Association of anti-nuclear matrix protein 2 antibody with complications in patients with idiopathic inflammatory myopathies: A meta-analysis of 20 cohorts

Validation of the International Myositis Assessment and Clinical Studies Group guideline on cancer risk stratification

OBJECTIVES

Adult-onset idiopathic inflammatory myopathies (IIMs) are associated with cancer. Guideline on cancer risk stratifications and screening in IIM patients was recently published, but their external validity remains verified. We evaluated its applicability and reliability among a Hong Kong IIM cohort.

METHODS

The longitudinal observational cohort collected data from IIM patients fulfilling relevant classification criteria from eight rheumatology centres in Hong Kong. Demographic, clinical and laboratory data were reviewed from 2004 to 2023. IIM patients were stratified into standard, intermediate or high-risk subgroups according to the IMACS guideline. The occurrence of malignancy at or after IIM diagnosis was analysed. Independent risk factors for cancer were evaluated.

RESULTS

A total of 479 patients were included with 327 females (68.3%) and mean age of IIM diagnosis at 54.5 ± 13.6 years. In total, 214 (44.7%) and 238 (49.7%) patients were stratified to high and intermediate risk groups, respectively. Only 5.6% belonged to the standard-risk group. Sixty patients (12.5%) had cancer within 3 years of IIM diagnosis. Nasopharyngeal (25%), lung (21.1%) and breast (10.5%) were the top three cancers. Significantly more patients (44, 20.6%) in the high-risk group developed cancer within 3 years, compared with intermediate (6.7%, P < 0.001) and standard-risk (0%, P = 0.009) groups. Risk factors for cancer included older age (OR: 1.048, 95%CI: 1.019-1.078), Gottron's rash (OR: 2.453, 95%CI: 1.123-5.356), absence of interstitial lung disease (OR 2.695, 95% CI: 1.154-6.295), anti-TIF1g positivity (OR: 4.627, 95% CI: 2.046-10.461) and anti-SAE1 positivity (OR: 5.325, 95% CI: 1.271-22.300).

CONCLUSIONS

Our real-world study supported the accuracy of cancer risk stratification. The vast majority of IIM patients would be subjected to extensive cancer screening when the guideline was applied.

Characterised intron retention profiles in muscle tissue of idiopathic inflammatory myopathy subtypes

OBJECTIVES

Idiopathic inflammatory myopathies (IIMs) are a group of heterogeneous autoimmune diseases. Intron retention (IR) serves as an important post-transcriptional and translational regulatory mechanism. This study aims to identify changes in IR profiles in IIM subtypes, investigating their influence on proteins and their correlations with clinical features.

METHODS

RNA sequencing and liquid chromatography-tandem mass spectrometry were performed on muscle tissues obtained from 174 patients with IIM and 19 controls, following QC procedures. GTFtools and iREAD software were used for IR identification. An analysis of differentially expressed IRs (DEIs), exons and proteins was carried out using edgeR or DEP. Functional analysis was performed with clusterProfiler, and SPIRON was used to assess splicing factors.

RESULTS

A total of 6783 IRs located in 3111 unique genes were identified in all IIM subtypes compared with controls. IIM subtype-specific DEIs were associated with the pathogenesis of respective IIM subtypes. Splicing factors YBX1 and HSPA2 exhibited the most changes in dermatomyositis and immune-mediated necrotising myopathy. Increased IR was associated with reduced protein expression. Some of the IIM-specific DEIs were correlated with clinical parameters (skin rash, MMT-8 scores and muscle enzymes) and muscle histopathological features (myofiber necrosis, regeneration and inflammation). IRs in IFIH1 and TRIM21 were strongly correlated with anti-MDA5+ antibody, while IRs in SRP14 were associated with anti-SRP+ antibody.

CONCLUSION

This study revealed distinct IRs and specific splicing factors associated with IIM subtypes, which might be contributing to the pathogenesis of IIM. We also emphasised the potential impact of IR on protein expression in IIM muscles.

[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.

Clinical profile of anti-NXP-2 antibody-positive inflammatory myositis and outcome in an Indian population

INTRODUCTION

Myositis-specific antibodies (MSA) play an important role in the clinical presentation and prognosis of patients with idiopathic inflammatory myositis (IIM). Anti-NXP-2 is one of the newly described MSA.

OBJECTIVE

We aimed to describe various clinical presentations associated with anti-NXP2 antibodies and assess response to treatment.

METHODS

In this retrospective study, the electronic medical records of all patients who tested positive for anti-NXP2 during June 2019 to April 2022 were screened. Details of demography, clinical presentation, and treatment data were recorded. The anti-NXP2 was tested using the Euro line test kit. Any patient who had an intensity of ≥1+ was considered testing positive. The diagnosis of IIM was reviewed after applying the 2017 European League of Rheumatology (EULAR)/American College of Rheumatology (ACR) criteria of myositis.

RESULTS

Among the 660 suspected patients, 470 (71.2%) patients were positive for IIM, and 28 (5.95%) patients were positive for anti-NXP2. From anti-NXP2-antibody positive, 21/470 (4.46%) patients fulfilled criteria for IIM. Among 12 adult (57.14%) patients with IIM, 7 (58.33%) presented as polymyositis (PM) and 5 (41.6%) as dermatomyositis (DM) with median age at presentation of 45 (IQR: 25-58) years. Calcinosis and subcutaneous oedema were observed in 4 (19%) and 2 (9.52%), respectively; myalgia in 6 (28.6%); and distal muscle weakness in 5 (23.8%) patients. Malignancy at the time of diagnosis was observed in two adults with IIM (16.7%), one with DM (intraductal breast cancer), and another with PM (anaplastic large cell lymphoma). Remaining, 9 had juvenile dermatomyositis (JDM) with a median age of 4 (IQR: 3-8) years. Seven (77.8%) patients with JDM had skin rash specific for DM (heliotrope rash and Gottron's papule). None of the patients had cardiac and lung involvement, while GI symptoms, especially dysphagia, were present in 5 (23.8%) patients. During a median follow-up of 19 months (IQR: 12-26 months), 19/19 patients reported improvement and were in remission with treatment.

CONCLUSION

The current study shows that adult DM patients with anti-NXP-2 autoantibodies have a unique clinical phenotype. Its presentation differs between adult and JDM, even in different parts of the world. Muscle weakness is mild and responds to treatment. Dysphagia needs more time and aggressive IS for improvement as compared to other muscle involvement. Key Points • Anti-NXP-2 antibody presentation varied from adult to child, as in different parts of the world. • In Indian adult patients, non-specific skin manifestations were more common, whereas in JDM, specific skin features were common. • There was less likely involvement of the lung and heart. But more risk of GI involvement requiring aggressive management. • Adult with anti-NXP-2 antibody should be screened for malignancy at the time of presentation.

Clinical Heterogeneity of Patients With Antinuclear Matrix Protein 2 Antibody-Positive Myositis: A Retrospective Cohort Study in China

OBJECTIVE

Heterogeneity exists among patients with myositis who have antinuclear matrix protein 2 (anti-NXP2) antibodies, although they usually present with severe muscle weakness. This study aimed to investigate the differences in phenotypes and prognoses among adult patients with myositis who have anti-NXP2 antibodies.

METHODS

Adult patients with myositis who have anti-NXP2 antibodies were enrolled from January 2010 to December 2019. Their clinical features and laboratory data were recorded retrospectively. We followed up on their survival status until June 30, 2020. A hierarchical cluster analysis, Kaplan-Meier curves, and classification and regression trees were used to analyze the data.

RESULTS

A total of 70 adult patients with myositis who have anti-NXP2 antibodies were enrolled. All patients experienced muscle weakness. A total of 11 patients did not present with rashes during disease progression, and 43 patients developed dysphagia. In total, 21 patients had interstitial lung disease (ILD), whereas no patients had rapidly progressive ILD. Hierarchical cluster analysis identified 2 clusters. Patients in cluster 1 were younger at disease onset, had a higher incidence of subcutaneous calcification, and had a lower incidence of V sign and shawl sign. Patients in cluster 2 had a higher frequency of ILD, accompanied by lower levels of lymphocytes and higher levels of serum ferritin. Moreover, patients in cluster 2 had worse prognoses.

CONCLUSION

Patients with myositis who have anti-NXP2 antibodies may present with different phenotypes that are characterized by unique features and prognoses.

Update on Malignancy in Myositis—Well-Established Association with Unmet Needs

Idiopathic inflammatory myopathies are a group of rare connective tissue diseases with a well-documented association with malignancy. The mechanisms underlying the increased risk of neoplasms in the course of myositis are not fully understood. The Pubmed database has been thoroughly screened for articles concerning cancer-associated myositis (CAM). The article summarizes the current state of knowledge on the epidemiology and pathogenesis of CAM. Furthermore, it analyses potential risk and protective factors for developing CAM, with particular emphasis on the association with distinct serological profiles. The review summarizes recommendations proposed so far for the management of CAM and presents a novel scheme for cancer screening proposed by the authors. Moreover, promising areas requiring further research were indicated.

An Italian Multicenter Study on Anti-NXP2 Antibodies: Clinical and Serological Associations

The identification of anti-NXP2 antibodies is considered a serological marker of dermatomyositis (DM), with calcinosis, severe myositis and, in some reports, with cancer. Historically, these associations with anti-NXP2 antibodies have been detected by immunoprecipitation (IP), but in the last few years commercial immunoblotting assays have been released. The aim of this collaborative project was to analyse the clinical features associated to anti-NXP2 antibodies, both with commercial line blot (LB) and IP. Myositis-specific and myositis-associated autoantibodies were detected in single centres by commercial line blot (LB); available sera were evaluated in a single centre by protein and RNA immunoprecipitation (IP), and IP-Western blot. Sixty patients anti-NXP2+ (NXP2+) positive by LB were compared with 211 patients anti-NXP2 negative with idiopathic inflammatory myositis (IIM). NXP2+ showed a younger age at IIM onset (p = 0.0014), more frequent diagnosis of dermatomyositis (p = 0.026) and inclusion-body myositis (p = 0.009), and lower rate of anti-synthetase syndrome (p < 0.0001). As for clinical features, NXP2+ more frequently develop specific skin manifestations and less frequently features related with overlap myositis and anti-synthetase syndrome. IP confirmed NXP2 positivity in 31 of 52 available sera (62%). Most clinical associations were confirmed comparing NXP2 LB+/IP+ versus NXP2-negative myositis, with the following exceptions: inclusion-body myositis diagnosis was not detected, whilst dysphagia and myositis were found more frequently in NXP2 LB+/IP+ patients. The 21 LB+ /IP-myositis patients did not show differences in clinical features when compared with the NXP2-myositis patients and more frequently displayed multiple positivity at LB. Risk of developing cancer-associated myositis was similar between NXP2-positive and NXP2-negative myositis patients, either when detected by LB or IP. Protein-IP confirmed NXP2 antibodies in nearly 60% of sera positive for the same specificity with commercial assay. Double-positive cases rarely occurred in myositis patients with a clinical diagnosis other than dermatomyositis. Patients only positive by LB (LB+/IP-) did not display clinical features typical of NXP2. NXP2 positivity by LB should be confirmed by other methods in order to correctly diagnose and characterize patients affected by idiopathic inflammatory myositis.

Myositis-specific antibodies and clinical characteristics in patients with autoimmune inflammatory myopathies: reported by the Argentine Registry of Inflammatory Myopathies of the Argentine Society of Rheumatology

INTRODUCTION/OBJECTIVES

To describe clinical features in patients with inflammatory myopathies (IMs) from the Argentine Registry of Inflammatory Myopathies, and their relationship with myositis-specific antibodies (MSAs).

METHODS

This cross-sectional study included 360 adult patients with dermatomyositis (DM), polymyositis (PM), and inclusion body myositis. Demographics, clinical, and serological characteristics were retrospectively recorded (2016-2019). MSAs were determined by immunoblotting. Patients who were positive for anti-Jo-1, Mi-2, and MDA5 were compared against a group of patients, taken as reference group, who were negative for all MSAs.

RESULTS

Women 72%, median age at diagnosis was 47.3 years (18-82). The most frequent subtypes were DM (43.9%) followed by PM (30%).The most frequent MSAs were anti-Jo-1 (51/317), 16.1%; MDA5 (12/111), 10.8%, and Mi-2 (23/226), 10.2%. Anti-Jo-1 was associated (p < 0.05) with a higher frequency of chronic disease course, interstitial lung disease (ILD), arthritis, and mechanic's hands. Anti-Mi-2 was found in patients who had higher frequency of skin manifestations and higher CK values (p < 0.001). Patients with anti-MDA5 had normal or low CK levels. Anti-MDA5 was associated (p < 0.05) with skin manifestations, arthritis, and ILD. The rest of MSAs had frequencies lower than 8%. Anti-TIF1ϒ was found in eight DM patients and one had cancer. Anti-SRP was found in seven patients who had PM and elevated CK.

CONCLUSION

Anti-Jo-1 was the most frequent MSA, and was associated with ILD; MDA5 was associated with CADM and ILD, and Mi-2, with classical DM. Despite the different prevalence with respect to other cohorts, the clinical characteristics for each MSA group were similar to the data reported in other studies. Key Points • This study describes the prevalence of MSAs in the Argentine Registry of IMs. • Anti-Jo-1 and anti-MDA5 were associated with ILD. • Anti-Mi-2 was the third most frequent MSA, associated with classical DM.

Clinical Features and Cutaneous Manifestations of Juvenile and Adult Patients of Dermatomyositis Associated with Myositis-Specific Autoantibodies

Dermatomyositis is one of the idiopathic inflammatory myopathies, which is characterized with specific skin manifestations, and considered as an autoimmune disease. Dermatomyositis is a heterogeneous disorder with various presences, severities and characteristics of myositis, dermatitis, and interstitial lung disease. Our and others' data showed that myositis-specific autoantibodies have been associated with distinct clinical features. This article reviewed the epidemiology and characteristic clinical features of the different types of antibody-associated dermatomyositis in adult and juvenile patients, which include the severity of myopathy, the potential complication of interstitial lung disease, potential association with malignancies, and characteristic cutaneous manifestations.

Clinical impact of myositis-specific autoantibodies on long-term prognosis of juvenile idiopathic inflammatory myopathies: multicenter study

OBJECTIVES

This study aimed to investigate the clinical characteristics, treatment, and prognosis of juvenile idiopathic inflammatory myopathies (JIIM) in Japan for each myositis-specific autoantibody (MSA) profile.

METHODS

A multicenter, retrospective study was conducted using data of patients with JIIM at nine pediatric rheumatology centers in Japan. Patients with MSA profiles, determined by immunoprecipitation using stored serum from the active stage, were included.

RESULTS

MSA were detected in 85 of 96 cases eligible for the analyses. Over 90% of the patients in this study had one of the following three MSA types: anti-MDA5 (n = 31), anti-TIF1γ (n = 25), and anti-NXP2 (n = 25) antibodies. Gottron papules and periungual capillary abnormalities were the most common signs of every MSA group in the initial phase. The presence of interstitial lung disease (ILD) was the highest risk factor for patients with anti-MDA5 antibodies. Most patients were administered multiple drug therapies: glucocorticoids and methotrexate were administered to patients with anti-TIF1γ or anti-NXP2 antibodies. Half of the patients with anti-MDA5 antibodies received more than three medications including intravenous cyclophosphamide, especially patients with ILD. Patients with anti-MDA5 antibodies were more likely to achieve drug-free remission (29% vs 21%) and less likely to relapse (26% vs 44%) than others.

CONCLUSION

Anti-MDA5 antibodies are the most common MSA type in Japan, and patients with this antibody are characterized by ILD at onset, multiple medications including intravenous cyclophosphamide, drug-free remission, and a lower frequency of relapse. New therapeutic strategies are required for other MSA types.

Pathologic Features of Anti-Mi-2 Dermatomyositis

OBJECTIVE

To identify the characteristic pathologic features of dermatomyositis (DM) associated with anti-Mi-2 autoantibodies (anti-Mi-2 DM).

METHODS

We reviewed 188 muscle biopsies from patients (1) pathologically diagnosed with DM through the sarcoplasmic expression for the myxovirus-resistant protein A and (2) serologically positive for 1 of 5 DM-specific autoantibodies (DMSAs) (anti-Mi-2, n = 30; other DMSAs, n = 152) or negative for all 5 DMSAs (n = 6). We then compared the histopathologic and immunohistochemical features of patients with anti-Mi-2 DM to those with non-Mi-2 DM and patients with anti-synthetase syndrome (ASS) (n = 212) using the t test, Fisher exact test, and a logistic regression model.

RESULTS

Patients with anti-Mi-2 DM showed significantly higher severity scores in muscle fiber and inflammatory domains than non-Mi-2 DM patients. The presence of perifascicular necrosis, increased perimysial alkaline phosphatase activity, and sarcolemmal membrane attack complex deposition was more frequent in patients with anti-Mi-2 DM (p < 0.01). After Bonferroni correction, there were no significant differences in the percentages of the features mentioned above between the patients with anti-Mi-2 DM and those with ASS (p > 0.01).

CONCLUSION

Perifascicular necrosis and perimysial pathology, features previously reported in ASS, are common in patients with anti-Mi-2 DM. Our findings not only assist in differentiating anti-Mi-2 DM from other DM subtypes but also suggest the possibility of an overlapping mechanism between anti-Mi-2 DM and ASS.

CLASSIFICATION OF EVIDENCE

This study provides Class II evidence that the muscle biopsies of DM patients with anti-Mi-2 autoantibodies are more likely to demonstrate higher severity scores in muscle fiber and inflammatory domains.

Clinical characteristics and prognostic analysis of Chinese dermatomyositis patients with malignancies

Although a strong association between idiopathic inflammatory myositis (IIM) and malignancy has been widely reported, few studies have solely focused on the concurrence of dermatomyositis (DM) and malignancies (DM-malignancy).We conducted a retrospective analysis of 37 DM-malignancy cases among 363 DM patients admitted to our hospital between January 2012 and December 2017.(1) The mean age at DM diagnosis was higher for DM-malignancy patients than for DM-non-malignancy patients [(54.76 ± 9.77) years vs (48.57 ± 12.82) years, t = 2.84, P = .005]. (2) Gynecological malignancies (35.90%/14 cases) were the most common malignancies. Malignancies were diagnosed before DM for 7 DM-malignancy patients. The interval between the DM and malignancy diagnoses for the remaining 32 DM-malignancy patients was less than 6 months for 18 patients (46.15%), less than 1 years for 23 patients (58.9%), and less than 2 years for 29 patients (74.26%). (3) There was no significant difference either in antinuclear antibody or anti-Ro-52 positivity between the 2 groups (P > .05). (4) Multivariate analysis demonstrated that DM onset age ≥50 years and concurrence with ILD increased the risk of death for DM patients [hazard ratio (HR): 1.62 and 2.72; 95% confidence interval (CI): (1.08-2.43) and (1.47-5.02); P = .02 and 0.001, respectively], and male gender decreased the risk of death [HR 0.66, 95% CI (0.44-0.98), P = .04]. DM-malignancy patients were older than DM-non-malignancy patients. Gynecological malignancies were the most common malignancies among these patients. A DM onset age ≥50 years, female sex and the presence of ILD were independent risk factors for death.

Assessment of diagnostic utility, clinical phenotypic associations, and prognostic significance of anti-NXP2 autoantibody in patients with idiopathic inflammatory myopathies: a systematic review and meta-analysis

The objectives of this study are to analyze the association between anti-nuclear matrix protein 2 (NXP2) autoantibody and idiopathic inflammatory myopathies (IIMs) and to assess the diagnostic and prognostic relevance of anti-NXP2 autoantibody in patients with IIMs. A systematic search was performed in PubMed, Web of Science, EMBASE, the Cochrane Library, and Scopus to identify studies published as of February 29, 2020. Data was analyzed using Stata 12.0 and Meta-DiSc 1.4. Twenty-eight studies (4764 patients with IIMs and 1981 controls) were included in the meta-analysis. Anti-NXP2 autoantibody showed a significant association with IIMs (odds ratio (OR) = 26.36, 95% confidence interval (CI): 12.05-57.67, P < 0.001), especially juvenile IIMs (OR = 62.48, 95% CI: 16.97-229.98, P < 0.001). The pooled sensitivity, specificity, and area under the curve were 0.19 (95% CI = 0.16-0.21), 1.00 (95% CI = 1.00-1.00), and 0.95 for patients with juvenile IIMs versus controls. Anti-NXP2 autoantibody was associated with an increased risk of developing five characteristics (edema, muscle weakness, myalgia/myodynia, dysphagia, and calcinosis) and reduced risk of interstitial lung disease (ILD) (P < 0.001). Anti-NXP2 autoantibody showed no association with increased risk of death in IIMs (P = 0.463). These findings suggest that anti-NXP2 autoantibody is specially related to IIMs and is related to edema, muscle weakness, myalgia/myodynia, dysphagia, calcinosis, and ILD in patients with IIMs. However, there is no evidence to suggest that the presence of anti-NXP2 autoantibody confers a poor prognosis with respect to overall survival. Key Points • This study summarized the diagnostic and prognostic accuracies of anti-NXP2 autoantibody for patients with IIMs. Anti-NXP2 autoantibody is related to edema, muscle weakness, myalgia/myodynia, dysphagia, calcinosis, and ILD in patients with IIMs.

The altered metabolism profile in pathogenesis of idiopathic inflammatory myopathies

Idiopathic inflammatory myopathies (IIMs) are a group of heterogeneous autoimmune diseases characterized by muscle weakness, muscle inflammation and extramuscular manifestations. Despite extensive efforts, the mechanisms of IIMs remain largely unknown, and treatment is still a challenge for physicians. Metabolism changes have emerged as a crucial player in autoimmune diseases, such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). However, little is known about metabolism changes in IIMs. In this review, we focus on the alteration of metabolism profile in IIMs, and the relationships with clinical information. We highlight the potential roles of metabolism in the pathogenesis of IIMs and discuss future perspectives for metabolic checkpoint-based therapeutic interventions.

Cutaneous manifestations of dermatomyositis characterized by myositis-specific autoantibodies

Dermatomyositis (DM) is an inflammatory myopathy with characteristic skin manifestations, the pathologies of which are considered autoimmune diseases. DM is a heterogeneous disorder with various phenotypes, including myositis, dermatitis, and interstitial lung disease (ILD). Recently identified myositis-specific autoantibodies have been associated with distinct clinical features. For example, anti-melanoma differentiation-associated protein 5 antibodies have a high specificity for clinically amyopathic DM presenting rapidly progressive ILD. Furthermore, anti-transcriptional intermediary factor 1γ antibodies found in patients with juvenile and adult DM are closely correlated with malignancies, especially in elderly patients. Finally, patients with anti-aminoacyl-transfer RNA synthetase antibodies share characteristic clinical symptoms, including myositis, ILD, arthritis/arthralgia, Raynaud’s phenomenon, and fever; thus, the term “anti-synthetase syndrome” is also used. With a focus on the characteristic cutaneous manifestations in each subgroup classified according to myositis-specific autoantibodies, we introduce the findings of previous reports, including our recent analysis indicating that skin eruptions can be histopathologically classified into myositis-specific autoantibody-associated subgroups and used to determine the systemic pathologies of the different types of antibody-associated DM.