expired on day 28 after hospitalisation. An autopsy revealed hyalinising to fibrotic stages of diffuse alveolar damage. Strong expression of myxovirus resistance protein A was observed in three skin biopsy specimens from the time of initial onset, consistent with ADM. Anti-MDA5 antibody-positive ADM not only manifests typical cutaneous symptoms, but also rarely occurs with localised panniculitis, such as in the present case. In patients with panniculitis of unknown aetiology, the possibility of initial symptoms of ADM should be included in the differential diagnosis.

Friend or foe: RIG- I like receptors and diseases

Retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs), which are pivotal sensors of RNA virus invasions, mediate the transcriptional induction of genes encoding type I interferons (IFNs) and proinflammatory cytokines, successfully establishing host antiviral immune response. A few excellent reviews have elaborated on the structural biology of RLRs and the antiviral mechanisms of RLR activation. In this review, we give a basic understanding of RLR biology and summarize recent findings of how RLR signaling cascade is strictly controlled by host regulatory mechanisms, which include RLR-interacting proteins, post-translational modifications and microRNAs (miRNAs). Furthermore, we pay particular attention to the relationship between RLRs and diseases, especially how RLRs participate in SARS-CoV-2, malaria or bacterial infections, how single-nucleotide polymorphisms (SNPs) or mutations in RLRs and antibodies against RLRs lead to autoinflammatory diseases and autoimmune diseases, and how RLRs are involved in anti-tumor immunity. These findings will provide insights and guidance for antiviral and immunomodulatory therapies targeting RLRs.

Slowly progressive interstitial lung disease preceding typical dermatomyositis symptoms in anti-melanoma differentiation-associated gene 5 antibody-positive clinically amyopathic dermatomyositis

A 73-year-old woman who visited our hospital complaining of dry cough for three months was refractory to antimicrobial therapy. Chest computed tomography revealed subpleural consolidation. Specimens obtained from surgical lung biopsy revealed subpleural perilobular airspace organization and fibrosis. After the biopsy, mechanic's hand and Gottron's papules appeared, and anti-melanoma differentiation-associated gene 5 (MDA5) antibody was found to be positive. Subsequently, anti-MDA5 antibody measured in cryopreserved serum from her first admission proved to be positive. It is difficult to suspect the presence of anti-MDA-5 antibody in patients with interstitial lung disease without typical dermatomyositis symptoms or slow disease progression.

Recommendations for the treatment of anti-melanoma differentiation-associated gene 5-positive dermatomyositis-associated rapidly progressive interstitial lung disease

OBJECTIVES

The study aimed to develop evidence-based recommendations for the treatment of rapidly progressive interstitial lung disease (RPILD) associated with the anti-Melanoma Differentiation-Associated Gene 5-positive dermatomyositis (DM) syndrome.

METHODS

The task force comprised an expert panel of specialists in rheumatology, intensive care medicine, pulmonology, immunology, and internal medicine. The study was carried out in two phases: identifying key areas in the management of DM-RPILD syndrome and developing a set of recommendations based on a review of the available scientific evidence. Four specific questions focused on different treatment options were identified. Relevant publications in English, Spanish or French up to April 2018 were searched systematically for each topic using PubMed (MEDLINE), EMBASE, and Cochrane Library (Wiley Online). The experts used evidence obtained from these studies to develop recommendations.

RESULTS

A total of 134 studies met eligibility criteria and formed the evidentiary basis for the recommendations regarding immunosuppressive therapy and complementary treatments. Overall, there was general agreement on the initial use of combined immunosuppressive therapy. Combination of high-dose glucocorticoids and calcineurin antagonists with or without cyclophosphamide is the first choice. In the case of calcineurin antagonist contraindication or treatment failure, switching or adding other immunosuppressants may be individualized. Plasmapheresis, polymyxin B hemoperfusion and/or intravenous immunoglobulins may be used as rescue options. ECMO should be considered in life-threatening situations while waiting for a clinical response or as a bridge to lung transplant.

CONCLUSIONS

Thirteen recommendations regarding the treatment of the anti-MDA5 positive DM-RPILD were developed using research-based evidence and expert opinion.

Fatal and extensive multiorgan hemorrhages in anti-melanoma differentiation-associated gene 5 antibody-positive dermatomyositis: An autopsy case report

INTRODUCTION

Anti-melanoma differentiation-associated gene 5 antibody (anti-MDA5 Ab) is an autoantigen associated with dermatomyositis (DM). Anti-MDA5 Ab-positive DM patients frequently exhibit clinically amyopathic dermatomyositis (CADM), and develop rapidly progressive interstitial lung disease (RPILD). Even with early detection and potent combination immunosuppressive therapy, anti-MDA5 Ab-positive DM patients have a poor prognosis. In the present case report, we present a rare autopsy case of a patient with anti-MDA5 Ab DM with RPILD who exhibited diffuse alveolar damage (DAD) patterning in lung specimens, and extensive hemorrhages in multiple organs.

PATIENT CONCERNS

An 82-year-old Japanese man admitted with bacterial pneumonia was subsequently diagnosed with anti-MDA5 Ab-positive DM based on skin manifestations (mechanic's hand, ulcerated palmar papules, and flagellate erythema), myositis, interstitial pneumonia, and elevation of anti-MDA5 Ab titer.

DIAGNOSIS

The patient was diagnosed with anti-MDA5 Ab DM, complicated with RPILD.

INTERVENTIONS

The patient received potent immunosuppressive therapy consisting of pulse methylpredonisolone at a dose of 1000 mg for 3 days, followed by prednisolone at 60 mg/d, a 1000 mg pulse of intravenous cyclophosphamide (IVCY), and oral tacrolimus at 6 mg/d. Intravenous immunoglobulin (IVIG) at a dose of 400 mg/kg/d for 5 days was subsequently administered.

OUTCOMES

Despite triple immunosuppressive therapy and IVIG, the patients' respiratory status deteriorated, and the patient died of respiratory failure on the twelfth day after admission. An autopsy revealed pulmonary DAD and multiorgan hemorrhages, including the left iliopsoas muscle, gastric and bowl mucosa, spleen, and left adrenal gland.

LESSONS

Multiorgan hemorrhages may be a fatal complication in anti-MDA5 Ab DM patients.

Histological Findings of Organizing Pneumonia, Based on Transbronchial Lung Biopsy, May Predict Poor Outcome in Polymyositis and Dermatomyositis: Report of Two Autopsied Cases

Interstitial lung disease in polymyositis and dermatomyositis is a serious complication, associated with poor prognosis. In this article, we describe two cases with histological findings of organizing pneumonia, based on transbronchial lung biopsy. One is a 66-year-old female patient with clinically amyopathic dermatomyositis with anti-melanoma differentiation-associated gene 5 antibody, and another is a 61-year-old female patient with polymyositis with anti-Jo-1 antibody. Both of our cases rapidly deteriorated to death, and autopsy findings showed diffuse alveolar damage. Our experience indicates that transbronchial biopsy findings of organizing pneumonia may be a poor prognostic factor in clinically amyopathic dermatomyositis and polymyositis, in spite of the profile of myositis-specific antibodies.