Interleukin-35: the future of hyperimmune-related diseases?

Serum Interleukin-35 Level in Correlation with T Regulatory and T helper-17 Cells Frequency in Chronic Viral Hepatitis C Patients

Interleukin-35 (IL-35), secreted mainly by T-regulatory cells (T-regs), has been considered to have immunosuppressive actions in many auto-immune diseases and tumors. However, information about its role in chronic hepatitis C (CHC) infection is still limited. We aimed to study the role of IL-35 within CHC infection and to assess its correlation with T-regs and T-helper 17 cells (Th-17). Therefore, we measured serum IL-35 concentrations using ELISA assay in 25 normal controls (NCs) and in 30 CHC patients before receiving direct antiviral agents (DAA) treatment and after 3 months of treatment end. T-regs and Th-17 cells frequencies were assessed via flow-cytometry in control group and patients’ group before treatment. The results showed that serum IL-35 levels revealed a highly significant increase in CHC patients compared to NCs (P <0.001). Moreover, IL-35 levels significantly decreased in patients 3 months after treatment end (P =0.02). Both Th-17 and T-regs were significantly increased in patients more than in NCs and a positive correlation was observed between them. However, T-regs/Th-17 ratio did not show significant difference from the ratio in NCs. IL-35 levels were positively correlated with viral load and T-regs frequency, but not with Th-17 frequency. IL-35 levels did not correlate with liver enzymes or functions. These results suggested that IL-35 enhances the immunosuppressive functions of T-regs, protecting the liver from HCV induced damage and contributes to viral persistence. IL-35 may represent a possible immunotherapeutic strategy for chronic persistent infection if given with DAA, especially in relapsing or non-responding cases.

Expression imbalance of IL-17/IL-35 in peripheral blood and placental tissue of pregnant women in preeclampsia

OBJECTIVES

The possible mechanism of preeclampsia is investigated in this study to facilitate the exploration of the future remediation of this disease by analysing the changes of IL-17 and IL-35 in peripheral blood and placental tissue of pregnant women with preeclampsia (PE).

MATERIALS AND METHODS

The study was conducted using 45 healthy pregnant women as the control group and 90 pregnant women in the preeclampsia group, including 45 cases with severe preeclampsia and 45 cases with mild preeclampsia. All of 135 pregnant women underwent caesarean delivery. IL-17 and IL-35 concentrations in the serum were measured by ELISA, and IL-17 and IL-35 expression in placental specimens was detected by immunohistochemistry.

RESULTS

There were no statistically significant differences in age among the three study groups. Serum IL-17 levels were significantly higher in PE patients than in healthy pregnant women (P < 0.01). The ratio of positive staining for IL-17 was markedly higher in mild PE tissues (84.44%; 38/45) and severe PE tissues (86.67%; 39/45) than in healthy pregnant tissues (35.56%; 16/45) (P < 0.01). The strong positive rates for IL-17 were markedly higher in mild PE tissues (48.89%; 22/45) and severe PE tissues (68.89%; 31/45) than in healthy pregnant tissues (13.33%; 6/45) (P < 0.01). No differences between mild PE tissues and severe PE tissues were noted in both positive case rates and strong positive rates. Consistent with this finding, the ratio of strong positive staining for IL-35 was higher in healthy pregnant tissues (66.67%; 30/45) than in mild PE tissues (33.11%; 14/45) and severe PE tissues (26.67%; 12/45) (P < 0.01).

CONCLUSIONS

The abnormal increase in serum and placental of IL-17 has an association with the formation and development of PE. IL-35 expression is significantly lower in severe PE placenta tissue and serum compared with normal pregnant women. These results suggested that IL-17/IL-35 imbalance may play a role in the pathophysiology of PE.

Interleukin-35 Regulates Immune Microenvironment of Autoimmune Hepatitis Through Inducing the Expansion of Myeloid-Derived Suppressor Cells

Interleukin-35 (IL-35) is a novel anti-inflammatory cytokine of IL12 cytokine family, however, the role of IL-35 in patients with AIH and its effect on myeloid-derived suppressor cells (MDSCs) has not yet been analyzed. The expression of IL-35 subunits (p35 and EBI3) in liver tissues was quantified by immunochemistry and its correlation with clinical parameters was explored in patients with AIH. The expression of MDSCs and IL-35 receptor (gp130 and IL-12Rβ2) were analyzed using flow cytometry and confocal staining. Besides, we utilized in vitro culture to explore the role of IL-35 on MDSCs expansion and activation. We found that the elevated expression of both IL-35 subunits (EBI3 and p35) in liver tissue was positively associated with degrees of hepatic inflammatory and fibrosis in patients with AIH. Furthermore, the expression of EBI3 in liver was positively correlated with patient age, serum IgG levels and serum AST, and was negatively correlated with hemoglobin and albumin. Moreover, our results showed that ratio of MDSC in peripheral blood increased significantly in AIH patients as compared with healthy controls. Further study showed that CD33, a representative marker of MDSCs, co-localized well with gp130 and IL12Rβ2, suggesting MDSCs as target cell for IL-35. Consistently, MDSCs from AIH displayed a substantial higher abundance of gp130 and IL12Rβ2 and were expanded by IL-35 in vitro. IL-35-induced MDSCs showed a significant increase in Nitric oxide (NO) production but not reactive oxygen species (ROS). Conclusions: IL-35 might play an important role in AIH by regulating MDSCs and it could provide new insights into the therapy of AIH.

Interleukin-35 as an Emerging Player in Tumor Microenvironment

IL-35 is the newest member of IL-12 family. A dimeric protein consisting of two separate subunits has manifested suppressive actions on immune system, which is counterproductive in the context of cancers. Various reports have confirmed its inhibitory role on immune system which is carried out via formation of IL-35-producing regulatory T cells (iTr35), increased Treg development and suppressive Th17 cells growth. Although last decade has seen a great deal of scientific interest on this subject, the exact role, precise signal transduction and elaborative functions of IL-35 in tumor microenvironment (TME) remained elusive. Search for anti-IL-35 therapies have exhibited limited success in animal models. Contrarily, few studies have denied the idea that IL-35 plays a role in cancer. The purpose of this review is to analyze the reported scientific data on continuous symphony of IL-35 in cancers since the inception of former.

Altered regulatory cytokine profiles in cases of pediatric respiratory syncytial virus infection

Objectives

Regulatory cytokines are associated with viral infection. The objective of this study was to evaluate the relation between serum regulatory cytokines concentrations and respiratory syncytial virus (RSV) disease.

Methods

We enrolled 325 children aged < 24 months who were diagnosed with acute respiratory tract infection. Twenty age-matched healthy children were enrolled as controls. Nasopharyngeal swabs were analyzed to identify virus by reverse transcription polymerase chain reaction, and blood samples were taken to quantify the regulatory cytokine concentrations, including interleukin (IL)-35, IL-10 and transforming growth factor (TGF)-β1 using the Bio-Plex immunoassay or enzyme-linked immunosorbent assay.

Results

RSV disease was associated with a great regulatory cytokine response than healthy children, among 89 RSV-infected patients, serum IL-35 (P = .0001) and IL-10 (P = .006) was significantly elevated in comparison with healthy controls. Young children (0< age ≤6 months) with RSV infection had significantly lower IL-35 and IL-10 expression but needed more oxygen therapy and more severe disease comparing with older children (12< age <24 months). Comparing with mild group, the expression levels of IL-10 were significantly lower in children with moderate and severe disease (P = .012 and P = .005, respectively). And levels of IL-10 was inversely associated with total duration of RSV infection symptoms (r = − 0.311, P = .019).

Conclusion

Children with RSV infected had increased serum regulatory cytokine IL-10 and IL-35 concentrations. Elevated expression of IL-10 and IL-35 were contributed to protect hypoxia and reduce the severity of disease.

Interleukin-35 mitigates the function of murine transplanted islet cells via regulation of Treg/Th17 ratio

Pancreatic islet transplantation is a promising treatment for type 1 diabetes (T1D). Interleukin-35 (IL-35) is a recently discovered cytokine that exhibits potent immunosuppressive functions. However, the role of IL-35 in islet transplant rejection remains to be elucidated. In this study, we isolated islet cells of BALB/c mouse and purified CD4+ T cell subsets of a C57BL/6 mouse. The model for islet transplantation was established in vitro by co-culture of the islet cells and CD4+ T cells. IL-35 (20 ng/ml) was administered every other day. Following co-culture, the islet function and Treg/Th17 ratio were analyzed on days 1, 3, and 5. Furthermore, the Th17/Treg ratio was modulated (1:0–2), and the function of islet cells as well as proliferation of Th17 cells were analyzed. T cell sorting was performed using the magnetic bead sorting method; Treg and Th17 count using flow cytometry; cell proliferation detection using the carboxyfluorescein diacetate succinimidyl ester (CFSE) method, and islet function test using the sugar stimulation test. Results showed that Th17 counts increased in the co-culture system. However, after administration of IL-35, the number of Treg cells increased significantly compared to that in the control group (50.7% of total CD4+ T cells on day 5 in IL-35 group vs. 9.5% in control group) whereas the proliferation rate of Th17 cells was significantly inhibited (0.3% in IL-35 group vs. 7.2% in control group on day 5). Reducing the Th17/Treg ratio significantly improved the function of transplanted islets. Treg inhibited Th17 proliferation and IL-35 enhanced this inhibitory effect. IL-35 mitigates the function of murine transplanted islet cells via regulation of the Treg/Th17 ratio. This might serve as a potential therapeutic strategy for in-vivo islet transplant rejection and T1D.

IL-35 recombinant protein reverses inflammatory bowel disease and psoriasis through regulation of inflammatory cytokines and immune cells

Interleukin‐35 (IL‐35), a member of the IL‐12 family, functions as a new anti‐inflammatory factor involved in arthritis, psoriasis, inflammatory bowel disease (IBD) and other immune diseases. Although IL‐35 can significantly prevent the development of inflammation in many diseases, there have been no early studies accounting for the role of IL‐35 recombinant protein in IBD and psoriasis. In this study, we assessed the therapeutic potential of IL‐35 recombinant protein in three well‐known mouse models: the dextransulfate sodium (DSS)‐induced colitis mouse model, the keratin14 (K14)‐vascular endothelial growth factor A (VEGF‐A)‐transgenic (Tg) psoriasis mouse model and the imiquimod (IMQ)‐induced psoriasis mouse model. Our results indicated that IL‐35 recombinant protein can slow down the pathologic process in DSS‐induced acute colitis mouse model by decreasing the infiltrations of macrophages, CD4⁺T and CD8⁺T cells and by promoting the infiltration of Treg cells. Further analysis demonstrated that IL‐35 recombinant protein may regulate inflammation through promoting the secretion of IL‐10 and inhibiting the expression of pro‐inflammatory cytokines such as IL‐6, TNF‐α and IL‐17 in acute colitis model. In addition, lower dose of IL‐35 recombinant protein could achieve long‐term treatment effects as TNF‐α monoclonal antibody did in the psoriasis mouse. In summary, the remarkable therapeutic effects of IL‐35 recombinant protein in acute colitis and psoriasis mouse models indicated that IL‐35 recombinant protein had a variety of anti‐inflammatory effects and was expected to become an effective candidate drug for the treatment of inflammatory diseases.

Increased interleukin-27 cytokine expression in the central nervous system of multiple sclerosis patients

Background

Multiple sclerosis (MS) is an autoimmune disorder characterized by chronic inflammation, demyelination, and neuronal damage. During autoimmunity, cytokines are important mediators of the inflammation. In this line, interleukin-27 (IL-27) modulates inflammation and can be produced directly at inflammatory sites such as in the joints during rheumatoid arthritis or in the central nervous system (CNS) during MS. While in animal models of MS, treatment with IL-27 decreases the disease severity, its role in humans is not clearly established and it is not known if IL-27 could be detected in the cerebrospinal fluid (CSF) of MS patients.

Methods

In this study, we measured IL-27 levels using a quantitative enzyme-linked immunosorbent assay in CSF of patients with relapsing remitting multiple sclerosis (RRMS), isolated optic neuritis (ON) and non-inflammatory neurological disease (NIND) as well as in the sera of healthy donors (HD) and RRMS patients undergoing different disease modifying treatments. We further confirmed by immunohistology of patient biopsies the identity of IL-27 producing cells in the brain of active MS lesions.

Results

We observed that IL-27 levels are increased in the CSF but not in the sera of RRMS compared to HD. We confirmed that IL-27 is expressed in active MS plaques by astrocytes of MS patients.

Conclusions

Our results point toward a local secretion of IL-27 in the CNS that is increased during autoimmune processes. We propose that local production of IL-27 could sign the induction of a regulatory response that promotes inflammation’s resolution. The effect of new immunomodulatory therapies on cerebral IL-27 production could be used to understand the biology of IL-27 in MS disease.

Significant reduction of peripheral blood interleukin-35 and CD4+EBI3+ T cells, which are negatively correlated with an increase in the plasma IL-17 and cTnI level, in viral myocarditis patients

Introduction

Viral myocarditis (VMC) has become an increasingly common heart disease that endangers human health. In the present study, the plasma interleukin-35 (IL-35) level and the percentage of CD4⁺EBI3⁺ T cells in VMC patients were detected to investigate the significance of changes in these parameters in the plasma of VMC patients and their association with the disease.

Material and methods

ELISA was performed to detect the plasma IL-35 level and the percentage of peripheral blood CD4⁺EBI3⁺ T cells in 40 VMC patients and in 20 healthy individuals. Moreover, the plasma IL-17 levels in the VMC patients and in the healthy individuals were detected using an ELISA, and the cardiac Troponin-I (cTnI) levels were detected using a chemiluminescent microparticle immunoassay to compare the differences in the groups.

Results

Plasma IL-35 level and the percentage of CD4⁺EBI3⁺ T cells in acute phase VMC patients was lower than that in the healthy control group and the convalescent phase VMC patients. Additionally, the plasma IL-35 level in the VMC patients exhibited a negative correlation with the levels of cTnI and IL-17. The percentage of CD4⁺EBI3⁺ T cells also showed a negative correlation with the levels of cTnI and IL-17.

Conclusions

The plasma IL-35 level and the percentage of CD4⁺EBI3⁺ T cells in VMC patients was reduced, and the amount of the decrease was associated with the severity of the disease. These results suggest that IL-35 and CD4⁺EBI3⁺ T might play important roles in the progression of VMC and could be used as indictors of the disease.

Anti-inflammatory effects of interleukin-35 in acquired aplastic anemia

Interleukin (IL)-35 is a novel regulatory cytokine primarily produced by regulatory T cells. Accumulating evidence has established that IL-35 plays an important role in the regulation of immune homeostasis, but little is known regarding the function of IL-35 in acquired aplastic anemia (AA). The aim of the present study was to investigate the expression of IL-35 and its effects on T cell response in AA. Our study demonstrated that significantly decreased plasma levels of IL-35 in AA were closely correlated with disease severity. In vitro stimulation experiment further confirmed the anti-inflammatory effects of IL-35, including suppressing the proliferation of CD4(+) and CD8(+) effector T cells, inhibiting the secretion of interferon-γ, tumor necrosis factor-α and IL-17 and promoting the production of transforming growth factor-β by peripheral blood mononuclear cells from patients with AA. Furthermore, we established that IL-35 inhibited the differentiation of type 1 T cells and T helper 17 cells but promoted the differentiation of type 2 T cells. Accordingly, the expression of T-bet and RORγt was inhibited while the expression of GATA3 was induced after IL-35 treatment. In summary, our findings suggested that decreased IL-35 might contribute to the loss of immune-tolerance and be critically involved in the pathogenesis of AA.

IL-35: a potential therapeutic target for controlling hepatitis B virus infection

Interleukin (IL)-35, a recently identified cytokine of the IL-12 family, is a potent immunosuppressive cytokine secreted by regulatory T (Treg) cells and the newly reported regulatory B (Breg) cells. IL-35 functions as a crucial immunosuppressive factor in immune-mediated diseases, and the predominant mechanism of suppression is its ability to suppress T cell proliferation and effector functions. The pathogenic processes of the non-cytopathic hepatitis B virus (HBV) infection-related liver diseases are immune-mediated, including liver damage and viral control. It has been found that IL-35 is detectable in peripheral CD4(+) T cells in chronic HBV-infected patients, whereas it is undetectable in healthy individuals. There is growing evidence that cytokine-mediated immune responses play a pivotal role in determining the clinical outcome during HBV infection. It is particularly important to investigate the effects of IL-35 in the immunopathogenesis of chronic HBV infection. In this study, the recent understanding of this issue is discussed.

Interleukin-12 family cytokines and sarcoidosis

Sarcoidosis is a systemic granulomatous disease predominantly affecting the lungs. It is believed to be caused by exposure to pathogenic antigens in genetically susceptible individuals but the causative antigen has not been identified. The formation of non-caseating granulomas at sites of ongoing inflammation is the key feature of the disease. Other aspects of the pathogenesis are peripheral T-cell anergy and disease progression to fibrosis. Many T-cell-associated cytokines have been implicated in the immunopathogenesis of sarcoidosis, but it is becoming apparent that IL-12 cytokine family members including IL-12, IL-23, IL-27, and IL-35 are also involved. Although the members of this unique cytokine family are heterodimers of similar subunits, their biological functions are very diverse. Whilst IL-23 and IL-12 are pro-inflammatory regulators of Th1 and Th17 responses, IL-27 is bidirectional for inflammation and the most recent family member IL-35 is inhibitory. This review will discuss the current understanding of etiology and immunopathogenesis of sarcoidosis with a specific focus on the bidirectional impact of IL-12 family cytokines on the pathogenesis of sarcoidosis.

Circulating levels of interleukin-35 in patients with multiple sclerosis: evaluation of the influences of FOXP3 gene polymorphism and treatment program

The regulatory T (Treg) cells play a major role in the control of the autoimmunity and inflammation, and IL-35 has been described as an immunosuppressive cytokine that is mainly produced by CD4(+)FOXP3(+) Treg cells. The aim of this study was to evaluate the serum levels of IL-35 and a single nucleotide polymorphism (SNP), rs3761548, in FOXP3 gene in patients with multiple sclerosis. The blood samples were collected from 140 multiple sclerosis (MS) patients (including 51 untreated and 89 treated patients) and 140 healthy subjects as a control group. The serum levels of IL-35 were measured by ELISA. The DNA was analyzed for SNP rs3761548 in FOXP3 gene using SSP-PCR. There was no significant difference between untreated MS patients and control group regarding the mean serum levels of IL-35, although this parameter was higher in untreated patients. However, the mean serum level of IL-35 in treated MS patients was significantly higher than that in the control group (P < 0.008). The mean serum levels of IL-35 in patients who were treated with interferon-β, methylprednisolone, or with the both interferon-β and methylprednisolone were significantly higher than that in the healthy group (P < 0.01, P < 0.01, and P < 0.2, respectively). The frequencies of AA and AC genotypes at rs3761548 in the FOXP3 gene were significantly higher in MS group as compared with healthy subjects (P < 0.05). The frequency of CC genotype at rs3761548 was significantly lower in the MS group in comparison with healthy control subjects (P < 0.001). Moreover, the frequency of A allele was significantly higher whereas the frequency of C allele was significantly lower in MS patients in comparison to healthy subjects (P < 0.001). The mean serum level of IL-35 was significantly lower in MS patients or healthy subjects with AA genotype as compared with those with CC genotype at rs3761548 in FOXP3 gene (P < 0.01 and P < 0.001, respectively). These results showed higher serum levels of IL-35 in treated MS patients representing that the benefit effects of treatment may in part performed through the upregulation of the IL-35 production. The SNP rs3761548 may influence the susceptibility to MS disease and the serum levels of IL-35.

The possible role of the novel cytokines il-35 and il-37 in inflammatory bowel disease

Interleukin- (IL-) 35 and IL-37 are newly discovered immune-suppressing cytokines. They have been described in inflammatory diseases such as collagen-induced arthritis and asthma. However, their expressions in inflammatory bowel disease (IBD) patients have not been yet explored. Our aim was to evaluate serum and inflamed mucosal levels in IBD patients. In 20 ulcerative colitis (UC) patients, 7 Crohn's disease (CD) patients, and 15 healthy subjects, cytokine levels in serum were determined using ELISA and mucosal expression studies were performed by immunohistochemistry, quantitative real-time PCR, and Western blot. The results showed that serums IL-35 and IL-37 levels were significantly decreased in UC and CD patients compared with healthy subjects. The cytokines levels correlated inversely with UC activity. IL-35 was expressed in infiltrating immune cells while IL-37 in intestinal epithelial cells as well as inflammatory cells. IBD patients had significantly higher Ebi3, p35 (two subunits of IL-35), and IL-37b gene expressions; IL-35 and IL-37 protein expressions were higher in IBD patients compared with controls. The study showed that serums IL-35 and IL-37 might be potentially novel biomarkers for IBD. Intestinal IL-35 and IL-37 proteins are upregulated, suggesting that regulating the expression of the two cytokines may provide a new possible target for the treatment of IBD.

Plasma IL-17, IL-35, interferon-γ, SOCS3 and TGF-β levels in pregnant women with preeclampsia, and their relation with severity of disease

Abstract Objective: To research the hypothesis of preeclampsia (PE) is associated with increased systemic inflammatory responses of Th1-type as well as decreased Th2-type responses; we evaluated the maternal plasma levels of IFN-gamma, TNF-alpha, TGF-beta, IL-4, IL-6, IL-10, IL-17, IL-35 and SOCS3 in preeclamptic and healthy pregnants.

METHODS

This study was conducted with 40 preeclamptic (study group) and 40 normotensive pregnant (control) women in third trimester when they were admitted to the labor and delivery unit. The extracted maternal plasma samples were assayed by an enzyme-linked immunosorbent assay. Statistical analysis was performed by SPSS 16.0 version.

RESULTS

While IFN-gamma and TGF-beta levels of preeclamptic women were significantly higher (p < 0.01), IL-35 and IL-17 levels of preeclamptic women were significantly lower (p < 0.01) than those of controls. The ratios of IFN-gamma/IL-10, IFN-gamma/IL-6, IFN-gamma/IL-4 were significantly high and ratio of IL-35/IL-17 was significantly low in the PE group compared to those in the control group. Maternal plasma SOCS3 levels showed negative correlation with blood pressure and proteinuria severity, but none of the cytokines showed influence on blood pressure and proteinuria after adjusting for maternal and gestational age.

CONCLUSIONS

Increased IFN-gamma/TGF-beta production and reduced IL-35/IL-17/SOCS3 production in preeclamptic women may lead to less cytokine inhibitory activity in PE, which may account for the increased proteinuria and blood pressure in PE.

Circulating IL-35 in pancreatic ductal adenocarcinoma patients

IL-35 is a novel inhibitory cytokine that is mainly produced by regulatory T-cells (Tregs) and is required for Treg-mediated immunosuppression. However, the plasma levels of IL-35 in patients with pancreatic ductal adenocarcinoma (PDAC) have never been investigated. In this study, we found that plasma IL-35 levels more significantly increased in PDAC patients than in normal controls (134.53 ± 92.45 pg/mL vs. 14.26 ± 6.56 pg/mL). IL-35 mRNA levels were positively correlated with plasma IL-35 levels (EBI3, R = 0.925, p<0.01; p35, R = 0.916, p<0.01). Furthermore, IL-35 expression levels were associated with lymph node metastasis (p = 0.001) and late tumor stage (p = 0.002). For the resected patients, high IL-35 expression levels were associated with large tumor size (p<0.01), higher TNM classification T staging (p<0.05), and late tumor stage (p<0.05). In conclusion, circulating IL-35 in PDAC patients significantly increased, suggesting that regulating the expression of IL-35 may provide a new possible target for the treatment of PDAC patients, especially for the resectable ones.