Antibody-positive Dermatomyositis Research Articles

Serum interleukin-34 levels in dermatomyositis: a potential biomarker for anti-MDA5-antibody-associated interstitial lung disease.

Interleukin (IL)-34 is a hematopoietic cytokine that promotes macrophage activation. Macrophage activation in interstitial lung disease (ILD) in patients with dermatomyositis (DM), especially in those with anti-melanoma differentiation-associated gene 5 (MDA5) antibody suggests the involvement of IL-34 in the disease. However, the association between IL-34 and DM is unknown. In this study, we aimed to determine serum IL-34 levels in DM patients and evaluate their association with DM-ILD. We measured serum IL-34 levels in 56 DM patients and 14 age- and sex- matched healthy controls by enzyme-linked immunosorbent assay, and examined their correlation with clinical parameters. In addition, pre- and post-treatment serum IL-34 levels were examined using serum samples from 7 anti-MDA5 antibody-positive DM patients. Serum IL-34 levels were significantly elevated in DM patients, especially in those with anti-MDA5 antibody, compared with healthy controls. In anti-MDA5-antibody-positive DM patients, serum IL-34 levels positively correlated with serum levels of ferritin and anti-MDA5 antibody, which are known biomarkers for rapidly progressive (RP)-ILD. Following combined immunosuppressive therapy, serum IL-34 levels decreased along with ferritin and anti-MDA5 antibody. These data suggest that IL-34 may be involved in the development of RP-ILD in anti-MDA5 antibody-positive DM. Serum IL-34 levels can serve as a potential biomarker for RP-ILD in this clinical entity.

Human umbilical cord mesenchymal stem cells treated anti-MDA5 antibody-positive dermatomyositis with interstitial lung disease: a case report.

Human umbilical cord mesenchymal stem cells treated anti-MDA5 antibody-positive dermatomyositis with interstitial lung disease: a case report.

Clinical utility of anti-Ro52 antibody confirmation in anti-MDA5 antibody-positive dermatomyositis: A Case Report.

This case report highlights dermatomyositis (DM) characterized by the concurrent presence of anti-melanoma differentiation-associated protein 5 (anti-MDA5) and anti-Ro52 antibodies. A 64-year-old woman initially presented with erythema on the palms, which later spread to the dorsum of the hands, followed by involvement of the face, forehead, and upper eyelids. The patient reported joint pain, fatigue, and dyspnea. Physical examination revealed characteristic cutaneous manifestations, including heliotrope rash and Gottron's sign, accompanied by skin ulceration and muscle weakness. Blood tests showed elevated levels of creatine phosphokinase and C-reactive protein. A high-resolution computed tomography (HRCT) scan revealed interstitial lung disease (ILD) with an organizing pneumonia (OP) pattern. Magnetic resonance imaging (MRI) confirmed the presence of myositis. Autoantibody analysis revealed concurrent positivity for both anti-MDA5 and anti-Ro52 antibodies. At the time of diagnosis, she had no respiratory impairment, but had an elevated C-reactive protein and high levels of anti-MDA5 antibody. She was started on triple combination therapy with glucocorticoids, cyclophosphamide, and tacrolimus. She had worsening oxygenation and elevated ferritin during the first weeks of treatment, but then her symptoms improved. Early detection of a co-positive anti-Ro52 antibody led to early initiation of triple combination therapy and a good prognosis.

Patient Perspectives of the Manifestations and Treatment of Anti-MDA5 Antibody-Positive Dermatomyositis: An Observational Survey.

Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of autoimmune disorders classically characterized by proximal skeletal muscle inflammation leading to weakness, but they often possess additional systemic manifestations such as cutaneous, pulmonary, and articular disease.1 Although originally dichotomized as either dermatomyositis (DM) or polymyositis, the discovery of new myositis-specific antibodies (MSA) and myositis-associated antibodies has led to the delineation of more refined IIM patient subgroups.

OA16 Clinical and biochemical improvement following daratumumab therapy for anti-MDA5 antibody positive dermatomyositis with rapidly progressive interstitial lung disease: a case report

Abstract Background/Aims Anti-melanoma differentiation-associated 5 gene autoantibody (anti-MDA5) positive dermatomyositis (DM) with rapidly progressive interstitial lung disease (RP-ILD) represents the most severe and difficult-to-treat form of autoimmune myositis with unfavourable 6-month survival rates despite intensive treatment strategies of combination therapy with glucocorticoids, cyclophosphamide, calcineurin inhibitors, mycophenolate mofetil and rituximab. We describe a case of anti-MDA5 positive DM with RP-ILD that was refractory to intensive combination therapy, requiring courses of rescue plasmapheresis, before eventually responding to intravenous daratumumab. Methods A 30-year-old non-smoking Chinese man who was previously well was hospitalised after 3 weeks of intermittent pyrexia, non-productive cough, lethargy, rashes and myalgia. Examination revealed typical cutaneous changes of dermatomyositis, bilateral mid-to-lower zone inspiratory crepitations in his chest with no proximal muscle weakness or synovitis. Initial investigations demonstrated elevations in creatine kinase, C-reactive protein, erythrocyte sedimentation rate, lactate dehydrogenase, ferritin and neutrophil-to-lymphocyte ratio. Although an initial chest radiograph was normal, CT thorax 4 days later showed non-specific ground-glass opacities with consolidation in both lower lobes. Anti-MDA5 antibodies were strongly positive on EUROLINE Inflammatory Myopathies 16 Ag (IgG) commercial line immunoblot. He was transferred to our centre for further care one week after hospitalisation and was intubated on arrival for type I respiratory failure. He was initiated on combination therapy of intravenous methylprednisolone, intravenous rituximab, hydroxychloroquine, tofacitinib and was also treated with plasmapheresis to remove pathogenic anti-MDA5 antibodies. Although his condition improved initially with successful extubation within one week, the disease remained active in the following months with several admissions for infection-related issues and progression of RP-ILD. Despite various combinations of immunosuppressives and further courses of plasmapheresis, at 6 months post-diagnosis he continued to require a minimum daily prednisolone dose of 45mg (0.625mg/kg/day), remaining positive for anti-MDA5 antibodies on the immunoblot assay, with persistently elevated serum ferritin and transaminases. As such, he was treated with four doses of intravenous daratumumab in an attempt to deplete the long-lasting plasma cells that may be driving the disease. Results Following daratumumab treatment, the anti-MDA5 antibody turned negative on the immunoblot assay with normalisation of ferritin and transaminases, with corresponding improvement in lung function tests and chest radiograph findings. 3 months post-daratumumab, he remains clinically well on hydroxychloroquine, tofacitinib and nintedanib, with successful continuing taper of prednisolone. Conclusion Daratumumab is an anti-CD38 monoclonal antibody licensed for the treatment of multiple myeloma which has been used off-label for other refractory autoimmune conditions such as SLE. It is postulated that besides CD19/20 positive B cells, CD38 positive long-lived autoantibody-secreting plasma cells are essential drivers of chronic inflammation in these autoimmune diseases. In our patient with anti-MDA5 DM and RP-ILD, the use of daratumumab was well-tolerated and led to definite clinical and biochemical improvement. Disclosure L. Koh: None. G. Chai: None. M. Manghani: None. X. Lim: None. B.P.L. Leung: None. C. Chua: None.

Longitudinal study of patients with anti-SAE antibody positive dermatomyositis: a multicenter cohort study in China.

To describe the longitudinal study and long-term prognosis of multicentre large inception cohort of patients with anti-SAE positive DM. We retrospectively recruited patients with anti-SAE+DM in four tertiary referral centers from China between March 2005 and December 2022. Long-term survival analysis was performed in the enrolled patients. The Myositis Damage Index (MDI) and Cutaneous Disease Area and Severity Index (CDASI) were used to evaluate the degree of different organ damage and the extent of skin rashes. Longitudinal computed tomographic (CT) patterns were analyzed. Phenotypes were characterized using unsupervised cluster analysis. All-cause death occurred in 10.5% (4/38) of all patients, in which three patients succumbed to malignancies at 13, 18, and 36 months. Most patients had favorable long-term outcomes, 35.3% of them were in drug-free remission. Skin rashes showed significant improvement evaluated by CDASI with time. However, damage to different systems was observed in 70.6% of the surviving patients using the MDI, which mainly consisted in skin damage, accounting for 47.1%. Nine patients with anti-SAE+DM associated interstitial lung disease (ILD) underwent repeat CT showed marked radiological improvement at 6 months or being stable after 12 months. In further, different characteristics and outcomes were also showed in three clusters identified by unsupervised analysis. Anti-SAE+DM is characterized with lower mortality rate and the development of malignancies being the primary cause of death. Patients who survived showed notable cutaneous damage, while the ILD tends to stabilize. Clusters identified with unsupervised analysis could assist physicians in identifying higher risk of mortality.

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

BackgroundRapid 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.MethodsSerums 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.ResultsSerum 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).ConclusionsSerum BAFF could be a useful prognostic biomarker for early detecting RP-ILD risk in anti-MDA5+DM patients.

Assessing Time of Onset for Interstitial Lung Disease in Anti-MDA5 Antibody-Positive Dermatomyositis

This cohort study seeks to describe the time interval between interstitial lung disease and anti–melanoma differentiation-associated gene 5 antibody-positive dermatomyositis diagnoses.

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.

A case of autoimmune pulmonary alveolar proteinosis during the course of treatment of rapidly progressive interstitial pneumonia associated with anti-MDA5 antibody-positive dermatomyositis.

Autoimmune pulmonary alveolar proteinosis (APAP) is a diffuse lung disease that causes abnormal accumulation of lipoproteins in the alveoli; however, its pathogenesis remains unclear. Recently, APAP cases have been reported during the course of dermatomyositis. The combination of these two diseases may be coincidental; however, it may have been overlooked because differentiating APAP from a flare-up of interstitial pneumonia associated with dermatomyositis is challenging. This didactic case demonstrates the need for early APAP scrutiny. A 50-year-old woman was diagnosed with anti-melanoma differentiation-associated gene 5 (anti-MDA5) antibody-positive dermatitis and interstitial pneumonia in April 2021. The patient was treated with corticosteroids, tacrolimus, and cyclophosphamide pulse therapy for interstitial pneumonia complicated by MDA5 antibody-positive dermatitis, which improved the symptoms and interstitial pneumonia. Eight months after the start of treatment, a new interstitial shadow appeared that worsened. Therefore, three additional courses of cyclophosphamide pulse therapy were administered; however, the respiratory symptoms and interstitial shadows did not improve. Respiratory failure progressed, and 14months after treatment initiation, bronchoscopy revealed turbid alveolar lavage fluid, numerous foamy macrophages, and numerous periodic acid-Schiff-positive unstructured materials. Blood test results revealed high anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) antibody levels, leading to a diagnosis of APAP. The patient underwent whole-lung lavage, and the respiratory disturbance promptly improved. Anti-GM-CSF antibodies were measured from the cryopreserved serum samples collected at the time of diagnosis of anti-MDA5 antibody-positive dermatitis, and 10months later, both values were significantly higher than normal. This is the first report of anti-MDA5 antibody-positive dermatomyositis complicated by interstitial pneumonia with APAP, which may develop during immunosuppressive therapy and be misdiagnosed as a re-exacerbation of interstitial pneumonia. In anti-MDA5 antibody-positive dermatomyositis, APAP comorbidity may have been overlooked, and early evaluation with bronchoalveolar lavage fluid and anti-GM-CSF antibody measurements should be considered, keeping the development of APAP in mind.

Anti-Mi-2 antibody-positive dermatomyositis following Spirulina intake.

Anti-Mi-2 antibody-positive dermatomyositis following Spirulina intake.

Characteristics of anti-melanoma differentiation associated gene 5 antibody-positive dermatomyositis with thrombotic microangiopathy.

Anti-melanoma differentiation associated gene 5 antibody (anti-MDA5 Ab)-positive dermatomyositis (DM) is representative of rapidly progressive interstitial pneumonia. However, its association with thrombotic microangiopathy (TMA), characterized by thrombocytopenia, hemolytic anemia, and organ dysfunction, has not been defined. This study aimed to elucidate the characteristics of anti-MDA5 Ab-positive DM accompanied by TMA. We reviewed our hospital records from November 2009 to September 2022. We included patients in accordance with the 2017 European League Against Rheumatism/American College of Rheumatology classification criteria and with the criteria of Bohan and Peter. TMA was diagnosed according to the criteria for transplantation-associated TMA proposed by the International Working Group. This study enrolled a total of 26 anti-MDA5 Ab-positive DM patients, four of whom developed TMA. The patients with TMA had an increased urine protein/creatinine ratio (UPCR). In addition, these four patients showed significantly elevated levels of ferritin and anti-MDA5 Ab titers and were considered to have high disease activity; yet, all of them survived. Out study indicated that anti-MDA5 Ab-positive DM patients with hyperferritinemia, a high anti-MDA5 Ab titer, and an increased UPCR should be carefully managed, bearing in mind a complication of TMA.

A case of anti-melanoma differentiation antigen 5 antibody-positive dermatomyositis in which monitoring of Ro52/IgG/HLA-DR complex antibody titer was useful to exclude interstitial pneumonia

A case of anti-melanoma differentiation antigen 5 antibody-positive dermatomyositis in which monitoring of Ro52/IgG/HLA-DR complex antibody titer was useful to exclude interstitial pneumonia

Examination of Prognostic Factors in Anti-Melanoma Differentiation-Associated Gene 5 Antibody-Positive Dermatomyositis.

This study investigated the prognostic factors of anti-melanoma differentiation-associated gene 5 antibody-positive dermatomyositis (MDA5-DM). This study analysed 34 MDA5-DM cases (20 and 14 in the survival and death groups, respectively) encountered at Kurume University between 2008 and 2021. The clinical, physiological, and computed tomography findings, pulmonary function, and serological results were retrospectively evaluated for each MDA5-DM case during the first visit and throughout the next 12 weeks. In the death group, the mean age of patients was higher (47.6 vs. 61.8 years), while the duration from symptom onset to consultation was shorter (110 vs. 34.9 days). During the first visit, the death group demonstrated a significantly higher serum C-reactive protein (CRP) level (0.52 vs. 1.99) and a significantly lower albumin level (3.23 vs. 2.63) than the survival group; this persisted throughout the next 12 weeks. Poor prognosis was associated with CRP and albumin levels above 0.19 mg/dL and below 2.3 g/dL, respectively, 4 weeks after starting treatment. Four weeks after beginning treatment, serum CRP and albumin levels of patients with MDA5-DM can be used to evaluate treatment response and predict prognosis.

Hypouricemia as a novel predictor of mortality in anti-MDA5 positive dermatomyositis patients with ILD: A retrospective cohort study

ObjectiveAnti-melanoma differentiation-associated gene 5 antibody positive dermatomyositis (MDA5+ DM) is a unique subtype of idiopathic inflammatory myopathy (IIM) that is associated with rapidly progressive interstitial lung disease (RPILD) and high mortality. This retrospective study aimed to identify predictors of mortality and discover novel easily detectable indicators. MethodsWe retrospectively reviewed 183 MDA5+ DM-ILD patients who were from West China Hospital of Sichuan University myositis cohort, the largest single-center cohort of southwest China, from January 2016 to October 2021. Clinical characteristics were reviewed, and risk factors for mortality were determined by univariate and multivariable Cox regression analyses. ResultsOf the 183 MDA5+ DM-ILD patients, 59 were presented with RP-ILD, and 53 died during the follow-up period. Compared with the survived patients, deceased patients had higher rates of dyspnea, higher concentrations of CRP, and LDH, but lower rates of heliotrope sign, lower quantity of lymphocyte and lower levels of serum uric acid (SUA). Notably, patients with hypouricemia (SUA <154 μmol/L) had higher concentrations of CRP and LDH, higher neutrophil counts, lower lymphocyte counts and higher mortality rate when compared with the non-hypouricemia group. Multivariate Cox regression analyses confirmed that hypouricemia, smoking, RPILD, high HRCT score, elevated LDH, and lymphopenia were independent risk factors for mortality in MDA5+ DM-ILD patients. Moreover, patients with hypouricemia had significantly lower survival rates than non-hypouricemia patients. ConclusionOur study identified hypouricemia as a non-redundant promising prognostic factor for the mortality of MDA5+ DM-ILD patients, which may hopefully provide insight into the prevention and pathogenesis study.

Short-term and long-term outcomes of patients with anti-melanoma differentiation-associated gene 5 antibody-positive dermatomyositis.

Anti-melanoma differentiation-associated gene 5 (MDA5) antibody-positive dermatomyositis (MDA5-DM) is a subtype of dermatomyositis characterized by frequent interstitial lung disease and reduced muscle involvement. This study aimed to determine the short-term and long-term outcomes of patients with MDA5-DM. Information on baseline characteristics, treatments, and short-term and long-term outcomes of patients with MDA5-DM including survival, relapse, and the titer of anti-MDA5 antibody, was retrospectively collected. Descriptive statistics regarding clinical outcomes were calculated, and a comparison of clinical parameters between patients with and without relapse was performed. The short-term survival according to the use of Janus kinase inhibitors (JAKi) was also assessed. A total of 154 patients with MDA5-DM were included in the study. Forty patients (25.9%) died during the remission induction phase, with respiratory failure being the most common cause of mortality. Among the 114 patients who survived the remission induction phase, the 5-year cumulative survival and relapse-free survival rates were 96.8% and 77.4%, respectively, and 7.9% of patients achieved complete drug-free remission. Fifty-four patients achieved normalization of anti-MDA5 antibody titers and only two of them relapsed after normalization. In the severe patients, the 6-month survival rate became significantly higher after the emergence of the JAKi treatment compared with before its existence (p= 0.03). Although relapse often occurs, the long-term survival of MDA5-DM patients who survived the remission induction phase is generally favorable. The status of the anti-MDA5 antibody is associated with relapse. JAKi may improve the survival of refractory patients with severe MDA5-DM.

Global trends in research of melanoma differentiation-associated gene 5: a bibliometric analysis from 2002 to 2022.

Melanoma differentiation-associated gene 5 (MDA5), as a cytoplasmic sensor for viral double-stranded RNAs, has received increasing attention in recent years. Although considerable headway has been made on the functional role of MDA5 in antiviral immunity and autoimmune disease, the available literature is insufficient to assess the vast field. This study performed a bibliometric analysis to investigate current hotspots in the global scientific output of MDA5 over the past two decades. Related publications and recorded information from 2002 to 2022 in the Web of Science Core Collection (WoSCC) database were retrieved. VOSviewer and CiteSpace were used for quantitative evaluation and visualization. A total of 2267 original articles and reviews were obtained, and the annual number of publications related to MDA5 was increasing rapidly. China has published the most papers, while the USA was the most influential country with the most citations and the highest H-index. The Chinese Academy of Sciences, the United States Department of Health and Human Services, and the Journal of Virology were the most prolific research affiliation, funding source, and journal, respectively. Fujita T (Kyoto University) was the most productive author with the highest H-index and had close cooperation with Kato H and Yoneyama M. The keywords "RIG-I," "MDA5," "innate immunity," "double-stranded-RNA," and "recognition" had the highest frequency, while "dermatomyositis" as well as "autoantibody" seemed to be the emerging hotspots. This study comprehensively demonstrated the research frontiers of MDA5 and will provide a useful resource for scholars to conduct future decisions. We conducted the first in-depth survey of the research frontiers on melanoma differentiation-associated gene 5 (MDA5) over the past two decades via bibliometric analysis. We found that many early breakthroughs have been made in the mechanism of MDA5-mediated antiviral immune responses, and the role of MDA5 in autoimmune and autoinflammatory diseases has raised the recent concern. We identified that the virus infection-associated pathogenesis and effective therapeutic strategy of anti-MDA5 antibody-positive dermatomyositis will remain the hotspots in the future.

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

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

Juvenile-onset anti-nuclear matrix protein 2 (NXP-2) antibody-positive dermatomyositis with joint contractures before manifestation of myositis: a case report

A 23-year-old man was admitted to our hospital with a one-year history of muscle weakness and atrophy. He had noticed contractures of the fingers of both hands from the age of 18. Examination revealed a skin rash including heliotrope rash and Gottron's sign, joint contractures in the extremities, dysphagia, extensive muscle weakness and marked muscle atrophy. The serum creatine kinase level was 272 ‍IU/l and muscle biopsy showed typical perifascicular atrophy but little lymphocyte invasion. There was no interstitial pneumonia or malignancy, but muscle tendons showed elevated CT values suggesting calcification or fibrosis. Anti-nuclear matrix protein 2 (NXP-2) antibody-positive dermatomyositis was diagnosed on the basis of the serum antibody level. Methylprednisolone pulse therapy ameliorated the skin rash and bulbar palsy, but muscle weakness, atrophy and joint contractures were resistant to the treatment. There have been no previous reports of young adults with anti-NXP-2 antibody-positive dermatomyositis in whom joint contracture became evident as early as 4 years beforehand, which is a important feature for differential diagnosis of dermatomyositis.

Antinuclear matrix protein 2 antibody-positive dermatomyositis: a rare entity.

Antinuclear matrix protein 2 antibody-positive dermatomyositis: a rare entity.