NXP-2 Positive Dermatomyositis: A Unique Clinical Presentation

[Two cases of anti-nuclear matrix protein 2 antibody-positive dermatomyositis sine dermatitis with severe diffuse subcutaneous edema and dysphagia]

Case 1 involved a 68-year-old woman who was admitted to our hospital because of muscle weakness, diffuse subcutaneous edema, dysphagia, and an elevated serum creatine kinase level that had worsened within the previous month. Case 2 involved a 78-year-old woman who was admitted to our hospital because of muscle weakness, bilateral shoulder pain, diffuse subcutaneous edema, and dysphagia that had gradually worsened during the past 5 months. Both patients showed severe diffuse subcutaneous edema and dysphagia and underwent enteral tube feeding. Although they had no skin lesions consistent with dermatomyositis, muscle biopsies showed myxovirus resistance protein A (MxA) expansion, and blood tests showed positivity for anti-nuclear matrix protein 2 (anti-NXP-2) antibody. Therefore, both presents were diagnosed with anti-NXP-2 antibody-positive dermatomyositis sine dermatitis (DMSD). Anti-NXP-2 antibody-positive dermatomyositis has been reported to be closely associated with DMSD, severe edema and dysphagia. Differential diagnosis for patients who develop myositis with severe subcutaneous edema and dysphagia should include anti-NXP-2 antibody-positive dermatomyositis, and it is important to consider measurement of anti-NXP-2 antibody.

Dermatomyositis Presenting with Generalized Subcutaneous Edema

Generalized subcutaneous edema is rare in dermatomyositis. We herein report an 82-year-old woman with dermatomyositis who presented with generalized subcutaneous edema. Three weeks before admission, she first noticed facial edema, and the symptoms exacerbated, with limb edema occurring. On admission, muscle weakness in the limbs and skin rash were noted. Her muscle enzyme levels were elevated, and serum anti-transcriptional intermediary factor 1-γ antibody was detected. She was diagnosed with dermatomyositis and treated with corticosteroids and tacrolimus, which improved her muscle weakness, muscle enzymes, and edema. Thus, generalized subcutaneous edema can occur during dermatomyositis, with facial edema as the initial symptom.

Unusual Bilateral Upper Extremity Pitting Edema in a Patient With Severe Dermatomyositis

A 56-year-old Hispanic female presented with six weeks of progressive dysphagia, proximal muscle weakness, erythematous rash, bilateral upper extremity pitting edema, and left lower extremity pitting edema. She had preserved heart function and a normal echocardiogram (ECG). She presented with elevated creatine kinase (CK) and aldolase, with normal renal function. Muscle biopsy suggested idiopathic polymyositis. No blood clot was seen on deep vein thrombosis (DVT) ultrasound. The myositis antibody panel showed the NXP-2 antibody, which is usually seen in pediatric dermatomyositis cases. In our literature search, extremity pitting edema is an unusual way of presentation in dermatomyositis. She responded with intravenous immunoglobulin (IVIg) and high-dose intravenous steroids. We used azathioprine for remission maintenance; her rash recurred after tapering steroids. We resumed tapering steroid therapy and started her on weekly methotrexate along with daily azathioprine. With this combination therapy, her rash and muscle function improved. We successfully tapered her steroids. In our literature search, combination therapy with azathioprine and methotrexate was not reported. Our patient is tolerating this therapy very well.

The Impact of Dysphagia in Myositis: A Systematic Review and Meta-Analysis

(1) Background: Dysphagia is a clinical hallmark and part of the current American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) diagnostic criteria for idiopathic inflammatory myopathy (IIM). However, the data on dysphagia in IIM are heterogenous and partly conflicting. The aim of this study was to conduct a systematic review on epidemiology, pathophysiology, outcome and therapy and a meta-analysis on the prevalence of dysphagia in IIM. (2) Methods: Medline was systematically searched for all relevant articles. A random effect model was chosen to estimate the pooled prevalence of dysphagia in the overall cohort of patients with IIM and in different subgroups. (3) Results: 234 studies were included in the review and 116 (10,382 subjects) in the meta-analysis. Dysphagia can occur as initial or sole symptom. The overall pooled prevalence estimate in IIM was 36% and with 56% particularly high in inclusion body myositis. The prevalence estimate was significantly higher in patients with cancer-associated myositis and with NXP2 autoantibodies. Dysphagia is caused by inflammatory involvement of the swallowing muscles, which can lead to reduced pharyngeal contractility, cricopharyngeal dysfunction, reduced laryngeal elevation and hypomotility of the esophagus. Swallowing disorders not only impair the quality of life but can lead to serious complications such as aspiration pneumonia, thus increasing mortality. Beneficial treatment approaches reported include immunomodulatory therapy, the treatment of associated malignant diseases or interventional procedures targeting the cricopharyngeal muscle such as myotomy, dilatation or botulinum toxin injections. (4) Conclusion: Dysphagia should be included as a therapeutic target, especially in the outlined high-risk groups.

Myositis Specific Autoantibodies: A Clinical Perspective

Dermatomyositis (DM) is an idiopathic inflammatory condition characterized by myositis and variable skin manifestation. The existence of myositis specific autoantibodies usually manifests with varying degrees of skin or muscle inflammations. The condition has a well-established association with most clinical phenotypes, and these autoantibodies are useful in informing the diagnosis, management and prognosis of the disease. DM-specific autoantibodies include anti-MDA5, anti-NXP2, anti-SAE, anti-Mi-2, anti-ARS, anti-TIF1-gamma. Anti-Mi-2 antibodies are widely associated with DM cases that exhibit mainly cutaneous symptoms, such as cuticular overgrowths, Gottron's papules while being less susceptible to complications like interstitial lung disease or malignancy. The most distinct clinical features of patients with anti-SAE antibodies are their high prevalence of dysphagia and cutaneous manifestations that antecede the development of myopathies. In addition, DM patients with positive anti-PL-7 antibodies tend to have milder myositis characterized by low levels of creatine kinase as compared to patients with positive anti-Jo-1 antibodies. The anti-NXP2 antibodies are associated with transcriptional regulation and production of various proteins targeted by other DM antibodies, while anti- TIF1-γ. facilitates the transcription of deoxyribonucleic acids and regulates the growth and subsequent differentiation of body cells by controlling the signaling of TGF-β. The present review targets DM specific autoantibodies, considering their association, significance, and clinical presentation.

CD8+ T Cells Prevent Lethality from Neonatal Murine Roseolovirus Infection

A recently described mouse homolog of the human roseoloviruses, murine roseolovirus (MRV), causes loss of peripheral and thymic CD4+ cells during neonatal infection of BALB/c mice. Despite significant disruptions to the normal adaptive immune response, infected BALB/c mice reproducibly recover from infection, consistent with prior studies on a related virus, mouse thymic virus. In this article, we show that, in contrast to published studies on mouse thymic virus, MRV appears to robustly infect neonatal C57BL/6 (B6) mice, causing severe depletion of thymocytes and peripheral T cells. Moreover, B6 mice recovered from infection. We investigated the mechanism of thymocyte and T cell loss, determining that the major thymocyte subsets were infected with MRV; however, CD4+ and CD4+CD8- T cells showed increased apoptosis during infection. We found that CD8+ T cells populated MRV-infected thymi. These CD8+ T cells expressed markers of activation, had restricted TCR repertoire, and accumulated intracellular effector proteins, consistent with a cytotoxic lymphocyte phenotype and suggesting their involvement in viral clearance. Indeed, absence of CD8+ T cells prevented recovery from MRV infection and led to lethality in infected animals, whereas B cell-deficient mice showed CD4+ T cell loss but recovered from infection without lethality. Thus, these results demonstrate that CD8+ T cells are required for protective immunity against a naturally occurring murine pathogen that infects the thymus and establish a novel infection model for MRV in B6 mice, providing the foundation for detailed future studies on MRV with the availability of innumerable mutant mice on the B6 background.