Personalised medicine in juvenile dermatomyositis: From novel insights in disease mechanisms to changes in clinical practice

Juvenile dermatomyositis is characterized by childhood-onset chronic inflammation of the muscles and skin, with potential involvement of other organs. Patients are at risk for long-term morbidity due to insufficient disease control and steroid-related toxicity. Personalised treatment is challenged by a lack of validated tools that can reliably predict treatment response and monitor ongoing (subclinical) inflammation, and by a lack of evidence regarding the best choice of medication for individual patients. A better understanding of the involved disease mechanisms could reveal potential biomarkers and novel therapeutic targets. In this review, we highlight the most relevant immune and non-immune mechanisms, elucidating the effects of interferon overexpression on tissue alongside the interplay between the interferon signature, mitochondrial function, and immune cells. We review mechanism-based biomarkers that are promising for clinical implementation, and the latest advances in targeted therapy development. Finally, we discuss key steps needed for translating these discoveries into clinical practice.

Single-cell mass cytometry in immunological skin diseases

Immune-related skin diseases represent a collective of dermatological disorders intricately linked to dysfunctional immune system processes. These conditions are primarily characterized by an immoderate activation of the immune system or deviant immune responses, involving diverse immune components including immune cells, antibodies, and inflammatory mediators. However, the precise molecular dysregulation underlying numerous individual cases of these diseases and unique subsets respond under disease conditions remains elusive. Comprehending the mechanisms and determinants governing the homeostasis and functionality of diseases could offer potential therapeutic opportunities for intervention. Mass cytometry enables precise and high-throughput quantitative measurement of proteins within individual cells by utilizing antibodies labeled with rare heavy metal isotopes. Imaging mass cytometry employs mass spectrometry to obtain spatial information on cell-to-cell interactions within tissue sections, simultaneously utilizing more than 40 markers. The application of single-cell mass cytometry presents a unique opportunity to conduct highly multiplexed analysis at the single-cell level, thereby revolutionizing our understanding of cell population heterogeneity and hierarchy, cellular states, multiplexed signaling pathways, proteolysis products, and mRNA transcripts specifically in the context of many autoimmune diseases. This information holds the potential to offer novel approaches for the diagnosis, prognostic assessment, and monitoring responses to treatment, thereby enriching our strategies in managing the respective conditions. This review summarizes the present-day utilization of single-cell mass cytometry in studying immune-related skin diseases, highlighting its advantages and limitations. This technique will become increasingly prevalent in conducting extensive investigations into these disorders, ultimately yielding significant contributions to their accurate diagnosis and efficacious therapeutic interventions.

Novel therapeutic targets in dermatomyositis

Dermatomyositis (DM) is a systemic autoimmune disease with variable clinical presentations, including inflammation in the skin, muscle, lungs, and/or joints. Current therapeutic strategies in DM typically include broad immunosuppression; however, the currently used modalities are not universally effective and are associated with various side effects, including risk of infection. There is currently a highly unmet need for more effective and well-tolerated therapies. Recent years have witnessed increased interest in pharmaceutical development of new therapeutic strategies for DM. This review aims to summarize the landscape of therapies that are currently being tested or planned in patients with DM. These therapies have a wide variety of immunological targets, including T cells, B cells, inflammatory signaling pathways, type I interferons, autoantibodies, and other targets.

Roles of interferon induced protein with tetratricopeptide repeats (IFIT) family in autoimmune disease

Interferon-induced tetrapeptide repeat (IFIT) family proteins are an important component of the antiviral immune response. There are four known members of the human IFIT family, namely IFIT1, IFIT2, IFIT3 and IFIT5. More and more evidence shows that IFIT family members are involved in a variety of pathophysiological processes in vivo, regulate the homeostasis and differentiation of a variety of cells including immune cells, and are closely related to a variety of autoimmune diseases, which is expected to become a new therapeutic target. This review reviews the biological roles of different IFIT proteins in various autoimmune diseases, and highlights the potential use of these molecules as biomarkers and prognostic factors in autoimmune diseases, with a view to providing ideas for exploring the diagnosis and treatment of autoimmune diseases.

Systemic Inflammatory Disorders, Immunosuppressive Treatment and Increase Risk of Head and Neck Cancers-A Narrative Review of Potential Physiopathological and Biological Mechanisms

Head and neck cancers (HNCs) are known to present multiple factors likely to influence their development. This review aims to provide a comprehensive overview of the current scientific literature on the interplay between systemic inflammatory disorders, immunosuppressive treatments and their synergistic effect on HNC risk. Both cell-mediated and humoral-mediated systemic inflammatory disorders involve dysregulated immune responses and chronic inflammation and these inflammatory conditions have been associated with an increased risk of HNC development, primarily in the head and neck region. Likewise, the interaction between systemic inflammatory disorders and immunosuppressive treatments appears to amplify the risk of HNC development, as chronic inflammation fosters a tumor-promoting microenvironment, while immunosuppressive therapies further compromise immune surveillance and anti-tumor immune responses. Understanding the molecular and cellular mechanisms underlying this interaction is crucial for developing targeted prevention strategies and therapeutic interventions. Additionally, the emerging field of immunotherapy provides potential avenues for managing HNCs associated with systemic inflammatory disorders, but further research is needed to determine its efficacy and safety in this specific context. Future studies are warranted to elucidate the underlying mechanisms and optimize preventive strategies and therapeutic interventions.

Type I Interferons in Autoimmunity: Implications in Clinical Phenotypes and Treatment Response

Type I interferon (IFN-I) is thought to play a role in many systemic autoimmune diseases. IFN-I pathway activation is associated with pathogenic features, including the presence of autoantibodies and clinical phenotypes such as more severe disease with increased disease activity and damage. We will review the role and potential drivers of IFN-I dysregulation in 5 prototypic autoimmune diseases: systemic lupus erythematosus, dermatomyositis, rheumatoid arthritis, primary Sjögren syndrome, and systemic sclerosis. We will also discuss current therapeutic strategies that directly or indirectly target the IFN-I system.

Two Amnion-Derived Mesenchymal Stem-Cells Injections to Osteoarthritic Elbows in Dogs-Pilot Study

The aim of the study was to investigate the potential of cell-based regenerative therapy for elbow joints affected by osteoarthritis. Interest was focused on two intra-articular applications of amnion-derived mesenchymal stem cells (A-MSCs) to a group of different breeds of dogs with elbow osteoarthritis (13 joints). Two injections were performed 14 days apart. We evaluated synovial fluid biomarkers, such as IFN-γ, IL-6, IL-15, IL-10, MCP-1, TNF-α, and GM-CSF, by multiplex fluorescent micro-bead immunoassay in the treated group of elbows (n = 13) (day 0, day 14, and day 28) and in the control group of elbows (n = 9). Kinematic gait analysis determined the joint range of motion (ROM) before and after each A-MSCs application. Kinematic gait analysis was performed on day 0, day 14, and day 28. Kinematic gait analysis pointed out improvement in the average range of motion of elbow joints from day 0 (38.45 ± 5.74°), day 14 (41.7 ± 6.04°), and day 28 (44.78 ± 4.69°) with statistical significance (p < 0.05) in nine elbows. Correlation analyses proved statistical significance (p < 0.05) in associations between ROM (day 0, day 14, and day 28) and IFN-γ, IL-6, IL-15, MCP-1, TNF-α, and GM-CSF concentrations (day 0, day 14, and day 28). IFN-γ, IL-6, IL-15, MCP-1, GM-CSF, and TNF- α showed negative correlation with ROM at day 0, day 14, and day 28, while IL-10 demonstrated positive correlation with ROM. As a consequence of A-MSC application to the elbow joint, we detected a statistically significant (p < 0.05) decrease in concentration levels between day 0 and day 28 for IFN-γ, IL-6, and TNF-α and statistically significant increase for IL-10. Statistical significance (p < 0.05) was detected in TNF-α, IFN-γ, and GM-CSF concentrations between day 14 and the control group as well as at day 28 and the control group. IL-6 concentrations showed statistical significance (p < 0.05) between day 14 and the control group.

Pruritogenic molecules in the skin of patients with dermatomyositis

Introduction

Pruritus is a common excruciating symptom in systemic autoimmune diseases such as dermatomyositis (DM) but the pathogenesis is not fully understood. We intended to investigate the targeted expression analysis of candidate molecules involved in the development of pruritus in lesional vs. non-lesional skin samples of patients affected with active DM. We looked for correlations between the investigated pruriceptive signaling molecules, disease activity, and itching sensation of DM patients.

Methods

Interleukins (IL-33 and IL-6), tumor necrosis factor α (TNF-α), peroxisome proliferator-activated receptor γ (PPAR-γ), and ion channels belonging to the transient receptor potential (TRP) family were analyzed. The expression of TNF-α, PPAR-γ, IL-33, IL-6, and TRP channels in lesional DM skin was evaluated by RT-qPCR and immunohistochemistry and was compared with non-lesional DM skin samples. Pruritus, disease activity, and damage of DM were evaluated by the 5-D itch scale and Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI), respectively. Statistical analysis was performed with IBM SPSS 28 software.

Results

A total of 17 active DM patients participated in the study. We could show that the itching score was positively correlated with the CDASI activity score (Kendall's tau-b = 0.571; p = 0.003). TNF-α gene expression was significantly higher in lesional DM skin than in non-lesional DM skin (p = 0.009) and differed in the subgroups of patients with different itch intensities (p = 0.038). The mRNA expression of lesional IL-6 correlated positively with 5-D itch and CDASI activity score (Kendall's tau-b = 0.585; p = 0.008 and 0.45; p = 0.013, respectively). TRPV4 expressions were positively correlated with CDASI damage score (Kendall's tau-b = 0.626; p < 0.001), but the mRNA expressions of the TRP family, PPAR-γ, IL-6, and IL-33 were not different in lesional and non-lesional samples. Immunohistochemistry analysis did not find significant alterations in the expressions of TNF-α, PPAR-γ, IL-6, and IL-33 in lesional and non-lesional regions.

Discussion

Our results argue that cutaneous disease activity, TNF-α, and IL-6 might play a central role in DM-associated itch, while TRPV4 plays a central role in tissue regeneration.

Targeting intracellular pathways in idiopathic inflammatory myopathies: A narrative review

In recent decades, several pieces of evidence have drawn greater attention to the topic of innate immunity, in particular, interferon (IFN) and Interleukin 6 in the pathogenesis of idiopathic inflammatory myopathies (IIM). Both of these molecules transduce their signal through a receptor coupled with Janus kinases (JAK)/signal transducer and activator of transcription proteins (STAT). In this review, we discuss the role of the JAK/STAT pathway in IIM, evaluate a possible therapeutic role for JAK inhibitors in this group of diseases, focusing on those with the strongest IFN signature (dermatomyositis and antisynthetase syndrome).

Association between type I interferon pathway activation and clinical outcomes in rheumatic and musculoskeletal diseases: a systematic literature review informing EULAR points to consider

BACKGROUND

Type I interferons (IFN-I) contribute to a broad range of rheumatic and musculoskeletal diseases (RMDs). Compelling evidence suggests that the measurement of IFN-I pathway activation may have clinical value. Although several IFN-I pathway assays have been proposed, the exact clinical applications are unclear. We summarise the evidence on the potential clinical utility of assays measuring IFN-I pathway activation.

METHODS

A systematic literature review was conducted across three databases to evaluate the use of IFN-I assays in diagnosis and monitor disease activity, prognosis, response to treatment and responsiveness to change in several RMDs.

RESULTS

Of 366 screened, 276 studies were selected that reported the use of assays reflecting IFN-I pathway activation for disease diagnosis (n=188), assessment of disease activity (n=122), prognosis (n=20), response to treatment (n=23) and assay responsiveness (n=59). Immunoassays, quantitative PCR (qPCR) and microarrays were reported most frequently, while systemic lupus erythematosus (SLE), rheumatoid arthritis, myositis, systemic sclerosis and primary Sjögren's syndrome were the most studied RMDs. The literature demonstrated significant heterogeneity in techniques, analytical conditions, risk of bias and application in diseases. Inadequate study designs and technical heterogeneity were the main limitations. IFN-I pathway activation was associated with disease activity and flare occurrence in SLE, but their incremental value was uncertain. IFN-I pathway activation may predict response to IFN-I targeting therapies and may predict response to different treatments.

CONCLUSIONS

Evidence indicates potential clinical value of assays measuring IFN-I pathway activation in several RMDs, but assay harmonisation and clinical validation are urged. This review informs the EULAR points to consider for the measurement and reporting of IFN-I pathway assays.

Identification and Characterization of a Novel Cathelicidin from Hydrophis cyanocinctus with Antimicrobial and Anti-Inflammatory Activity

The abuse of antibiotics and lack of new antibacterial drugs has led to the emergence of superbugs that raise fears of untreatable infections. The Cathelicidin family of antimicrobial peptide (AMP) with varying antibacterial activities and safety is considered to be a promising alternative to conventional antibiotics. In this study, we investigated a novel Cathelicidin peptide named Hydrostatin-AMP2 from the sea snake Hydrophis cyanocinctus. The peptide was identified based on gene functional annotation of the H. cyanocinctus genome and bioinformatic prediction. Hydrostatin-AMP2 showed excellent antimicrobial activity against both Gram-positive and Gram-negative bacteria, including standard and clinical Ampicillin-resistant strains. The results of the bacterial killing kinetic assay demonstrated that Hydrostatin-AMP2 had faster antimicrobial action than Ampicillin. Meanwhile, Hydrostatin-AMP2 exhibited significant anti-biofilm activity including inhibition and eradication. It also showed a low propensity to induce resistance as well as low cytotoxicity and hemolytic activity. Notably, Hydrostatin-AMP2 apparently decreased the production of pro-inflammatory cytokines in the LPS-induced RAW264.7 cell model. To sum up, these findings indicate that Hydrostatin-AMP2 is a potential peptide candidate for the development of new-generation antimicrobial drugs fighting against antibiotic-resistant bacterial infections.

Experience with the use of mycophenolate mofetil in juvenile idiopathic inflammatory myopathies

OBJECTIVE

The objective of this study was to evaluate the efficacy and safety of MMF in juvenile idiopathic inflammatory myopathies (JIIMs).

METHODS

Patients diagnosed with JIIM and treated with MMF enrolled in the Juvenile Dermatomyositis Research Group (JDRG) in the UK or followed at the Giannina Gaslini Institute in Genoa, Italy, were included. The following information was collected retrospectively at MMF initiation, at 3, 6 and 12 months after treatment start, and at last follow-up visit: clinical manifestations, laboratory data, physicians' subjective assessment of disease activity, standardized outcome measures of muscle strength/endurance, cutaneous disease activity, physical function, global disease activity, cumulative damage, and ongoing treatment.

RESULTS

Of the 29 patients included, 23 had juvenile DM and 6 had overlap myositis. During administration of MMF, improvement in measures of muscle strength, skin disease activity, and overall disease activity was seen, with an increase in the frequency of normal scores for Manual Muscle Test-8 from 50.0% to 83.3%, Childhood Myositis Activity Score from 53.5% to 88.9%, muscle component of DAS from 55.2% to 84.2%, skin component of DAS from 31.0% to 42.1%, visual analogue scale for skin disease activity from 25.0% to 47.4%, and visual analogue scale for overall disease activity from 7.1% to 42.1%. The number of patients with inactive disease increased from 10.3% at baseline to 68.5% at last follow-up. CS dose was significantly reduced, from 0.3 to 0.1 mg/kg/day. No relevant side effects were reported.

CONCLUSION

Our experience suggests that MMF is a valuable therapeutic option for the management of JIIM.

The role of bDMARDs in idiopathic inflammatory myopathies: A systematic literature review

Idiopathic inflammatory myopathies (IIM) are a group of different conditions typically affecting striate muscle, lung, joints, skin and gastrointestinal tract. Treatment typically relies on glucocorticoids and synthetic immunosuppressants, but the occurrence of refractory, difficult to treat, manifestations, may require more aggressive treatment, borrowed from other autoimmune diseases, including biologic disease modifying drugs (bDMARDs). In this regard, we conducted a systemic literature review in order to depict the current evidence about the use of bDMARDs in IIM. A total of 78 papers, published during the last 21 years, were retrieved. The majority of patients was treated with TNF-α inhibitors, whose effectiveness was assessed particularly in recalcitrant striate muscle, skin and joints involvement. Rituximab, whose evidence is supported by a large number of real-life studies and trials, seems to be an excellent option in case of ILD and anti-synthetase syndrome, while Tocilizumab, despite not meeting primary and secondary endpoints in a recently published clinical trial, proved its effectiveness in rapidly progressing ILD. Similarly, Abatacept, studied in a phase IIb clinical trial with conflicting evidence, was reported to be effective in some case reports of refractory dermatomyositis. Less data exist for anti-IL1 and anti-IL23 agents, which were employed particularly for inclusion body myositis and severe skin disease, respectively. This study provides an organ-focused assessment of bDMARDs in IIM, which display encouraging results in the treatment of refractory subsets of disease.

Proteomics Analysis of Plasma-Derived Exosomes Unveils the Aberrant Complement and Coagulation Cascades in Dermatomyositis/Polymyositis

Dermatomyositis and polymyositis (DM/PM) are systemic autoimmune diseases characterized by proximal muscle weakness. The underlying pathogenetic mechanism of this disease remains under-researched. Here, using proteomics analysis, a great overlap of differentially expressed plasma exosomal proteins involved in the complement and coagulation cascade pathway, including FGA, FGB, FGG, C1QB, C1QC, and VWF, was identified in DM/PM patients versus healthy controls. Correlation analysis showed that the expression levels of complement-associated proteins (C1QB and C1QC) correlated positively with CRP, ESR, and platelet count. ROC curve analysis demonstrated that complement and coagulation cascade-associated proteins could be strong predictors for DM/PM. In addition, we also identified several other proteins that were differentially expressed in DM and PM. The selected candidate proteins were further validated by parallel reaction monitoring (PRM) and enzyme-linked immunosorbent assay (ELISA). Together, our findings indicate that these exosome-derived proteins might participate in microvascular damage in DM/PM through the activation of the complement and coagulation cascade pathway and function as biomarkers for the clinical diagnosis of DM/PM.

Single-cell profiling of peripheral blood and muscle cells reveals inflammatory features of juvenile dermatomyositis

Introduction: Juvenile dermatomyositis (JDM) is a rare yet serious childhood systemic autoimmune condition that primarily causes skin rashes and inflammatory myopathy of the proximal muscles. Although the associated immune response involves the innate and adaptive arms, a detailed analysis of the pertinent immune cells remains to be performed. This study aims to investigate the dynamic changes of cell type, cell composition and transcriptional profiles in peripheral blood and muscle tissues, and in order to clarify the involvement of immune cells in the pathogenesis of JDM and provide a theoretical reference for JDM. Methods: Single-cell RNA sequencing combined with bioinformatic analyses were used to investigate the dynamic changes in cell composition and transcriptional profiles. Results: Analysis of 45,859 cells revealed nine and seven distinct cell subsets in the peripheral blood and muscle tissues respectively. IFITM2+ and CYP4F3+ monocytes were largely produced, and CD74⁺ smooth muscle cells (SMCs) and CCL19+ fibroblasts were identified as inflammatory-related cell subtypes in JDM patients, exhibiting patient-specific cell population heterogeneity.The dynamic gene expression patterns presented an enhanced type I interferon response in peripheral blood monocytes and T-cells, and SMCs and fibroblasts in muscle of untreated JDM patients. EGR1 and IRF7 may play central roles in the inflammation in both CD74⁺ SMCs and CCL19+ fibroblasts. Moreover, inflammatory-related monocytes could regulate T-cells, and the interaction between immune cells and SMCs or fibroblasts in muscle was enhanced under the inflammatory state. Conclusions: Immune dysregulation is one of the key pathogenic factors of JDM, and type I interferon responses are significantly enhanced in peripheral blood Monos and T cells as well as SMCs and fibroblasts. EGR1 and IRF7 may play central roles in the inflammation and are considered as potential therapeutic targets for JDM.

Comparison of cytokine/chemokine profiles between dermatomyositis and anti-synthetase syndrome

Objectives

Dermatomyositis (DM) and anti-synthetase syndrome (ASS) are autoimmune diseases with multisystem involvement. Despite sharing some clinical and myopathological features, these are two diseases with different pathogeneses and prognoses. We aimed to clarify and compare cytokine/chemokine profiles in both disorders, which may help in the differential diagnosis.

Materials and methods

We collected clinical data and serum samples of consecutive patients with DM and ASS. Quantibody^® Human Inflammation Array 3 for cytokines/chemokines was performed in the serum of all participants. Receiver operating characteristic analysis with the area under the curve and Youden's index were performed.

Results

Eight newly diagnosed and treatment-naïve patients with DM, nine newly diagnosed and treatment-naïve patients with ASS, and 14 healthy controls were enrolled. Serum C-C motif chemokine ligand (CCL) 2, CCL4, C-X-C motif chemokine ligand (CXCL) 13, and tumor necrosis factor receptor 2 (TNFR2) were increased in patients with both DM and ASS. Serum interleukin (IL)-1 receptor type 1 (IL-1ra), IL-1b, CCL1, CXCL11, and CCL3 were modulated in patients with DM only, and IL-8, CXCL9, and tissue inhibitors of metalloproteinases-1 (TIMP-1) in patients with ASS only. Serum CCL2, CXCL13, and TNFR2 accurately distinguished patients with DM and ASS from healthy controls, as shown by the area under the curve >0.80. Moreover, receiver operating characteristic analysis showed that, as biomarkers for discrimination between DM and ASS, the combination of IL-1ra and TIMP-1, had an area under the curve of 0.944, a sensitivity of 87.5%, and a specificity of 88.9%.

Conclusion

Our study demonstrated that serum levels of cytokines/chemokines showed a different pattern in newly diagnosed patients with DM and ASS, in which serum IL-1ra and TIMP-1 could be used to distinguish between the two diseases.

Apremilast in Recalcitrant Cutaneous Dermatomyositis: A Nonrandomized Controlled Trial

Importance

Cutaneous disease in dermatomyositis has no standardized treatment approach and so presents a challenging task for patients and clinicians.

Objective

To study the efficacy and safety of apremilast as an add-on therapy in patients with recalcitrant cutaneous dermatomyositis.

Design, Setting, and Participants

This phase 2a, open-label, single-arm nonrandomized controlled trial was conducted at a single center from June 2018 to June 2021. Participants were 8 patients with recalcitrant cutaneous dermatomyositis, defined by a cutaneous disease activity severity index (CDASI) score greater than 5 despite treatment with steroids, steroid-sparing agents, or both. Data were analyzed from June 2018 to June 2021.

Interventions

Apremilast 30 mg orally twice daily was added to ongoing treatment regimens.

Main Outcomes and Measures

The primary outcome was the overall response rate (ORR) at 3 months. Key secondary outcomes were the safety and toxicity of apremilast and the durability of response at 6 months. The CDASI, muscle score, dermatology life quality index (DLQI), and depression assessments were performed at baseline and regularly until month 7. Skin biopsies were performed at baseline and 3 months after apremilast (defined as 3 months into active apremilast therapy) and tested for gene expression profiling and immunohistochemical stains. Adverse events were assessed using the Common Terminology Criteria for Adverse Events version 5.0.

Results

Among 8 patients with recalcitrant cutaneous dermatomyositis (all women; mean [SD] age, 54 [15.9] years), a response was found at 3 months after apremilast among 7 patients (ORR, 87.5%). The mean (SD) decrease in CDASI was 12.9 (6.3) points at 3 months (P < .001). Apremilast was well tolerated, with no grade 3 or higher adverse events. Sequencing of RNA was performed on skin biopsies taken from 7 patients at baseline and at 3 months after therapy. Appropriate negative (ie, no primary antibody) and positive (ie, tonsil and spleen) controls were stained in parallel with each set of slides studied. Of 39 076 expressed genes, there were 195 whose expression changed 2-fold or more at P < .01 (123 downregulated and 72 upregulated genes). Gene set enrichment analysis identified 13 pathways in which apremilast was associated with downregulated expression, notably signal transducers and activators of transcription 1 (STAT1), STAT3, interleukin 4 (IL-4), IL-6, IL-12, IL-23, interferon γ (IFNγ), and tumor necrosis factor α (TNFα) pathways. In immunohistochemical staining, there was a mean (SD) decrease in phosphorylation levels STAT1 (22.3% [28.3%] positive cells) and STAT3 (13.4% [11.6%] positive cells) at the protein level, a downstream signaling pathway for the downregulated cytokines.

Conclusions and Relevance

These findings suggest that apremilast was a safe and efficacious add-on treatment in recalcitrant dermatomyositis, with an overall response rate of 87.5% and associations with downregulation of multiple inflammatory pathways.

Trial Registration

ClinicalTrials.gov Identifier: NCT03529955.

Randomized Trial of Tocilizumab in the Treatment of Refractory Adult Polymyositis and Dermatomyositis

OBJECTIVE

To assess the efficacy and tolerability of tocilizumab in a multicenter, randomized, double-blind, placebo-controlled trial in refractory adult patients with dermatomyositis (DM) and polymyositis (PM).

METHODS

Thirty-six subjects with probable or definite DM/PM were enrolled in a 6-month phase 2B clinical trial and randomized 1:1 to receive tocilizumab (8 mg/kg intravenously) or placebo every 4 weeks for 24 weeks. Eligible subjects had either a DM rash, a myositis-associated autoantibody or an adjudicated PM diagnosis. Active disease was defined by at least three of six abnormal core set measures (CSMs), including a manual muscle testing (MMT)-8 score of less than 136/150. If the MMT-8 score was greater than 136, then a cutaneous score of 3 or more (10 cm visual analogue scale) was required along with three additional abnormal CSMs indicating disease activity. The primary endpoint compared the Total Improvement Score (TIS) between both arms from week 4 to 24. Secondary outcomes included time to meeting minimal TIS improvement, changes in CSMs, time to worsening, steroid-sparing effect, proportion of subjects meeting more stringent improvement criteria, and safety outcomes.

RESULTS

There was no significant difference (P = 0.86) in the TIS over 24 weeks between tocilizumab and placebo arms. The secondary endpoints of time to improvement (minimal, moderate, or major), time to worsening, CSM changes, safety outcomes, and steroid-sparing effect were also not significantly different between arms.

CONCLUSION

Tocilizumab was safe and well tolerated but did not meet the primary or secondary efficacy outcomes in refractory DM and PM in this 24-week phase 2B study.

Impaired muscle strength is associated with ultrastructure damage in myositis

The muscle fiber ultrastructure in Idiopathic Inflammatory Myopathies (IIM) has been scarcely explored, especially in Inclusion Body Myositis. The aim of this study was to implement the Scanning Electron Microscopy (SEM) in a small cohort of IIM patients, together with the characterization of immunological profile for a better understanding of the pathophysiology. For immunological profile characterization, we identified the presence of autoantibodies (Ro-52, OJ, EJ, PL7, PL12, SRP, Jo-1, PMScl75, PMScl100, Ku, SAE1, NXP2, MDA5, TIF1γ, Mi-2α, Mi-2β) and quantified cytokines (IL-1β, IFN-α2, IFN-γ, TNF-α, IL-6, IL-10, IL-12p70, IL-17A, IL-18, IL-23, IL-33) and chemokines (CCL2, CXCL8). The histological analysis was made by hematoxylin-eosin staining while the muscle fiber ultrastructure was characterized by SEM. We observed changes in the morphology and structure of the muscle fiber according to muscle strength and muscle enzymes. We were able to find and describe muscle fiber ultrastructure with marked irregularities, porosities, disruption in the linearity and integrity of the fascicle, more evident in patients with increased serum levels of muscle enzymes and diminished muscle strength. Despite the scarce reports about the use of SEM as a tool in all clinical phenotypes of IIM, our work provides an excellent opportunity to discuss and reframe the clinical usefulness of SEM in the diagnostic approach of IIM.

Identification of hub biomarkers and immune cell infiltration characteristics of polymyositis by bioinformatics analysis

Background

Polymyositis (PM) is an acquirable muscle disease with proximal muscle involvement of the extremities as the main manifestation; it is a category of idiopathic inflammatory myopathy. This study aimed to identify the key biomarkers of PM, while elucidating PM-associated immune cell infiltration and immune-related pathways.

Methods

The gene microarray data related to PM were downloaded from the Gene Expression Omnibus database. The analyses using Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes, gene set enrichment analysis (GSEA), and protein-protein interaction (PPI) networks were performed on differentially expressed genes (DEGs). The hub genes of PM were identified using weighted gene co-expression network analysis (WGCNA) and least absolute shrinkage and selection operator (LASSO) algorithm, and the diagnostic accuracy of hub markers for PM was assessed using the receiver operating characteristic curve. In addition, the level of infiltration of 28 immune cells in PM and their interrelationship with hub genes were analyzed using single-sample GSEA.

Results

A total of 420 DEGs were identified. The biological functions and signaling pathways closely associated with PM were inflammatory and immune processes. A series of four expression modules were obtained by WGCNA analysis, with the turquoise module having the highest correlation with PM; 196 crossover genes were obtained by combining DEGs. Subsequently, six hub genes were finally identified as the potential biomarkers of PM using LASSO algorithm and validation set verification analysis. In the immune cell infiltration analysis, the infiltration of T lymphocytes and subpopulations, dendritic cells, macrophages, and natural killer cells was more significant in the PM.

Conclusion

We identified the hub genes closely related to PM using WGCNA combined with LASSO algorithm, which helped clarify the molecular mechanism of PM development and might have great significance for finding new immunotherapeutic targets, and disease prevention and treatment.

Current and new targets for treating myositis

As treatment of refractory idiopathic inflammatory myopathies (IIM) has been challenging, there is growing interest in assessing new therapies that target various pathways implicated in the pathogenesis of IIM. In the largest clinical trial to date, rituximab was studied in adult and juvenile myositis, but the primary outcome was not met despite 83 percent of subjects with refractory myositis meeting the definition of improvement. The U.S. Food and Drug Administration (FDA) has recently granted approval to Octagam 10% immune globulin intravenous (IVIg), for the treatment of adult dermatomyositis based on impressive results from a double-blind placebo-controlled trial. Anti-tumor necrosis factor (anti-TNF) utility in IIM is not recommended and recent reports suggest this therapy may induce systemic autoimmune disease including myositis. Further, anti-IL6 therapy cannot be recommended as a recent trial of tocilizumab failed to reach its primary endpoint. Further studies are needed to assess the role of newer therapies such as abatacept (inhibition of T cell co-stimulation), sifalimumab (anti-IFNα), Janus kinase [JAK] inhibitors, apremilast (phosphodiesterase 4 inhibitor), and KZR-616 (selective inhibitor of the immunoproteasome) given their biological plausibility and encouraging recent small-case series results. The future of IIM therapy will depend on exploring biomarkers implicated in the etiopathogenesis of IIM, improvements in myositis classification based on serological and histopathological features, and well-designed controlled clinical trials using validated consensus outcome measures.

Update on Biomarkers of Vasculopathy in Juvenile and Adult Myositis

PURPOSE OF REVIEW

Although rare, idiopathic inflammatory myopathies (IIM) comprise a heterogeneous group of autoimmune conditions in adults and children. Increasingly, vasculopathy is recognised to be key in the underlying pathophysiology and plays a crucial role in some of the more challenging complications including calcinosis, gastrointestinal involvement and interstitial lung disease. The exciting prospect of development of biomarkers of vasculopathy would enable earlier detection and monitoring of these complications and possible prevention of their potentially devastating consequences. The purpose was to review the current literature on biomarkers of vasculopathy in IIM and offer insight as to the biomarkers most likely to have an impact on clinical care.

RECENT FINDINGS

Multiple candidate biomarkers have been studied including circulating endothelial cells (CEC), microparticles (MP), soluble adhesion markers (ICAM-1, ICAM-3, VCAM-1), selectin proteins (E-, L-, P-selectin), coagulation factors, angiogenic factors, cytokines (including (IL-6, IL-10, TNF-α, IL-18) and interferon (IFN)-related biomarkers (including IFNα, IFN-β, IFNγ, galectin-9, interferon signature and interferon-related chemokines (MCP-1, IP-10 and MIG). There is a growing body of evidence of the potential role of biomarkers in detecting and monitoring the vasculopathy in IIM, detecting disease activity and predicting disease flares and overall prognosis. Exciting progress has been made in the search for biomarkers of vasculopathy of IIM; however, none of the studies are validated and further research is required.

Case Report: Simultaneously Developed Amyopathic Dermatomyositis and Autoimmune Sclerosing Cholangitis - a Coincidence or a Shared Immunopathogenesis?

Inflammatory rheumatic diseases (IRD) and autoimmune liver diseases (AILD) share many similarities regarding epidemiology, genetics, immunology and therapeutic regimens, so it is not surprising that approximately 20% of patients with AILD are diagnosed with an IRD as well. Clinical features and biochemical hallmarks of IRD and AILD often intertwine and cross diagnostic criteria. Therefore, the real distinction of underlying disorders in a patient with these comorbidities may be challenging. The present report is the first report of simultaneously developed juvenile dermatomyositis (JDM) and autoimmune sclerosing cholangitis (ASC) with both entities fulfilling the latest guidelines for a definite diagnosis. Both of these diagnoses are difficult to definitely establish since ASC has a similar serologic profile as autoimmune hepatitis and liver histological analysis is frequently non-specific, whereas clinically amyopathic JDM diagnosis depends mostly on classical dermatological symptoms, while the rest of the diagnostic criteria, including the necessity for skin or muscle biopsy and the presence of myositis specific antibodies, are still not uniformed. In spite of these challenges, our patient clearly met European League Against Rheumatism/American College of Rheumatology classification criteria for CAJDM and The European Society for Pediatric Gastroenterology, Hepatology and Nutrition diagnostic criteria for ASC. Since elevated serum transaminases, the presence of serum antinuclear antibodies and hypergammaglobulinemia could be explained as a part of both JDM and ASC, the underlying pathophysiology remains debatable. Intriguingly, JDM and ASC share genetic predisposition including human leukocyte antigen allele DRB1*0301 and tumor necrosis factor α 308A allele. Furthermore, both humoral and cellular components of the adaptive immune system contribute to the pathogenesis of JDM and ASC. Moreover, recent findings indicate that the loss of the CD28 expression on T-cells plays a significant role in their pathogenesis along with the Th17 immune pathway. Despite these common features that suggest shared autoimmunity, AILD and autoimmune myositis are traditionally studied and managed independently. The lack of therapies that target the underlying cause results in a high rate of adverse events due to unspecific immunosuppressive therapy. Shared autoimmunity is an ideal area to develop new, targeted immunotherapy that would hopefully be beneficial for more than one disease.

Type I Interferons in Autoimmunity

Dysregulated IFN-1 responses play crucial roles in the development of multiple forms of autoimmunity. Many patients with lupus, systemic sclerosis, Sjogren's syndrome, and dermatomyositis demonstrate enhanced IFN-1 signaling. IFN-1 excess is associated with disease severity and autoantibodies and could potentially predict response to newer therapies targeting IFN-1 pathways. In this review, we provide an overview of the signaling pathway and immune functions of IFN-1s in health and disease. We also review the systemic autoimmune diseases classically associated with IFN-1 upregulation and current therapeutic strategies targeting the IFN-1 system.

SIGLEC1 enables straightforward assessment of type I interferon activity in idiopathic inflammatory myopathies

Objective

To evaluate sialic acid binding Ig-like lectin 1 (SIGLEC1) expression on monocytes by flow cytometry as a type I interferon biomarker in idiopathic inflammatory myopathies (IIM).

Methods

We performed a retrospective analysis of adult and paediatric patients with the diagnosis of IIM. SIGLEC1 expression was assessed by flow cytometry and was compared with Physician Global Assessment or Childhood Myositis Assessment Scale disease activity scores. Mann Whitney U test and receiver operating characteristic curves were used for cross-sectional data analysis (n=96), two-level mixed-effects linear regression model for longitudinal analyses (n=26, 110 visits). Response to treatment was analysed in 14 patients within 12 months, using Wilcoxon test. SIGLEC1 was compared with interferon-stimulated gene 15/MxA status by immunohistochemical staining of muscle biopsies (n=17).

Results

96 patients with adult (a) and juvenile (j) dermatomyositis (DM, n=38), antisynthetase syndrome (AS, n=19), immune-mediated necrotising myopathy (IMNM, n=8), inclusion body myositis (IBM, n=9) and overlap myositis (n=22) were included. SIGLEC1 distinguished significantly between active and inactive disease with an area under the curve of 0.92 (95% CI 0.83 to 1) in DM and correlated with disease activity longitudinally (aDM: standardised beta=0.54, p<0.001; jDM: standardised beta=−0.70, p<0.001). Response to treatment in DM was associated with a decreasing SIGLEC1 (p<0.01, Wilcoxon test). SIGLEC1 was found upregulated in 8 of 19 patients with AS, 2 of 9 patients with IBM but not in IMNM.

Conclusion

SIGLEC1 is a candidate biomarker to assess type I interferon activity in IIM and proved useful for monitoring disease activity and response to treatment in juvenile and adult DM.

The interferon gene signature as a clinically relevant biomarker in autoimmune rheumatic disease

The interferon gene signature (IGS) is derived from the expression of interferon-regulated genes and is classically increased in response to type I interferon exposure. A raised whole blood IGS has increasingly been reported in rheumatic diseases as sequencing technology has advanced. Although its role remains unclear, we explore how a raised IGS can function as a clinically relevant biomarker, independent of whether it is a bystander effect or a key pathological process. For example, a raised IGS can act as a diagnostic biomarker when predicting rheumatoid arthritis in patients with arthralgia and anti-citrullinated protein antibodies, or predicting systemic lupus erythematous (SLE) in those with antinuclear antibodies; a theragnostic biomarker when predicting response for patients receiving disease modifying therapy, such as rituximab in rheumatoid arthritis; a biomarker of disease activity (early rheumatoid arthritis, dermatomyositis, systemic sclerosis, SLE); or finally a predictor of clinical characteristics, such as lupus nephritis in SLE or disease burden in primary Sjögren's syndrome. A high IGS does not uniformly predict worse clinical phenotypes across all diseases, as demonstrated by a reduced disease burden in primary Sjögren's syndrome, nor does it predict a universally poorer response to all therapies, as shown in rheumatoid arthritis. This dichotomy highlights both the complexity of type I interferon signalling in vivo and the current lack of standardisation when calculating the IGS. The IGS as a biomarker warrants further exploration, with beneficial clinical applications anticipated in multiple rheumatic diseases.

Body composition in longstanding juvenile dermatomyositis; Associations with disease activity, muscle strength and cardiometabolic measures

OBJECTIVE

To (i) compare body composition parameters in patients with longstanding juvenile dermatomyositis (JDM) and controls and (ii) explore associations between body composition and disease activity/inflammation, muscle strength, health-related quality of life (HRQL) and cardiometabolic measures.

METHODS

In a cross-sectional study, we included 59 patients (median disease duration 16.7 y; median age 21.5 y) and 59 age- and sex-matched controls. Active/inactive disease were defined by the PRINTO criteria. Body composition was assessed by total body dual-energy absorptiometry (DXA), inflammation by hs-CRP and cytokines, muscle strength by manual muscle test (MMT-8), HRQL by 36-item short form survey physical component score (SF-36 PCS) and cardiometabolic function by echocardiography (systolic and diastolic function) and serum-lipids.

RESULTS

DXA analyses revealed lower appendicular lean mass index (ALMI) (reflecting limb skeletal muscle mass), higher body fat percentage (BF%) and higher android: gynoid fat ratio (A: G ratio) (reflecting central fat distribution) in patients than controls, despite similar BMI. Patients with active disease had lower ALMI and higher BF% than those with inactive disease; lower ALMI and higher BF% were associated with inflammation (elevated monocyte attractant protein-1 (MCP-1) and hs-CRP). Lower ALMI was associated with reduced muscle strength; higher BF% was associated with impaired HRQL. Central fat distribution (higher A: G ratio) was associated with impaired cardiac function and unfavorable serum-lipids.

CONCLUSION

: Despite normal BMI, patients with JDM, especially those with active disease, had unfavorable body composition, which was associated with impaired HRQL/muscle strength and cardiometabolic function. The association between central fat distribution and cardiometabolic alterations is a novel finding in JDM.

JAK inhibitors: a potential treatment for JDM in the context of the role of interferon-driven pathology

Juvenile Idiopathic Inflammatory Myopathies (IIM) are a group of rare diseases that are heterogeneous in terms of pathology that can include proximal muscle weakness, associated skin changes and systemic involvement. Despite options for treatment, many patients continue to suffer resistant disease and lasting side-effects. Advances in the understanding of the immunopathology and genetics underlying IIM may specify new therapeutic targets, particularly where conventional treatment has not achieved a clinical response. An upregulated type I interferon signature is strongly associated with disease and could be a prime target for developing more specific therapeutics. There are multiple components of the IFN pathway that could be targeted for blockade therapy.Downstream of the cytokine receptor complexes are the Janus kinase-signal transducers and activators of transcription (JAK-STAT) pathway, which consists of JAK1-3, TYK2, and STAT1-6. Therapeutic inhibitors have been developed to target components of this pathway. Promising results have been observed in case studies reporting the use of the JAK inhibitors, Baricitinib, Tofacitinib and Ruxolitinib in the treatment of refractory Juvenile Dermatomyositis (JDM). There is still the question of safety and efficacy for the use of JAK inhibitors in JDM that need to be addressed by clinical trials. Here we review the future for the use of JAK inhibitors as a treatment for JDM.

Atezolizumab-associated Dermatomyositis in Advanced Small-cell Lung Carcinoma

Dermatomyositis is a rare immune-related adverse event caused by immune checkpoint inhibitors. We herein report a 75-year-old Japanese man with small-cell lung carcinoma who developed dermatomyositis after the administration of atezolizumab. He developed rashes on day 13 and myalgia and motor weakness on day 30 of the first administration of atezolizumab. Anti-transcriptional intermediary factor 1-gamma antibody was positive, and serum interleukin-6 levels were prominently elevated in the acute phase. Symptoms were improved by corticosteroid therapy. This is the first report of dermatomyositis associated with atezolizumab. Clinicians should be aware of the possibility of dermatomyositis after the administration of immune checkpoint inhibitors.

Updates on interferon in juvenile dermatomyositis: pathogenesis and therapy

PURPOSE OF REVIEW

This review provides updates regarding the role of interferon (IFN) in juvenile dermatomyositis (JDM), including comparison to interferonopathies and therapeutic implications.

RECENT FINDINGS

Transcriptomic and protein-based studies in different tissues and peripheral IFN-α assessment have demonstrated the importance of the dysregulated IFN pathway in JDM. Additional studies have validated IFN-regulated gene and protein expression correlation with disease activity in blood and muscle, with potential to predict flares. Type I and II IFN both are dysregulated in peripheral blood and muscle, with more type I IFN in skin. Muscle studies connects hypoxia to IFN production and IFN to vascular dysfunction and muscle atrophy. JDM overlaps with interferonopathy phenotype and IFN signature. There are multiple case reports and case series noting decreased IFN markers and clinical improvement in refractory JDM with Janus kinase (JAK) inhibitors.

SUMMARY

Studies confirm IFN, particularly type I and II IFN, is an important part of JDM pathogenesis by the level of dysregulation and correlation with disease activity, as well as IFN recapitulating key JDM muscle pathology. Smaller studies indicate there may be differences by myositis-specific autoantibody group, but validation is needed. JAK inhibitors are a promising therapy as they can inhibit IFN signaling, but further study is needed regarding which patients will benefit, dosing, and safety monitoring.

Siglec-1 expression on monocytes is associated with the interferon signature in juvenile dermatomyositis and can predict treatment response

Objective

JDM is a rare chronic immune-mediated inflammatory disease with a predominant role for type I IFN responses. We aimed to determine the potential of Siglec-1 expression on monocytes as a novel IFN-inducible biomarker for disease activity monitoring and prediction of treatment response in patients with JDM.

Methods

Siglec-1 was measured by flow cytometry on circulating monocytes of 21 newly diagnosed JDM patients before start of treatment and, for 10 of these, also during follow-up. The expression levels of five type I IFN-stimulated genes, MX1, IFI44, IFI44L, LY6E and IFIT3, were measured by RT-qPCR to determine the IFN signature and calculate an IFN score. IFN-inducible plasma proteins CXCL10 and galectin-9 were measured by multiplex immunoassay.

Results

Siglec-1 and IFN score were increased in JDM patients compared with controls and correlated with clinical disease activity. Stratification of patients by Siglec-1 expression at diagnosis identified those with high Siglec-1 expression as having a higher risk of requiring treatment intensification within the first 3 months after diagnosis (55% vs 0% of patients, P = 0.01). Siglec-1 expression strongly correlated with plasma levels of previously validated biomarkers CXCL10 (r_s = 0.81, P < 0.0001) and galectin-9 (r_s = 0.83, P < 0.0001), and was superior to the IFN score in predicting treatment response (area under the curve 0.87 vs 0.53, P = 0.01).

Conclusion

Siglec-1 on monocytes is a novel IFN-inducible biomarker in JDM that correlates with clinical disease activity and identifies patients at risk for a suboptimal treatment response. Further studies are required to validate these findings and their clinical potential.

The Vasculopathy of Juvenile Dermatomyositis: Endothelial Injury, Hypercoagulability, and Increased Arterial Stiffness

OBJECTIVE

Vasculopathy is considered central to the pathogenesis of juvenile dermatomyositis (DM) and is associated with severe extramuscular manifestations. We undertook this study to investigate the hypothesis that the vasculopathy of juvenile DM can be noninvasively tracked by examining biomarkers of endothelial injury, subclinical inflammation, hypercoagulability, and vascular arterial stiffness.

METHODS

The study population was a UK cohort of children with juvenile DM. Circulating endothelial cells (CECs) and microparticles (MPs) were identified using immunomagnetic bead extraction and flow cytometry, respectively. Plasma thrombin generation was determined using a fluorogenic assay. Cytokine and chemokine levels were measured by electrochemiluminescence. Arterial stiffness was assessed using pulse wave velocity (PWV). Results were expressed as the median and interquartile range (IQR), and statistical significance was assessed using nonparametric analyses.

RESULTS

Ninety patients with juvenile DM and 79 healthy control subjects were included. The median age of the patients was 10.21 years (IQR 6.68-13.40), and the median disease duration was 1.63 years (IQR 0.28-4.66). CEC counts were higher in all patients with juvenile DM compared to controls (median 96 cells/ml [IQR (40-192] and 12 cells/ml [IQR 8-24], respectively; P < 0.0001). Circulating MP numbers were also significantly higher in patients with active juvenile DM compared to controls (median 204.7 × 103 /ml [IQR 87.9-412.6] and 44.3 × 103 /ml [IQR 15.0-249.1], respectively; P < 0.0001). MPs were predominantly of platelet and endothelial origin. Enhanced plasma thrombin generation was demonstrated in patients with active juvenile DM compared to those with inactive disease (P = 0.0003) and controls (P < 0.0001). Carotid-radial PWV adjusted for age was increased in patients with juvenile DM compared to controls (P = 0.003).

CONCLUSION

We observed increased endothelial injury and increased levels of proinflammatory cytokines in patients with active juvenile DM. MP profiles reflected distinct disease activity status in juvenile DM and are markers of vascular pathology, platelet activation, and thrombotic propensity. Ongoing long-term vascular injury may result in increased arterial stiffness in patients with juvenile DM.

Metabolomics Analysis Identifies a Lipidomic Profile in Treatment Naïve Juvenile Dermatomyositis Patients versus Healthy Control Subjects

Objectives

To perform an exploratory study to identify a JDM serum metabolic profile that differs from healthy controls (HCs) and responds to immunosuppressive treatment.

Methods

Blood was collected from 9 HCs and 10 patients diagnosed with probable (n = 4) or definite (n = 6) JDM based on the criteria of Bohan and Peter for myositis, with 7 of the 10 providing longitudinal samples following initiation of treatment; these patients comprised the treatment-naïve cohort. Sera underwent mass spectroscopy–based measurements of targeted metabolic intermediates, including 15 amino acids, 45 acylcarnitines (ACs), 15 ceramides and 29 sphingomyelins. Principal components analysis reduced metabolites into smaller sets of factors each comprised of correlated metabolic intermediates. Factor scores and metabolite concentrations were compared with HCs using two-sample t-tests while treatment effects were evaluated using paired t-tests.

Results

Of eight principal components analysis–derived metabolite factors (one AC, two amino acids, three sphingosine and two ceramide), two were significantly associated with JDM: one AC factor containing mostly long-chain ACs (P = 0.049) and one ceramide factor (P < 0.01). For 12 individual ACs, mostly long chain, and three ceramides, concentrations were significantly greater for JDM than HCs. Factors based on these individual metabolites showed decreasing scores with treatment (P = 0.03 and P < 0.01, respectively).

Conclusion

While additional validation is needed, these lipids have potential as JDM serum diagnostic and/or treatment biomarkers. Additionally, the significant association of long-chain ACs and ceramides with JDM offers insights regarding pathogenesis, implicating dysregulation of mitochondrial fatty acid β-oxidation.

Chemokine/Cytokine Levels Correlate with Organ Involvement in PR3-ANCA-Associated Vasculitis

Background: ANCA-associated vasculitis (AAV) is a rare small vessel disease characterized by multi-organ involvement. Biomarkers that can measure specific organ involvement are missing. Here, we ask whether certain circulating cytokines and chemokines correlate with renal involvement and if distinct cytokine/chemokine patterns can differentiate between renal, ear/nose/throat, joints, and lung involvement of AAV. Methods: Thirty-two sets of Birmingham vasculitis activity score (BVAS), PR3-ANCA titers, laboratory marker, and different cytokines were obtained from 17 different patients with AAV. BVAS, PR3-ANCA titers, laboratory marker, and cytokine concentrations were correlated to different organ involvements in active AAV. Results: Among patients with active PR3-AAV (BVAS > 0) and kidney involvement we found significant higher concentrations of chemokine ligand (CCL)-1, interleukin (IL)-6, IL21, IL23, IL-28A, IL33, monocyte chemoattractant protein 2 (MCP2), stem cell factor (SCF), thymic stromal lymphopoietin (TSLP), and thrombopoietin (TPO) compared to patients without PR3-ANCA-associated glomerulonephritis. Patients with ear, nose, and throat involvement expressed higher concentrations of MCP2 and of the (C-X-C motif) ligand-12 (CXCL-12) compared to patients with active AAV and no involvement of these organs. Conclusion: We identified distinct cytokine patterns for renal manifestation and for ear, nose and throat involvement of PR3-AAV. Distinct plasma cytokines might be used as non-invasive biomarkers of organ involvement in AAV.

Comparison of Lesional Juvenile Myositis and Lupus Skin Reveals Overlapping Yet Unique Disease Pathophysiology

OBJECTIVE

Skin inflammation heralds systemic disease in juvenile myositis, yet we lack an understanding of pathogenic mechanisms driving skin inflammation in this disease. We undertook this study to define cutaneous gene expression signatures in juvenile myositis and identify key genes and pathways that differentiate skin disease in juvenile myositis from childhood-onset systemic lupus erythematosus (SLE).

METHODS

We used formalin-fixed paraffin-embedded skin biopsy samples from 15 patients with juvenile myositis (9 lesional, 6 nonlesional), 5 patients with childhood-onset SLE, and 8 controls to perform transcriptomic analysis and identify significantly differentially expressed genes (DEGs; q ≤ 5%) between patient groups. We used Ingenuity Pathway Analysis (IPA) to highlight enriched biologic pathways and validated DEGs by immunohistochemistry and quantitative real-time polymerase chain reaction.

RESULTS

Comparison of lesional juvenile myositis to control samples revealed 221 DEGs, with the majority of up-regulated genes representing interferon (IFN)-stimulated genes. CXCL10, CXCL9, and IFI44L represented the top 3 DEGs (fold change 23.2, 13.3, and 13.0, respectively; q < 0.0001). IPA revealed IFN signaling as the top canonical pathway. When compared to childhood-onset SLE, lesional juvenile myositis skin shared a similar gene expression pattern, with only 28 unique DEGs, including FBLN2, CHKA, and SLURP1. Notably, patients with juvenile myositis who were positive for nuclear matrix protein 2 (NXP-2) autoantibodies exhibited the strongest IFN signature and also demonstrated the most extensive Mx-1 immunostaining, both in keratinocytes and perivascular regions.

CONCLUSION

Lesional juvenile myositis skin demonstrates a striking IFN signature similar to that previously reported in juvenile myositis muscle and peripheral blood. Further investigation into the association of a higher IFN score with NXP-2 autoantibodies may provide insight into disease endotypes and pathogenesis.

The role of interferons type I, II and III in myositis: A review

The classification of idiopathic inflammatory myopathies (IIM) is based on clinical, serological and histological criteria. The identification of myositis-specific antibodies has helped to define more homogeneous groups of myositis into four dominant subsets: dermatomyositis (DM), antisynthetase syndrome (ASyS), sporadic inclusion body myositis (sIBM) and immune-mediated necrotising myopathy (IMNM). sIBM and IMNM patients present predominantly with muscle involvement, whereas DM and ASyS patients present additionally with other extramuscular features, such as skin, lung and joints manifestations. Moreover, the pathophysiological mechanisms are distinct between each myositis subsets. Recently, interferon (IFN) pathways have been identified as key players implicated in the pathophysiology of myositis. In DM, the key role of IFN, especially type I IFN, has been supported by the identification of an IFN signature in muscle, blood and skin of DM patients. In addition, DM-specific antibodies are targeting antigens involved in the IFN signalling pathways. The pathogenicity of type I IFN has been demonstrated by the identification of mutations in the IFN pathways leading to genetic diseases, the monogenic interferonopathies. This constitutive activation of IFN signalling pathways induces systemic manifestations such as interstitial lung disease, myositis and skin rashes. Since DM patients share similar features in the context of an acquired activation of the IFN signalling pathways, we may extend underlying concepts of monogenic diseases to acquired interferonopathy such as DM. Conversely, in ASyS, available data suggest a role of type II IFN in blood, muscle and lung. Indeed, transcriptomic analyses highlighted a type II IFN gene expression in ASyS muscle tissue. In sIBM, type II IFN appears to be an important cytokine involved in muscle inflammation mechanisms and potentially linked to myodegenerative features. For IMNM, currently published data are scarce, suggesting a minor implication of type II IFN. This review highlights the involvement of different IFN subtypes and their specific molecular mechanisms in each myositis subset.

Novel associations between cytokines and pulmonary involvement in juvenile dermatomyositis - a cross-sectional study of long-term disease

OBJECTIVES

To examine associations between cytokines and pulmonary involvement in patients with medium- to long-term JDM.

METHODS

In a cross-sectional study, 58 patients examined median (range) 16.8 (6.6-27.0) years after symptom onset were stratified in inactive (JDM-inactive) and active (JDM-active) disease (updated PRINTO criteria); 56 age/sex matched controls were included. Twenty-nine cytokines (in serum) were analysed (Luminex technology/ELISA). Pulmonary function test included forced vital capacity, total lung capacity (TLC) and diffusing capacity for carbon monoxide reported as % of predicted and low forced vital capacity/TLC/diffusing capacity for carbon monoxide. In patients, the presence of clinical pulmonary damage was assessed and high resolution computed tomography scans were scored for interstitial lung disease, chest wall calcinosis and airways disease.

RESULTS

Median age of patients was 21 (7-55) years, 59% were female and 36% inactive. In JDM-active and all patients, higher MCP-1, IP-10 and eotaxin correlated with high-resolution computed tomography findings (rs 0.34-0.61; P < 0.05). MCP-1 and eotaxin correlated with pulmonary damage in JDM-active and all patients (rs 0.41-0.49; P < 0.01). Higher TGF-β1 and PDGF (growth factors) were associated with lower lung volumes (forced vital capacity/TLC measures) in all patients; PDGF in JDM-active and TGF-β1 in JDM-inactive patients. IP-10 correlated with TLC% in JDM-active patients. No associations between cytokines and pulmonary function test were found in controls.

CONCLUSIONS

In JDM, we found a novel association (not previously described in myositis) between eotaxin and pulmonary involvement; we have previously shown an association between eotaxin and cardiac dysfunction. The associations between IP-10/growth factors/MCP-1 and pulmonary involvement are novel in JDM and were mostly seen in JDM-active patients.

Dermatomyositis: immunological landscape, biomarkers, and potential candidate drugs

INTRODUCTION

Dermatomyositis (DM) is a rare inflammatory disease characterized by the invasion of the skin and muscles. Environmental, genetic, and immunological factors contribute to disease pathology. To date, no bioinformatics studies have been conducted on the potential pathogenic genes and immune cell infiltration in DM. Therefore, we aimed to identify differentially expressed genes (DEGs) and immune cells, as well as potential pathogenic genes and immune characteristics, which may be useful for the diagnosis and treatment of DM.

METHOD

GSE1551, GSE5370, GSE39454, and GSE48280 from Gene Expression Omnibus were included in our study. Limma, ClusterProfiler, and Kyoto Encyclopedia of Genes and Genomes were used to identify DEGs, Gene Ontology (GO), and perform pathway analyses, respectively. Cytoscape was used to construct the protein-protein interaction (PPI) network. Small-molecule drugs were identified using a connectivity map (CMap), and the TIMER database was used to identify infiltrating cells.

RESULTS

DEG analysis identified 12 downregulated and 163 upregulated genes. GO analysis showed that DEGs were enriched in immune-related pathways. Ten hub genes were identified from the PPI network. Additionally, CMap analysis showed that caffeic acid, sulfaphenazole, molindone, tiabendazole, and bacitracin were potential small-molecule drugs with therapeutic significance. We identified eight immune cells with differential infiltration in patients with DM and controls. Finally, we constructed a powerful diagnostic model based on memory B cells, M1, and M2 macrophages.

CONCLUSIONS

This study explored the potential molecular mechanism and immunological landscape of DM and may guide future research and treatment of DM.

KEY POINTS

• We explored the molecular mechanism and immunological landscape of dermatomyositis. • GO analysis showed that DEGs were enriched in immune-related pathways. • We predicted small-molecular drugs with potential therapeutic significance based on bioanalytical techniques. • We identified six immune cells with differential infiltration in patients with DM and controls.

The Role of Cutaneous Type I IFNs in Autoimmune and Autoinflammatory Diseases

IFNs are well known as mediators of the antimicrobial response but also serve as important immunomodulatory cytokines in autoimmune and autoinflammatory diseases. An increasingly critical role for IFNs in evolution of skin inflammation in these patients has been recognized. IFNs are produced not only by infiltrating immune but also resident skin cells, with increased baseline IFN production priming for inflammatory cell activation, immune response amplification, and development of skin lesions. The IFN response differs by cell type and host factors and may be modified by other inflammatory pathway activation specific to individual diseases, leading to differing clinical phenotypes. Understanding the contribution of IFNs to skin and systemic disease pathogenesis is key to development of new therapeutics and improved patient outcomes. In this review, we summarize the immunomodulatory role of IFNs in skin, with a focus on type I, and provide insight into IFN dysregulation in autoimmune and autoinflammatory diseases.

Correlation between osteoarthritis and monocyte chemotactic protein-1 expression: a meta-analysis

Objective

We evaluated the association between monocyte chemotactic protein-1 (MCP-1) and osteoarthritis.

Methods

We searched PubMed, Cochrane Library, Embase, Web of Science, China National Knowledge Infrastructure (CNKI), VIP (Chinese database), and Wan Fang (Chinese database) (before May 10, 2020), with no language limitations. STATA version 12.0 and Revman version 5.3 were used for data analysis. The standard mean difference (SMD) and corresponding 95% confidence intervals (95% CIs) were calculated. Nine clinical studies, including 376 patients with osteoarthritis and 306 healthy controls, were evaluated.

Results

The combined SMDs of MCP-1 expression levels suggested that MCP-1 expression was significantly higher in patients with osteoarthritis than healthy controls (SMD = 1.97, 95% CI = 0.66–3.28, p = 0.003). Moreover, subgroup analysis implied that osteoarthritis patients from both Asians and mixed populations had higher MCP-1 expression levels than controls, whereas Caucasians did not (p > 0.05). Serum MCP-1 levels (SMD = 2.83, 95% CI = 1.07–4.6, p < 0.00001) were significantly higher in patients with osteoarthritis than in controls; however, this difference was not significant in synovial fluid and cartilage tissue. Subgroup analysis for ethnicity showed that MCP-1 levels were significantly higher in Chinese, Dutch, and Brazilian patients with osteoarthritis than in control groups, although significant differences were not observed for American and Italian subgroups.

Conclusions

Our meta-analysis demonstrated that MCP-1 expression levels were higher in patients with osteoarthritis than in healthy controls and that MCP-1 may play important roles in the progression of osteoarthritis. Serum MCP-1 levels may serve as a potential biomarker for the diagnosis of osteoarthritis.

Inflammatory milieu of muscle biopsies in juvenile dermatomyositis

Juvenile dermatomyositis (JDM) is an inflammatory myopathy which causes severe morbidity and high mortality if untreated. In this study, we aimed to define the T-helper cell profile in the muscle biopsies of JDM patients. Muscle biopsies of twenty-six patients (50% female) were included in the study. Immunohistochemical expression of CD3, CD20, CD138, CD68, IL-17, Foxp3, IFN-ɣ, IFN-alpha and IL-4 was studied and muscle biopsies were scored using the JDM muscle biopsy scoring tool. Inflammatory cells were in small clusters in perimysium and perivascular area or scattered throughout the endomysium in most biopsies; however in 2 biopsies, lymphoid follicle-like big clusters were observed, and in one, there was a very dense and diffuse inflammatory infiltration nearly destroying all the muscle architecture. Seventy-three per cent of the biopsies had T cells, 88% had B cells, 57% had plasma cells, and all had macrophages. As for T-helper cell subtypes, 80% of the biopsies were Th1 positive, 92% Th17 positive and 30% Treg positive. No IL-4 positive inflammatory cell was detected, and only 2 biopsies showed IFN-alpha positivity. The mean JDM biopsy score was 17.6, meaning moderate to severe muscular involvement. Visual analogue score of the pathologist was strongly correlated with histopathological features. B cells, macrophages, plasma cells and T cells constitute the inflammatory milieu of the JDM muscle biopsies. As for T cells, JDM is a disease mainly related with Th1 and Th17 T-helper cell subtypes and to some extend Treg. Th2 cells are not involved in the pathogenesis.

Serum protein biomarkers for juvenile dermatomyositis: a pilot study

BACKGROUND

Blood accessible biomarkers to assess disease activity and their response to therapies in Juvenile Dermatomyositis (JDM) are urgently needed. This pilot study aims to identify serum protein biomarkers associated with clinical disease activity in untreated JDM and their response to medical therapy.

METHODS

SomaScan® technology screened JDM patients for 1305 proteins at three points: 1) before start of treatment, 2) while on therapy, and 3) after treatment tapering when patients were clinically inactive. To define disease associated biomarkers, SomaScan® data from untreated JDM patients (n = 8) were compared to SomaScan® data from an independent age-matched healthy control group (n = 12). Longitudinal analysis defined treatment responsive proteins at three time points: untreated (7 samples), treated (7 samples), and clinically inactive (6 samples). To confirm the SomaScan® data, a subset of nine candidate proteins (CXCL11, IL-17B, IL-17D, IL-22, CXCL10, MCP-1, ANGPT2, MIF, IL-23) were tested by ELISA after adding 2 JDM (one untreated, one clinically inactive) serum samples to the same group of JDM girls (8 untreated, 7 treated; 7 clinically inactive) as well as with 17 age, gender, matched healthy controls.

RESULTS

Comparison of untreated JDM versus healthy controls identified 202 elevated and 49 decreased serum proteins in JDM patients with an adjusted p-value < 0.001. Only 82 out of 251 identified biomarker candidates responded to treatment while 12 out of these 82 proteins returned to their original untreated disease levels upon therapy tapering. The ELISA testing of the untreated samples for nine candidate proteins confirmed previously known biomarkers (CXCL10 or IP-10, CXCL11 or I-TAC and MCP-1) and identified novel biomarkers including IL-22, Angiopoetin-2, and IL-17B in a cross-sectional analysis comparing 8 untreated JDM and 17 age/gender matched controls. The subsequent longitudinal data by ELISA were not concordant for some biomarkers (IL-22 and IL-17B), but the other biomarkers either normalized or rebounded concordantly.

CONCLUSIONS

Blood accessible protein biomarkers reflecting JDM pathophysiology were identified; some of them rebounded after therapy was tapered. Further studies bridging these biomarkers to specific clinical features of JDM are required to confirm the clinical utility of these serum protein biomarkers.

Role of Myokines in Myositis Pathogenesis and Their Potential to be New Therapeutic Targets in Idiopathic Inflammatory Myopathies

Idiopathic inflammatory myopathies (IIM) represent a heterogeneous group of autoimmune diseases whose treatment is often a challenge. Many patients, even after immunosuppressive therapy, do not respond to treatment, so new alternatives have been sought for this. Therefore, other signaling pathways that could contribute to the pathogenesis of myositis have been investigated, such as the expression of myokines in skeletal muscle in response to the inflammatory process. In this review, we will refer to these muscle cytokines that are overexpressed or downregulated in skeletal muscle in patients with various forms of IIM, thus being able to contribute to the maintenance of the autoimmune process. Some muscle cytokines, through their antagonistic action, may be a helpful contributor to the disease modulation, and thus, they could represent personalized treatment targets. Here, we consider the main myokines involved in the pathogenesis of myositis, expressing our view on the possibility of using them as potential therapeutic targets: interleukins IL-6, IL-15, and IL-18; chemokines CXCL10, CCL2, CCL3, CCL4, CCL5, and CCL20; myostatin; follistatin; decorin; osteonectin; and insulin-like 6. An interesting topic regarding the complex connection between myokines and noninflammatory pathways implied in IIM has also been briefly described, because it is an important scientific approach to the pathogenesis of IIM and can be a therapeutic alternative to be considered, especially for the patients who do not respond to immunosuppressive treatment.

Clinical trials and novel therapeutics in dermatomyositis

INTRODUCTION

Currently, there are no proven drugs that are FDA approved for the treatment of dermatomyositis (DM), even though multiple clinical trials are ongoing to evaluate safety and efficacy of novel therapeutics in DM. The purpose of this review is to highlight the biological plausibility, existing clinical evidence as well as completed and ongoing clinical trials for various drugs in pipeline for development for use in dermatomyositis.

AREAS COVERED

The drugs with the strongest evidence have been included in this review with a focus on the mechanism of their action pertaining to the disease process, clinical studies including completed and ongoing trials. With better understanding of the underlying pathophysiologic process, there are new molecular targets that have been identified that can be targeted by these novel drugs, predominantly biologic drugs.

EXPERT OPINION

There are various drugs being evaluated in phase II/III clinical trials that hold promise in DM. At the forefront of these are immunoglobulin, Lenabasum, and Abatacept for which phase III clinical trials are ongoing. In addition, promising clinical studies are ongoing or reported for KZR-616, anti-B cell therapy, anti-interferon drugs, and Repository Corticotrophin Injection (RCI).

Using peripheral blood immune signatures to stratify patients with adult and juvenile inflammatory myopathies

OBJECTIVE

The inflammatory idiopathic myopathies (IIM) are a group of rare autoimmune diseases defined by muscle weakness and characterized by pro-inflammatory infiltrates in muscle. Little is known about the immunological profile in peripheral blood of these patients and how this relates to IIM subtypes. This study aimed to stratify adult and juvenile-onset IIM patients according to immune cell profile.

METHODS

Peripheral blood mononuclear cells from 44 patients with adult myositis (AM), 15 adolescent-onset juvenile dermatomyositis (a-JDM), and 40 age-matched healthy controls were analysed by flow cytometry to quantify 33 immune cell subsets. Adult myositis patients were grouped according to myositis subtype; DM and polymyositis; and also autoantibody specificity. Disease activity was determined by the myositis disease activity assessment tool and clinicians' decision on treatment.

RESULTS

Unique immune signatures were identified for DM, polymyositis and a-JDM compared with healthy controls. DM patients had a T-cell signature comprising increased CD4+ and TH17 cell frequencies and increased immune cell expression of IL-6. Polymyositis patients had a B-cell signature with reduced memory B cells. A-JDM had decreased naïve B cells and increased CD4+T cells. All patient groups had decreased CD8+central memory T-cell frequencies. The distinct immune signatures were also seen when adult myositis patients were stratified according to auto-antibody expression; patients with anti-synthetase-antibodies had reduced memory B cells and patients with autoimmune rheumatic disease overlap had an elevated Th17 profile.

CONCLUSION

Unique immune signatures were associated with adult vs juvenile disease. The Th17 signature in DM patients supports the potential use of IL-17 inhibitors in treatment of IIMs.

Differential CpG DNA methylation in peripheral naïve CD4+ T-cells in early rheumatoid arthritis patients

Background

The genetic risk associated with rheumatoid arthritis (RA) includes genes regulating DNA methylation, one of the hallmarks of epigenetic re-programing, as well as many T-cell genes, with a strong MHC association, pointing to immunogenetic mechanisms as disease triggers leading to chronicity. The aim of our study was to explore DNA methylation in early, drug-naïve RA patients, towards a better understanding of early events in pathogenesis.

Result

Monocytes, naïve and memory CD4⁺ T-cells were sorted from 6 healthy controls and 10 RA patients. DNA methylation was assessed using a genome-wide Illumina 450K CpG promoter array. Differential methylation was confirmed using bisulfite sequencing for a specific gene promoter, ELISA for several cytokines and flow cytometry for cell surface markers. Differentially methylated (DM) CpGs were observed in 1047 genes in naïve CD4⁺ T-cells, 913 in memory cells and was minimal in monocytes with only 177 genes. Naive CD4⁺ T-cells were further investigated as presenting differential methylation in the promoter of > 500 genes associated with several disease-relevant pathways, including many cytokines and their receptors. We confirmed hypomethylation of a region of the TNF-alpha gene in early RA and differential expression of 3 cytokines (IL21, IL34 and RANKL). Using a bioinformatics package (DMRcate) and an in-house analysis based on differences in β values, we established lists of DM genes between health and RA. Publicly available gene expression data were interrogated to confirm differential expression of over 70 DM genes. The lists of DM genes were further investigated based on a functional relationship database analysis, which pointed to an IL6/JAK1/STAT3 node, related to TNF-signalling and engagement in Th17 cell differentiation amongst many pathways. Five DM genes for cell surface markers (CD4, IL6R, IL2RA/CD25, CD62L, CXCR4) were investigated towards identifying subpopulations of CD4⁺ T-cells undergoing these modifications and pointed to a subset of naïve T-cells, with high levels of CD4, IL2R, and CXCR4, but reduction and loss of IL6R and CD62L, respectively.

Conclusion

Our data provided novel conceptual advances in the understanding of early RA pathogenesis, with implications for early treatment and prevention.

Expression of interferon-regulated genes in juvenile dermatomyositis versus Mendelian autoinflammatory interferonopathies

Background

Juvenile dermatomyositis (JDM) is a systemic autoimmune disease with a prominent interferon (IFN) signature, but the pathogenesis of JDM and the etiology of its IFN signature remain unknown. The Mendelian autoinflammatory interferonopathies, Chronic Atypical Neutrophilic Dermatosis with Lipodystrophy and Elevated temperature (CANDLE) and STING-Associated Vasculopathy with onset in Infancy (SAVI), are caused by genetic mutations and have extremely elevated IFN signatures thought to drive pathology. The phenotypic overlap of some clinical features of CANDLE and SAVI with JDM led to the comparison of a standardized interferon-regulated gene score (IRG-S) in JDM and myositis-specific autoantibody (MSA) JDM subgroups, with CANDLE and SAVI.

Methods

A peripheral 28-component IRG-S assessed by NanoString™ in 57 JDM patients subtyped by MSA was compared with IRG-S in healthy controls (HC) and CANDLE/SAVI patients. Principal component analysis (PCA) was performed, and individual genes were evaluated for their contribution to the score. IRG-S were correlated with disease assessments and patient characteristics.

Results

IRG-S in JDM patients were significantly higher than in HC but lower than in CANDLE or SAVI. JDM IRG-S overlapped more with SAVI than CANDLE by PCA. Among MSA groups, anti-MDA5 autoantibody-positive patients’ IRG-S overlapped most with SAVI. The IFI27 proportion was significantly higher in SAVI and CANDLE than JDM, but IFIT1 contributed more to IRG-S in JDM. Overall, the contribution of individual interferon-regulated genes (IRG) in JDM was more similar to SAVI. IRG-S correlated moderately with JDM disease activity measures (r_s = 0.33–0.47) and more strongly with skin activity (r_s = 0.58–0.79) in anti-TIF1 autoantibody-positive patients. Weakness and joint disease activity (multinomial OR 0.91 and 3.3) were the best predictors of high IRG-S.

Conclusions

Our findings demonstrate peripheral IRG expression in JDM overlaps with monogenic interferonopathies, particularly SAVI, and correlates with disease activity. Anti-MDA5 autoantibody-positive JDM IRG-S were notably more similar to SAVI. This may reflect both a shared IFN signature, which is driven by IFN-β and STING pathways in SAVI, as well as the shared phenotype of vasculopathy in SAVI and JDM, particularly in anti-MDA5 autoantibody-positive JDM, and indicate potential therapeutic targets for JDM.

Management of refractory cutaneous dermatomyositis: potential role of Janus kinase inhibition with tofacitinib

OBJECTIVES

Some patients with cutaneous DM demonstrate incomplete responses to conventional therapy while some, including those with extra-cutaneous manifestations, experience disease recurrences. Janus kinase/signal transducers and activators of transcription pathway inhibition has been reported to mitigate IFN signalling, which is thought to contribute to disease pathogenesis in DM. Four cases of refractory DM responsive to tofacitinib have been reported in the literature. Our case series investigated the use of tofacitinib in refractory cutaneous DM.

METHODS

Our case series includes four subjects with refractory DM who received tofaticinib after failure of several immunosuppressive and immunomodulatory agents.

RESULTS

All four subjects responded well to tofacitinib with significant improvement in cutaneous and extra-cutaneous manifestations.

CONCLUSION

Tofacitinib can improve cutaneous and inflammatory articular manifestations in refractory DM.

Comparison of cytokine profiles between anti-ARS antibody-positive interstitial lung diseases and those with anti-MDA-5 antibodies

INTRODUCTION/OBJECTIVES

Interstitial lung disease (ILD) is a significant cause of mortality among patients with dermatomyositis (DM) or polymyositis (PM). There are two subtypes of PM and DM often complicated with ILD: those with anti-aminoacyl-tRNA synthetase (anti-ARS) antibodies and those with anti-MDA-5-associated amyopathic DM (ADM). Our aim is to clarify the inflammatory and immunological differences between the disorders.

METHODS

We retrospectively collected consecutive patients with anti-ARS-ILD and those with anti-MDA-5 antibody-positive ADM-ILD. The serum concentration of 38 cytokines was measured using a cytokine panel. The relative risks for anti-MDA-5 antibody-positive ADM-ILD were examined with univariate and multivariate logistic regression models. Spearman's rank correlation coefficient was calculated between cytokine levels and clinical parameters in the disease. Levels of cytokines were compared between anti-ARS-ILD and anti-MDA-5-positive ADM-ILD patients (alive or dead) using Dunnett's test.

RESULTS

Twenty-three patients with anti-ARS-ILD and the same number of patients with anti-MDA-5-positive ADM-ILD were enrolled. The anti-MDA-5 group had poor survival (p = 0.025). Univariate logistic regression models showed that eotaxin, IL-10, IP-10, and MCP-1 were associated with the diagnosis of anti-MDA-5-positive ADM-ILD. Multivariate logistic regression models revealed that IP-10 was the most significantly associated (p = 0.001). Relationship analyses showed that IL-10 had significant positive correlations with CK (r = 0.5267, p = 0.009) and ferritin (r = 0.4528, p = 0.045). A comparison of the cytokine levels found that IP-10 was elevated in both patients who were alive and patients who had died with ADM-ILD compared with the levels in those with ARS-ILD (p = 0.003 and p = 0.001, respectively).

CONCLUSIONS

Anti-MDA-5-positive ADM-ILD had poorer survival than anti-ARS-ILD. IP-10 seems to be most deeply involved in the pathophysiology of anti-MDA-5-associated ADM-ILD.Key Points• To clarify differences in the inflammatory and immunological features of anti-MDA-5-positive ADM-ILD and anti-ARS-ILD, we performed an observational study to measure serum cytokine concentrations before treatment using a multiplex immunoassay system.• Multivariate logistic regression models revealed that IP-10 was associated with the most significant relative risk for ADM-ILD with anti-MDA-5 antibodies.• Levels of IP-10 were elevated considerably in anti-MDA-5-positive survivors and nonsurvivors compared with the levels in anti-ARS patients.• These results suggest that IP-10 is the most deeply involved in the pathophysiology of anti-MDA-5-positive ADM-ILD.