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

Age-Related Differences Between Juvenile and Adult Autoimmune Inflammatory Myopathies

BACKGROUND

Clinical features and prognosis of autoimmune inflammatory myopathies (AIMs) can vary depending on the age of disease onset. The aim of this study was to compare the demographic characteristics, clinical features, laboratory findings, and long-term prognosis of juvenile and adult AIMs.

METHODS

Patients diagnosed with AIM between 2009 and 2023 in the pediatric rheumatology and rheumatology departments of our hospital were included in this medical records review study. Demographic characteristics, clinical features, laboratory findings, treatments, and prognosis of juvenile and adult AIM patients were compared with statistical methods.

RESULTS

Of the 94 patients diagnosed with AIM, 34 (36.2%) patients were juvenile and 60 (63.8%) patients were adult. At the time of diagnosis, while Gottron papules, dysphonia, and subcutaneous edema were more common in juvenile patients, fever was more common in adult patients ( p = 0.003, p = 0.05, p = 0.005 p = 0.05, respectively). During follow-up, while calcinosis was more common in juvenile patients, lung involvement and malignancy were more common in adult patients ( p = 0.022, p = 0.009, p = 0.006, respectively). The methylprednisolone pulse therapy requirement was significantly higher in juvenile patients ( p = 0.0001). Clinically inactive disease was more common in juvenile patients ( p = 0.01).

CONCLUSIONS

AIM with different onset ages is associated with distinct clinical manifestations and outcomes. The present study reported that in AIM patients, lung involvement and malignancy increase with age while clinically inactive disease decreases.

Clinical characteristics of idiopathic inflammatory myopathies patients with anti-PM/Scl antibodies

OBJECTIVES

To analyze the clinical features of idiopathic inflammatory myopathies (IIMs) patients with anti-PM/Scl antibodies.

METHODS

In this retrospective cohort study, we compared the clinical manifestations between patients who were solely positive for anti-PM/Scl antibodies (isolated anti-PM/Scl group) and those with a coexistence of anti-PM/Scl antibodies and myositis-specific antibodies (MSAs) (double-positive group).

RESULTS

Sixty-five IIMs patients positive for anti-PM/Scl antibodies were included, among whom 51 (78.5 %) were females, with a mean age of 49.1 years. Thirty-four (52.3 %) patients coexisted with MSAs. Compared to the double-positive group, the isolated anti-PM/Scl group demonstrated a higher proportion of women (90.3 % vs 67.6 %, p = 0.026) and a higher incidence of sclerodactyly (16.1 % vs 0, p = 0.021). Although there were no differences in the incidence of muscular weakness, dysphagia, or creatine kinase levels, thigh magnetic resonance imaging (MRI) revealed less muscle edema, atrophy, and fatty replacement in the isolated anti-PM/Scl group (p < 0.05). Interstitial lung disease (ILD) occurred in 80 % of patients, more frequently in the double-positive group (90.6 % vs 67.9 %, p = 0.028). According to HRCT, non-specific interstitial pneumonia (NSIP) was the most common pattern among anti-PM/Scl antibodies positive IIMs patients. The double-positive group exhibited higher ferritin levels, and a lower peripheral lymphocyte count (p < 0.05). The mortality rate in the double-positive group was higher than that in the isolated anti-PM/Scl group (20.6 % vs 0, p = 0.034).

CONCLUSION

Among IIMs patients who tested positive for anti-PM/Scl antibodies, ILD emerged as the predominant clinical feature, particularly when combined with MSA. Notably, patients with isolated anti-PM/Scl antibodies exhibited a favorable prognosis following immunotherapy.

Auto-immuno-deficiency syndromes

Autoimmune diseases constitute a broad, heterogenous group with many diverse and often overlapping symptoms. Even so, they are traditionally classified as either systemic, rheumatic diseases or organ-directed diseases. Several theories exist about autoimmune diseases, including defective self-recognition, altered self, molecular mimicry, bystander activation and epitope spreading. While there is no consensus about these theories, it is generally accepted that genetic, pre-disposing factors in combination with environmental factors can result in autoimmune disease. The relative contribution of genetic and environmental factors varies between diseases, as does the significance of individual contributing factors within related diseases. Among the genetic factors, molecules involved in antigen (Ag) recognition, processing, and presentation stand out (e.g., MHC I and II) together with molecules involved in immune signaling and regulation of cellular interactions (i.e., immuno-phenotypes). Also, various immuno-deficiencies have been linked to development of autoimmune diseases. Among the environmental factors, infections (e.g., viruses) have attracted most attention, but factors modulating the immune system have also been the subject of much research (e.g., sunlight and vitamin D). Multiple sclerosis currently stands out due to a very strong and proven association with Epstein-Barr virus infection, notably in cases of late infection and in cases of EBV-associated mononucleosis. Thus, a common picture is emerging that both systemic and organ-directed autoimmune diseases may appropriately be described as auto-immuno-deficiency syndromes (AIdeSs), a concept that emphasizes and integrates existing knowledge on the role of immuno-deficiencies and chronic infections with development of overlapping disease syndromes with variable frequencies of autoantibodies and/or autoreactive T cells. This review integrates and exemplifies current knowledge on the interplay of genetically determined immuno-phenotypes and chronic infections in the development of AIdeSs.

Murine models of idiopathic inflammatory myopathies

Idiopathic inflammatory myopathies (IIMs) are divided into polymyositis and dermatomyositis (DM) with specific cutaneous manifestation. Several myositis-specific autoantibodies (MSAs) have been identified in IIMs and were found to be associated with distinct clinical features, including anti-synthetase syndrome (ASyS) and immune-mediated necrotizing myopathy (IMNM). Moreover, MSA-related clinical features have been identified even within DM. Although MSAs are valuable for the diagnosis of IIMs, the pathogenic roles of these antibodies remain unknown. To investigate the pathogenesis of IIMs, classical murine models of autoimmune myositis, experimental autoimmune myositis, and C protein-induced myositis have been established by immunization with muscle-specific antigens, myosin, and myosin-binding skeletal C protein, respectively. To according to MSA-related autoimmunity, a murine model of ASyS was generated by immunization with a murine recombinant histidyl-transfer RNA (tRNA) synthetase, Jo-1, in which muscle and lung inflammation are induced depending on acquired immunity. Furthermore, it was found that the transfer of human Immunoglobulin G (IgGs) from patients with IMNM, comprising anti-signal recognition particles and anti-3-hydroxy-3-methylglutaryl coenzyme A reductase antibodies, induced complement-mediated myositis in recipient mice. We found that CD8+ T cell-mediated myositis can be established depending on autoimmunity against transcriptional intermediary factor 1γ (TIF1γ), an autoantigen for MSAs induced by recombinant human TIF1γ immunization. These new murine models reflecting MSA-associated IIMs will reveal the immunological mechanisms underlying IIMs.

Possible correlation between serum interleukin-8 levels and the activity of myositis in anti-NXP2 antibody-positive dermatomyositis

Anti-nuclear matrix protein 2 (NXP2) antibody-positive dermatomyositis (DM) is characterized by extensive and severe myositis. In this study, we evaluated which cytokines/chemokines involved with the activity of the myositis. We performed quantitative immunoassays using the MILLIPLEX® Multiplex Assays Using Luminex to evaluate serum levels of interferon-γ, interleukin (IL)-1β, IL-6, IL-8, IL-12p40, and tumor necrosis factor-α in samples collected over time from a 9-year-old female with anti-NXP2 antibody-positive DM. In our case, the serum level of IL-8 was elevated when the myositis worsened, and decreased in accordance with the improvement of myositis, suggesting that the serum IL-8 levels were correlated with the myositis activity. Serum levels of IL-8 in samples from five patients with anti-NXP2 antibody-positive DM and five patients with anti-transcriptional intermediary factor 1γ (TIF1γ) antibody-positive DM without both interstitial lung disease (ILD) and malignancy before starting treatments, along with five healthy controls, were also evaluate by an enzyme-linked immunosorbent assay. Serum IL-8 levels were significantly elevated in anti-NXP2 or anti-TIF1γ antibody-positive DM patients with myositis but not ILD, than healthy controls. It was suggested that serum levels of IL-8 correlate with the activity of myositis in DM including anti-NXP2 antibody-positive DM.

Murine models of idiopathic inflammatory myopathy

Idiopathic inflammatory myopathies (IIMs) are characterized by inflammation of muscles and other organs. Several myositis-specific autoantibodies (MSAs) have been identified in IIMs and were found to be associated with distinct clinical features. Although MSAs are valuable for the diagnosis of IIMs, the pathogenic roles of these antibodies remain unknown. To investigate the pathogenesis of IIMs, several animal models of experimental myositis have been established. Classical murine models of autoimmune myositis, experimental autoimmune myositis, and C protein-induced myositis are established by immunization with muscle-specific antigens, myosin, and skeletal C protein, respectively. Furthermore, a murine model of experimental myositis was generated by immunization with a murine recombinant histidyl-tRNA synthetase, Jo-1, in which muscle and lung inflammation reflecting anti-synthetase syndrome are induced depending on acquired immunity. Recently, the transfer of human IgGs from patients with immune-mediated necrotizing myopathy, comprising anti-signal recognition particles and anti-3-hydroxy-3-methylglutaryl coenzyme A reductase antibodies, was found to induce complement-mediated myositis in recipient mice. CD8⁺ T cell-mediated myositis can be established depending on autoimmunity against transcriptional intermediary factor 1γ (TIF1γ), an autoantigen for MSAs induced by recombinant human TIF1γ immunization. These new murine models reflecting MSA-related IIMs are useful tools for accurately understanding the pathological mechanisms underlying IIMs.

Juvenile dermatomyositis associated with autoantibodies to small ubiquitin-like modifier activating enzyme: a report of 4 cases from North India and a review of literature

BACKGROUND

Juvenile dermatomyositis (JDM) is the commonest inflammatory myositis in children. The clinical phenotype is often characterized by the presence of myositis-specific antibodies (MSA). Antibodies to small ubiquitin-like modifier activating enzyme (SAE) are amongst the rarest MSA reported in children.

MATERIALS AND METHODS

A review of medical records of all patients diagnosed to have JDM during the period January 1992-April 2022 in our institute was done. Case records of children with JDM who had significant positivity for anti-SAE antibody by myositis immunoblot were analysed in detail.

RESULTS

Of the 140 children with JDM, MSA immunoblot was carried out in 53 patients-4 (7.5%) amongst these had significant positivity for anti-SAE antibodies. Median age of onset of symptoms was 5.5 years (range: 5-11 years). Clinical features at presentation included fever, photosensitivity, heliotrope rash, and Gottron papules. Clinically significant proximal muscle weakness was noted in 3/4 patients; 1 had no discernible weakness but had radiological evidence of myositis. None of the 4 patients had evidence of interstitial lung disease or calcinosis. All patients were treated with intravenous pulse methylprednisolone: subcutaneous weekly methotrexate and hydroxychloroquine. One patient received mycophenolate mofetil because of a relapse of muscle disease, while none received cyclophosphamide or biologics. Median follow-up duration was 21.5 months (range: 6-39 months).

CONCLUSION

Anti-SAE antibodies were found in 4/53 (7.5%) of North Indian children with JDM. All 4 patients had predominant cutaneous manifestations followed by muscle disease. Response to treatment was brisk and sustained. None had developed calcinosis in the follow-up.

KEY MESSAGES

1. We report high prevalence of anti-SAE antibody positivity (7.5%) in North Indian cohort of JDM. 2. Cutaneous disease precedes muscle weakness in children with anti-SAE positive JDM. 3. No evidence of interstitial lung disease/calcinosis was seen in these children.

The Role of Autoantibody Testing in Modern Personalized Medicine

Personalized medicine (PM) aims individualized approach to prevention, diagnosis, and treatment. Precision Medicine applies the paradigm of PM by defining groups of individuals with akin characteristics. Often the two terms have been used interchangeably. The quest for PM has been advancing for centuries as traditional nosology classification defines groups of clinical conditions with relatively similar prognoses and treatment options. However, any individual is characterized by a unique set of multiple characteristics and therefore the achievement of PM implies the determination of myriad demographic, epidemiological, clinical, laboratory, and imaging parameters. The accelerated identification of numerous biological variables associated with diverse health conditions contributes to the fulfillment of one of the pre-requisites for PM. The advent of multiplex analytical platforms contributes to the determination of thousands of biological parameters using minute amounts of serum or other biological matrixes. Finally, big data analysis and machine learning contribute to the processing and integration of the multiplexed data at the individual level, allowing for the personalized definition of susceptibility, diagnosis, prognosis, prevention, and treatment. Autoantibodies are traditional biomarkers for autoimmune diseases and can contribute to PM in many aspects, including identification of individuals at risk, early diagnosis, disease sub-phenotyping, definition of prognosis, and treatment, as well as monitoring disease activity. Herein we address how autoantibodies can promote PM in autoimmune diseases using the examples of systemic lupus erythematosus, antiphospholipid syndrome, rheumatoid arthritis, Sjögren syndrome, systemic sclerosis, idiopathic inflammatory myopathies, autoimmune hepatitis, primary biliary cholangitis, and autoimmune neurologic diseases.

Long-Term Outcomes and Prognosis Factors in Patients With Idiopathic Inflammatory Myopathies Based on Myositis-Specific Autoantibodies: A Single Cohort Study

OBJECTIVE

This study was undertaken to investigate the long-term survival rates and prognostic factors in patients with idiopathic inflammatory myopathies (IIMs) based on myositis-specific antibody (MSA) stratification.

METHODS

Exactly 628 patients with an IIM were included. Kaplan-Meier survival curves, univariate, and multivariate Cox regression were used to analyze the outcomes and risk factors.

RESULTS

The cumulative 1-, 5-, and 10-year survival rates for IIM patients overall were 91.4%, 82.8%, and 75.6%, respectively. The survival rate in the MSA subset was significantly different (P < 0.001). The 1- and 10-year survival rates in the anti-melanoma differentiation-associated protein 5 (anti-MDA-5)-positive subgroup were 79.5% and 58.5%, respectively, which were the lowest among all subgroups. The 10-year survival rate of anti-signal recognition particle (anti-SRP)-positive patients was the highest (96.4%). Independent risk factors that impacted the long-term prognosis for IIM patients included rapidly progressive interstitial lung disease (RP-ILD), malignancy, and elevated serum ferritin levels (hazard ratio [HR] 17.47, 20.36, and 9.15, respectively, P < 0.01), whereas disease duration was a protective factor (HR 0.27, P = 0.003). Among these subsets, the strongest independent risk factor for death in the anti-MDA-5-positive subgroup was RP-ILD (HR 3.4, P = 0.017). Malignancy was an independent risk factor in the anti-aminoacyl-tRNA synthetase antibody-positive, anti-transcription intermediary factor 1γ-positive, and MSA-negative subgroups (HR 46.69, 6.65, and 4.48, respectively; P < 0.001). RP-ILD was also a risk factor in the prognosis of individuals in the MSA-negative subgroup (HR 72.28, P < 0.001).

CONCLUSION

Despite favorable overall survival in patients with IIM, the anti-MDA-5-positive subgroup had the highest mortality rate among all MSA subgroups, highlighting the distinctive prognosis for patients with different MSAs. RP-ILD and malignancy are the most common causes of death in IIM patients.