Association of increased serum IL-33 levels with clinical and laboratory characteristics of systemic lupus erythematosus in Chinese population

IL-33/ST2 axis in diverse diseases: regulatory mechanisms and therapeutic potential

Interleukin-33 (IL-33) is a nuclear factor and member of the IL-1 cytokine family. IL-33 is mainly expressed by epithelial and endothelial cells and exerts its function through interaction with various immune cells, and binding to its receptor can form the IL-33/Suppression of tumorigenicity 2 (ST2) signaling pathway. While most cytokines are actively synthesized within cells, IL-33 is produced passively in response to tissue damage or cell necrosis, indicating its role as a signaling molecule following cellular infection, stress, or trauma. IL-33/ST2 signaling pathway has been proved to play diverse role in the pathological process of central nervous system disorders, cancer, fibrosis, autoimmune diseases, etc. Although research on the IL-33/ST2 signaling pathway has deepened recently, relevant treatment strategies have been proposed, and even targeted drugs are in the preclinical stage; further research on the effect of the IL-33/ST2 signaling pathway in different diseases is still necessary, to provide a clearer understanding of the different roles of IL-33/ST2 in disease progression and to develop new drugs and treatment strategies. Because IL-33/ST2 plays an important role in the occurrence and progression of diseases, the study of therapeutic drugs targeting this pathway is also necessary. This review focused on recent studies on the positive or negative role of IL-33/ST2 in different diseases, as well as the current related drugs targeting IL-33/ST2 in the preclinical and clinical stage. The mechanism of IL-33/ST2 in different diseases and its mediating effect on different immune cells have been summarized, as well as the antibody drugs targeting IL-33 or ST2, natural compounds with a mediating effect, and small molecule substances targeting relative pathway. We aim to provide new ideas and treatment strategies for IL-33/ST2-related drugs to treat different diseases.

Biological effects of IL-33/ST2 axis on oral diseases: autoimmune diseases and periodontal diseases

IL-33 is a relatively new member of the IL-1 cytokine family, which plays a unique role in autoimmune diseases, particularly some oral diseases dominated by immune factors. The IL-33/ST2 axis is the main pathway by which IL-33 signals affect downstream cells to produce an inflammatory response or tissue repair. As a newly discovered pro-inflammatory cytokine, IL-33 can participate in the pathogenesis of autoimmune oral diseases such as Sjogren's syndrome and Behcet's disease. Moreover, the IL-33/ST2 axis also recruits and activates mast cells in periodontitis, producing inflammatory chemokines and mediating gingival inflammation and alveolar bone destruction. Interestingly, the high expression of IL-33 in the alveolar bone, which exhibits anti-osteoclast effects under appropriate mechanical loading, also confirms its dual role of destruction and repair in an immune-mediated periodontal environment. This study reviewed the biological effects of IL-33 in autoimmune oral diseases, periodontitis and periodontal bone metabolism, and elaborated its potential role and impact as a disease enhancer or a repair factor.

Associations between blood IL-33 levels and IL-33 gene polymorphisms with susceptibility to systemic lupus erythematosus: A meta-analysis

OBJECTIVES

This study investigated the relationship between circulating interleukin-33 (IL-33) levels and systemic lupus erythematosus (SLE) along with polymorphisms in the IL-33 gene and SLE susceptibility.

METHOD

The MEDLINE, EMBASE, and Cochrane Library databases (to May 2023) were searched for relevant publications. Using a meta-analysis we investigated serum/plasma IL-33 levels in patients with SLE and controls, and the relationship between IL-33 rs1929992, rs1891385, rs7044343, rs1095498, and rs10975579 polymorphisms and the risk of developing SLE.

RESULTS

Nine studies focusing on 1,935 patients with SLE were included. IL-33 levels were significantly higher in the SLE group than in the control group (SMD = 2.140, 95% CI = 1.068-3.212, p < .001). Asian, European, and Arab groups have shown increased IL-33 levels in SLE populations, according to ethnic stratification. Regardless of the sample size, variable adjustment, data format, or publication year, the subgroup analysis showed significantly higher IL-33 levels in the SLE group. This meta-analysis supported the significance of the link between SLE and the IL-33 rs1891385 C allele (OR, 1.525; 95% CI, 11.310-1.777; p = .010). A similar association was found between the IL-33 rs1891385 C/A polymorphism and SLE, using homozygote comparisons and dominant and recessive models. However, this meta-analysis found no association between the IL-33 polymorphisms rs1929992, rs7044343, rs1095498, and rs10975579 and susceptibility to SLE.

CONCLUSIONS

This meta-analysis identified significantly higher levels of circulating IL-33 in patients with SLE as well as an association between IL-33 rs1891385 and SLE.

Association of interleukin 33 gene polymorphisms with susceptibility and regulation of inflammatory mediators in Systemic lupus erythematosus patients

BACKGROUND

Studies have indicated the involvement of interleukin (IL)-33 in the pathogenesis of Systemic lupus erythematosus (SLE). This research intended to evaluate the association of IL33 gene rs1929992 and rs7044343 Single nucleotide polymorphisms (SNPs) with risk of SLE. In addition, the association between these SNPs and inflammatory cytokines was determined.

METHODS

In this study, 200 SLE cases and 200 healthy subjects were recruited. Using allelic discrimination Real-time PCR, IL33 gene rs1929992 and rs7044343 SNPs were genotyped. The mRNA expression levels of IL-1β, IL-6, IL-33, TNF-α were determined in the peripheral blood mononuclear cells (PBMCs). The serum levels of cytokines were also measured.

RESULTS

The G allele (OR = 1.57, CI: 1.18-2.08, P = 0.0017), GG genotype (OR = 2.52, CI: 1.33-4.77, P = 0.0043), and GA genotype (OR = 2.12, CI: 1.34-3.34, P = 0.0011) of rs1929992 SNP was significantly associated with an increased SLE risk. The C allele (OR = 1.44, CI: 1.08-1.90; P = 0.0105), CC genotype (OR = 2.07, CI: 1.15-3.71; P = 0.0146), and CT genotype (OR = 1.61, CI: 1.02-2.53, P = 0.0395) of rs7044343 was significantly associated with increased SLE risk. The PBMC mRNA expression and serum levels of IL-1β, IL-6, IL-33, TNF-α were significantly increased in the SLE patients compared to controls. However, there was no significant difference in the mRNA expression and serum levels of IL-1β, IL-6, IL-33, and TNF-α among the SLE patients with three genotypes for both rs1929992 and rs7044343 polymorphisms.

CONCLUSIONS

IL33 gene rs1929992 and rs7044343 SNPs are involved in SLE pathogenesis but they might not influence on the inflammatory pathway.

PADI4 and IL-33 gene polymorphisms with susceptibility to systemic lupus erythematosus and juvenile idiopathic arthritis, a systematic review and meta-analysis

BACKGROUND

This study evaluated the association between peptidyl arginine deiminase type IV (PADI4) and interleukin 33 (IL-33) with systemic lupus erythematosus (SLE) and juvenile idiopathic arthritis (JIA).

METHOD

We searched the PubMed, Web of Science, Embase and Cochrane Library databases to retrieve articles published up to January 20, 2023. Stata/SE 17.0 (College Station, TX) software was used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs). The cohort study, case-control study focusing on the PADI4, IL-33 polymorphism, and SLE, JIA were retrieved. The data included basic information of each study and the genotypes and allele frequencies.

RESULTS

Studies in PADI4 rs2240340 = 2 and 3 IL-33(rs1891385 = 3, rs10975498 = 2, rs1929992 = 4) were found in 6 articles. Overall, only the IL-33 rs1891385 show significant association between SLE in all 5 models. The results were OR (95% CI) = 1.528 (1.312, 1.778), P = .000 in Allele model (C vs A), OR (95% CI) =1.473 (1.092, 1.988), P = .000 in Dominant model (CC + CA vs AA), 2.302 (1.583, 3.349), P = .000 in Recessive model (CC vs CA + AA), 2.711 (1.845, 3.983), P = .000 in Homozygote model (CC vs AA), 5.568 (3.943, 7.863), P = .000 in Heterozygote model (CA vs AA). PADI4 rs2240340, IL-33 rs10975498, IL-33 rs1929992 were not found to be association with the risk of SLE and JIA. In gene model, statistically significant association was found between IL-33 rs1891385 and SLE in sensitivity analysis. Egger's publication bias plot showed there was no publication bias (P = .165). Only in recessive model the heterogeneity test was significant (I2 = 57.9%, P ≤ .093) of IL-33 rs1891385.

CONCLUSION

The current study suggests that in all 5 model, IL-33 rs1891385 polymorphism may be associated with genetic susceptibility to SLE. There was unclear association found between PADI4 rs2240340, IL-33 rs10975498, and IL-33 rs1929992 polymorphisms and SLE and JIA. Due to the limitations of included studies and the risk of heterogeneity, additional research is required to confirm our findings.

PROSPERO REGISTRATION NUMBER

CRD42023391268.

Evaluating performance of the 2019 EULAR/ACR, 2012 SLICC, and 1997 ACR criteria for classifying adult-onset and childhood-onset systemic lupus erythematosus: A systematic review and meta-analysis

Introduction

The American College of Rheumatology (ACR) 1997, Systemic Lupus International Collaborating Clinics (SLICC) 2012, and European League Against Rheumatism (EULAR)/ACR 2019 SLE criteria are often used to classify patients with adult-onset and childhood-onset systemic lupus erythematosus (SLE) in clinical practice because there are currently no diagnostic criteria for SLE. However, there is scarce evidence regarding which criteria are best for diagnosing patients with adult-onset and childhood-onset SLE.

Methods

We searched Medline and Scopus databases for English-language articles from inception through October 2021. Data were extracted from the included publications by two independent reviewers. We performed bivariate meta-analysis with a random-effects model to pool diagnostic parameters. Meta-regression and subgroup analyses were performed to explore heterogeneity sources. We used network meta-analysis to compare diagnosis performance among the three criteria and ranked them in descending order. Publication bias was assessed using Deeks' funnel plot.

Results

We included 29 studies for systematic review and meta-analysis. Of these, 18 studies involved adult-onset SLE and 11 studies involved childhood-onset SLE. The pooled sensitivities of the three criteria for diagnosis of adult-onset SLE were comparable between SLICC 2012 and EULAR/ACR 2019 [95.86, 95% confidence interval (CI) 92.28-97.81 vs. 94.79, 95% CI 92.03-96.63]; pooled specificity was highest in ACR 1997 (92.24, 95% CI 87.06-95.46). In childhood-onset SLE, pooled sensitivity was highest in SLICC 2012 (93.76, 95% CI 89.45-96.39), and pooled specificity was highest in ACR 1997 (95.89, 95% CI 91.73-98.00). In network meta-analysis, the pooled diagnostic odds ratio ranked highest for EULAR/ACR 2019 (131.570, 95% CI 61.50-281.47) in adult-onset SLE and ranked highest for SLICC 2012 (191.07, 95% CI 76.06-480.01) in childhood-onset SLE. Deeks' funnel plot showed no publication bias.

Conclusion

We found that the diagnostic performance of the ACR 1997, SLICC 2012, and EULAR/ACR 2019 criteria differed between adult-onset and childhood-onset SLE. EULAR/ACR 2019 performed best for adult-onset SLE and SLICC 2012 was best for childhood-onset SLE in classifying patients with SLE.

Systematic review registration

[www.ClinicalTrials.gov], identifier [CRD420 21281586].

PADI4 and IL-33 gene polymorphisms associated with differential susceptibility to juvenile-onset systemic lupus erythematosus and juvenile idiopathic arthritis in Chinese children

BACKGROUND

Juvenile systemic lupus erythematosus (JSLE) and juvenile idiopathic arthritis (JIA) are two common types of autoimmune diseases in children with unclear pathogenesis. Both peptidyl arginine deiminase type IV (PADI4) and interleukin 33 (IL-33) are the key molecular involved in immune responses in autoimmune diseases. Usually, it may share the same risk genetic alleles for autoimmune diseases.

METHODS

So measurement of PADI4 and IL-33 polymorphisms was conducted with 303 healthy controls, 144 JSLE patients and 160 JIA patients in this study.

RESULTS

It demonstrated that there was a significant association between PADI4 genotypes (rs2240340: CT, CT + CC), IL-33 genotype (rs1929992: TT) and JSLE susceptibility in Southwest China population. While no significant association with the risk of JIA were observed no matter at allelic or genotypic levels.

CONCLUSIONS

Our study reveals the importance of PADI4 and IL-33 polymorphisms with JSLE risk and their roles in the development of the diseases need more further researches.

Quercetin Ameliorates Renal Injury and Pyroptosis in Lupus Nephritis through Inhibiting IL-33/ST2 Pathway In Vitro and In Vivo

Lupus nephritis (LN) is a common and serious symptom in patients with systemic lupus erythematosus (SLE). Tubular interstitial fibrosis is a common underlying mechanism in the development of lupus nephritis to end-stage renal failure (ESRD). Quercetin is widely proven to prevent tissue fibrosis. Therefore, the purpose of this study is to investigate the beneficial effects of quercetin on the inhibition of fibrosis and inflammation pathways in in vitro and in vivo lupus nephritis models. In the current study, MRL/lpr mice as animal models, and HK-2 human renal tubular epithelial cells were stimulated by interleukin-33 (IL-33) to mimic the cellular model of lupus nephritis. Immunohistochemical staining, immunoblotting assay, immunofluorescence staining, and quantitative real-time polymerase chain reaction assay were used. The in vivo results showed that quercetin improved the renal function and inhibited both fibrosis- and inflammation-related markers in MRL/lpr mice animal models. The in vitro results indicated that quercetin ameliorated the accumulation of fibrosis- and inflammation-related proteins in IL-33-induced HK-2 cells and improved renal cell pyroptosis via the IL33/ST2 pathway. Overall, quercetin can improve LN-related renal fibrosis and inflammation, which may offer an effective potential therapeutic strategy for lupus nephritis.

Interrelationship and Sequencing of Interleukins4, 13, 31, and 33 - An Integrated Systematic Review: Dermatological and Multidisciplinary Perspectives

The interrelations and sequencing of interleukins are complex (inter)actions where each interleukin can stimulate the secretion of its preceding interleukin. In this paper, we attempt to summarize the currently known roles of IL-4, IL-13, IL-31, and IL-33 from a multi-disciplinary perspective. In order to conduct a comprehensive review of the current literature, a search was conducted using PubMed, Google Scholar, Medscape, UpToDate, and Key Elsevier for keywords. The results were compiled from case reports, case series, letters, and literature review papers, and analyzed by a panel of multi-disciplinary specialist physicians for relevance. Based on 173 results, we compiled the following review of interleukin signaling and its clinical significance across a multitude of medical specialties. Interleukins are at the bed rock of a multitude of pathologies across different organ systems and understanding their role will likely lead to novel treatments and better outcomes for our patients. New interleukins are being described, and the role of this inflammatory cascade is still coming to light. We hope this multi-discipline review on the role interleukins play in current pathology assists in this scope.

IL-33/ST2 axis in autoimmune disease

Interleukin-33 (IL-33) is a member of the IL-1 family and plays an ambivalent role in autoimmune diseases. IL-33 signals via the ST2 receptor and drives cytokine production in mast cells, basophils, eosinophils, NK cells, and T lymphocyte cells. The vital role of IL-33 as an active component gives rise to aberrant local and systemic damage which has been demonstrated in numerous inflammatory disorders and immune-mediated pathological conditions including multiple sclerosis (MS), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), psoriasis, Sjogren's syndrome, inflammatory bowel disease (IBD), etc. IL-33/ST2 axis can up-regulate pro-inflammatory cytokine release in autoimmune disease, however, in some metabolic diseases like diabetes mellitus type 1 IL-33 can be considered an anti-inflammatory cytokine. The purpose of this review is to discuss selected studies on IL-33/ST2 axis in autoimmune diseases and its potential role as a pathogenic or protective cytokine.

Potential role of interleukin-33 in systemic lupus erythematosus by regulating toll like receptor 4

Introduction

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by immune activation and multi-immunologic phenotypes. Interleukin-33 (IL-33) has been shown to be a critical and pleiotropic immunoregulatory mediator in the pathogenesis of many autoimmune diseases. At present, there are conflicting findings in the research of IL-33 in SLE. The purpose of this study was to investigate whether and how IL-33 is involved in the occurrence and development of SLE.

Methods

43 SLE patients and 43 healthy volunteers were recruited for this study. Serum levels of IL-33, IL-4, IL-6, IL-10 and IL-21 were measured by ELISA. The expression of IL-33 was investigated in kidney sections by immunohistochemistry in lupus nephritis patients ( n = 5) and controls ( n = 3). The mRNA expressions of Toll like receptor 4 (TLR4), TLR2, and tumorigenicity 2 (ST2)L were quantified in peripheral blood mononuclear cells (PBMCs) by real-time PCR. The surface expression of TLR4 on T cells, B cells, monocytes, and neutrophils was assessed by flow cytometry ( n = 22). Mann–Whitney U-test and Spearman’s test were used for statistical analysis.

Results

Serum concentrations of IL-33 were significantly higher in SLE patients than in healthy controls ( p < 0.0001). IL-33 expressions were positively correlated with IL-4 and IL-6 levels in SLE patients, which play pivotal roles in the autoantibody production. In addition, TLR4 and TLR2 mRNA were markedly increased in PBMCs from SLE patients ( p < 0.05). TLR4 was positively associated with IL-33, while TLR2 was not.

Conclusions

These results imply that upregulated expression of serum IL-33 together with increased TLR4 in PBMCs may contribute to the pathogenesis of SLE via promotion of inflammatory cytokines production.

Interleukin-33 Exacerbates IgA Glomerulonephritis in Transgenic Mice Overexpressing B Cell Activating Factor

BACKGROUND

The cytokine IL-33 is an activator of innate lymphoid cells 2 (ILC2s) in innate immunity and allergic inflammation. B cell activating factor (BAFF) plays a central role in B cell proliferation and differentiation, and high levels of this protein cause excess antibody production, including IgA. BAFF-transgenic mice overexpress BAFF and spontaneously develop glomerulonephritis that resembles human IgA nephropathy.

METHODS

We administered IL-33 or PBS to wild-type and BAFF-transgenic mice. After treating Rag1-deficient mice with IL-33, with or without anti-CD90.2 to preferentially deplete ILC2s, we isolated splenocytes, which were adoptively transferred into BAFF-transgenic mice.

RESULTS

BAFF-transgenic mice treated with IL-33 developed more severe kidney dysfunction and proteinuria, glomerular sclerosis, tubulointerstitial damage, and glomerular deposition of IgA and C3. Compared with wild-type mice, BAFF-transgenic mice exhibited increases of CD19+ B cells in spleen and kidney and ILC2s in kidney and intestine, which were further increased by administration of IL-33. Administering IL-33 to wild-type mice had no effect on kidney function or histology, nor did it alter the number of ILC2s in spleen, kidney, or intestine. To understand the role of ILC2s, splenocytes were transferred from IL-33-treated Rag1-deficient mice into BAFF-transgenic mice. Glomerulonephritis and IgA deposition were exacerbated by transfer of IL-33-stimulated Rag1-deficient splenocytes, but not by ILC2 (anti-CD90.2)-depleted splenocytes. Wild-type mice infused with IL-33-treated Rag1-deficient splenocytes showed no change in kidney function or ILC2 numbers or distribution.

CONCLUSIONS

IL-33-expanded ILC2s exacerbated IgA glomerulonephritis in a mouse model. These findings indicate that IL-33 and ILC2s warrant evaluation as possible mediators of human IgA nephropathy.

T Helper 2-Associated Immunity in the Pathogenesis of Systemic Lupus Erythematosus

Systemic Lupus Erythematosus (SLE) is a chronic autoimmune disease that mainly affects women in their reproductive years. A complex interaction of environmental and genetic factors leads to the disruption of immune tolerance towards self, causing overt immune activation and production of autoantibodies that attack multiple organs. Kidney damage, termed lupus nephritis, is the leading cause of SLE-related morbidity and mortality. Autoantibodies are central to propagating lupus nephritis through forming immune complexes and triggering complements. Immunoglobulin G (IgG) potently activates complement; therefore, autoantibodies were mainly considered to be of the IgG isotype. However, studies revealed that over 50% of patients produce autoantibodies of the IgE isotype. IgE autoantibodies actively participate in disease pathogenesis as omalizumab treatment, a humanized anti-IgE monoclonal antibody, improved disease severity in an SLE clinical trial. IgE is a hallmark of T helper 2-associated immunity. Thus, T helper 2-associated immunity seems to play a pathogenic role in a subset of SLE patients. This review summarizes human and animal studies that illustrate type 2 immune responses involved during the pathology of SLE.

Involvement of IL-33 in the Pathophysiology of Systemic Lupus Erythematosus: Review

IL-33 is a newly discovered cytokine displaying pleiotropic localizations and functions. More specifically, it also functions as an alarmin, following its release from cells undergoing cell death or necrosis, to alert the innate immune system. The role of IL-33 has been underlined in several inflammatory and autoimmune diseases including systemic lupus erythematosus (SLE). The expressions of IL-33 as well as its receptor, ST2, are significantly upregulated in SLE patients and in patients with lupus nephritis. This review discusses the involvement of IL-33 in the pathology of SLE.

High-throughput identification of autoantibodies that target the human exoproteome

Autoantibodies that recognize extracellular proteins (the exoproteome) exert potent biological effects but are challenging to detect. Here, we developed rapid extracellular antigen profiling (REAP), a high-throughput technique for the comprehensive discovery of exoproteome-targeting autoantibodies. Patient samples are applied to a genetically barcoded yeast surface display library containing 2,688 human extracellular proteins. Antibody-coated yeast are isolated, and sequencing of barcodes is used to identify displayed antigens. To benchmark REAP's performance, we screened 77 patients with autoimmune polyglandular syndrome type 1 (APS-1). REAP sensitively and specifically detected both known and previously unidentified autoantibodies in APS-1. We further screened 106 patients with systemic lupus erythematosus (SLE) and identified numerous autoantibodies, several of which were associated with disease severity or specific clinical manifestations and exerted functional effects on cell signaling ex vivo. These findings demonstrate the utility of REAP to atlas the expansive landscape of exoproteome-targeting autoantibodies and their impacts on patient health outcomes.

Roles of IL-1 and IL-10 family cytokines in the progression of systemic lupus erythematosus: Friends or foes?

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease of unknown etiology that can affect nearly every organ system in the body. Besides genetic and environmental factors, unbalanced pro-inflammatory and anti-inflammatory cytokines contribute to immune dysregulation, trigger an inflammatory response, and induce tissue and organ damage. Inflammatory responses in SLE can be promoted and/or maintained by the availability of cytokines that are overproduced systemically and/or in local tissues. Several key cytokines have been considered potential targets for the reduction of chronic inflammation in SLE. Recent studies indicated that dysregulated production of several cytokines, including those of the IL-1 family and IL-10 family, orchestrate immune activation and self-tolerance, play critical roles in the pathogenesis of SLE. Among IL-1 family cytokines, IL-1, IL-18, IL-33, IL-36, IL-37, and IL-38 had been the most thoroughly investigated in SLE. Additionally, IL-10 family cytokines, IL-10, IL-20, IL-22, IL-26, IL-28, and IL-29 are dysregulated in SLE. Therefore, a better understanding of the initiation and progression of SLE may provide suitable novel targets for therapeutic intervention. In this review, we discuss the involvement of inflammation in the pathogenesis of SLE, with a focus on IL-1 family and IL-10 family cytokines, and highlight pathophysiological approaches and therapeutic potential for treating SLE.

IL-33 in Rheumatic Diseases

Interleukin-33 (IL-33) is a nuclear factor mainly expressed in barrier epithelium, endothelial cells, and fibroblast reticular cells. Some inflammatory cells also express IL-33 under certain conditions. The important role of IL-33 in allergic reactions, helminth infection, cancer, tissue fibrosis, chronic inflammation, organ transplantation, and rheumatic immune diseases has been extensively studied in recent years. IL-33 primarily activates various circulating and tissue-resident immune cells, including mast cell, group 2 innate lymphoid cell (ILC2), regulatory T cell (Treg), T helper 2 cell (Th2), natural killer cell (NK cell), and macrophage. Therefore, IL-33 plays an immunomodulatory role and shows pleiotropic activity in different immune microenvironments. The IL-33/serum stimulation-2 (ST2) axis has been shown to have a detrimental effect on rheumatoid arthritis, systemic lupus erythematosus, and other rheumatic diseases. Interestingly, IL-33 also plays a protective role in the repair of barrier epithelium and the activation of Tregs. Therefore, the role of IL-33/ST2 depends on the underlying pathological conditions in rheumatic diseases. This review focuses on the dual role of the IL-33/ST2 axis in rheumatic diseases.

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.

Genetic Association of Interleukin 33/ST2 Polymorphisms With Behcet's Uveitis

Interleukin (IL)33, a member of the IL1 superfamily, functions as a nuclear factor and mediates biological effects by interacting with the ST2 receptor. Recent studies have described IL33 as an emerging pro-inflammatory cytokine in the immune system, and IL33/ST2 gene polymorphisms have been implicated in the pathogenesis of various immune diseases. However, the underlying mechanisms of IL33/ST2 in Behcet's disease (BD) remain to be defined. Here, we investigated the association between IL33/ST2 gene polymorphisms and BD in 585 BD uveitis (BDU) patients and 834 healthy controls using Agena MassARRAY iPLEX platform. We found that rs3821204 was associated with the development of BDU. Moreover, the frequency of rs2210463 G allele was lower in patients with genital involvement. Association analysis revealed a much greater genetic difference between complete-type and incomplete-type BD groups, including three SNPs (rs7044343, rs1048274, and rs2210463). Our findings suggest that IL33/ST2 gene polymorphisms are involved in the pathogenesis of BDU. Different genetic backgrounds may exist in complete-type and incomplete-type BD patients.

Early Treatment of Interleukin-33 can Attenuate Lupus Development in Young NZB/W F1 Mice

Interleukin-33 (IL-33), a member of the IL-1 cytokine family, has been recently associated with the development of autoimmune diseases, including systemic lupus erythematosus (SLE). IL-33 is an alarmin and a pleiotropic cytokine that affects various types of immune cells via binding to its receptor, ST2. In this study, we determine the impact of intraperitoneal IL-33 treatments in young lupus, NZB/W F1 mice. Mice were treated from the age of 6 to 11 weeks. We then assessed the proteinuria level, renal damage, survival rate, and anti-dsDNA antibodies. The induction of regulatory B (Breg) cells, changes in the level of autoantibodies, and gene expression were also examined. In comparison to the control group, young NZB/W F1 mice administered with IL-33 had a better survival rate as well as reduced proteinuria level and lupus nephritis. IL-33 treatments significantly increased the level of IgM anti-dsDNA antibodies, IL-10 expressing Breg cells, and alternatively-induced M2 macrophage gene signatures. These results imply that IL-33 exhibits a regulatory role during lupus onset via the expansion of protective IgM anti-dsDNA as well as regulatory cells such as Breg cells and M2 macrophages.

Interleukin (IL)-33: an orchestrator of immunity from host defence to tissue homeostasis

Interleukin (IL)-33, a member of the IL-1 superfamily, functions as an alarm signal, which is released upon cell injury or tissue damage to alert the immune system. It has emerged as a chief orchestrator in immunity and has a broad pleiotropic action that influences differentiation, maintenance and function of various immune cell types via the ST2 receptor. Although it has been strongly associated with immunopathology, critically, IL-33 is involved in host defence, tissue repair and homeostasis. In this review, we provide an overview of the signalling pathway of IL-33 and highlight its regulatory functions in immune cells. Furthermore, we attempt a broader discussion of the emerging functions of IL-33 in host defence, tissue repair, metabolism, inflammatory disease and cancer, suggesting potential avenues to manoeuvre IL-33/ST2 signalling as treatment options.

Early echocardiographic detection of left ventricular diastolic dysfunction in patients with systemic lupus erythematosus asymptomatic for cardiovascular disease

Cardiovascular disease (CVD) is a major complication of systemic lupus erythematosus (SLE) and is now a leading cause of death for these patients. In this study, 23 SLE patients asymptomatic for CVD underwent a comprehensive echocardiographic examination to detect subclinical cardiac involvement. According to their SELENA-SLEDAI score, they were divided into two groups: SELENA-SLEDAI ≤ 12 (n = 13, 12 females) and SELENA-SLEDAI > 12 (n = 10, all females), indicative of mild-to-moderate and severe SLE, respectively. Patients in the latter group had significant increases in left ventricular (LV) mass, LV end-diastolic volume, left atrial volume and right heart parameters (pulmonary arterial pressure, tricuspid regurgitation velocity and diameter of the inferior cava) compared to the mild-to-moderate group. Alterations of the early to late diastolic trans-mitral flow velocity (E/A) were found in 39% of patients, equally distributed between the two groups. The Framingham score of all patients correlated directly with LV mass, interventricular septum thickness and posterior wall thickness, but did not significantly differ between patients with severe and mild-to-moderate SLE. These findings reveal the presence of early-stage, and thus clinically silent, diastolic dysfunction in patients with severe SLE. They demonstrate the poor predictive value of the Framingham score in CVD risk stratification of patients with SLE, thus highlighting the crucial role of echocardiography in the diagnostic workup of these patients.

IL-33/IL-31 Axis in Immune-Mediated and Allergic Diseases

Several allergic and immunologic diseases including asthma, food allergy (FA), chronic spontaneous urticaria (CSU), atopic dermatitis (AD), systemic lupus erythematosus (SLE), systemic sclerosis (SSc), rheumatoid arthritis (RA), and Behçet's disease (BD) are characterized by the involvement of Th2 immunity. Several mediators lead to immunoglobulin (Ig)E production, thus including key cytokines such as interleukin (IL)-4, IL-5, and IL-13. Among them, IL-31 and IL-33 have been recently studied as novel biomarkers and future therapeutic targets for allergic and immunological disorders. IL-31 is a proinflammatory cytokine-it regulates cell proliferation and is involved in tissue remodeling. IL-33, acting through its receptor suppression of tumorigenity (ST2L), is an alarmin cytokine from the IL-1 family, whose expression is mediated by tissue damage. The latter has a pleiotropic effect, as it may modulate specific and innate immune cells functions. To date, several researchers have investigated the involvement of IL-31 and IL-33 in several allergic and immune-mediated diseases. Further studies are needed to understand the future applications of these molecules as novel therapeutic agents. This paper aims to give the readers a complete and updated review of IL-31 and IL-33 involvement among the most common autoimmune and allergic disorders.

Serum Biomarkers Related to Glucocorticoid-Induced Osteonecrosis of the Femoral Head: A Prospective Nested Case-Control Study

Early diagnosis and prevention of glucocorticoid (GC)-induced osteonecrosis of the femoral head (ONFH) continues to be a challenging problem for clinicians and researchers. However, the role of circulating biomarkers for GC-induced ONFH, which may reveal individual susceptibility and facilitate earlier diagnosis, remains to be determined. The aim of this study was to identify potential biomarkers that may predict early GC-induced ONFH. A total of 123 patients scheduled for initial systemic GC therapy were enrolled in this prospective nested case-control study. The serum concentrations of 13 potential biomarkers were measured in seven patients with GC-induced ONFH, diagnosed instantly after short-term use of GCs and in 20 controls who did not develop osteonecrosis despite similar GC therapy. Biomarkers were measured both before and after taking GCs to identify any differences in marker levels and the changes during GC therapy between two groups. Type I collagen cross-linked C-telopeptide (β-CTX; p = 0.000) was significantly lower, high-density lipoprotein cholesterol (p = 0.092) and apolipoprotein (apo)-B/apo-A1 (p = 0.085) tended to be lower and higher, respectively, before GC treatment in osteonecrosis group. After GC therapy, β-CTX (p = 0.014) was significantly lower and amino terminal telopeptide of procollagen type I (PINP; p = 0.068) tended to be lower in the osteonecrosis group. As secondary outcomes, we observed remarkable changes in nine potential biomarkers following short-term GC therapy in both groups. In conclusion, we found that β-CTX, could potentially be used to predict GC-induced ONFH before GC therapy. Lower β-CTX and PINP are promising biomarkers for the early diagnosis of GC-induced ONFH. These findings need to be confirmed in large-scale prospective studies. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2348-2357, 2019.

Severe thrombocytopenia in pregnancy: a case series from west China

Thrombocytopenia is the second most common hematological disease during pregnancy and is mainly caused by gestational thrombocytopenia, immune thrombocytopenia, or preeclampsia/HELLP syndrome. This study aims to investigate the causes and pregnancy outcomes of thrombocytopenia in pregnancies with platelet counts below 50 × 10⁹/L. We retrospectively analyzed the pregnancies diagnosed with severe thrombocytopenia at a tertiary care center in western China between January 2009 and December 2017. All enrolled pregnancies were divided into three groups according to the lowest platelet counts: group A (30-50 × 10⁹/L), group B (10-30 × 10⁹/L), and group C (< 10 × 10⁹/L). Maternal and fetal outcomes were observed and compared among these three platelet levels. A total of 533 consecutive pregnancies were included. A relatively large proportion (37.3%, 199/533) of them showed a history of thrombocytopenia before pregnancy or during a previous pregnancy. Most of the women (70.2%, 374/533) received corticosteroids, intravenous immunoglobulin, or platelet transfusion treatments. The incidence of preterm birth < 37 weeks (26.3%, 15/57), cesarean section (93%, 53/57), and neonatal intensive care unit (NICU) admission (31.6%, 18/57) occurred significantly more often in group C than in groups A and B. Neonatal platelet counts were detected in 28.2% of the infants (155/549), and neonatal thrombocytopenia was found in 40.6% of the infants (63/155). Intracranial hemorrhage occurred in 0.9% of the neonates (5/549) throughout the study period, with neonatal nadir platelet counts between 20 × 10⁹/L and 245 × 10⁹/L. One perinatal death occurred in group C. Pregnancies with the lowest platelet counts below 10 × 10⁹/L are more often complicated by preterm birth, cesarean section, and NICU admission compared with those lowest platelet counts 30-50 × 10⁹/L and 10-30 × 10⁹/L. Neonatal intracranial hemorrhage was uncommon in pregnancies with severe thrombocytopenia. Active management should be performed to avoid possible preterm birth and neonatal NICU admission in pregnancies with the lowest platelet counts below 10 × 10⁹/L.

Paradoxical role of Breg-inducing cytokines in autoimmune diseases

Regulatory B cells (Breg) are crucial immunoregulators that maintain peripheral tolerance and suppress inflammatory autoimmune responses. In recent years, our understanding on the nature and mechanism of action of Bregs has revealed the important role of cytokines in promoting the regulatory properties of this unique B cell subset, both in animal and human models. In this review, we compiled the cytokines that have been reported by multiple studies to induce the expansion of Breg. The Breg-inducing cytokines which are currently known include IL-21, IL-6, IL1β, IFNα, IL-33, IL-35, BAFF and APRIL. As cytokines are also known to play a pivotal role in the pathogenesis of autoimmune diseases, in parallel we reviewed the pattern of expression of the Breg-inducing cytokines in Systemic Lupus Erythematosus (SLE), Rheumatoid Arthritis (RA), Inflammatory Bowel Diseases (IBD) and Multiple Sclerosis (MS). We show here that Breg-inducing cytokines are commonly implicated in these inflammatory diseases where they typically have a higher expression than in healthy individuals, suggesting their paradoxical nature. Interestingly, despite the general overexpression of Breg-inducing cytokines, it is known that Breg cells are often numerically or functionally impaired in various autoimmune conditions. Considering these alterations, we explored the possible parameters that may influence the function of Breg-inducing cytokines in exhibiting either their regulatory or pro-inflammatory properties in the context of autoimmune conditions.

Pleiotropic Effects of IL-33 on CD4+ T Cell Differentiation and Effector Functions

IL-33, a member of the IL-1 family of cytokines, was originally described in 2005 as a promoter of type 2 immune responses. However, recent evidence reveals a more complex picture. This cytokine is released locally as an alarmin upon cellular damage where innate cell types respond to IL-33 by modulating their differentiation and influencing the polarizing signals they provide to T cells at the time of antigen presentation. Moreover, the prominent expression of the IL-33 receptor, ST2, on GATA3+ T helper 2 cells (TH2) demonstrated that IL-33 could have a direct impact on T cells. Recent observations reveal that T-bet+ TH1 cells and Foxp3+ regulatory T (TREG) cells can also express the ST2 receptor, either transiently or permanently. As such, IL-33 can have a direct effect on the dynamics of T cell populations. As IL-33 release was shown to play both an inflammatory and a suppressive role, understanding the complex effect of this cytokine on T cell homeostasis is paramount. In this review, we will focus on the factors that modulate ST2 expression on T cells, the effect of IL-33 on helper T cell responses and the role of IL-33 on TREG cell function.

Dysregulated Interleukin -33/ST2 Pathway Perpetuates Chronic Inflammation in Hashimoto's Thyroiditis

OBJECTIVE

Hashimoto's Thyroiditis (HT) is an autoimmune disease, characterized by chronic inflammation of the thyroid gland with unknown etiologies. Recently, interleukin-33/ST2 (IL- 33/ST2) pathway reveals its participation in the process of several autoimmune diseases. In this study, the role of IL-33/ST2 pathway in the development of HT is investigated.

METHODS

The levels of plasma IL-33, sST2 and the frequency of circulating CD4+ST2L+T cells in 30 HT patients and 20 healthy controls were determined by enzyme-linked immunosorbent assay (ELISA) and flow cytometry respectively. The mRNA expressions of related molecules in IL-33/ST2 pathway in thyroid tissues (12 HT patients and 10 controls) were detected by real-time quantitative PCR (RTqPCR). The protein expressions of IL-33 and ST2 were determined by Western blot and immunohistochemistry staining.

RESULTS

The mRNA expressions of plasma IL-33 and sST2 were elevated in HT patients, with an increased ratio of IL-33/sST2. The number of CD4+ST2L+ T cells in PBMCs of HT group was significantly increased when compared to the control group (CON) by Flow cytometry assay. MRNA Expression of IL-33 and ST2 in thyroid tissue and the level of IL-1β and IL-18 were significantly upregulated in HT patients, while IL-5 was down-regulated in HT patients, compared to CON. The expression of IL-1β and IL-18 were positively correlated with the expression of IL-33. Results of western blot and immunohistochemical staining were consistent with qPCR.

CONCLUSION

IL-33/ST2 pathway participates in HT via affecting the production of inflammatory cytokines.

Interleukin-33 Contributes Toward Loss of Tolerance by Promoting B-Cell-Activating Factor of the Tumor-Necrosis-Factor Family (BAFF)-Dependent Autoantibody Production

Breaking tolerance is a key event leading to autoimmunity, but the exact mechanisms responsible for this remain uncertain. Here we show that the alarmin IL-33 is able to drive the generation of autoantibodies through induction of the B cell survival factor BAFF. A temporary, short-term increase in IL-33 results in a primary (IgM) response to self-antigens. This transient DNA-specific autoantibody response was dependent on the induction of BAFF. Notably, radiation resistant cells and not myeloid cells, such as neutrophils or dendritic cells were the major source of BAFF and were critical in driving the autoantibody response. Chronic exposure to IL-33 elicited dramatic increases in BAFF levels and resulted in elevated numbers of B and T follicular helper cells as well as germinal center formation. We also observed class-switching from an IgM to an IgG DNA-specific autoantibody response. Collectively, the results provide novel insights into a potential mechanism for breaking immune-tolerance via IL-33-mediated induction of BAFF.

IL-1 family cytokines and soluble receptors in systemic lupus erythematosus

Background

Dysregulated production of cytokines has a critical role in systemic lupus. The aim of this work is to identify, by a comprehensive analysis of IL-1 family cytokines and receptors in serum, correlation between cytokines/receptors’ levels and the clinical and serological features of the disease.

Methods

A full clinical evaluation was performed in 74 patients with systemic lupus erythematosus (SLE). C3, C4, anti-dsDNA and anti-C1q antibodies were measured. Cytokines of the IL-1 family (IL-1α, IL-1β, IL-33, IL-18), soluble receptors (sIL-1R1, sIL-1R2, sIL-1R3, ST2/sIL-1R4) and antagonists (IL-1Ra, IL-18 binding protein (IL-18BP)) were measured in serum by multiarray ELISA. Free IL-18 was calculated as the amount of IL-18 not inhibited by IL-18BP. Data were analysed by non-parametric tests and by multivariate analysis, using partial least squares (PLS) models.

Results

Total IL-18, IL-18BP, sIL-1R4 and IL-1Ra levels were higher in SLE vs. controls. Total and free IL-18 and sIL-1R4 were higher in patients with active vs. inactive disease and correlated with ECLAM, anti-C1q and anti-dsDNA antibodies. sIL-1R2 was higher in patients with inactive disease, was negatively correlated with ECLAM and anti-C1q antibodies and was positively correlated with C3 levels. PLS identified sIL-1R4, sIL-1R2 and anti-dsDNA as variables distinguishing patients with active from those with inactive disease; sIL-1R4, IL-18BP and anti-dsDNA identified patients with active nephritis; sIL-1R4, C3, IL-18 and free IL-18 identified patients with haematological involvement.

Conclusion

The data support the use of IL-18, sIL-1R2 and sIL-1R4 as biomarkers of disease activity and organ involvement, and suggest that failure in the inhibition of IL-1 activation may be a critical event in the active stages of SLE.

Increased soluble ST2 and IL‑4 serum levels are associated with disease severity in patients with membranous nephropathy

The interleukin (IL)‑33/suppression of tumorigenicity 2 (ST2) axis regulates Th2 reactivity, and ST2 is the receptor for IL‑33. In this study, the roles of IL‑33 and soluble ST2 (sST2) in the pathogenesis of membranous nephropathy (MN), and their association with disease severity were evaluated. Serum levels of IL‑33 and sST2 in 93 patients, and 34 healthy controls (HCs) were measured by enzyme‑linked immunosorbent assays. Clinical characteristics were recorded and the estimated glomerular filtration rates (eGFRs) were computed. In addition, the association between serum IL‑33 and sST2 levels, and clinical measurements in patients with MN was analyzed. No difference in the serum levels of IL‑33 was identified between the patients with MN and HCs. However, the serum levels of sST2 were considerably higher in the MN patients compared with in the HCs at every stage. Higher concentrations of serum IL‑2, IL‑4, IL‑10, IL‑17A, and IFN‑γ were measured in the MN patients compared with in the HCs. Serum sST2 concentrations were negatively correlated with IL‑4 concentrations in the patients with MN. Furthermore, serum sST2 levels were negatively correlated with the eGFRs and serum calcium levels. Serum sST2 levels, but not IL‑33 levels, were positively correlated with the 24‑h urine protein and serum phosphorus levels. Following treatment, serum sST2 levels were considerably reduced, whereas serum IL‑4 and IL‑10 levels were significantly increased. These data suggest that sST2 and IL‑4, but not IL‑33, contribute to the pathogenesis of MN.

Investigating the role of IL-33 in the pathogenesis of Behçet's Disease

OBJECTIVES

Behçet's disease (BD) is an inflammatory disease, characterized by oral aphthous lesions, recurrent uveitis, skin lesions, and genital ulcerations. Increased release of several cytokines may play a role in the inflammatory stages of BD. IL-33, a member of the IL-1 cytokine superfamily, plays an important role in inflammation. We analyzed serum IL-33 concentration in BD patients to assess its possible role in the pathophysiology of this disease.

METHODS

The study included 54 BD patients, 31 with active BD and 23 with inactive BD as well as 18 matched healthy controls. Serum IL-33 levels were measured using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

The mean serum IL-33 levels were 4.84 ± 2.81 pg/ml in the BD patients (6.16 ± 2.94 pg/ml in the active stage and 2.86 ± 0.54 pg/ml in the inactive stage) and 2.88 ± 0.42 pg/ml in the healthy controls. Serum IL-33 levels were significantly higher in patients with BD compared with the healthy controls (p < 0.01). In active Behçet patients with arthritis the mean serum IL-33 level was higher but this finding was not statistically significant (p = 0.122).

CONCLUSION

IL-33 may play a significant role of in the pathogenesis of BD.

Emerging Roles of IL-33/ST2 Axis in Renal Diseases

Renal diseases, including acute kidney injury (AKI) and chronic kidney disease (CKD), have a great impact on health care systems worldwide. Similar to cardiovascular diseases, renal diseases are inflammatory diseases involving a variety of cytokines. Primary causes of renal injury include ischemia, uremic toxins, bacteremia, or nephrotoxicity. Inflammation represents an important component following kidney injury. Interleukin (IL)-33 is a member of the IL-1 cytokine family, which is widely expressed in epithelial barrier tissues and endothelial cells, and mediates both tissue inflammation and repair responses. IL-33 is released as a nuclear alarmin in response to tissue damage and triggers innate and adaptive immune responses by binding to its receptor, suppression of tumorigenicity 2 (ST2). Recent evidence from clinical and experimental animal studies indicates that the IL-33/ST2 axis is involved in the pathogenesis of CKD, renal graft injury, systemic lupus nephritis, and AKI. In this review, we discuss the pathological and tissue reparative roles of the IL-33/ST2 pathway in different types of renal diseases.

IL-33/ST2 contributes to severe symptoms in Plasmodium chabaudi-infected BALB/c mice

It has been reported that IL-33 contributes to potentiation of Th2 inflammatory diseases and protection against helminth infection. Increased plasma IL-33 levels have been observed in patients with severe falciparum malaria, however, the role of IL-33 in malaria remains unclear. Here we report that IL-33 enhances inflammatory responses in malaria infection. ST2-deficiency altered severity of inflammation in the liver and serum levels of pro-inflammatory cytokines such as TNF-α and IL-6, and IL-13 that is a Th2 cytokine during Plasmodium chabaudi infection. IL-13-deficient mice have similar phenotype with ST2-deficient mice during P. chabaudi infection. Furthermore, ST2- and IL-13-deficiency reduced mortality from P. chabaudi infection. These results indicate that IL-33/ST2 can induce production of proinflammatory cytokines, such as TNF-α and IL-6, through production of IL-13 in P. chabaudi-infected BALB/c mice, suggesting that IL-33/ST2 play a critical role in inflammatory responses to malaria infection. Thus, these findings may define a novel therapeutic target for patients with severe malaria.

Subgingival microbiota dysbiosis in systemic lupus erythematosus: association with periodontal status

BACKGROUND

Periodontitis results from the interaction between a subgingival biofilm and host immune response. Changes in biofilm composition are thought to disrupt homeostasis between the host and subgingival bacteria resulting in periodontal damage. Chronic systemic inflammatory disorders have been shown to affect the subgingival microbiota and clinical periodontal status. However, this relationship has not been examined in subjects with systemic lupus erythematosus (SLE). The objective of our study was to investigate the influence of SLE on the subgingival microbiota and its connection with periodontal disease and SLE activity.

METHODS

We evaluated 52 patients with SLE compared to 52 subjects without SLE (control group). Subjects were classified as without periodontitis and with periodontitis. Oral microbiota composition was assessed by amplifying the V4 region of 16S rRNA gene from subgingival dental plaque DNA extracts. These amplicons were examined by Illumina MiSeq sequencing.

RESULTS

SLE patients exhibited higher prevalence of periodontitis which occurred at a younger age compared to subjects of the control group. More severe forms of periodontitis were found in SLE subjects that had higher bacterial loads and decreased microbial diversity. Bacterial species frequently detected in periodontal disease were observed in higher proportions in SLE patients, even in periodontal healthy sites such as Fretibacterium, Prevotella nigrescens, and Selenomonas. Changes in the oral microbiota were linked to increased local inflammation, as demonstrated by higher concentrations of IL-6, IL-17, and IL-33 in SLE patients with periodontitis.

CONCLUSIONS

SLE is associated with differences in the composition of the microbiota, independently of periodontal status.

Serum Levels of Soluble ST2 and IL-10 Are Associated with Disease Severity in Patients with IgA Nephropathy

Background. The IL-33/ST2 axis is involved in humoral immune responses. Method. The concentrations of sera IL-33 and sST2 in 74 patients and 34 healthy controls (HC) were measured by ELISA. Clinical and laboratory data were examined. The potential association between sera IL-33 and sST2 and the clinical parameters in IgAN patients were analyzed. Results. No difference was discovered in IL-33 concentrations between IgAN patients and HCs; however, the sST2 were significantly higher in each stage of IgAN progression than in the HC. The concentration of sST2 was positively correlated with IL-33 levels in IgAN patients. Higher levels of sera IL-2, IL-4, IL-10, IL-17A, and IFN-γ were detected in patients compared to the HC. The concentration of serum sST2 was positively correlated with the levels of IL-10 in IgAN patients. Furthermore, serum sST2 was negatively correlated with the values of eGFR and serum calcium. Serum sST2 was positively correlated with 24-hour urinary protein, serum phosphorus, and serum IgA; however, serum IL-33 was not associated with these. Following treatment, serum sST2 was significantly decreased, while sera IL-4 and IL-10 were significantly increased. Conclusions. Increased sST2 and IL-10 but not IL-33 may be involved in the pathogenic process of IgAN.

Association between IL-33 Gene Polymorphisms (rs1929992, rs7044343) and Systemic Lupus Erythematosus in a Chinese Han Population

OBJECTIVE

Interleukin-33 (IL-33) is a member of the IL-1 family, and previous studies found the single-nucleotide polymorphisms (SNPs) in the IL-33 gene was related to susceptibility to autoimmune diseases, including rheumatoid arthritis, ankylosing spondylitis and Behcet's disease. To date, no study has discussed the potential association between IL-33 gene polymorphisms and systemic lupus erythematosus (SLE).

METHODS

We conducted a case-control study including 371 SLE patients and 408 healthy controls to investigate the correlation between the SNPs of IL-33 gene (rs1929992, rs7044343) and SLE in a Chinese Han population.

RESULTS

There was significantly lower expression of allele G for rs1929992 in SLE patients than that in controls (G versus A, P = 0.012, OR = 1.310, 95% CI: 1.060-1.624 after adjustment with sex). Similarly, genotype GG was associated with the susceptibility to SLE as compared with the AA genotype (P = 0.017, OR = 1.714, 95% CI: 1.101-2.669 after adjustment with sex). We also found statistical significance in the dominant model (GG+GA versus AA, P = 0.017, OR = 1.481, 95% CI: 1.074-2.044 after adjustment with sex). However, we found no strong evidence for the association of IL-33 rs7044343 polymorphism with SLE. Moreover, association studies were performed on the relationship between the IL-33 gene polymorphisms and lupus nephritis as well as nine clinical features of SLE, but there was no significant association regarding the distribution of allele and genotype frequencies between SLE patients positive and negative for the presence of sub-phenotypes.

CONCLUSION

Our findings indicate that IL-33 rs1929992 polymorphism may be a potential biomarker for susceptibility to SLE.

The association of novel IL-33 polymorphisms with sIL-33 and risk of systemic lupus erythematosus

The serum level of IL-33 was upregulated in systemic lupus erythematosus (SLE), which may be used as biomarkers and/or therapeutic targets for SLE. The aim of this study was to investigate the association of four novel polymorphisms of IL-33 with risk of SLE. The study population comprised 540 Chinese individuals, including 257subjects with SLE and 283 healthy controls. The gene polymorphism was measured using Snapshot SNP genotyping assays and confirmed by sequencing. Serum IL-33 (sIL-33) levels were measured by ELISA. The serum SLE levels were significantly higher in the group of patients with SLE than those in the control group (P<0.001). The rs1891385C allele was associated with a significantly increased risk of SLE as compared with the rs1891385 A allele (OR=1.405, 95% CI, 1.052-1.875, P=0.021). The C-T-T-G haplotype was significantly increased the risk of SLE (OR=1.411; 95% CI, 1.021-1.948; P=0.036). IL-33 gene rs1891385 polymorphism was significantly associated with the expression of sIL-33 in the SLE patients. Besides, in our study, we found that the unregulated sIL-33 level was significantly associated with the abnormal changed CRP and ESR. This is the first study reporting the IL-33 gene polymorphisms and SLE, which may help refine the SLE risk profile.

Signal transducer and activator of transcription 5 is implicated in disease activity in adult and juvenile onset systemic lupus erythematosus

The Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway is one of a handful of pleiotropic cascades used to transduce a multitude of signals for development and homeostasis in humans. It is the principal signaling mechanism for a wide array of cytokines and growth factors. Dysregulated cytokine action on immune cells plays an important role in the initiation and progress of systemic lupus erythematosus (SLE). In this study, we tried to assess the role of STAT5 in systemic lupus erythematosus and correlate its phosphorylation level with the disease activity. The activation of the STAT5 was assessed by measuring the level of expression of phosphorylated STAT5 (pSTAT5) using flow cytometry on the peripheral blood T and B cells in 58 SLE patients (40 adult and 18 juvenile onset) and on 23 healthy age- and sex-matched controls for both groups. Serum prolactin level was also assessed in the patients and control by ELISA. The study revealed that the level of pSTAT5 was higher in adult SLE patients than in healthy control (p = 0.001) and in juvenile-onset SLE patients versus age-matched control (p = 0.031). A positive correlation existed between the pSTAT5 levels and Systemic Lupus Activity Measure (SLAM) score and also with multiple clinical manifestations indicating a potential role of STAT5 signaling in pathogenesis SLE. The pSTAT5 signaling is implicated in the disease activity of SLE and may be a useful target of therapy by correcting the dysregulation of cytokines involved in the disease pathogenesis.

IL-33 reflects dynamics of disease activity in patients with autoimmune hemolytic anemia by regulating autoantibody production

Background

Autoimmune hemolytic anemia (AIHA), a life-threatening anemia with rapid onset, is caused by autoantibody directed to self red blood cells (RBCs). Currently, mechanisms underlying AIHA pathogenesis are largely undefined. Here we explored the correlation of IL-33 with AIHA disease activity and evaluated IL-33 based therapeutics in AIHA treatment.

Methods

Thirty patients diagnosed with AIHA of warm-type autoantibodies without treatment were enrolled and followed up for 6 months. Levels of cytokines including IL-33, IL-4, IL-6 and IL-13 was determined with ELISA. AIHA disease activity was presented by levels of reticulocyte count, hemoglobin and lactate dehydrogenase. Serum RBC-bound IgG autoantibody was detected using anti-IgG antibody with flow cytometry. To evaluate the effect of IL-33 blockade on AIHA development, groups of B6 mice were immunized with rat RBCs plus recombinant IL-33 protein or IL-33 neutralizing antibody respectively and detected for levels of anti-RBC antibody, frequency of reticulocytes and destruction of transfused syngeneic mouse RBCs.

Results

Serum level of IL-33 was higher in AIHA patients compared with healthy individuals. Of interest, serum IL-33 was positively correlated with AIHA disease activity and sensitive to their changes in AIHA patients under clinical management. Mechanistically, IL-33 could promote the production of anti-RBC autoantibody. Serum IL-33 was closely associated with serum anti-RBC autoantibody and sensitive to their changes in AIHA patients. Accordingly, blockade of IL-33 interfered with AIHA incidence and ameliorated disease activity. Vice vasa, enforced IL-33 promoted AIHA incidence and disease activity.

Conclusions

IL-33 was a potential biomarker for monitoring disease activity and therapeutic response in AIHA patients. Targeting IL-33 was a promising strategy for controlling autoantibody production in AIHA patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-015-0745-0) contains supplementary material, which is available to authorized users.

IL‑33 and kidney disease (Review)

Interleukin (IL)-33, is a novel member of the IL-1 superfamily, and act as a dual-function molecule as a nuclear factor and cytokine. The expression of IL-33 can be detected in several tissues and cells in humans and in mice. In addition to the conventional secretion approach for cytokines, full-length IL-33 can also be released into the extracellular space following cell damage or mechanical injury. IL-33 mediates its biological effects by interacting with the receptors, suppression of tumorigenicity 2 (ST2) and IL-1 receptor accessory protein, activating intracellular molecules in the nuclear factor-κB and mitogen-activated protein kinase signaling pathways, which drive the production of type 2 cytokines, including IL-4, IL-5 and IL-3, from polarized T helper 2 cells. Increasing evidence indicates that IL-33 is important in chronic kidney disease, and may be involved in the progression of renal fibrosis associated with systemic lupus erythematosus and renal graft damage. In addition, IL-33 contributes to acute kidney injury. In the present review, the biology of IL-33, and the association of IL-33 with kidney diseases are discussed.

IL-33 neutralization suppresses lupus disease in lupus-prone mice

IL-33 is a new member of the IL-1 family that plays a role in inflammation. In this study, we evaluated the potential of IL-33 inhibition as a treatment for systemic lupus erythematosus (SLE) using the lupus-prone model MRL/lpr mice and the underlying mechanisms of action. We treated mice with anti-mouse IL-33 antibody (anti-IL-33Ab) via intraperitoneal injection every other day from week 14 until week 20 for 6 weeks. A control group received the same amount of IgG control. Renal damage and mouse survival were compared. Cytokines, antibodies, immune complex, Tregs, myeloid-derived suppressor cells (MDSCs), and Th17 cells were also analyzed. Correlations between serum IL-33 and SLE disease activity index in human SLE were also investigated. MRL/lpr mice treated with anti-IL-33Ab showed reduced proteinuria and reduced serum anti-dsDNA levels. Nephritis, immune complex deposits, and the circulating antibodies and immune complex besides the mortality were significantly reduced by anti-IL-33Ab. Anti-IL-33Ab remarkably increased Tregs and MDSCs and reduced the Th17 cells and IL-1β, IL-6, and IL-17 levels in MRL/lpr mice. These results suggest that IL-33 inhibition may inhibit SLE via expansion of Tregs and MDSCs and inhibition of Th17 cells and proinflammatory responses, indicating that blockade of IL-33 has a protective effect on SLE.

Overexpression of serum sST2 is associated with poor prognosis in acute-on-chronic hepatitis B liver failure

BACKGROUND AND OBJECTIVE

Interleukin-33 (IL-33) and soluble ST2 (sST2) have been demonstrated to be involved in liver injury. The present study aims to evaluate serum IL-33 and sST2 level in acute-on-chronic hepatitis B liver failure (ACHBLF) and determine their predictive value for prognosis.

METHODS

Serum IL-33 and sST2 level in patients with ACHBLF, chronic hepatitis B (CHB) and healthy controls (HCs) were determined by enzyme-linked immunosorbent assay (ELISA). Clinical and laboratory parameters were obtained.

RESULTS

Serum IL-33 was significantly higher in patients with ACHBLF (313.10±419.97pg/ml) than those with CHB (97.25±174.67pg/ml, P<0.01) and HCs (28.39±6.53pg/ml, P<0.01). Serum sST2 was significantly higher in patients with ACHBLF (1545.87±1135.70pg/ml) than those with CHB (152.55±93.28pg/ml, P<0.01) and HCs (149.27±104.90pg/ml, P<0.01). In all participants, serum IL-33 was significantly correlated with sST2 (r=0.43, P<0.01). In patients with ACHBLF, serum IL-33 was significantly correlated with alanine aminotransferase (ALT; r=0.26, P=0.04). Serum sST2 was significantly correlated with total bilirubin (TBIL; r=0.59, P<0.01), Log10 [HBV DNA] (r=-0.47, P<0.01) and model for end-stage liver diseases (MELD; r=0.28, P=0.03). Serum sST2 had an area under the receiver operating characteristic curve (AUC) of 0.81 in predicting 3-month mortality of ACHBLF. Patients with ACHBLF who had sST2 >1507pg/ml showed significantly poorer survival than those who had sST2 ≤1507pg/ml (P<0.01). Moreover, measurement of sST2 and MELD together significantly improved the diagnostic value of MELD alone (P<0.05).

CONCLUSIONS

Our study showed that serum IL-33 and sST2 were overexpressed in ACHBLF and sST2 might potentially serve as a prognostic marker for it.