Phenotypes of Peripheral Blood Lymphocytes and Cytokine Expression in Polymyositis and Dermatomyositis before Treatment and after Clinical Remission

Belimumab treatment of adult idiopathic inflammatory myopathy

OBJECTIVE

To evaluate belimumab addition to the standard of care in patents with refractory idiopathic inflammatory myopathy (IIM).

METHODS

We conducted a 40-week multicentre, randomized, double-blind, placebo-controlled trial with 1:1 IV belimumab 10 mg/kg or placebo randomization and a 24-week open-label extension. Clinical responses were measured by the definition of improvement (DOI) and total improvement score (TIS). Flow cytometry analyses were performed on available samples before randomization, at 24 and 60-64 weeks. Descriptive statistics, t-test, Fisher's exact test and analysis of variance tests were used.

RESULTS

A total of 17 patients were randomized, 15 received five or more doses of belimumab or placebo and were included in the intention-to-treat analysis. More belimumab patients vs placebo attained a TIS ≥40 [55.5% vs 33.3%; P = non-significant (NS)] and achieved the DOI (33.3% vs 16.7%; P = NS) at weeks 40 and 64; the mean TIS was similar among groups. Two patients achieved major responses (TIS = 72.5) after week 40 in the belimumab arm and none in the placebo arm. No improvement in the placebo arm after switching to the open-label phase was observed. There was no steroid-sparing effect. No new safety signals were detected. Although total B cells were not reduced, belimumab induced naïve B cell depletion while enhancing the number and frequency memory B cells.

CONCLUSION

The study did not meet the primary endpoint and no statistically significant differences were observed in clinical responses between arms. More patients achieved sustained TIS ≥40 and reached the DOI. Most patients who received belimumab for >40 weeks had clinical improvement. Phenotypic changes in B cell populations were not associated with clinical responses.

CLINICAL TRIAL REGISTRATION NUMBER

Clinicaltrials.gov (https://clinicaltrials.gov/), NCT02347891.

CCL18 as a Biomarker of Interstitial Lung Disease (ILD) and Progressive Fibrosing ILD in Patients with Idiopathic Inflammatory Myopathies

OBJECTIVES

To assess CCL18 and OX40L as biomarkers of interstitial lung disease (ILD) and/or progressive fibrosing (PF-) ILD in idiopathic inflammatory myopathies (IIMs).

METHODS

Patients with IIMs seen in our center from July 2020 to March 2021 were consecutively enrolled. ILD was detected by high-resolution CT. CCL18 and OX40L serum levels were measured by validated ELISA assays in 93 patients and 35 controls. At the 2-year follow-up, PF-ILD was evaluated according to the INBUILD criteria.

RESULTS

ILD was diagnosed in 50 (53.7%) patients. CCL18 serum levels were higher in IIMs patients vs. controls (232.9 [IQR 134.7-399.07] vs. 48.4 [29.9-147.5], p < 0.0001), with no difference for OX40L. IIMs-ILD patients exhibited higher levels of CCL18 than those without ILD (306.8 [190.8-520.5] vs. 162 [75.4-255.8], p < 0.0001). High CCL18 serum levels were independently associated with IIMs-ILD diagnosis. At follow-up, 22/50 (44%) patients developed a PF-ILD. Patients who developed PF-ILD had higher CCL18 serum levels than non-progressors (511 [307-958.7] vs. 207.1 [149.3-381.7], p < 0.0001). Multivariate logistic regression analysis revealed CCL18 as the only independent predictor of PF-ILD (OR 1.006 [1.002-1.011], p = 0.005).

CONCLUSIONS

Although in a relatively small sample, our data suggest that CCL18 is a useful biomarker in IIMs-ILD, particularly in the early identification of patients at risk of developing PF-ILD.

Peripheral T helper subset profiling in idiopathic inflammatory myositis: Proof of concept

INTRODUCTION

There is a dearth of biomarkers in Idiopathic Inflammatory Myopathies (IIM) to recognize ongoing muscle inflammation and distinguish damage from activity. Since IIM is an autoantibody-mediated disease with tertiary lymphoid organogenesis reported in the diseased muscles, we aimed to study the peripheral blood T helper (Th) subset profiling as a plausible reflection of ongoing muscle inflammation.

METHODS

Fifty-six patients of IIM were compared with 21 healthy controls (HC) and 18 patients with sarcoidosis. Th1, Th17, Th17.1, and Treg cells were identified after stimulation assays (BD Biosciences). Myositis autoantibodies were tested by line immunoassay (Euroimmune, Germany).

RESULTS

All Th subsets were elevated in IIM as compared with HC. As compared to HC, PM had elevated Th1 and Treg while Th17 and Th17.1 populations were higher in OM. Patients with sarcoidosis had higher Th1 and Treg but lower Th17 population as compared to IIM {Th1(69.1% vs 49.65%, p<0.0001), {Treg (12.05% vs 6.2%, p<0.0001), {Th17 (2.49% vs 4.4%, p<0.0001)}. Similar results were obtained when sarcoidosis ILD was compared with IIM ILD with a higher Th1 and Treg population but lower Th17 population in the former. No difference in T cell profile was observed after stratification for MSA positivity, type of MSA, clinical features of IIM and disease activity.

CONCLUSION

Th subsets in IIM are distinct from sarcoidosis and HC with a TH17 predominant paradigm, creating a case of exploring Th17 pathway and IL-17 blockers for the treatment of IIM. However, cell profiling cannot distinguish active from inactive disease limiting its predictive potential as a biomarker of activity in 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.

Identification of Latent Diagnostic Biomarkers and Biological Pathways in Dermatomyositis Based on WGCNA

Introduction

Dermatomyositis (DM) is a chronic autoimmune disease of predominantly lymphocytic infiltration mainly involving the transverse muscle. Its pathogenesis is remaining unknown. This research is designed to probe the latent pathogenesis of dermatomyositis, identify potential biomarkers, and reveal the pathogenesis of dermatomyositis through information biology analysis of gene chips.

Methods

In this study, we utilised the GSE14287 and GSE11971 datasets rooted in the Gene Expression Omnibus (GEO) databank, which included a total of 62 DM samples and 9 normal samples. The datasets were combined, and the differentially expressed gene sets were subjected to weighted gene coexpression network analysis, and the hub gene was screened using a protein interaction network from genes in modules highly correlated with dermatomyositis progression.

Results

A total of 3 key genes-myxovirus resistance-2 (MX2), oligoadenylate synthetase 1 (OAS1), and oligoadenylate synthetase 2 (OAS2)-were identified in combination with cell line samples, and the expressions of the 3 genes were verified separately. The results showed that MX2, OAS1, and OAS2 were highly expressed in LPS-treated cell lines compared to normal cell lines. The results of pathway enrichment analysis of the genes indicated that all 3 genes were enriched in the cytosolic DNA signalling and cytokine and cytokine receptor interaction signalling pathways; the results of functional enrichment analysis showed that all 3 were enriched in interferon-α response and interferon-γ response functions.

Conclusions

This is important for the study of the pathogenesis and objective treatment of dermatomyositis and provides important reference information for the targeted therapy of dermatomyositis.

Lymphocyte immunophenotyping in inflammatory myositis: a review

PURPOSE OF REVIEW

This is a comprehensive review of the current knowledge on predominant immune cell phenotypes involved in idiopathic inflammatory myopathies (IIM).

RECENT FINDINGS

Major circulating immune cell subpopulations described in IIM encompass the lymphocyte compartment. An unbalance in T cell subsets seems to consistently affect the peripheral and muscle compartment, with a predominance of CD4+ T and B cells in dermatomyositis, CD8+ T cells in polymyositis/inclusion body myositis (IBM) and novel findings highlighting novel proinflammatory T subsets, that is, CD8+Tbet+ and CD28- T cells across different IIM subsets. On the other hand, an impairment in Treg cells number and function has been described especially across polymyositis/dermatomyositis and IBM. Total T follicular helper (Tfh) cells, increased in immune-mediated necrotizing myopathy, skewed toward Tfh2 and Tfh17 in dermatomyositis, polymyositis, and juvenile dermatomyositis. B cell compartment is more rarely described in IIM, yet an unbalance in this pool is as well likely. Evidence of plasma cells increased in polymyositis, dermatomyositis, IBM, and Bregs decreased in dermatomyositis have been reported. Perturbations in the memory and naïve subsets are common in dermatomyositis/polymyositis and antisynthetase syndrome.

SUMMARY

Protean immune cell abnormalities characterize different IIM subsets, reflecting the complexity of these autoimmune conditions. A deeper understanding of B-cell and T-cell immunophenotyping may promote early diagnosis and identification of new potential therapeutic targets.

Prognostic value of peripheral blood markers in patients with myositis-associated interstitial lung diseases

Objectives: The aim of this study was to investigate the association between survival of anti-MDA5 autoantibody-positive/negative patients with myositis-associated interstitial lung disease (MA-ILD) and neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), monocyte-lymphocyte ratio (MLR), C-reactive protein-albumin ratio (CAR), and erythrocyte sedimentation rate-albumin ratio (EAR).Method: The study included 104 patients diagnosed with MA-ILD between January 2017 and February 2019 at the First Affiliated Hospital, University of Science and Technology of China. The clinical and laboratory results were compared between survivors and non-survivors in anti-MDA5 autoantibody-positive and anti-MDA5 autoantibody-negative patients. Cox proportional hazard models were used for univariable and multivariate analyses to determine survival-related factors. A logistic regression model was used to establish a joint diagnosis, and the feasibility of the combined diagnosis to evaluate the prognosis of MA-ILD was explored.Results: Among 47 anti-MDA5-positive patients with MA-ILD, EAR was an independent predictor of survival. When separated into high and low subgroups, high MLR (> 0.604) and EAR (> 1.458) were predictive of survival (p < 0.05). High MLR, high EAR, and age combined with lactate dehydrogenase were the highest (0.886) in predicting the prognosis of MA-ILD, and were higher than the area under the curve diagnosed separately. In 57 anti-MDA5-negative patients with MA-ILD, NLR and high EAR (> 0.872) were independent predictors of survival (p < 0.05).Conclusion: MLR and EAR are associated with prognosis in anti-MDA5-positive patients. NLR and EAR are associated with prognosis in anti-MDA5-negative patients. Using NLR, MLR, and EAR, inflammatory conditions of MA-ILD can be predicted and possible outcomes estimated.

Serum levels of interleukins and S100A8/A9 correlate with clinical severity in patients with dermatomyositis-associated interstitial lung disease

Background

Dermatomyositis (DM) is a systemic autoimmune inflammatory disorder that affects primarily skin, muscle and lung, frequently associated with interstitial lung disease (ILD). The objective of this study is to investigate the association between serum cytokines and clinical severity in patients with DM-ILD.

Methods

Serum samples of 30 healthy controls, 14 DM patients without ILD and 40 DM patients with ILD were collected. Serum S100A8/A9 levels were analyzed by enzyme-linked immunosorbent assay (ELISA) and levels of interleukins were measured by cytometric beads array (CBA). Then we performed multivariate logistic regression analysis to determine factors independently associated with ILD development.

Results

Serum IL-4, IL-6 and S100A8/A9 levels were significantly higher in DM patients with ILD than those in healthy controls (p = 0.0013, 0.0017 and < 0.0001, respectively). Serum IL-10 level of patients was dramatically lower than that in controls (p = 0.0001). In DM patients, the levels were significantly higher in patients with A/SIP than in those with CIP (p = 0.0046, 0.0339 and 0.0133) or without ILD (p = 0.0165, 0.0370 and < 0.0001). IL-4 (r = 0.1171, p = 0.0040), IL-6 (r = 0.1174, p = 0.0040) and IL-10 (r = − 0.1829, p = 0.0003) were significantly correlated with S100A8/A9 in DM-ILD patients. S100A8/A9 was significantly correlated with high-resolution computed tomography (HRCT) (r = 0.1642, p = 0.0157) and lung function (DLCO%: r = − 0.2066, p = 0.0061, FVC%: r = − 0.2156, p = 0.0050). Moreover, logistic regression analysis revealed that S100A8/A9 levels were independently associated with ILD development in DM patients (p = 0.004).

Conclusions

Serum level of S100A8/A9 may be a valuable predictor for assessing the clinical severity of DM-ILD patients. Serum IL-4, IL-6 and IL-10 levels were highly correlated with S100A8/A9, so these cytokines may play a synergistic effect on the progression of DM-ILD.

Treatment of inflammatory myopathies

INTRODUCTION

The idiopathic inflammatory myopathies (IIM) dermatomyositis (DM) and polymyositis (PM) are chronic diseases affecting the striated muscles with variable involvement of other organs. Glucocorticoids are considered the cornerstone of treatment, but some patients require adjunctive immunosuppressive agents because of insufficient response to glucocorticoids, flares upon glucocorticoid tapering, or glucocorticoid-related adverse events. Areas covered: The aim of this article was to review (PubMed search until February 2018) the evidence on established and new therapies derived from randomized controlled trials (RCTs) on adult DM and PM. In addition, key data from open-label trials, case reports, and abstracts were included where data from RCT were lacking. Expert commentary: Numerous synthetic and biological immunosuppressive agents are currently available to treat the IIM, sometimes in combination. The choice of the specific medication in the individual patient depends upon the disease phenotype and patient's characteristics. Exercise improves muscle performance without causing disease flares and should be an integral part of the treatment of the IIM. Prompt diagnosis and treatment can lead to better outcome.

Itch in dermatomyositis: the role of increased skin interleukin-31

BACKGROUND

Interleukin (IL)-31 is implicated in pruritus associated with pruritic skin diseases like atopic dermatitis. Although pruritus is a prominent feature in dermatomyositis (DM), few studies have evaluated the pathogenesis of DM-associated itch.

OBJECTIVES

To establish the prevalence of itch in DM, and to investigate the role of IL-31 in DM-related itch.

METHODS

Pruritus and disease activity of DM were evaluated by a visual analogue scale (VAS) and the Cutaneous Disease and Activity Severity Index (CDASI), respectively. Expression of IL-31 and IL-31 receptor alpha (IL-31RA) in lesional DM, nonlesional DM and healthy control skin was evaluated by quantitative reverse-transcriptase polymerase chain reaction and immunofluorescence. Flow cytometry was performed on skin cells isolated from lesional DM skin to identify cellular sources of IL-31 in DM.

RESULTS

Among 191 patients with DM, 50·8% had moderate-to-severe itch, and itch was correlated with increased cutaneous severity (r = 0·34). In patients with itchy DM, gene expression of IL31 and IL31RA in lesional skin was upregulated compared with nonlesional skin and healthy control skin. IL31 mRNA expression positively correlated with VAS itch score (r = 0·67). On immunofluorescence, immunoreactivity for IL-31 and IL-31RA was stronger in lesional skin. Flow cytometry showed that lesional DM skin contained significantly more IL-31-producing cells, and CD4⁺ cells were the most common cell type. Lenabasum, an emerging treatment for DM, significantly downregulated IL-31 from CpG-stimulated peripheral blood mononuclear cells.

CONCLUSIONS

Increased skin IL-31 may play a role in DM-associated itch, and ongoing trials will evaluate the effects of systemic treatment on IL-31 and itch in DM.

The role of interleukin-4 in rheumatic diseases

Rheumatism is a group of diseases, most of which are autoimmune diseases, that violate joints, bones, muscles, blood vessels and related soft tissue. As is well known, cytokines play a role in the pathogenesis of several rheumatic diseases, such as rheumatoid arthritis, spondyloarthritides, and systemic lupus erythematosus. Recently, the role of interleukin-4 (IL-4), which may participate in the mechanism of rheumatism, have been discovered. It is reported that IL-4 takes part in the regulation of T cell activation, differentiation, proliferation, and survival of different T cell types. IL-4 also has an immunomodulatory effect on B cells, mast cells, macrophages, and many cell types. A review of the literature on functions of IL-4 in rheumatic diseases is presented.

Elevated IL-4 and IFN-γ Levels in Muscle Tissue of Patients with Dermatomyositis

BACKGROUND/AIM

To investigate the contribution of muscle tissue-derived cytokines in dermatomyositis (DM).

MATERIALS AND METHODS

Muscle homogenates were prepared from deltoid muscle biopsy specimens of 10 patients with DM and eight controls with no pathological signs of myopathy. Interleukin (IL)-4, interferon (IFN)-γ and IL-17 levels were evaluated by enzyme-linked immunosorbent assay (ELISA) and immunoblotting analysis. Muscle strength grades were recorded.

RESULTS

Patients with DM showed significantly elevated muscle tissue IL-4 and IFN-γ levels, whereas IL-17 levels were comparable between patients with DM and controls. Immunoblotting studies confirmed ELISA results. In DM muscle specimens, IL-4 and IFN-γ levels were positively correlated, while no correlation was observed between IL-17 and the other two cytokines. Moreover, IL-4 and IFN-γ levels were significantly negative correlated with muscle strength grades for the deltoid muscle.

CONCLUSION

Our results confirm the involvement of T helper (Th) 1-type and Th2-type immunity in DM pathogenesis. Muscle tissue appears to contribute to muscle weakness in DM by producing inflammatory cytokines.

T-cell receptor-mediated characteristic signaling pathway of peripheral blood T cells in dermatomyositis and polymyositis

The characteristics of T cell expression in peripheral blood have been previously described in dermatomyositis (DM) and polymyositis (PM); however, their intracellular signaling profiles remain unknown. The purpose of this study was to investigate the T-cell receptor (TCR)-mediated intracellular signaling in peripheral blood T cells in DM and PM. Peripheral blood T cells from 86 patients with DM (n = 57) and PM (n = 29) were used for experimental investigations. T-cell subtypes and TCR-induced phosphorylated zeta-chain-associated protein kinase 70 (pZAP70) were analyzed by flow cytometry. Signal transducer and activator of transcription (STAT) and some inhibitory factors in T cells with TCR stimulation were also investigated by quantitative real-time polymerase chain reaction. T cell counts were significantly lower in DM than in PM. In addition, STAT, forkhead box transcription factor (FoxP3), and pZAP70 expression in CD4⁺ T cells was suppressed in DM, whereas STAT and pZAP70 expression in CD8⁺ T cells was induced in PM. Especially in DM, a positive correlation between CD4⁺ T cell counts and STAT expression was detected. In addition, low CD4⁺ T cell counts as well as reduced STAT expression were prominent in patients with interstitial lung disease. STAT and pZAP70 expression significantly improved after clinical remission in both DM and PM, although expression of FoxP3 remained suppressed. Besides, upregulation of suppressor of cytokine signaling-3 (SOCS3) and downregulation of interleukin 6 signal transducer (IL6ST) in CD4⁺ T cells were observed in both DM and PM; however, no significant improvements were detected after clinical remission. The results of the present study suggested that TCR-mediated signaling may be a key pathway to determine the different characteristics of peripheral blood T cells between DM and PM. In addition, upregulation of SOCS3 and downregulation of IL6ST and FoxP3 in CD4⁺ T cells may cause an imbalance in intracellular signaling, especially in DM, suggesting that further studies are required to identify how the impaired signaling contributes to the development of the disease.

Sex differential association of dermatomyositis with Sjögren syndrome

BACKGROUND

Although dermatomyositis and Sjögren syndrome share serologic autoantibodies and genetic polymorphisms, population data about the incidence of Sjögren syndrome in patients with dermatomyositis is unavailable. We performed a nationwide cohort study to explore the potential relation between dermatomyositis and Sjögren syndrome and, if an association exists, to elucidate whether it varies by sex.

METHODS

We identified all patients with newly diagnosed dermatomyositis from the Registry of Catastrophic Illness Database in Taiwan between Jan. 1, 1998, and Dec. 31, 2011. Each patient was matched to, at most, 5 control patients from the National Health Insurance Research Database by age, sex and entry date. Cox regression was used to calculate the hazard ratio (HR) and 95% confidence interval (CI) of Sjögren syndrome after adjusting for age, sex, rheumatoid arthritis, systemic lupus erythematosus and systemic sclerosis.

RESULTS

A total of 1602 patients with dermatomyositis and 7981 control patients were enrolled in the study. There was a positive association of having Sjögren syndrome among patients with dermatomyositis after adjusting for age, sex, rheumatoid arthritis, systemic lupus erythematosus and systemic sclerosis (HR 2.67, 95% CI 2.01-3.54). The association was more pronounced in the male cohort (HR 2.69, 95% CI 1.19-6.09).

INTERPRETATION

We found a sex differential association of Sjögren syndrome among patients with dermatomyositis independent of age and concomitant autoimmune disease. Further studies are required to determine the clinical importance of this association for both outcomes and therapeutic options.

Toll-Like Receptor 4-Myeloid Differentiation Primary Response Gene 88 Pathway Is Involved in the Inflammatory Development of Polymyositis by Mediating Interferon-γ and Interleukin-17A in Humans and Experimental Autoimmune Myositis Mouse Model

OBJECTIVE

Toll-like receptor 4 (TLR4) is one of the key players in the development of many autoimmune diseases. To determine the possible role of TLR4 in polymyositis (PM) development, we collected muscle samples from PM patients and mice subjected to an experimental autoimmune myositis (EAM) model.

METHODS

We measured TLR4-MyD88 pathway-related factors, interferon-γ (IFN-γ), and interleukin-17A (IL-17A) in EAM mice and PM patients. Then, we observed the changes of above factors and the inflammatory development of EAM mice with TLR4 antagonist TAK-242, IFN-γ, or IL-17A antibody treatment.

RESULTS

The expression of TLR4, MyD88, and NF-κB was significantly upregulated in the muscle tissues both in 22 patients with PM and in the EAM model. As expected, increased levels of various cytokines, such as IL-1β, IL-6, IL-10, IL-12, tumor necrosis factor-α, TGF-β, IFN-γ, and IL-17A, were evident in the serum of EAM mice. Moreover, mRNA expression levels of IFN-γ and IL-17A were significantly increased in both PM patients and EAM mice. Consistently, the levels of these factors were positively correlated with the degree of muscle inflammation in EAM mice. However, when EAM mice were treated with TLR4 antagonist TAK-242, the expression of IFN-γ and IL-17A was decreased. When the cytokines were neutralized by anti-IFN-γ or anti-IL-17A antibody, the inflammatory development of EAM exacerbated or mitigated.

CONCLUSION

The present study provided the important evidence that the TLR4-MyD88 pathway may be involved in the immune mechanisms of PM by mediating IFN-γ and IL-17A.