Th17/Treg imbalance and increased interleukin-21 are associated with liver injury in patients with chronic severe hepatitis B

AhR may be involved in Th17 cell differentiation in chronic hepatitis B

Th17 cells which are crucial for host immunity have been demonstrated to increase HBV infection. However, the mechanism of the Th17 cell increase is unknown. Hence, the mechanism of Th17 cell enhancement is important to provide a theoretical foundation for chronic hepatitis B immunotherapy. This study included 15 instances in the healthy control (HC) and 15 cohorts in the chronic hepatitis B (CHB). Their CD4+ T cells were isolated from their peripheral blood and then subjected to RNA transcriptome sequencing. Then, to identify target genes linked to Th17-cell differentiation, DEGs associated with CHB were convergent with the Th17-cell-associated genes from the KEGG database. Hub genes of DEG and target genes linked to Th17 cells were analysed for correlation. The AhR-related genes were located using the GeneMANIA database. To analyse the function of the genes, GO and KEGG pathways were employed. Protein-protein interaction network analysis employed the Metascape, STRING and Cytoscape databases. Finally, Western blotting and RT-qPCR were used to validate AhR. A total of 348 differential genes were identified in CHB patients. CytoHubba was used for screening five hub genes associated with CHB: CXCL10, RACGAP1, TPX2, FN1 and GZMA. This study aimed to determine the mechanism of elevated Th17 cells in CHB. As a result, further investigation using the convergence of DGEs and Th17 cell-related genes identified three target genes: AhR, HLA-DQA1 and HLA-DQB1, all of which were elevated in CHB. The three genes were primarily involved in immune response-related processes, according to the GO enrichment analysis. Correlation analysis of CXCL10, RACGAP1, TPX2, FN1 and GZMA genes with AhR, HLA-DQA1 and HLA-DQB1 revealed that AhR was positively associated with CXCL10 and GZMA genes, which best respond to the severity of CHB disease. Combined with the role of AhR in Th17 cell differentiation, the genes AhR was chosen for confirmation by RT-qPCR and WB in this study. The results showed that the CHB group had higher expression levels of AhR at both RT-qPCR and WB levels. Furthermore, this study's findings revealed that AhR may contribute to the development of CHB by affecting the differentiation of Th17 cells.

HMGB1/PTEN/PI3K axis participates in the peripheral immune cell differentiation in two representative TCM syndromes of chronic hepatitis B patients

Liver depression and spleen deficiency syndrome (LDSDS) and spleen-gastric damp-heat syndrome (SGDHS) are two major traditional Chinese medicine syndromes observed in chronic hepatitis B (CHB). Both syndromes exhibit significant differences in the pathogenesis and prognosis, and are closely related to the immune system. However, the underlying mechanisms are largely unknown. This study aimed to explore the immunoregulatory mechanisms of the two syndromes and promote the differentiation precision between the two syndromes. Thirty-six patients with CHB (18 LDSDS patients and 18 SGDHS patients) and 14 healthy controls were recruited into this study and blood was collected from all the subjects for testing. We studied the contents of T lymphocytes by flow cytometry and the expression levels of HMGB1/PTEN/PI3K axis proteins by enzyme-linked immunosorbent assay (Elisa). Protein-protein interaction (PPI) networks among HMGB1/PTEN/PI3K axis were constructed for functional enrichment. The correlations between T lymphocytes and proteins were analyzed by constructing multiple regression equations. The results revealed that the CD8+ T cells level in the two syndromes were lower than that in healthy controls, and the levels of Th17, Treg cells, and HMGB1, PI3K, PDK1, Akt were higher than those of the healthy controls (p < 0.05). Moreover, the levels of CD4+ T, Th17 cells, and HMGB1, PTEN, PI3K in LDSDS were higher than SGDHS (p < 0.05). PPI network indicated that HMGB1/PTEN/PI3K axis participated in T cell activation and liver pathology. Our results revealed that HMGB1/PTEN/PI3K axis may play an important role in regulating the formation of peripheral immune differences between the two syndromes. CD4+ T and Th17 are two representative immune cells that may serve as potential biological markers for LDSDS and SGDHS in CHB.

The Role of Interleukins in HBV Infection: A Narrative Review

Hepatitis B virus (HBV) infection is a worldwide medical issue with significant morbidity and mortality, as it is the main cause of chronic liver disease and hepatocellular carcinoma (HCC). Both innate and adaptive immune responses play a key role in HBV replication and suppression. Recently, the pathophysiological function of interleukins (IL) in the natural course of HBV has gained much attention as a result of the broad use of anti-interleukin agents for a variety of autoimmune diseases and the accompanying risk of HBV reactivation. We present a narrative review regarding the role of IL in HBV infection. Collectively, the pro-inflammatory ILs, namely IL-1, IL-5, IL-6, IL-12 and IL-21, seem to play a critical role in the suppression of HBV replication. In contrast, the anti-inflammatory cytokines IL-10, IL-23 and IL-35 probably act as HBV replication enhancers, while IL-17 has been correlated with HBV-related liver injury. Interestingly enough, IL-2, IL-4 and IL-12 have been tried as therapeutic options against HBV infection with contradictory results. Lastly, the role of IL-22 remains largely ill defined, although preliminary data suggest that it may play a significant role in HBV replication, proliferation and subsequent liver damage.

Interleukin-21 modulates balance between regulatory T cells and T-helper 17 cells in chronic hepatitis B virus infection

BACKGROUND

Chronic HBV infection is always accompanied by differences in the balance between regulatory T cells (Tregs) and T-helper 17 (Th17) cells in infection phases. IL-21 plays an important role in the progression of chronic HBV infection. Thus, the aim of our study was to investigate the role of the regulatory function of IL-21 in maintaining the balance between Tregs and Th17 cells in chronic HBV infection.

METHODS

Twenty-five chronic HBV-infected patients in the immune-tolerant (IT) phase and 23 chronic hepatitis B (CHB) patients were recruited in this study. Cytokines production was measured by ELISA. The mRNA expression levels were determined by qPCR. CD4+T cells were stimulated with or without IL-21. Tregs and Th17 cells were measured by flow cytometry. pSTAT3 and STAT3 expression was assessed by Western blotting.

RESULTS

The concentration of IL-21 in the serum of CHB were significantly higher than that in the serum from IT patients, and IL-21 and IL-21R levels in the PBMCs from CHB were higher than those from IT patients. IL-21 promoted Th17 cells differentiation and function but inhibited Treg cells differentiation and function by activating STAT3 signaling pathways, upregulating RORγt expression, downregulating Foxp3 expression, by increasing IL-17and IL-22 secretion, and decreasing TGF-β secretion in chronic HBV infection. The proportion of Tregs and TGF-β concentrations in CHB was significantly lower than that in IT patients. Furthermore, the percentage of Th17 cells and the IL-17 concentration in CHB was markedly higher than that in IT patients, causing a reduction in the Tregs/Th17 ratio in CHB patients.

CONCLUSIONS

Our results suggest that IL-21 may contribute to inflammation in chronic HBV infection by modulating the balance between Treg and Th17 cells.

Immune response and treatment targets of chronic hepatitis B virus infection: innate and adaptive immunity

Chronic hepatitis B virus (HBV) infection is a major global public health risk that threatens human life and health, although the number of vaccinated people has increased. The clinical outcome of HBV infection depends on the complex interplay between viral replication and the host immune response. Innate immunity plays an important role in the early stages of the disease but retains no long-term immune memory. However, HBV evades detection by the host innate immune system through stealth. Therefore, adaptive immunity involving T and B cells is crucial for controlling and clearing HBV infections that lead to liver inflammation and damage. The persistence of HBV leads to immune tolerance owing to immune cell dysfunction, T cell exhaustion, and an increase in suppressor cells and cytokines. Although significant progress has been made in HBV treatment in recent years, the balance between immune tolerance, immune activation, inflammation, and fibrosis in chronic hepatitis B remains unknown, making a functional cure difficult to achieve. Therefore, this review focuses on the important cells involved in the innate and adaptive immunity of chronic hepatitis B that target the host immune system and identifies treatment strategies.

Dysregulation of T Cell Differentiation and the IL17A(+)Foxp3(+)Treg Subset in Chronic Hepatitis B Patients with Hepatitis Flare

The regulatory T (Treg) and T helper 17 (Th17) cells modulate the immune response in chronic hepatitis B virus (HBV) infection by promoting immune tolerance and restricting liver damage or stimulating inflammatory response and rendering hepatocyte injury. These cells act through signaling transcription factors and secreting cytokines. We aimed to observe the percentages of Treg, Th17 cells, and their messenger RNA (mRNA) level of forkhead box protein 3 (Foxp3) and retinoid orphan receptor γt (RORγt) in the chronic hepatitis B (CHB)-infected group and CHB patients with hepatitis flare (HF). We recruited 103 participants, including 88 CHB-infected cases and 15 healthy controls (HCs) in Ho Chi Minh City. CHB cases were enrolled into two groups: HBeAg+ CHB infection (e+CHBI; n = 42) and HF (including 20 mild HF and 26 severe HF [sHF]). The Foxp3(+)Treg and Th17 cells were measured by flow cytometry. The mRNA levels of Foxp3 and RORγt were analyzed by real-time polymerase chain reaction. The percentages of Foxp3(+)Treg, of Th17, and the Foxp3(+)Treg/Th17 ratio were significantly higher in the sHF compared to the e+CHBI group. The sHF and e+CHBI groups had significantly higher mRNA levels of Foxp3 and RORγt compared to the HC group. Furthermore, a special subset, interleukin 17A(+)Foxp3(+)Treg cells, were observed with a significantly higher percentage in the sHF compared to the e+CHBI group. This finding revealed the contributions of this new subset on the severe flare cases. Our results explained the diversity of T cells and their subsets in the immune response in CHB. This subset should be further investigated as a specific tool in HBV immune response.

Serum cytokine change profile associated with HBsAg loss during combination therapy with PEG-IFN-α in NAs-suppressed chronic hepatitis B patients

Objective

The aim of this study was to explore the profile of cytokine changes during the combination therapy with pegylated interferon alpha (PEG-IFN-α) and its relationship with HBsAg loss in nucleos(t)ide analogs (NAs)-suppressed chronic hepatitis B patients.

Methods

Seventy-six patients with chronic hepatitis B with HBsAg less than 1,500 IU/ml and HBV DNA negative after receiving ≥ 1-year NAs therapy were enrolled. Eighteen patients continued to take NAs monotherapy (the NAs group), and 58 patients received combination therapy with NAs and PEG-IFN-α (the Add-on group). The levels of IFNG, IL1B, IL1RN, IL2, IL4, IL6, IL10, IL12A, IL17A, CCL2, CCL3, CCL5, CXCL8, CXCL10, TNF, and CSF2 in peripheral blood during treatment were detected.

Results

At week 48, 0.00% (0/18) in the NAs group and 25.86% (15/58) in the Add-on group achieved HBsAg loss. During 48 weeks of combined treatment, there was a transitory increase in the levels of ALT, IL1RN, IL2, and CCL2. Compared to the NAs group, CXCL8 and CXCL10 in the Add-on group remain higher after rising, yet CCL3 showed a continuously increasing trend. Mild and early increases in IL1B, CCL3, IL17A, IL2, IL4, IL6, and CXCL8 were associated with HBsAg loss or decrease >1 log, while sustained high levels of CCL5 and CXCL10 were associated with poor responses to Add-on therapy at week 48.

Conclusions

The serum cytokine change profile is closely related to the response to the combination therapy with PEG-IFN-α and NAs, and may help to reveal the mechanism of functional cure and discover new immunological predictors and new therapeutic targets.

Hepatitis B functional cure and immune response

Hepatitis B virus (HBV) is a hepatotropic virus, which damage to hepatocytes is not direct, but through the immune system. HBV specific CD4⁺ T cells can induce HBV specific B cells and CD8⁺ T cells. HBV specific B cells produce antibodies to control HBV infection, while HBV specific CD8⁺ T cells destroy infected hepatocytes. One of the reasons for the chronicity of HBV infection is that it cannot effectively activate adoptive immunity and the function of virus specific immune cells is exhausted. Among them, virus antigens (including HBV surface antigen, e antigen, core antigen, etc.) can inhibit the function of immune cells and induce immune tolerance. Long term nucleos(t)ide analogues (NAs) treatment and inactive HBsAg carriers with low HBsAg level may "wake up" immune cells with abnormal function due to the decrease of viral antigen level in blood and liver, and the specific immune function of HBV will recover to a certain extent, thus becoming the "dominant population" for functional cure. In turn, the functional cure will further promote the recovery of HBV specific immune function, which is also the theoretical basis for complete cure of hepatitis B. In the future, the complete cure of chronic HBV infection must be the combination of three drugs: inhibiting virus replication, reducing surface antigen levels and specific immune regulation, among which specific immunotherapy is indispensable. Here we review the relationship, mechanism and clinical significance between the cure of hepatitis B and immune system.

Cytokines and Chemokines in HBV Infection

Chronic hepatitis B virus (HBV) infection remains a leading cause of hepatic inflammation and damage. The pathogenesis of chronic hepatitis B (CHB) infection is predominantly mediated by persistent intrahepatic immunopathology. With the characterization of unique anatomical and immunological structure, the liver is also deemed an immunological organ, which gives rise to massive cytokines and chemokines under pathogenesis conditions, having significant implications for the progression of HBV infection. The intrahepatic innate immune system is responsible for the formidable source of cytokines and chemokines, with the latter also derived from hepatic parenchymal cells. In addition, systemic cytokines and chemokines are disturbed along with the disease course. Since HBV is a stealth virus, persistent exposure to HBV-related antigens confers to immune exhaustion, whereby regulatory cells are recruited by intrahepatic chemokines and cytokines, including interleukin-10 and transforming growth factor β, are involved in such series of causal events. Although the considerable value of two types of available approved treatment, interferons and nucleos(t)ide analogues, effectively suppress HBV replication, neither of them is sufficient for optimal restoration of the immunological attrition state to win the battle of the functional or virological cure of CHB infection. Notably, cytokines and chemokines play a crucial role in regulating the immune response. They exert effects by directly acting on HBV or indirectly manipulating target immune cells. As such, specific cytokines and chemokines, with a potential possibility to serve as novel immunological interventions, combined with those that target the virus itself, seem to be promising prospects in curative CHB infection. Here, we systematically review the recent literature that elucidates cytokine and chemokine-mediated pathogenesis and immune exhaustion of HBV infection and their dynamics triggered by current mainstream anti-HBV therapy. The predictive value of disease progression or control and the immunotherapies target of specific major cytokines and chemokines in CHB infection will also be delineated.

Treg/Th17 Cell Balance in Patients with Hepatitis B Virus-Related Acute-on-Chronic Liver Failure at Different Disease Stages

Background

T-helper 17 (Th17) and CD4⁺CD25⁺ T-regulatory (Treg) cells play important roles in the pathogenesis of hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF). This study is aimed at investigating shifts in Treg/Th17 balance in the peripheral blood of HBV-ACLF patients at different disease stages.

Methods

Sixty HBV-ACLF patients, admitted to the First Hospital of Hunan University of Chinese Medicine, China, including early-stage (n = 20), middle-stage (n = 20), and late-stage patients (n = 20), were enrolled in the study. In addition, 20 patients with chronic hepatitis B and 20 healthy volunteers were also included in the study as controls. Flow cytometry, cytometric bead array, and quantitative real-time PCR protocols were used to evaluate the expression of Treg and Th17 cells as well as of related cytokines.

Results

The levels of Th17 cells and their effectors interleukin- (IL-) 17A, IL-23, and tumor necrosis factor-α increased with disease progression. Similarly, Treg cells and their effector cytokines transforming growth factor-β and IL-10 also increased. Although Treg and Th17 levels were positively correlated, the latter were always at higher numbers. Noteworthy, the Treg/Th17 ratio gradually decreased and was negatively correlated with ACLF severity. FoxP3 levels in the peripheral blood gradually decreased with ACLF progression, whereas ROR-γt gradually increased. Serum c-reactive protein, procalcitonin, and lipopolysaccharide were also upregulated with disease progression and positively correlated with Th17 abundance. Further, Th17, IL-17A, and IL-23 were independent risk factors for ACLF. A prognostic model for HBV-ACLF was established, with a correct prediction rate of 90.00% (54/60).

Conclusion

Treg/Th17 imbalance occurs throughout the pathogenic course of HBV-ACLF, with an imbalance shift toward Th17. Hence, the Th17-mediated inflammatory response drives HBV-ACLF-associated inflammation and supports the pathological mechanisms of liver failure.

Up-regulated DNA-binding inhibitor Id3 promotes differentiation of regulatory T cell to influence antiviral immunity in chronic hepatitis B virus infection

AIM

Elevated Treg is relevant to persistent HBV infection, and the regulatory mechanism of Treg levels remains unclear. E proteins are important transcriptional regulators and could be antagonized by inhibitors of DNA-binding (Id) 1-4. We aim to clarify the role of Ids during HBV infection.

MAIN METHODS

Changes of Ids and their relationship with Treg were investigated in both HBV transfection model and hepatitis B patients. Significance of Ids was studied by in vitro Treg differentiation induction with Id inhibited or over-expressed. The role of inflammatory cytokines for Id was studied by co-culture. RNA-Seq was conducted to explore the differentially expressed genes in Id-overexpressed CD4 T cells upon Treg differentiation induction conditions.

KEY FINDINGS

Id-overexpressed mice attenuated virus clearance in HBV transfection model. In the HBV transfection mouse model, Tregs were up-regulated, with Id3 increased in Treg as well. Clinically, circulating Tregs in chronic hepatitis B (CHB) patients were elevated, and elevated Id3 transcriptional levels were positively correlated with Tregs. IL-1β could up-regulate Id3 in Treg cells induced in vitro. RNA-Seq revealed that increased Id could cause a series of signaling pathway changes during Treg differentiation.

SIGNIFICANCE

Id3 is elevated during HBV infection to ease Treg differentiation, and the antiviral immunity is influenced that make the infection to develop into chronic state.

CD4+ T Cells in Chronic Hepatitis B and T Cell-Directed Immunotherapy

The impaired T cell responses observed in chronic hepatitis B (HBV) patients are considered to contribute to the chronicity of the infection. Research on this impairment has been focused on CD8⁺ T cells because of their cytotoxic effector function; however, CD4⁺ T cells are crucial in the proper development of these long-lasting effector CD8⁺ T cells. In this review, we summarize what is known about CD4⁺ T cells in chronic HBV infection and discuss the importance and opportunities of including CD4⁺ T cells in T cell-directed immunotherapeutic strategies to cure chronic HBV.

IL-35: A Novel Immunomodulator in Hepatitis B Virus-Related Liver Diseases

Chronic hepatitis B virus (HBV) infection is a risk factor for liver cirrhosis (LC) and hepatocellular carcinoma (HCC), however, little is known about the mechanisms involved in the progression of HBV-related diseases. It has been well acknowledged that host immune response was closely related to the clinical outcomes of patients with HBV infection. As the factors closely related to the immunomodulatory process, cytokines are crucial in the cell-cell communication and the host responses to HBV infection. Recently, a newly discovered cytokine, designated as interleukin-35 (IL-35), has been proved to be essential for the progression of chronic HBV infection, the development of cirrhosis, the transformation of cirrhosis to HCC, and the metastasis of HCC. Specifically, it showed various biological activities such as inhibiting the HBV-specific cytotoxic T lymphocyte (CTL) proliferation and cytotoxicity, deactivating the immature effector T-cells (Teffs), as well as delaying the proliferation of dendritic cells. It regulated the immune responses by acting as a “brake” on the activation of Teffs, which subsequently played important roles in the pathogenesis of various inflammatory diseases and malignancies. In this review, we focused on the most recent data on the relationship between IL-35 and chronic HBV infection, LC and HCC.

Increased proportion of functional subpopulations in circulating regulatory T cells in patients with chronic hepatitis B

AIM

This study was designed to investigate the levels of circulating regulatory T cells (Tregs), and their functional subpopulations and related cytokines in chronic hepatitis B patients (CHB) and inactive hepatitis B surface antigen carriers.

METHODS

The peripheral blood of 24 hepatitis B virus inactive carriers, 26 CHB patients, and 34 healthy controls was collected and analyzed by flow cytometry for Tregs and CD4⁺ CXCR5⁺ FoxP3⁺ follicular regulatory T cells. Interleukin (IL)-10, transforming growth factor-β, and IL-21 levels in plasma were determined by enzyme-linked immunosorbent assay. Proportions of functional Treg subpopulations were analyzed by staining of Helios, CD45RA and FoxP3, TIGIT, and CD226, and the correlations between Treg subsets and clinical indicators were explored.

RESULTS

CD4⁺ FoxP3⁺ levels in the peripheral blood of CHB patients were significantly increased, and the inhibitory ability of Tregs in CHB patients for cytokine secretion was stronger, and CD4⁺ CXCR5⁺ FoxP3⁺ follicular Tregs were also significantly higher than inactive carriers and healthy controls. Transforming growth factor-β and IL-10 in the plasma of CHB patients were significantly higher than those of healthy controls, with IL-21 levels not significantly changed. Circulating CD4⁺ CXCR5-FoxP3⁺ Treg cells in CHB patients were positively correlated with hepatitis B surface antigen, hepatitis B e antigen, and hepatitis B virus DNA. The proportions of Helios⁺ FoxP3⁺ , CD45RA^- FoxP3^hi , and CD226^- TIGIT⁺ functional subpopulations in CD4⁺ CXCR5^- FoxP3⁺ Tregs in CHB patients were significantly increased, and they were significantly correlated with clinical indicators.

CONCLUSIONS

Circulating Tregs in CHB patients not only have elevated levels, but their follicular Treg subpopulations are also increased, and Tregs tend to have stronger immunosuppressive functions.

Molecular immune mechanisms of HPV-infected HaCaT cells in vitro based on toll-like receptors signaling pathway

OBJECTIVE

To explore the molecular immune mechanism of HPV-infected HaCaT cells in vitro based on TLRs signaling pathway by analyzing the effects of interfering TLRs on inflammatory and immune factors in the signaling pathway.

METHODS

FCM was used to analyze the proportion of Th1, Th2, Th17, and Treg cells in blood samples. HPV-infected HaCaT cells were divided into five groups: A, B, C, D, and E. Group A added TLR3 antagonist, group B added TLR9 antagonist, group C added equivalent saline, group D added IRF3 agonist, and group E added IRF3 inhibitor. Immunohistochemistry was used to analyze the expression of TLR3 and TLR9 in HaCaT cell model; ELISA was used to analyze the expression of inflammatory factors IL-2, TNF-a, and IFN-beta; WB was used to analyze the expression of TRAF3, IKK epsilon, and TBK1; RT-PCR was used to analyze the expression of IRF3 and IRF7 in each cell model.

RESULTS

The proportion of blood immune cells in patients with HPV infection was Th1, Th17, Th2, and Treg, with statistical significance (P < .05); the expression of TLR3 and TLR9 in HPV-infected cells was higher than that in negative control group, with statistical significance (P < .05); TLR3 was higher than TLR9, with no significant difference (P > .05); the expression of IL-2, TNF-alpha, IFN-beta in each group, TLR3, and TLR9 was higher than that in negative control group (P < .05). The expression of TRAF3, IKK epsilon, and TBK1 in the control group was higher than that in the TLR3 and TLR9 inhibitor groups, and the expression of IRF3 and IRF7 in the TLR9 inhibitor group was higher than that in the TLR3 inhibitor group (P < .05); the expression of IRF3 and IRF7 in the TLR3i and TLR9i inhibitor groups was lower than that in the TLR3 inhibitor group (P < .05). Compared with the control group, IRF3a group was higher than the control group, IRF3i group was lower than the control group, the difference was statistically significant (P < .05).

CONCLUSION

TLR3 and TLR9, the key factors of TLRs, are highly expressed in HaCaT cells infected with HPV. Through TLRs-IKK-e-IRFs-IFN signaling pathway, they can induce high expression of inflammatory factors, IKK-e, IRFs, and IFN, and improve immunity.

The protective and pathogenic roles of IL-17 in viral infections: friend or foe?

Viral infections cause substantial human morbidity and mortality, and are a significant health burden worldwide. Following a viral infection, the host may initiate complex antiviral immune responses to antagonize viral invasion and replication. However, proinflammatory antiviral immune responses pose a great threat to the host if not properly held in check. Interleukin (IL)-17 is a pleiotropic cytokine participating in a variety of physiological and pathophysiological conditions, including tissue integrity maintenance, cancer progression, autoimmune disease development and, more intriguingly, infectious diseases. Abundant evidence suggests that while IL-17 plays a crucial role in enhancing effective antiviral immune responses, it may also promote and exacerbate virus-induced illnesses. Accumulated experimental and clinical evidence has broadened our understanding of the seemingly paradoxical role of IL-17 in viral infections and suggests that IL-17-targeted immunotherapy may be a promising therapeutic option. Herein, we summarize current knowledge regarding the protective and pathogenic roles of IL-17 in viral infections, with emphasis on underlying mechanisms. The various and critical roles of IL-17 in viral infections necessitate the development of therapeutic strategies that are uniquely tailored to both the infectious agent and the infection environment.

miR-146a-5p enhances hepatitis B virus replication through autophagy to promote aggravation of chronic hepatitis B

The objective of this study was to investigate the mechanism by which miR-146a-5p mediated autophagy and hepatitis B virus (HBV) replication. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the mRNA expression levels of miR-146a-5p and X-linked inhibitor of apoptosis (XIAP) and HBV DNA and RNA. The protein expression levels of XIAP, IκB-α, murine double minute 2 oncoprotein (MDM2) and p53, the phosphorylation of p65, and the conversion of light chain 3 (LC3)-I to LC3-II were detected by Western blotting. The expression levels of XIAP, HBV-related pro-inflammatory cytokines, and serum markers were detected by enzyme-linked immunosorbent assay (ELISA). miR-146a-5p was highly expressed in patients with chronic hepatitis B (CHB) and HBV-expressing hepatocytes. HBV core protein (HBc) and HBV X protein (HBx) were responsible for its effects on miR-146a-5p expression through the nuclear factor-κB pathway. Furthermore, the miR-146a-5p inhibitor suppressed autophagic response and HBV replication as well as MDM2/p53 expression. Luciferase reporter assay confirmed that XIAP was a direct target of miR-146a-5p. We therefore demonstrated that miR-146a-5p mediated positive feedback loop by regulating autophagy-induced HBV replication via targeting the XIAP-mediated MDM2/p53 axis. © 2019 IUBMB Life, 71(9):1336-1346, 2019.

Interleukin-35 modulates the balance between viral specific CD4+CD25+CD127dim/- regulatory T cells and T helper 17 cells in chronic hepatitis B virus infection

Background

Interleukin (IL)-35 regulates imbalance between regulatory T cells (Tregs) and T helper (Th) 17 cells, leading to an important modulator in autoimmune disorder, cancer, and infectious diseases. Our previous study revealed an immunosuppressive activity of IL-35 in chronic hepatitis B virus (HBV) infection. Thus, the aim of the current study was to investigate the role of regulatory function of IL-35 to viral specific Tregs/Th17 cells balance in chronic HBV infection.

Methods

A total of 44 HLA-A2 restricted chronic HBV infected patients, including 21 of chronic hepatitis B (CHB) and 23 of asymptomatic HBV carriers (ASC) were enrolled. Purified CD4⁺ T cells or CD4⁺CD25⁺CD127^dim/− Tregs were stimulated with recombinant IL-35. HBV core antigen specific Tregs and Th17 cells were determined by flow cytometry. FoxP3 and RORγt mRNA was measured by real-time PCR. Cytokines production (IL-10 and IL-17) was investigated by ELISA.

Results

Peripheral viral specific Tregs was comparable between CHB and ASC. However, increased percentage of viral specific Th17 cells was found in CHB, leading to the reduction of Tregs/Th17 ratio in CHB patients. IL-35 stimulation elevated viral specific Tregs, but not Th17 cells frequency, in both CHB and ASC, resulting in the elevation of Tregs/Th17 ratio in both groups. This process was accompanied by increased expression of FoxP3 mRNA and IL-10 production, and decreased IL-17 secretion and STAT3 phosphorylation in purified CD4⁺ T cells. Moreover, IL-35 stimulation inhibited viral specific Th17-like phenotype differentiation from Tregs in CHB patients. Effective anti-HBV therapy did not affect viral specific Tregs/Th17 cells frequency or IL-35 expression in CHB patients, however, reduced responsiveness of CD4⁺ T cells or Tregs to IL-35 stimulation in vitro.

Conclusion

Our findings indicated that IL-35 regulation to viral specific Tregs/Th17 balance may contribute to viral persistence in chronic HBV infection.

Interleukin-21 receptor gene polymorphism is associated with hepatitis B virus-related hepatocellular carcinoma in Chinese patients

Background

We investigated the relationship between hepatitis B virus (HBV)‐related pathogenesis and single nucleotide polymorphisms (SNPs) in interleukin‐21 (IL‐21)‐JAK‐STAT signaling pathway genes.

Methods

We used the high‐resolution melting (HRM) method to genotype five SNPs (IL‐21 rs2221903, IL‐21 rs4833837, IL‐21 receptor (IL‐21R) rs2285452, JAK3 rs3008, and STAT3 rs1053023) in 546 HBV‐infected patients and 353 healthy Chinese subjects. The HBV‐infected patients were further divided into subgroups based on the HBV‐related pathologies: chronic hepatitis B (CHB), HBV‐related liver cirrhosis (LC), and HBV‐related hepatocellular carcinoma (HCC).

Results

There were no significant differences in the genotype and allele distributions of the five SNPs between the HBV‐infected patients and healthy subjects. The genotype and allele frequencies were similar in the two groups for IL‐21 rs2221903 (A>G, P = 0.83 and 0.67), rs4833837 (A>G, P = 0.80 and 0.49), IL‐21R rs2285452 (G>A, P = 0.25 and 0.68), STAT3 rs1053023 (A>G, P = 1.00 and 0.96), and JAK3 rs3008 (C>T, P = 0.32 and 0.54). However, patients with the IL‐21R rs2285452 AA genotype were more susceptible to HBV‐related HCC than those with the IL‐21R rs2285452 GA/GG genotype (P = 0.03, OR = 3.27, 95% CI = 1.16‐9.20). The serological marker model of “HBsAg+, HBeAg+, HBcAb+” was predominant among patients with HBV infection. However, there was no association between the genotype's distribution of the five SNPs and the serological marker models (P > 0.05).

Conclusions

These findings demonstrate that the IL‐21R rs2285452 AA genotype increases the risk of HBV‐related HCC in Chinese patients.

Dual effect of T helper cell 17 (Th17) and regulatory T cell (Treg) in liver pathological process: From occurrence to end stage of disease

Liver disease is a complicated pathological status with acute or chronic progressions, causing a series of damages to liver and massive burden to public health and society. Th17 and Treg, two subsets of CD4⁺ T helper cells, seem to keep a subtle balance in the maintenance of organic immune homeostasis including liver. The dysfunction of Th17/Treg balance in liver has been proved associated with hepatic injury and disease. Herein, we summarized the research advance of Th17 and Treg cells in different phenotypes of liver diseases in the past decade. It is known to all that hepatic diseases start from stimulations or infections like virus, autoimmune, alcohol and so on in the early stage, which would cause inflammation. With the disease consistently existed, severe outcomes like cirrhosis and hepatocellular carcinoma appear finally. In conclusion, it is found that Th17 and Treg cells serve as an important role in the immune response imbalance of liver diseases from the beginning to the end stage. However, the effect of these two subsets of CD4⁺ T helper cells is not a stereotype. Pathological role which exacerbates the disease and protective character which inhibits damage to liver are co-existed in the effect of Th17 and Treg cells. Still, more studies should be carried out to enrich the understandings of liver disease and Th17/Treg immune balance in the future.

IL-17 and IL-17-producing cells and liver diseases, with focus on autoimmune liver diseases

The pro-inflammatory cytokine interleukin(IL)-17 and IL-17-producing cells are important players in the pathogenesis of many autoimmune / inflammatory diseases. More recently, they have been associated with liver diseases. This review first describes the general knowledge on IL-17 and IL-17 producing cells. The second part describes the in vitro and in vivo effects of IL-17 on liver cells and the contribution of IL-17 producing cells to liver diseases. IL-17 induces immune cell infiltration and liver damage driving to hepatic inflammation and fibrosis and contributes to autoimmune liver diseases. The circulating levels of IL-17 and the frequency of IL-17-producing cells are elevated in a variety of acute and chronic liver diseases. The last part focuses on the effects of IL-17 deletion or neutralization in various murine models. Some of these observed beneficial effects suggest that targeting the IL-17 axis could be a new therapeutic strategy to prevent chronicity and progression of various liver diseases.

Expression and significance of peripheral myeloid-derived suppressor cells in chronic hepatitis B patients

BACKGROUND

Myeloid-derived suppressor cells (MDSCs) exert their suppressive effects on multiple immune response and contribute to the development of many diseases. However, limited data is available on the involvement of MDSCs in human chronic HBV infection.

OBJECTIVE

To investigate whether the progression of chronic HBV infection was associated with imbalance of MDSCs.

METHODS

The percentages of MDSCs, regulatory T (Treg), Th1 and Tc1 cells in the peripheral blood from chronic hepatitis B (CHB) patients and healthy controls (HC) were determined by flow cytometry. Plasma levels of IL-10, TGF-β and IFN-γ were measured using enzyme-linked immunosorbent assay. The potential association of the frequencies of MDSCs with clinical parameters was assessed.

RESULTS

The percentages of MDSCs and Treg cells were significantly higher in CHB patients than those in HC. The percentages of MDSCs were negatively correlated with Th1 cells. Increased plasma IL-10 level and decreased IFN-γ level were found in CHB patients compared with HC. Moreover, the frequencies of MDSCs and plasma IL-10 levels were positively correlated with serum HBV DNA loads, as well as liver function impairment.

CONCLUSION

The expanded peripheral MDSCs may contribute to poor viral clearance and disease progression during chronic HBV infection.

Detection of Treg/Th17 cells and related cytokines in peripheral blood of chronic hepatitis B patients combined with thrombocytopenia and the clinical significance

Changes of regulatory T (Treg) cells and Th17 cells, and related cytokines in peripheral blood of patients with chronic hepatitis B combined with thrombocytopenia were investigated to explore the relationship with treatment outcomes. A total of 45 chronic hepatitis B patients combined with thrombocytopenia were selected in Heilongjiang Provincial Hospital from June 2015 to December 2016. All patients were treated with prednisolone acetate + γ globulins for 60 days. Treg cells and Th17 cells in peripheral blood were detected by flow cytometry, and IL-10, TGF-β, IL-17, IL-21 and IL-22 in peripheral blood were detected by ELISA before and after treatment. No significant differences in the percentages of Treg and Th17, and levels of IL-10, TGF-β, IL-17, IL-21 and IL-22 were found in non-responders (n=17, platelets <100×10⁹/l) before and after treatment (P>0.05). After treatment, percentage of Treg was significantly increased (higher than that of non-responders) and percentage of Th17 was significantly decreased (lower than that of non-responders) in responders (P<0.05). In addition, serum levels of IL-10 and TGF-β were significantly increased (higher than that of non-responders) and serum levels of IL-17, IL-21 and IL-22 were significantly decreased (lower than that of non-responders) in responders (P<0.05). The results showed that after treatment, the number of Treg cells was increased, the number of Th17 cells was decreased, the levels of anti-inflammatory factors IL-10 and TGF-β were increased, and levels of pro-inflammatory factors IL-17, IL-21 and IL-22 were decreased in chronic hepatitis B patients combined with thrombocytopenia, indicating the decreased autoimmune response and improved thrombocytopenia. The changes were closely related to the complete response.

Chronic hepatitis C liver microenvironment: role of the Th17/Treg interplay related to fibrogenesis

The role of the different lymphocyte populations in liver microenvironment of chronic hepatitis C (CHC) patients is still matter of debate. Since Th17 and Treg have opposite functions, their balance could affect disease progression. The aim was to explore liver microenvironment and its peripheral blood counterpart in adult CHC patients. CD4⁺ lymphocytes were predominant in the liver, with high Foxp3⁺ but low IL-17A⁺ frequency. IL-17A⁺ lymphocytes and IL-17A⁺/Foxp3⁺ ratio displayed association with advanced fibrosis (p = 0.0130; p = 0.0236, respectively), while Foxp3⁺ lymphocytes and IL-10 expression level inversely correlated with fibrosis severity (p = 0.0381, p = 0.0398, respectively). TGF-β/IL-6 ratio correlated with IL-17A⁺/Foxp3⁺ ratio (p = 0.0036, r = 0.5944) and with IL-17A⁺ lymphocytes (p = 0.0093; r = 0.5203). TNF-α and TGF-β were associated with hepatitis severity (p = 0.0409, p = 0.0321). Peripheral blood lymphocyte frequency was not associated with liver damage. There are functionally different immune cell populations actively involved in liver damage, but the liver cytokine milieu actually drives the pathogenesis. The intrahepatic Foxp3⁺ lymphocytes predominance beside the low IL-17A⁺ lymphocytes frequency, delineate a skewed IL-17A⁺/Foxp3⁺ balance towards Foxp3⁺ lymphocytes. However, the IL-17A⁺ lymphocytes association with advanced fibrosis denotes their role in the pathogenesis. Therefore, the interplay between Th17 and Treg conditions liver fibrogenesis.