Kinetics of Th17 cytokines during telbivudine therapy in patients with chronic hepatitis B

Role of the type 3 cytokines IL-17 and IL-22 in modulating metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) comprises a spectrum of liver diseases that span simple steatosis, metabolic dysfunction-associated steatohepatitis (MASH) and fibrosis and may progress to cirrhosis and cancer. The pathogenesis of MASLD is multifactorial and is driven by environmental, genetic, metabolic and immune factors. This review will focus on the role of the type 3 cytokines IL-17 and IL-22 in MASLD pathogenesis and progression. IL-17 and IL-22 are produced by similar adaptive and innate immune cells such as Th17 and innate lymphoid cells, respectively. IL-17-related signaling is upregulated during MASLD resulting in increased chemokines and proinflammatory cytokines in the liver microenvironment, enhanced recruitment of myeloid cells and T cells leading to exacerbation of inflammation and liver disease progression. IL-17 may also act directly by activating hepatic stellate cells resulting in increased fibrosis. In contrast, IL-22 is a pleiotropic cytokine with a dominantly protective signature in MASLD and is currently being tested as a therapeutic strategy. IL-22 also exhibits beneficial metabolic effects and abrogates MASH-related inflammation and fibrosis development via inducing the production of anti-oxidants and anti-apoptotic factors. A sex-dependent effect has been attributed to both cytokines, most importantly to IL-22 in MASLD or related conditions. Altogether, IL-17 and IL-22 are key effectors in MASLD pathogenesis and progression. We will review the role of these two cytokines and cells that produce them in the development of MASLD, their interaction with host factors driving MASLD including sexual dimorphism, and their potential therapeutic benefits.

Unraveling IL-17 and IL-22 role in occult hepatitis C versus chronic hepatitis C virus infection

BACKGROUND

Cytokines play a crucial role in regulating the function of the immune system by controlling the production, differentiation, and activity of immune cells. Occult hepatitis C virus (OHCV) infection can lead to liver damage, including cirrhosis and hepatocellular carcinoma. This study investigates the immunopathogenic impact of the cytokines IL-17 and IL-22 in OHCV infection compared to chronic hepatitis C (CHC) infection.

METHODS

We studied three groups of patients: 35 with OHCV, 100 untreated patients with CHC, and 30 healthy control subjects. All subjects underwent physical examination and biochemical testing. We used the sandwich enzyme-linked immunosorbent assay method to measure serum IL-17 and IL-22 levels in all groups.

RESULTS

Compared to the occult and control groups, the CHC group had significantly higher serum IL-17 levels (p < 0.001). The occult group also had higher serum IL-17 levels compared to the control group (p < 0.0001). There were no significant differences in IL-22 levels across the research groups. In the OHCV group, individuals with moderate inflammation (A2-A3) had significantly higher serum IL-17 levels than those with minimal inflammation (A0-A1), while in the CHC group, this difference was not statistically significant (p = 0.601). Neither the occult nor the CHC groups showed a correlation between serum IL-22 and inflammatory activity. There was no significant correlation between the levels of IL-17 or IL-22 and the stage of fibrosis/cirrhosis in either group. ROC curves were calculated for serum IL-17 and IL-22 levels and occult HCV infection, with cut-off values set at ≤ 32.1 pg/ml and < 14.3 pg/ml for IL-17 and IL-22, respectively. The AUROC (95%CI) was significantly higher for IL-17 than IL-22 (0.829 (0.732-0.902) vs. 0.504 (0.393-0.614), p < 0.001), suggesting that IL-17 has a stronger correlation with infection risk than IL-22.

CONCLUSION

This study suggests that IL-17 may be involved in the immunopathogenesis of OHCV infection, especially in patients with moderate inflammation.

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.

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.

HBV promotes the recruitment of IL-17 secreting T cells via chemokines CCL22 and CCL17

BACKGROUND AND AIMS

Little is known about the mechanisms of IL-17 secreting T cells accumulation in HBV-transfected livers. Here, we investigated the role of the chemokines CCL17, CCL20 and CCL22 in this process.

METHODS

Peripheral blood and liver tissues were obtained from 30 chronic hepatitis B (CHB) patients and 15 healthy volunteers and were evaluated by flow cytometric analysis and immunohistochemistry. Chemokine production by monocyte-derived dendritic cells (MoDCs) cocultured with HBV-transfected or untransfected Huh7 cells was measured by quantitative real-time PCR and enzyme-linked immunosorbent assay. The chemotactic activity of the culture supernatants was also tested.

RESULTS

The proportions of IL-17 secreting CD4 (Th17) and CD8 (Tc17) T cells were both increased in liver and peripheral blood mononuclear cells of CHB patients compared to those in HVs. CHB patients showed higher intrahepatic levels of CCL17 mRNA, CCL22 mRNA, CCR6 mRNA and CCR4 mRNA than HVs. The expression of CCR6 and CCR4 on the surface of Th17 and Tc17 cells in CHB patients was also significantly higher than that in HVs. Significant correlations existed between the CCR4/CCR6 levels and both the alanine transaminase levels and HBV DNA loads. Contact between MoDCs and pBlue-HBV-transfected Huh7 cells induced the expression of CCL17 and CCL22 dependent on the dose of HBV DNA. However, CCL20 expression was lower in CHB patients than in HVs. Transwell experiments showed that upregulation of CCL17 and CCL22 enhanced the migration of IL-17 secreting T cells.

CONCLUSIONS

Contact of HBV-transfected cells with MoDCs induces CCL17 and CCL22 chemokine production, which may favour the recruitment of Th17 and Tc17 cells to liver tissue in CHB. Our results reveal the mechanism of IL-17 secreting T cells recruitment to liver tissue and thus provide new immunotherapy targets for CHB patients.

Recovery of circulating CD56dim NK cells and the balance of Th17/Treg after nucleoside analog therapy in patients with chronic hepatitis B and low levels of HBsAg

BACKGROUND AND AIMS

Much evidence indicates that the soluble antigens secreted by hepatitis B virus (HBV) inhibit the function of the immune system. The aim of this study is to investigate, after treatment with nucleoside (acid) analogs (NAs) and the inhibition of viral replication, whether the immune systems of patients with a peripheral blood HBV-DNA level <1000 IU/mL, hepatitis B e antigen (HBeAg) disappearance, and a decrease in hepatitis B surface antigen (HBsAg) levels could be reconstructed.

METHODS

The frequency and phenotype of circulating natural killer (NK) cells, dendritic cells (DCs), T-helper (Th) cells, regulatory T (Treg) cells, CD4⁺, CD8⁺ T cells, T follicular helper (Tfh) cells and B cells subtypes were tested by flow cytometry in chronic hepatitis B (CHB) patients and healthy controls (HCs). The levels of HBV-related serum HBsAg, HBeAg, HBV-DNA load, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined.

RESULTS

Regarding the innate immune system, an increased frequency of CD56^dim NK cells was found in the therapeutic response (TR) group compared with that in the immune-active phase (IA) group. Additionally, regarding the adaptive immune system, the Th17/CD4⁺CD25⁺CD127^dimTreg ratio was reduced in the TR group. Additionally, the frequency of CD40L⁺CXCR5⁺CD4⁺T cells and CD40⁺CD19⁺CD27⁺CD38⁺B cells was significantly higher than that of HCs, while that of PDL1⁺CD19⁺ B cells was lower. Furthermore, the frequencies of CTLA4⁺CD4⁺T cells and CTLA4⁺CD8⁺T cells in patients with CHB were significantly higher than those in HCs.

CONCLUSION

After NA treatment and the inhibition of viral replication, circulating CD56^dim NK cells and the balance of Th17/Treg can be recovered. Restoring circulating CD56^dim NK cells and the Th17/Treg balance may help reduce HBsAg levels in patients.

Immunity and Fibrogenesis: The Role of Th17/IL-17 Axis in HBV and HCV-induced Chronic Hepatitis and Progression to Cirrhosis

Cirrhosis is a common final pathway for most chronic liver diseases; representing an increasing burden worldwide and is associated with increased morbidity and mortality. Current evidence has shown that, after an initial injury, the immune response has a significant participation in the ongoing damage, and progression from chronic viral hepatitis (CVH) to cirrhosis, driving the activation and maintenance of main fibrogenic pathways. Among immune deregulations, those related to the subtype 17 of T helper lymphocytes (Th17)/interleukin-17 (IL-17) axis have been recognized as key immunopathological and prognostic elements in patients with CVH. The Th17/IL-17 axis has been found involved in several points of fibrogenesis chain from the activation of stellate cells, increased expression of profibrotic factors as TGF-β, promotion of the myofibroblastic or epithelial–mesenchymal transition, stimulation of the synthesis of collagen, and induction of imbalance between matrix metalloproteinases and tissue inhibitors of metalloproteinases (TIMPs). It also promotes the recruitment of inflammatory cells and increases the expression of proinflammatory cytokines such as IL-6 and IL-23. So, the Th17/IL-17 axis is simultaneously the fuel and the flame of a sustained proinflammatory and profibrotic environment. This work aims to present the immunopathologic and prognostic role of the Th17/IL-17 axis and related pathways in fibrogenesis and progression to cirrhosis in patients with liver disease due to hepatitis B virus (HBV) and hepatitis C virus (HCV).

Toward cure chronic hepatitis B infection and hepatocellular carcinoma prevention: Lessons learned from nucleos(t)ide analogues therapy

Nucleos(t)ide analogues (NAs) could successfully suppress hepatitis B virus (HBV) replication in patients with chronic hepatitis B (CHB). However, due to probable development of drug resistance or low/delayed response, these treatments may not be satisfactory. In addition to the HBV DNA polymerase inhibiting activity, these drugs could lead to changes in cytokines profiles. It is important to monitor these changes so that they could be used as target of treatment. Evaluating the previously reported immune responses due to NAs treatments, it was concluded that interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), interleukin-4 (IL-4), and IL-12 increase after the treatment. This will be followed by the improved capacity of immune cells for eliminating HBV. In contrast, regulatory responses including IL-10 and transforming growth factor-beta (TGF-β) significantly decreased as the result of NAs therapy. Unexpectedly, T helper (Th) 17-associated cytokines also decreased significantly. These results could be used to employ the new strategies to suppress viral replication, minimize HBV DNA levels, inducing hepatitis B e antigen (HBeAg) seroconversion or even hepatitis B surface antigen (HBsAg) seroclearance. In order to accomplish these goals, extended treatment with high dose of both IL-12 and IFN in combination with high barrier to resistance NA might significantly improve the HBsAg seroclearance rate. Considering the danger of emerging aberrant immune responses, determining the optimum dosage as well as close monitoring of patients during the treatment is strongly advised. In order to make HBV immunotherapy practical, further studies are needed to confirm these results.

Low Ratio of Treg to Th17 Cells After 36 Weeks of Telbivudine Therapy Predict HBeAg Seroconversion

Changes of Treg/Th17 cells ratio and their associated cytokines have some correlations with an immune modulatory effect of Telbivudine treatment. The aim of our study was to investigate the role of the dynamic ratio of Treg/Th17 cells in the mechanism of LdT therapy and their relationships with the clinical responses. We detected the frequency and cytokines production of Treg and Th17 cells in 28 hepatitis B envelope antigen (HBeAg)-positive CHB patients at 0, 12, 24, 36, 48, and 96 weeks after initial LdT therapy. LdT could upregulate the frequency of Th17 cells and Th17 cells associated cytokines, downregulated the frequency of Treg cells and level of TGF-β, which leads to the decrease of Treg/Th17 ratio in HBeAg-positive CHB patients. Treg/Th17 ratio at treatment week 36 could independently predict HBeAg seroconversion in the first 2 years of Telbivudine treatment. Telbivudine therapy can decrease Treg/Th17 ratio, which may predict HBeAg seroconversion during treatment.

Sustained Changes of Treg and Th17 Cells During Interferon-α Therapy in Patients with Chronic Hepatitis B

Chronic hepatitis B (CHB) is a worldwide infectious disease caused by hepatitis B virus (HBV). HBV mainly damages liver cells through immune response. The purpose of this study was to determine whether there were dynamic changes of Treg and Th17 cells and to judge the value of these indicators to antiviral treatment. Twenty-two CHB patients and selected 30 healthy adults were enrolled. Results showed that the expression of Treg (5.72±0.46 vs. 4.42±0.17, p=0.0019) and Th17 (3.94±0.64 vs. 2.66±3.12, p=0.0436) cells was significantly increased in CHB patients, as well as the level of interleukin-17 (IL-17) (16.88±5.37 vs. 8.59±3.31; p=0.004). Then, we monitored longitudinally the impact of the treatment with interferon-α and found that the suppression of viral replication induced by interferon-α resulted in a decrease in Treg, Th17 cells, and IL-17; we also found that the percentage of Treg and Th17 cells went up without clear evidence of clinical autoimmune disease at the end of treatment. Thus, Treg and Th17 cells might play an important role in interferon-α treatment to eliminate HBV. The level of changes may be served to determine the antiviral efficacy of interferon-α therapy.

Imbalance of regulatory T cells and T helper type 17 cells in patients with chronic hepatitis C

Pegylated interferon and ribavirin combination therapy is known to be effective in suppressing viral replication in 50-60% of hepatitis C virus (HCV)-infected patients. However, HCV-infected patients often exhibit varied responses to therapy. Therefore, the identification of immunological markers associated with the clinical outcomes of antiviral treatment is critical for improvement of therapeutic options. In this study, we aimed to investigate the ratio of CD4(+) CD25(+) FoxP3(+) regulatory T (Treg) cells to interleukin-17A (IL-17A) -producing T helper type 17 (Th17) cells, and its association with clinical outcomes in response to anti-HCV treatment. In all, 114 patients with HCV infection received pegylated interferon-α2a and ribavirin therapy for 48 weeks, and the frequency of Treg cells and Th17 cells as well as the levels of secreted cytokines were longitudinally analysed by flow cytometry and ELISA. Treg cell proportions and IL-10 production were significantly elevated in HCV-infected patients, especially for HCV genotype 1b. However, the frequency of Th17 cells as well as the secretion of IL-17, IL-22 and IL-23 did not reveal notable difference between HCV infections and healthy individuals. Inhibition of HCV replication was accompanied by a reduction in Treg cells, but little influence on Th17 cells, which led to a significant decrease in Treg : Th17 ratios. Skewed Treg : Th17 ratios existed in chronic hepatitis C. HCV RNA load is closely associated with Treg : Th17 ratios during pegylated interferon-α2a and ribavirin treatment in HCV-infected patients. The imbalance of Treg cells to Th17 cells might play an important role in persistent HCV infection.

The influences of antiviral therapy on T-cell function in adult patients with chronic hepatitis B

ABSTRACT 

T cells play an important role in the clearance of acute infection and control of hepatitis B virus (HBV) infection during the chronic phase. Chronic HBV is characterized by a weak and limited T-cell response. Several hypotheses, such as presence of Tregs or occurrence of T-cell exhaustion have been proposed to explain these observations. The two registered classes of anti-HBV drugs: pegylated-IFN-α (PEG-IFN-α) and nucleos(t)ide analogs (NUCs) have, next to their antiviral effect, also an immunomodulatory effect. Although NUCs have no direct immunomodulatory effects, they may indirectly positively affect the T-cell response through their viral suppressive action. In this review, effects of both PEG-IFN-α and NUC therapy will be discussed with regard to the cellular immune response against HBV.

A possible role for NKT-like cells in patients with chronic hepatitis B during telbivudine treatment

Natural killer T-like (NKT-like) cells are a source of different pro-inflammatory cytokines and therefore may be involved in inflammatory processes. However, little is known about NKT-like cells during antiviral therapy. In this study, we observed significantly higher numbers of CD3(+)CD56(+) cells in patients with chronic hepatitis B (CHB) than healthy controls. Importantly, CD3(+)CD56(+) NKT-like cells markedly decreased during telbivudine treatment in patients with CHB, and a positive correlation between NKT-like cell frequency and the serum HBV DNA level was observed during early antiviral therapy. Interestingly, NKT-like cell frequency significantly reduced in well-responders at week 12 of telbivudine therapy compared to baseline, but did not significantly change in non-responders after treatment. Previous studies have shown that interleukin (IL)-17 plays a role in the pathogenesis of CHB. Serum IL-17 levels reduced significantly during early antiviral therapy, however, interferon (IFN)-γ, IL-6 and tumor necrosis factor (TNF)-α levels did not change significantly. A positive correlation was observed between the NKT-like cell frequency and serum IL-17 level in CHB patients, and NKT-like cells isolated from patients with CHB secreted substantial amounts of IL-17 in vitro. These results suggest that the NKT-like cell frequency may be one of useful immunologic marker for evaluating the efficacy of anti-HBV therapy, and that NKT-like cells are also an important source of IL-17 (in addition to conventional T cells) in patients with CHB.