The pro-inflammatory potential of T cells in juvenile-onset systemic lupus erythematosus

Molecular consideration relevant to the mechanism of the comorbidity between psoriasis and systemic lupus erythematosus (Review)

Systemic lupus erythematosus (SLE), a common autoimmune disease with a global incidence and newly diagnosed population estimated at 5.14 (range, 1.4-15.13) per 100,000 person-years and 0.40 million people annually, respectively, affects multiple tissues and organs; for example, skin, blood system, heart and kidneys. Accumulating data has also demonstrated that psoriasis (PS) can be a systemic inflammatory disease, which can affect organs other than the skin and occur alongside other autoimmune diseases, such as inflammatory bowel disease, multiple sclerosis, rheumatoid arthritis and SLE. The current explanations for the possible comorbidity of PS and SLE include: i) The two diseases share susceptible gene loci; ii) they share a common IL-23/T helper 17 (Th17) axis inflammatory pathway; and iii) the immunopathogenesis of the two conditions is a consequence of the interactions between IL-17 cytokines with effector Th17 cells, T regulatory cells, as well as B cells. In addition, the therapeutic efficacy of IL-17 or TNF-α inhibitors has been demonstrated in PS, and has also become evident in SLE. However, the mechanisms have not been investigated. To the best of our knowledge, there remains a lack of substantial studies on the correlation between PS and SLE. In the present review, the literature, with regards to the epidemiology, genetic predisposition, inflammatory mechanisms and treatment of the patients with both PS and SLE, has been reviewed. Further investigations into the molecular pathogenic mechanism may provide drug targets that could benefit the patients with concomitant PS and SLE.

CD8+ T-Cells in Juvenile-Onset SLE: From Pathogenesis to Comorbidities

Diagnosis of systemic lupus erythematosus (SLE) in childhood [juvenile-onset (J) SLE], results in a more severe disease phenotype including major organ involvement, increased organ damage, cardiovascular disease risk and mortality compared to adult-onset SLE. Investigating early disease course in these younger JSLE patients could allow for timely intervention to improve long-term prognosis. However, precise mechanisms of pathogenesis are yet to be elucidated. Recently, CD8+ T-cells have emerged as a key pathogenic immune subset in JSLE, which are increased in patients compared to healthy individuals and associated with more active disease and organ involvement over time. CD8+ T-cell subsets have also been used to predict disease prognosis in adult-onset SLE, supporting the importance of studying this cell population in SLE across age. Recently, single-cell approaches have allowed for more detailed analysis of immune subsets in JSLE, where type-I IFN-signatures have been identified in CD8+ T-cells expressing high levels of granzyme K. In addition, JSLE patients with an increased cardiometabolic risk have increased CD8+ T-cells with elevated type-I IFN-signaling, activation and apoptotic pathways associated with atherosclerosis. Here we review the current evidence surrounding CD8+ T-cell dysregulation in JSLE and therapeutic strategies that could be used to reduce CD8+ T-cell inflammation to improve disease prognosis.

High intelligence may exacerbate paediatric inflammatory response to SARS-CoV-2 infection

The body's innate and acquiredimmunesystems are critical in responses to a wide spectrum of assaults, including SARS-CoV-2 infection. We identify studies of autoimmunity to support our hypothesis that a high intelligence quotient (IQ) may put children at increased risk for severe COVID-19 sequelae; especially those whose viral load is high and/or who develop multisystem inflammatory syndrome in children (MIS-C). MIS-C is associated with a higher risk of COVID-19 morbidity and death, even in otherwise healthy children. As information and evidence about SARS-CoV-2 infection continue to expand, our hypothesis suggests adding a potentially intriguing piece to the pandemic puzzle for further investigation. Drawing on a select review of published research and case reports, we discuss immune dysregulation in paediatric patients with a high IQ, including post-infection cytokine expression in the myocardium. Further, we provide a review of 27 paediatric (≤19 years; median age 16) cases of severe COVID-19 outcomes, drawn from media sources published between March and September 2020, in which we identify possible evidence of a 'hyper brain, hyper body' response to infection. We aver these cases are noteworthy given that paediatric death with COVID-19 disease is remarkably rare, and the estimated prevalence of a high IQ (or giftedness) is only 2% in the general population. These observations warrant prospective and retrospective studies of autoinflammatory markers and mechanisms to elucidate any special psychoneuroimmunological vulnerability in children with a high IQ, as such studies may raise implications for how and when prophylactic medical care is provided to children.

Serum protein signatures differentiate paediatric autoimmune/inflammatory disorders

Because of their rarity, limited awareness among non-specialists, and significant overlaps in their clinical presentation, childhood autoimmune/inflammatory conditions represent a diagnostic and therapeutic challenge. Juvenile idiopathic arthritis (JIA), with its 7 sub-forms, is the most common paediatric "rheumatic" disease. Juvenile-onset systemic lupus erythematosus (jSLE) is a severe autoimmune/inflammatory disease that can affect any organ system and shares clinical features with JIA. To overcome issues around diagnostic approaches in the context of clinical overlap, we aimed at the definition of disease sub-form specific cytokine and chemokine profiles. Serum samples from patients with JIA (n = 77) and jSLE (n = 48), as well as healthy controls (n = 30), were collected. Samples were analysed using the Meso Scale Discovery (MSD) U-PLEX Biomarker Group 1 (hu) panel. Distinct serum protein signatures associate with JIA vs jSLE disease groups. Proteins with high discriminatory ability include IL-23, MIP-1β, MCP-1, M-CSF and MDC. Furthermore, serum IL-18, MIF, MIP-5 and YKL-40 discriminate between systemic JIA and other JIA subtypes. Thus, simultaneous quantification of serum proteins in a panel format may provide an avenue for the diagnosis and monitoring of childhood autoimmune/inflammatory conditions.

Disease-associated and patient-specific immune cell signatures in juvenile-onset systemic lupus erythematosus: patient stratification using a machine-learning approach

BACKGROUND

Juvenile-onset systemic lupus erythematosus (SLE) is a rare autoimmune rheumatic disease characterised by more severe disease manifestations, earlier damage accrual, and higher mortality than in adult-onset SLE. We aimed to use machine-learning approaches to characterise the immune cell profile of patients with juvenile-onset SLE and investigate links with the disease trajectory over time.

METHODS

This study included patients who attended the University College London Hospital (London, UK) adolescent rheumatology service, had juvenile-onset SLE according to the 1997 American College of Rheumatology revised classification criteria for lupus or the 2012 Systemic Lupus International Collaborating Clinics criteria, and were diagnosed before 18 years of age. Blood donated by healthy age-matched and sex-matched volunteers who were taking part in educational events in the Centre for Adolescent Rheumatology Versus Arthritis at University College London (London, UK) was used as a control. Immunophenotyping profiles (28 immune cell subsets) of peripheral blood mononuclear cells from patients with juvenile-onset SLE and healthy controls were determined by flow cytometry. We used balanced random forest (BRF) and sparse partial least squares-discriminant analysis (sPLS-DA) to assess classification and parameter selection, and validation was by ten-fold cross-validation. We used logistic regression to test the association between immune phenotypes and k-means clustering to determine patient stratification. Retrospective longitudinal clinical data, including disease activity and medication, were related to the immunological features identified.

FINDINGS

Between Sept 5, 2012, and March 7, 2018, peripheral blood was collected from 67 patients with juvenile-onset SLE and 39 healthy controls. The median age was 19 years (IQR 13-25) for patients with juvenile-onset SLE and 18 years (16-25) for healthy controls. The BRF model discriminated patients with juvenile-onset SLE from healthy controls with 90·9% prediction accuracy. The top-ranked immunological features from the BRF model were confirmed using sPLS-DA and logistic regression, and included total CD4, total CD8, CD8 effector memory, and CD8 naive T cells, Bm1, and unswitched memory B cells, total CD14 monocytes, and invariant natural killer T cells. Using these markers patients were clustered into four distinct groups. Notably, CD8 T-cell subsets were important in driving patient stratification, whereas B-cell markers were similarly expressed across the cohort of patients with juvenile-onset SLE. Patients with juvenile-onset SLE and elevated CD8 effector memory T-cell frequencies had more persistently active disease over time, as assessed by the SLE disease activity index 2000, and this was associated with increased treatment with mycophenolate mofetil and an increased prevalence of lupus nephritis. Finally, network analysis confirmed the strong association between immune phenotype and differential clinical features.

INTERPRETATION

Machine-learning models can define potential disease-associated and patient-specific immune characteristics in rare disease patient populations. Immunological association studies are warranted to develop data-driven personalised medicine approaches for treatment of patients with juvenile-onset SLE.

FUNDING

Lupus UK, The Rosetrees Trust, Versus Arthritis, and UK National Institute for Health Research University College London Hospital Biomedical Research Centre.

The evaluation of cytokines to help establish diagnosis and guide treatment of autoinflammatory and autoimmune diseases

Our knowledge of the role of cytokines in pathologic conditions has increased considerably with the emergence of molecular and genetic studies, particularly in the case of autoinflammatory monogenic diseases. Many rare disorders, considered orphan until recently, are directly related to abnormal gene regulation, and the treatment with biologic agents (biologics) targeting cytokine receptors, intracellular signaling or specific cytokines improve the symptoms of an increasing number of chronic inflammatory diseases. As it is currently impossible to systematically conduct genetic studies for all patients with autoinflammatory and autoimmune diseases, the evaluation of cytokines can be seen as a simple, less time consuming, and less expensive alternative. This approach could be especially useful when the diagnosis of syndromes of diseases of unknown etiology remains problematic. The evaluation of cytokines could also help avoid the current trial-and-error approach, which has the disadvantages of exposing patients to ineffective drugs with possible unnecessary side effects and permanent organ damages. In this review, we discuss the various possibilities, as well as the limitations of evaluating the cytokine profiles of patients suffering from autoinflammatory and autoimmune diseases, with methods such as direct detection of cytokines in the plasma/serum or following ex vivo stimulation of PBMCs leading to the production of their cytokine secretome. The patients' secretome, combined with biomarkers ranging from genetic and epigenetic analyses to immunologic biomarkers, may help not only the diagnosis but also guide the choice of biologics for more efficient and rapid treatments.

Elevated Circulating Interleukin-17 Levels in Patients with Systemic Lupus Erythematosus: A Meta-analysis

BACKGROUND

Previous studies concerning the circulating interleukin-17 (IL-17) in systemic lupus erythematosus (SLE) were contradictory.

AIMS

To further precisely investigate circulating IL-17 in SLE and evaluate its influential factors by meta-analysis.

METHODS

EMBASE, PubMed and Cochrane Library were comprehensively searched to obtain studies on circulating IL-17 in SLE patients by November 22, 2018. The results were illustrated by pooled standard mean difference (SMD) with corresponding 95% confidence interval (CI) using random-effects model as there was significant heterogeneity, which was estimated using Cochran Q and I² statistics. Subgroup analyses and sensitivity analyses were also conducted.

RESULTS

Overall, 1872 articles were reviewed and 20 studies involving 1067 subjects with SLE and 721 healthy controls (HCs) were enrolled in the final analysis according to inclusion criteria. Compared with HCs, circulating IL-17 levels in SLE patients were elevated (SMD: 1.183, 95% CI: 0.763-1.603; P < .001). Moreover, in comparison to HCs, European and Asian SLE patients, age <30 years, disease duration ≥5 years, NOS scores <7 and using ELISA showed increased circulating IL-17 status, whereas no significant change was observed in other subgroups. There was no significant publication bias. Sensitivity analyses demonstrated that the results of our meta-analysis were robust.

CONCLUSIONS

SLE patients have higher circulating IL-17 levels, which is influenced by ethnic, age and disease duration, literature quality and measurements.

Altered Homeostasis of Regulatory T Lymphocytes and Differential Regulation of STAT1/STAT5 in CD4+ T Lymphocytes in Childhood-onset Systemic Lupus Erythematosus

OBJECTIVE

Childhood-onset systemic lupus erythematosus (cSLE) is usually a more severe and aggressive disease than adult-onset SLE (aSLE), but cellular and subcellular reasons for these differences are not well understood. The present study analyzed Th subsets, STAT1/STAT5 signaling response, and cytokine profiles of cSLE.

METHODS

FOXP3+ regulatory (Treg) and effector Th subsets, expression and phosphorylation of STAT1/STAT5 in Th, and cytokine profiles were measured in the peripheral blood of patients with cSLE and healthy controls (HC), using flow cytometry and immunoassay on a biochip.

RESULTS

Significant correlation between expression of the activation marker HLA-DR and decreased Th counts, an increase in the percentage of FOXP3+ Th, and a decrease in the activated Treg (aTreg) subset among them were found in cSLE. In contrast to our previous findings in aSLE, no significant differences in percentages and a significant decrease in the numbers of the naive-resting Treg (rTreg) subset compared to HC were found. The percentages of CD25- cells, possibly reflecting interleukin 2 depletion, were significantly increased in cSLE aTreg, but not in the rTreg subset. Consistent with the results of our previous studies in aSLE, increased expression of STAT1, along with significant correlation between decreased Th counts and their increased basal phosphorylation of STAT5, were also found in cSLE.

CONCLUSION

Our results suggest that the key difference in Treg homeostasis between cSLE and aSLE is in the rTreg subset. However, perturbed aTreg homeostasis, increased levels of STAT1 protein, and homeostatic STAT5 signaling appear to be intrinsic characteristics of the disease, present in cSLE and aSLE alike.

Serum and urine interleukin-17A levels as biomarkers of disease activity in systemic lupus erythematosus

OBJECTIVES

This study examined the correlations of both serum and urine interleukin-17A (IL-17A) levels with disease activity in systemic lupus erythematosus (SLE). This study was also aimed at determining their sensitivity and specificity as biomarkers of disease activity in SLE.

METHODS

A cross-sectional study was performed involving SLE patients (n = 120 patients) from Universiti Kebangsaan Malaysia Medical Centre (UKMMC). Serum and urinary IL-17A levels were determined by immunoassay while disease activity was assessed using Systemic Lupus Erythematosus Disease Activity Index-2000 (SLEDAI-2K) and British Isles Lupus Assessment Group's 2004 index (BILAG 2004) scores. The correlations between serum and urinary IL-17A levels with total SLEDAI-2K and BILAG 2004 scores were determined using bivariate correlation analyses. Receiver operating characteristic curves were calculated to determine their sensitivity and specificity as disease activity biomarkers.

RESULTS

Both serum and urinary IL-17A levels correlated with total scores of BILAG 2004, BILAG renal, BILAG mucocutaneous, and SLEDAI-2K (P < 0.05). Urine IL-17A levels correlated positively with urine protein : creatinine index while serum IL-17 level correlated with the BILAG hematology score (all P < 0.05). The area under curve of serum IL-17A and urine IL-17A with BILAG and SLEDAI scores were low (<0.75).

CONCLUSION

Despite positive correlations between serum and urine IL-17A with SLE disease activity, both were neither sensitive nor specific as biomarkers to predict active disease. Hence, IL-17 measurement has no role in SLE disease activity assessments and future studies are needed to search for other reliable activity biomarkers.

B Cells as a Therapeutic Target in Paediatric Rheumatic Disease

B cells carry out a central role in the pathogenesis of autoimmune disease. In addition to the production of autoantibodies, B cells can contribute to disease development by presenting autoantigens to autoreactive T cells and by secreting pro-inflammatory cytokines and chemokines which leads to the amplification of the inflammatory response. Targeting both the antibody-dependent and antibody-independent function of B cells in adult rheumatic disease has led to the advent of B cell targeted therapies in clinical practice. To date, whether B cell depletion could also be utilized for the treatment of pediatric disease is relatively under explored. In this review, we will discuss the role of B cells in the pathogenesis of the pediatric rheumatic diseases Juvenile Idiopathic Arthritis (JIA), Juvenile Systemic Lupus Erythematosus (JSLE) and Juvenile Dermatomyositis (JDM). We will also explore the rationale behind the use of B cell-targeted therapies in pediatric rheumatic disease by highlighting new case studies that points to their efficacy in JIA, JSLE, and JDM.

Induction therapy downregulates the expression of Th17/Tfh cytokines in patients with active lupus nephritis

To determine the potential changes of IL-6, IL-17A and IL-21 levels during induction therapy, and to assess their relationship with disease activity and immunologic features on patients with active lupus nephritis, twenty-eight patients treated with corticosteroid and immunosuppressants were included in this study. Demographic, clinical, serological data and disease activity were assessed. Blood samples were collected at week 0, 12 and 24, and serum concentrations of IL-17A, IL-6 and IL-21 were measured by cytometric bead array. The serum concentrations of IL-6, IL-17A and IL-21 (P<0.001, P<0.01, P=0.001, respectively) decreased progressively during induction therapy. Concentration of IL-6, IL-17A and IL-21 was higher in non-remission group than that in remission group. A positive correlation was established between the concentration of these cytokines and the severity of proteinuria (P<0.001, P=0.020, P=0.045, respectively), ESR (P<0.001), SLEDAI scores (P<0.05), and ANA titers (P=0.018, P=0.048, P<0.05, respectively). Additionally, ROC curve analysis for IL-6, IL-17A and IL-21 was performed to predict the disease activity. The optimal cutoff level was 5.78 pg/ml, 1.98 pg/ml and 8.59 pg/ml, with AUC=0.809, 0.735 and 0.786. The concentration of IL-6 and IL-21 may be regarded as an indicator for the remission of active lupus nephritis, with cutoff value of 9.12 pg/ml and 11.30 pg/ml, while AUC=0.930 and 0.896. The production of serum IL-6, IL-17A and IL-21 in active LN was dramatically declined during induction therapy, which may improve disease activity while delay disease progression of LN.

Cytokine profile in childhood-onset systemic lupus erythematosus: a cross-sectional and longitudinal study

Childhood-onset systemic lupus erythematosus (cSLE) exhibits an aggressive clinical phenotype and severe complications. This could be due to a pro-inflammatory cytokine milieu. Therefore, we determined plasma levels of Th1 (IL-2, IFN-γ, TNF), Th2 (IL-4), Th17 (IL-17A, IL-6), and Treg (IL-10) cytokines in a cohort of cSLE patients and healthy controls, and we evaluated the association between these cytokines and disease activity. We conducted a cross-sectional study with 51 cSLE patients from two pediatric rheumatology services. Ten cSLE patients participated in a longitudinal follow-up study. Blood samples were collected from the same patient during active and inactive disease. Disease activity was evaluated according to SLE Disease Activity Index 2000 (SLEDAI-2K). Cytokines levels were measured by cytometric bead array technique. cSLE patients had higher IL-6 (P<0.001) and IL-10 (P<0.001) levels than healthy controls. Patients with active disease had higher IL-6 and IL-10 levels than patients with inactive disease (P=0.001 and P=0.014, respectively) and the control group (both P<0.001). IL-6 (P=0.022), IL-10 (P=0.013), and IL-17A (P=0.041) levels were significantly higher during active than inactive disease. Linear regression analysis revealed IL-6 (P=0.002, 95%CI=0.006-0.025) and IL-10 (P=0.01 95%CI=0.021-0.150) as independent factors for increased SLEDAI-2K. IL-6, IL-10, and IL-17A are candidate biomarkers for disease activity in cSLE patients. This is the first longitudinal study to support their pivotal role in the pathogenesis of the disease.

Cytokine changes in response to TPO receptor agonist treatment in primary immune thrombocytopenia

Thrombopoietin receptor agonists (TPO-RAs) have been clinically used in primary immune thrombocytopenia (ITP) with favorable outcomes, while their effect on cytokine regulation in ITP remains unknown. In the present study, plasma and mRNA expression levels of interleukin (IL)-2, interferon gamma (IFN-γ), IL-4, IL-17A, and transforming growth factor-β1 (TGF-β1) were determined by ELISA and real-time quantitative PCR in 26 corticosteroid-resistant/relapsed ITP patients receiving eltrombopag or rhTPO therapy and 15 healthy controls (HCs). Results showed that plasma and mRNA levels of IL-2, IFN-γ, IL-4, and IL-17A in ITP patients did not change significantly after TPO-RA treatment, whereas TGF-β1 levels increased remarkably. The pre- and post-treatment plasma and mRNA levels of IFN-γ and IL-2 were significantly higher, while the pre- and post-treatment IL-4 levels as well as the pre-treatment TGF-β1 levels were remarkably lower in ITP patients compared with HCs. There was no significant difference in TGF-β1 levels between TPO-RA-treated ITP patients and HCs. No statistical difference was found in plasma levels of IL-17A between ITP patients before or after treatment and HCs. However, the pre- and post-treatment mRNA expression of IL-17A and retinoic orphan receptor (ROR) γt in ITP patients were higher than that in HCs. Overall, these findings indicated that TPO-RA treatment could promote the secretion of TGF-β1, while it could not correct the Th1 and Th17 polarization in ITP patients. This study might improve our understanding of the mechanism of action of TPO-RAs and provide important information for optimizing therapeutic strategies for ITP.

Down-regulation of expression of retinoid acid-related orphan receptor C (RORC) in systemic lupus erythematosus

CONTEXT

Retinoic acid-related orphan receptor C (RORC), the key factor orchestrating the transcription of genes encoding interleukin 17, plays a critical role in the regulation of inflammatory responses.

OBJECTIVE

The objective of this study was to analyze the expression of RORC in the peripheral blood of patients with systemic lupus erythematosus (SLE) for a better understanding of the pathogenesis of SLE especially in relation to disease activity and clinical and biochemical findings.

METHODS

The study included 24 patients with SLE and a control group of 18 healthy gender- and age-matched individuals. Evaluation of the level of expression of RORC mRNA was performed by real-time polymerase chain reaction.

RESULTS

The results showed that patients with SLE had lower RORC gene expression levels compared with healthy subjects that were not correlated with disease activity. The down-regulation of RORC was significantly lower in patients with lupus nephritis in remission than active lupus nephritis and nonrenal patients.

CONCLUSIONS

The findings suggest that RORC plays a significant role in the dysregulated immune response associated with SLE. Deciphering the intricate regulatory network and the target genes of RORC will help unravel new specific treatments for SLE.

The role of IL-23/Th17 pathway in patients with primary immune thrombocytopenia

Background

Primary immune thrombocytopenia (ITP) is an autoimmune bleeding disorder with an unclear etiology. This study aims to investigate the role of IL-23/Th17 pathway in patients with ITP.

Method

The gene expressions of IL-17, IL-23 and their receptors in ITP patients and healthy controls were analyzed by quantitative real-time PCR. ELISA was used to test the IL-17 and IL-23 levels in plasma. Flow cytometry was used to detect the frequency of Th17 cells. The correlation between plasma IL-23 and IL-17 levels, Th17 cells, platelets were analyzed. The level of Th17-related cytokines was measured by ELISA following stimulation with IL-23. Subsequently, the IL-23 and IL-17 levels were measured in patients post-treatment.

Results

The PBMCs of ITP patients showed increased mRNA expression levels in each of the following: IL-23p19, IL-12p40, IL-23R, IL-12Rβ1, IL-17A, IL-17F, and RORC. In addition, elevated Th17 cells and plasma IL-17, IL-23 levels were also observed in these ITP patients. Furthermore, it was found that IL-23 levels in plasma are positively correlated with IL-17 levels and Th17 cells, yet negatively correlated with platelet count. Following IL-23 stimulation in vitro, IL-17 levels showed significant elevation. Furthermore, both IL-23 and IL-17 levels decreased after effective treatment.

Conclusion

The IL-23/Th17 pathway may be involved in the pathogenesis of ITP through enhancement of the Th17 response. Moreover, our results suggest that the IL-23/Th17 pathway is a potential therapeutic target in future attempts of ITP treatment.