Host immunity influences disease progression and antiviral efficacy in humans infected with hepatitis B virus

JNK/c-Jun pathway activation is essential for HBx-induced IL-35 elevation to promote persistent HBV infection

BACKGROUND

Immunoregulation plays pivotal roles during chronic hepatitis B virus (HBV) infection. Studies have shown that Interleukin (IL)-35 is an important molecule associated with inadequate immune response against HBV. However, the mechanisms involved in the up-regulation of IL-35 expression during persistent HBV infection remain unknown.

METHODS

In this study, we constructed a plasmid expressing the HBV X protein (pCMV-HBx) to evaluate the relationship between HBx and IL-35. Activation of the JNK/c-Jun pathway was analyzed and chromatin immunoprecipitation followed by sequencing and luciferase reporter assays were performed to determine whether c-Jun could regulate IL-35 transcription.

RESULTS

HBx can significantly activate IL-35 promoter in both LO2 and HepG2 cells compared to the control plasmid (pCMV-Tag2) using the dual-luciferase assay. Whereas other viral proteins, such as S, preS1, the core protein, had no significant effect on IL-35 expression. Similarly, WB and qRT-PCR also showed that HBx can significantly promote IL-35 expression at protein and mRNA levels in the aforementioned cells. The relevant pathway mechanism showed that the expression of JNK and c-Jun genes was significantly higher in transfected cells carrying pCMV-HBx than in the pCMV-Tag2-transfected and -untransfected cells. WB analysis revealed that phosphorylated JNK and c-Jun were overexpressed after HBx action. Conversely, the addition of the JNK/c-Jun signaling pathway inhibitor could significantly suppress HBx-induced IL-35 expression in a dose-dependent manner.

CONCLUSIONS

A novel molecular mechanism of HBV-induced IL-35 expression was revealed, which involves JNK/c-Jun signaling in up-regulating IL-35 expression via HBx, resulting in transactivation of the IL-35 subunit EBI3 and p35 promoter.

Comparing the efficacy and safety of tenofovir and adefovir or combined drug treatment for the treatment of chronic hepatitis B infection: a systematic review and meta-analysis

BACKGROUND

Chronic hepatitis B (CHB) affects a vast population globally. A variety of drugs are available for the treatment of CHB, including tenofovir (TDF) and adefovir (ADV). However, the efficacy of monotherapy drug treatment is inconclusive, the safety and efficacy of TDF remain unclear, more data are needed to be included and combined drug treatment is considered to exhibit higher efficacy. To explore this issue, we performed a current literature review and meta-analysis to compare the efficacy and safety of ADV vs. TDF, TDF vs. ADV + lamivudine (LAM); TDF vs. ADV + entecavir (ETV).

METHODS

We systematically searched China National Knowledge Infrastructure, the Cochrane Library, Embase, PubMed, Chinese VIP, and Wanfang Data, for relevant clinical trials since July 2015, all included studies were based on PICOS principles and evaluated independently by the reviewers in accordance with the Cochrane Handbook (Rob2.0). A meta-analysis was performed by using Review Manager 5.4.

RESULTS

We included a total of 32 studies, including 31 randomized controlled trials and one retrospective study involving 2,473 patients. The results revealed a low risk of bias in included studies, that the virologic response of TDF was superior to ADV (P<0.05). And TDF was also superior to ADV in Serum creatinine levels, Immunologic function, and safety profile. However, when ADV was combined with other medications, it was superior to TDF in alanine aminotransferase (ALT) level and Tbil level and adverse reactions, but on other indicators, TDF was superior to drug combination therapy.

CONCLUSIONS

Results showed that TDF was superior to ADV in the parameters of ALT, hepatitis B virus (HBV)-DNA reduction, HBeAg-negative conversion rate, safety, and total bilirubin levels in patients with CHB. However, when ADV was combined with LAM or ETV, they often showed the same therapeutic effect as TDF in parameters such as ALT level and Tbil level and combined therapy can effectively reduce the occurrence of adverse reactions. In this study, because the sample source countries were limited, a greater number of global studies are needed in the future to verify the current findings.

Screening and Identification of HBV Epitopes Restricted by Multiple Prevalent HLA-A Allotypes

Although host T cell immune responses to hepatitis B virus (HBV) have been demonstrated to have important influences on the outcome of HBV infection, the development of T cell epitope-based vaccine and T cell therapy and the clinical evaluation of specific T cell function are currently hampered markedly by the lack of validated HBV T cell epitopes covering broad patients. This study aimed to screen T cell epitopes spanning overall HBsAg, HBeAg, HBx and HBpol proteins and presenting by thirteen prevalent human leukocyte antigen (HLA)-A allotypes which gather a total gene frequency of around 95% in China and Northeast Asia populations. 187 epitopes were in silico predicted. Of which, 62 epitopes were then functionally validated as real-world HBV T cell epitopes by ex vivo IFN-γ ELISPOT assay and in vitro co-cultures using peripheral blood mononuclear cells (PBMCs) from HBV infected patients. Furthermore, the HLA-A cross-restrictions of each epitope were identified by peptide competitive binding assay using transfected HMy2.CIR cell lines, and by HLA-A/peptide docking as well as molecular dynamic simulation. Finally, a peptide library containing 105 validated epitopes which cross-binding by 13 prevalent HLA-A allotypes were used in ELISPOT assay to enumerate HBV-specific T cells for 116 patients with HBV infection. The spot forming units (SFUs) was significantly correlated with serum HBsAg level as confirmed by multivariate linear regression analysis. This study functionally validated 62 T cell epitopes from HBV main proteins and elucidated their HLA-A restrictions and provided an alternative ELISPOT assay using validated epitope peptides rather than conventional overlapping peptides for the clinical evaluation of HBV-specific T cell responses.

Efficacy and safety of a nanoparticle therapeutic vaccine in patients with chronic hepatitis B: A randomized clinical trial

BACKGROUND AND AIM

HBV DNA can be reduced using antiviral drugs in patients with chronic hepatitis B (CHB); however, the rate of HBeAg seroconversion remains low. A clinical trial was conducted to assess the efficacy and safety of a de novo designed liposome-based nanoparticle lipopeptide vaccine, εPA-44, for CHB.

APPROACH AND RESULTS

A two-stage phase 2 trial, which included a 76-week, randomized, double-blind, placebo-controlled trial (stage 1) and a 68-week open-label extension (stage 2), was conducted in 15 centers across China (Clinicaltrials.gov No. NCT00869778). In stage 1, 360 human leukocyte antigen A2 (HLA-A2)-positive and HBeAg-positive patients were randomly and equally distributed to receive six subcutaneous injections of 600 µg or 900 µg εPA-44 or placebo at week 0, 4, 8, 12, 20, and 28. In stage 2, 183 patients received extended 900 µg εPA-44, and 26 patients were observed for relapse without further treatment. The primary endpoint was the percentage of patients with HBeAg seroconversion at week 76. At week 76, patients receiving 900 µg εPA-44 achieved significantly higher HBeAg seroconversion rate (38.8%) versus placebo (20.2%) (95% CI, 6.9-29.6%; p = 0.002). With a combined endpoint of HBeAg seroconversion, alanine aminotransferase normalization and HBV DNA < 2,000 IU/mL, both 900 µg (18.1%) and 600 µg (14.3%), resulted in significantly higher rate versus placebo (5.0%) (p = 0.002 and p = 0.02, respectively) at week 76. In stage 2, none (0 of 20) of 900 µg εPA-44-treated patients experienced serologic relapse. The safety profile of εPA-44 was comparable to that of placebo.

CONCLUSIONS

Among HLA-A2-positive patients with progressive CHB, a finite duration of 900 µg εPA-44 monotherapy resulted in significantly higher HBeAg seroconversion rate than placebo and sustained off-treatment effect. A phase 3 trial is ongoing (ChiCTR2100043708).

Entecavir-associated thrombocytopenia

Entecavir (ETV) is widely used in the treatment of hepatitis B, but there are only a few reports about entecavir-associated thrombocytopenia, and it is considered as an immediate response and inappropriate to continue the treatment with other nucleoside analogues. Now, we report the third case, and this case was delayed response and we switched to treatment with tenofovir (TDF). There was a 66-year-old female who was infected with hepatitis B virus (HBV). Her platelet count decreased from 111*10⁹/L to 3*10⁹/L and was prone to gum bleeding and skin ecchymosis after she received ETV treatment for 88 days. As a treatment option, ETV was replaced by TDF immediately, frequent platelets transfusions and thrombopoietin were applied for several days, daily prednisone of 50 mg was concomitantly taken, and then platelet count improved after 10 days. She was diagnosed with entecavir-associated thrombocytopenia after analysis of the temporal relationship and exclusion of other causes of thrombocytopenia by blood and bone marrow examinations. Our case suggested that the platelet count should be monitored regularly in patients during ETV treatment, and it may be a feasible option to choose TDF to maintain antiviral treatment when entecavir-associated thrombocytopenia occurs.

Skewed CD39/CD73/adenosine pathway contributes to B-cell hyperactivation and disease progression in patients with chronic hepatitis B

Background

The mechanisms underlying B-cell hyperactivation in patients with chronic hepatitis B virus (HBV) infection remain largely undefined. The present study assessed the clinical characteristics of the CD39/CD73/adenosine pathway in patients with chronic hepatitis B (CHB).

Methods

We examined CD39 and CD73 expression and adenosine production by B-cells from 202 HBV-infected patients. B-cell-activation phenotypes were assessed by flow cytometry after CpG+CD40 ligand stimulation with or without blockade and activation of the adenosine pathway.

Results

CD39 and CD73 expression on circulating B-cells was decreased in CHB patients with high HBV DNA, HBeAg positivity, high HBsAg levels, and active liver inflammation, and was hierarchically restored in complete responders according to HBeAg seroconversion or HBsAg reduction. However, CD39 and CD73 expression on activated memory and tissue-like memory B-cell subsets in complete responders was not increased despite effective antiviral treatments. Furthermore, CD39 and CD73 expression on intra-hepatic B-cells was decreased in inflammatory livers. In vitro, B-cells from CHB patients showed a markedly reduced capacity to generate CD39/CD73-dependent extracellular adenosine and expressed increased levels of activation markers after adenosine-production blockade. Contrastingly, metformin significantly reduced activation-marker expression via regulating AMP-activated protein kinase.

Conclusions

The skewed CD39 and CD73 expression on B-cells was associated with a high viral burden, liver inflammation, and antiviral efficacy in CHB patients, and the skewed CD39/CD73/adenosine pathway contributed to B-cell hyperactivation. Regulation of the CD39/CD73/adenosine pathway using metformin may represent a therapeutic option to reverse HBV-induced immune pathogenesis.

Next generation sequencing reveals novel alterations in B-cell heavy chain receptor repertoires associated with acute-on-chronic liver failure

Acute-on-chronic liver failure (ACLF) is a newly-defined serious syndrome with major features of acute decompensation (AD) of hepatic cirrhosis, liver failure and failure of multiple other organs. To date, the mechanism underlying the development and progression of ACLF remains to be fully elucidated. It has been noted that ACLF is associated with immune dysregulation. However, studies have mainly focused on T-cell responses. The present study aimed to determine the composition and alterations of B-cell receptor (BCR) heavy chain repertoires associated with ACLF using next generation sequencing (NGS). A total of six patients with hepatitis B virus (HBV)-related ACLF and six healthy control subjects were prospectively enrolled in the present study. The B-cell immunoglobulin heavy chain (IGH) repertoires in peripheral blood mononuclear cells (PBMCs) obtained from the patients with HBV-related ACLF and the control subjects were analyzed using NGS, coupled with multiplex polymerase chain reaction, were Illumina sequenced, and were further characterized using the international ImMunoGeneTics database. The distribution of the BCR complementarity-determining region 3 (CDR3) variable (V), diversity (D) and joining (J) and V-J gene segments were found to be comparable between the ACLF and control groups. Of note, the degree of clonal expansion in the ACLF group was significantly higher than that in the control group (P<0.05). Furthermore, a t-test of the distribution ratio of the V, D, J and V-J combinations in patients with ACLF and control subjects revealed differentially expressed genes. In total, six genes were upregulated and 19 genes were downregulated in response to ACLF. The difference between these two groups was statistically significant (P<0.05). The approach used in the present study was feasible and effective for analyzing peripheral B-cell repertoires in HBV-related ACLF. These results provide direct evidence that the BCR repertoire is important in immune responses, autoimmunity and alloreactivity, and that there is a link between the BCR repertoire and HBV-ACLF. Therefore, ACLF-specific BCR CDR3 sequences hold promise for therapeutic benefit to HBV-ACLF in the future.

Comparison of overall survival between antiviral-induced viral suppression and inactive phase chronic hepatitis B patients

Nucleot(s)ide analogues (NAs) reduce the risk of hepatocellular carcinoma (HCC) in chronic hepatitis B (CHB) patients. However, the risk of HCC is reportedly higher for NA-treated patients than for patients in the inactive CHB phase. This study aimed to compare the long-term outcomes of CHB patients with NA-induced viral suppression and those of patients with inactive CHB. This retrospective study involved 1118 consecutive CHB patients whose HBV DNA level was continuously <2000 IU/mL during follow-up with/without antiviral agents. The patients were classified into inactive CHB (n = 373) or NA groups (n = 745). The primary endpoint was overall survival. Secondary endpoints included development of HCC and other liver-related events. The median duration of follow-up was 41.0 (interquartile range = 26.5-55.0) months. The difference in overall survival between the NA group vs. the inactive CHB group was not significant (hazard ratio [HR] = 0.78; 95% confidence interval [CI] = 0.33-1.85; P = .57). The NA group showed a significantly higher risk of HCC (HR = 3.44; 95% CI = 1.82-6.52; P < .01), but comparable risk for non-HCC liver-related events (HR = 1.02; 95% CI = 0.66-1.59; P = .93), compared with the inactive CHB group. Among patients with cirrhosis, the NA group showed a significantly lower risk of death (HR = 0.31; 95% CI = 0.097-0.998; P = .05) and non-HCC liver-related events (HR = 0.51; 95% CI = 0.31-0.83; P < .01), but a slightly higher risk of HCC (HR = 2.39; 95% CI = 0.85-6.75; P = .09), compared to the inactive CHB group. The overall survival of untreated patients with inactive CHB and of CHB patients achieving viral suppression with NA was comparable. However, NA treatment of cirrhotic patients was significantly associated with longer overall survival and lower risk of liver-related events.

Gut microbiota and hepatitis-B-virus-induced chronic liver disease: implications for faecal microbiota transplantation therapy

Hepatitis B is one of the most common infectious diseases globally. It has been estimated that there are 350 million chronic hepatitis B virus (HBV) carriers worldwide. The liver is connected to the small intestine by the bile duct, which carries bile formed in the liver to the intestine. Nearly all of the blood that leaves the stomach and intestines must pass through the liver. Human intestines contain a wide diversity of microbes, collectively termed the 'gut microbiota'. Gut microbiota play a significant role in host metabolic processes and host immune modulation, and influence host development and physiology (organ development). Altered gut microbiota is a common complication in liver disease. Changes in intestinal microbiota seem to play an important role in induction and promotion of HBV-induced chronic liver disease progression, and specific species among the intestinal commensal bacteria may play either a pathogenic or a protective role in the development of HBV-induced chronic liver disease. Thus, the gut microbiome may represent fertile targets for prevention or management of HBV-induced chronic liver disease. Faecal microbiota transplantation (FMT) may be a useful therapy for HBV-related disease in the future. However, the data available in this field remain limited, and relevant scientific work has only just commenced. New technologies have enabled systematic studies of gut microbiota, and provided more realistic information about its composition and pathological variance. This review summarizes the cutting edge of research into the relationship between gut microbiota and HBV-induced chronic liver disease, and the future prospects of FMT therapy.

Relationship of Treg/Th17 balance with HBeAg change in HBeAg-positive chronic hepatitis B patients receiving telbivudine antiviral treatment: A longitudinal observational study

Telbivudine (LdT) is an orally L-nucleoside with potent and specific antihepatitis B virus (HBV) activity. The higher rate of hepatitis B e antigen (HBeAg) seroconversion of LdT treatment than other anti-HBV agents suggests a potential immunomodulatory effect. The aim of the study was to investigate the changes of regulatory T cell (Treg)/interleukin (IL)-17-producing CD4+T helper (Th17) balance during LdT treatment and to discuss the relationship of Treg/Th17 balance with HBeAg change in HBeAg-positive chronic hepatitis B (CHB) patients receiving LdT antiviral treatment. Twenty-seven HBeAg-positive CHB patients received LdT for 24 weeks and the percentages of Tregs and cells (Th17 cells) in peripheral blood as well as the serum TGF-β1 and IL-17 levels in these patients were longitudinally analyzed. We found that the frequencies of Tregs and Th17 cells in peripheral blood as well as the serum TGF-β1 and IL-17 levels increased significantly in CHB patients compared with healthy controls. During the LdT treatment, the Tregs frequency and TGF-β1 level tended to decrease, and Th17 cells frequency and IL-17 level showed a reverse "V"-type change. The frequency of Tregs and the ratio of Treg/Th17 were significantly lower in the HBeAg loss group than those in the HBeAg no-loss group at the baseline. More important, the Tregs frequency and TGF-β1 level were both positively correlated with HBeAg level during the LdT treatment for 24 weeks. Our data suggest that the lower Tregs frequency and Treg/Th17 ratio at the baseline of LdT treatment, the more likely to get the HBeAg loss. HBeAg negative can be predicted using changes in Tregs frequency and TGF-β1 level during LdT treatment in CHB patients. Maybe we could provide the immunology marker for exploring the mechanism of the higher HBeAg seroconversion rate of LdT therapy.

Polymorphisms in the IL-17 Gene (rs2275913 and rs763780) Are Associated with Hepatitis B Virus Infection in the Han Chinese Population

AIM

Interleukin-17 (IL-17) can accelerate the release of many pro-inflammatory cytokines. The purpose of our study was to investigate the potential association between polymorphisms in the IL-17 gene and susceptibility to hepatitis B virus (HBV) infection in the Han Chinese population.

METHODS

We recruited 596 HBV-infected patients and 612 ethnically matched controls, who were then genotyped for the IL-17A and IL-17F polymorphisms, rs2275913 and rs763780, respectively, by using TaqMan probe-based real-time polymerase chain reaction. The frequencies of the alleles and genotypes in patients and controls were compared by the χ² test.

RESULTS

Statistically significant differences in genotypic and allelic frequencies were revealed at both polymorphic sites between HBV-positive patients and controls (rs2275913: genotype χ² = 37.74, p < 0.001 and allele χ² = 22.17, p < 0.001, odds ratio [OR] = 0.654, 95% confidence interval [CI] = 0.548-0.781. rs763780: genotype χ² = 19.80, p < 0.001 and allele χ² = 18.78, p < 0.001, OR = 0.507, 95% CI = 0.371-0.692).

CONCLUSIONS

These results indicate that the IL-17A rs2275913 and IL-17F rs763780 polymorphisms are associated with HBV infection in the Han Chinese population. We conclude that possession of the GG genotype and the G allele at rs2275913, and the TT genotype and the T allele at rs763780 might increase the risk of HBV infection. Larger-scale, multiracial studies are necessary to evaluate the role of IL-17 polymorphisms in relation to an enhanced risk of HBV infection.

Cynomolgus monkeys (Macaca fascicularis) experimentally infected with B19V and hepatitis A virus: no evidence of the co-infection as a cause of acute liver failure

This study was conducted to analyse the course and the outcome of the liver disease in the co-infected animals in order to evaluate a possible synergic effect of human parvovirus B19 (B19V) and hepatitis A virus (HAV) co-infection. Nine adult cynomolgus monkeys were inoculated with serum obtained from a fatal case of B19V infection and/or a faecal suspension of acute HAV. The presence of specific antibodies to HAV and B19V, liver enzyme levels, viraemia, haematological changes, and necroinflammatory liver lesions were used for monitoring the infections. Seroconversion was confirmed in all infected groups. A similar pattern of B19V infection to human disease was observed, which was characterised by high and persistent viraemia in association with reticulocytopenia and mild to moderate anaemia during the period of investigation (59 days). Additionally, the intranuclear inclusion bodies were observed in pro-erythroblast cell from an infected cynomolgus and B19V Ag in hepatocytes. The erythroid hypoplasia and decrease in lymphocyte counts were more evident in the co-infected group. The present results demonstrated, for the first time, the susceptibility of cynomolgus to B19V infection, but it did not show a worsening of liver histopathology in the co-infected group.

Molecular mechanisms of HBeAg in persistent HBV infection

PURPOSE

The aim of this study is to investigate the T-lymphocyte subpopulation and expression of programmed cell death-1 (PD-1), toll-like receptor (TLR)3, TLR4, and interferon (INF)-γ to illustrate the relationship between hepatitis B e antigen (HBeAg) and persistent hepatitis B virus (HBV) infection.

METHODS

Blood was taken from normal subjects into anticoagulation tubes to separate peripheral blood mononuclear cells (PBMCs). The PBMCs were divided into four groups and cultured with various concentrations of HBeAg for 72 h. Changes in the T-cell subset were analyzed through cell counting by flow cytometry, and expression of TLR3, TLR4, and PD-1 was assessed by flow cytometry and Western blot. The concentration of IFN-γ was analyzed using enzyme-linked immunospot (ELISPOT) experiments.

RESULTS

PBMCs were stimulated with various concentrations of HBeAg for 72 h and assayed by flow cytometry to determine CD4+ and CD8+ cell counts. The relative frequencies of CD4+ and CD8+ subpopulations and the CD4+/CD8+ ratio decreased compared with the control group, and T-cell impairment was significantly associated with higher HBeAg load. TLR3, TLR4, and PD-1 protein expression was assessed using flow cytometry and Western blotting. Expression of TLR3, TLR4, and PD-1 increased with increasing concentration of HBeAg. ELISPOT experiments were used to determine the concentration of IFN-γ. IFN-γ production in treatment groups was lower than in the control group. Comparing IFN-γ production in treatment groups, IFN-γ production in PBMCs stimulated with high dose of HBeAg was lower than for those stimulated with low-dose HBeAg.

CONCLUSIONS

HBeAg can inhibit proliferation of lymphocytes, increase TLR3, TLR4, and PD-1 expression, and decrease IFN-γ production. This may be one of the molecular mechanisms of HBV immune tolerance.

Tfh cell-mediated humoral immune response and HBsAg level can predict HBeAg seroconversion in chronic hepatitis B patients receiving peginterferon-α therapy

Hepatitis B e antigen (HBeAg) seroconversion constitutes a significant milestone in the treatment of HBeAg-positive patients with chronic hepatitis B (CHB), but studies have yet to identify the specific humoral immune mechanisms behind the process or any accurate markers that can determine the virus-host immune status and, thereby, predict the degree of HBeAg seroconversion achievable. In the present longitudinal study, higher frequencies of circulating CXCR5(+)CD4(+) T cells and CD19(+)CD38(+) B cells were found in peginterferon-α treated HBeAg-positive CHB patients in whom HBeAg seroconversion had been achieved. What's more, both cell types peaked at 24 weeks for the HBeAg seroconversion group, while showing only a slight variation in the HBeAg non-seroconversion group. In addition, circulating CXCR5(+)CD4(+) T cells and hepatitis B surface antigens (HBsAg) were assessed at 24 weeks and 12 weeks, respectively, and the use of their ratio was explored in terms of its ability to predict HBeAg seroconversion.

CONCLUSION

Dysfunction of the humoral immune response mediated by CXCR5(+)CD4(+) T cells is associated with the failure of HBeAg seroconversion. The CXCR5(+)CD4(+) T cells/HBsAg ratio is an ideal marker for predicting HBeAg seroconversion in CHB patients.

Crosstalk between innate and adaptive immunity in hepatitis B virus infection

Hepatitis B virus (HBV) infection is a major public health problem worldwide. HBV is not directly cytotoxic to infected hepatocytes; the clinical outcome of infection results from complicated interactions between the virus and the host immune system. In acute HBV infection, initiation of a broad, vigorous immune response is responsible for viral clearance and self-limited inflammatory liver disease. Effective and coordinated innate and adaptive immune responses are critical for viral clearance and the development of long-lasting immunity. Chronic hepatitis B patients fail to mount efficient innate and adaptive immune responses to the virus. In particular, HBV-specific cytotoxic T cells, which are crucial for HBV clearance, are hyporesponsiveness to HBV infection. Accumulating experimental evidence obtained from the development of animal and cell line models has highlighted the importance of innate immunity in the early control of HBV spread. The virus has evolved immune escape strategies, with higher HBV loads and HBV protein concentrations associated with increasing impairment of immune function. Therefore, treatment of HBV infection requires inhibition of HBV replication and protein expression to restore the suppressed host immunity. Complicated interactions exist not only between innate and adaptive responses, but also among innate immune cells and different components of adaptive responses. Improved insight into these complex interactions are important in designing new therapeutic strategies for the treatment HBV infection. In this review, we summarize the current knowledge regarding the cross-talk between the innate and adaptive immune responses and among different immunocytes in HBV infection.

Correlation between Th17 and nTreg cell frequencies and the stages of progression in chronic hepatitis B

Several studies have suggested that the balance of T helper 17 (Th17) and natural regulatory T (nTreg) cells in the Th17‑mediated immune response are critical in the pathogenesis of viral hepatitis. The aim of the present study was to examine the role of circulating Th17 and nTreg cells in the disease progression of hepatitis B virus (HBV) infection. A total of 40 patients with chronic HBV (CHB), 27 patients with HBV‑associated cirrhosis, 20 patients with HBV‑associated liver failure and 20 healthy controls were enrolled in the present study. The frequencies of Th17 and nTreg cells in the peripheral blood were examined using flow cytometry. Th17‑associated serum cytokine levels were measured using an enzyme‑linked immunosorbent assay. The results revealed a significantly higher frequency of circulating Th17 cells in the patients with CHB, cirrhosis and liver failure compared, with the normal controls, particularly in the patients with liver failure. The same trend was observed in the serum levels of interleukin (IL)‑17. The frequency of Th17 cells and the serum levels of IL‑17 were positively correlated with the levels of alanine aminotransferase and the prothrombin times. There was a significantly higher frequency of circulating nTreg cells in the patients with CHB, compared with the normal controls. The nTreg cell frequencies were significantly and positively correlated with plasma HBV DNA load, and were negatively correlated with Th17 frequencies in the cohort of patients with HBV. Taken together, the results suggested that Th17 cell‑mediated inflammation is associated with progression from CHB to cirrhosis, and to liver failure. Peripheral Th17 cell frequency and serum levels of IL‑17 may assisting in predicting the severity of liver damage and fibrosis.

Restoring homeostasis of CD4+ T cells in hepatitis-B-virus-related liver fibrosis

Immune-mediated liver injury is widely seen during hepatitis B virus (HBV) infection. Unsuccessful immune clearance of HBV results in chronic hepatitis and increases the risk of liver cirrhosis and hepatocellular carcinoma. HBV-related liver fibrosis (HBVLF), occurring as a result of HBV-induced chronic hepatitis, is a reversible, intermediate stage of chronic hepatitis B (CHB) and liver cirrhosis. Therefore, defining the pathogenesis of HBVLF is of practical significance for achieving better clinical outcomes. Recently, the homeostasis of CD4⁺ T cells was considered to be pivotal in the process of HBVLF. To better uncover the underlying mechanisms, in this review, we systematically retrospect the impacts of different CD4⁺ T-cell subsets on CHB and HBVLF. We emphasize CD4⁺ T-cell homeostasis and the important balance between regulatory T (Treg) and T helper 17 (Th17) cells. We discuss some cytokines associated with Treg and Th17 cells such as interleukin (IL)-17, IL-22, IL-21, IL-23, IL-10, IL-35 and IL-33, as well as surface molecules such as programmed cell death protein 1, cytotoxic T lymphocyte-associated antigen 4, T cell immunoglobulin domain and mucin domain-containing molecule 3 and cannabinoid receptor 2 that have potential therapeutic implications for the homeostasis of CD4⁺ T cells in CHB and HBVLF.

Gut microbiota modulate the immune effect against hepatitis B virus infection

The immunological mechanisms by which hepatitis B virus (HBV) initiates and maintains acute or chronic infection, even the formation of cirrhosis and hepatocellular carcinoma, are still undefined. An increasing number of studies have shown that intestinal flora regulate immune homeostasis, and, thus, protect the immunologic function against hepatitis virus infection. In this article, we discuss gut microbiota and its potential immune effects against HBV infection. It may provide a novel insight into the pathogenesis of HBV infection, as well as a potential therapeutic target to HBV-related disease.

Regulation of T cell function by microRNA-720

Chronic hepatitis B virus (HBV) infection is a major global health burden. Functional exhaustion and numerical reduction of HBV-specific cytotoxic T lymphocytes (CTLs) in the liver and peripheral blood limit anti-HBV CTL activity in patients with chronic HBV infection (CHB). However, the ongoing anti-HBV CD8⁺ T cell responses in the lymphoid organs are largely unknown due to the infeasibility of obtaining lymphoid organs from CHB patients. Here we demonstrate that the percentage of HBV-specific CD8⁺ T cells is higher in the spleen of CHB patients than that from peripheral blood and liver. Although they do respond to TCR stimulation and produce IFNγ, the cells proliferate poorly. Furthermore, miR-720 expression is upregulated in HBV-specific CD8⁺ T cells. Overexpression of miR-720 in primary human CD8⁺ T cells inhibits TCR stimulation-induced proliferation. We also demonstrate that TGFβ sustains miR-720 upregulation after TCR stimulation, and blood TGFβ levels are associated with the outcome of type I interferon treatment of CHB patients. Thus, therapies targeting miR-720 may help restore impaired immunity in CHB patients.

Reversal of B-cell hyperactivation and functional impairment is associated with HBsAg seroconversion in chronic hepatitis B patients

B cells play an important role in the clearance of hepatitis B virus (HBV) and protection against reinfection. However, the functional characteristics of these cells that are associated with the outcome of chronic HBV infection remain unknown. We comprehensively investigated the frequency, phenotype, and function of peripheral B-cell subsets from CHB patients in different phases: immune tolerance (IT), immune activation (IA), immune clearance (IC), responders with HBsAg seroconversion (resolved patients, RP), and healthy controls (HC). IA patients displayed lower percentages of peripheral blood memory B cells compared with the other groups. Overall polyclonal activation of B cells, indicated by higher levels of activation markers and secretion of IgG and IgM, was observed in IA patients. This B-cell hyperactivation could be induced by increased IFN-α and soluble CD40 ligands in IA patients. Notably, the expression of the co-stimulator molecule CD80 and serum HBsAb and the frequency of HBsAg-specific B cells were significantly decreased in IT, IA, and IC patients compared with HC subjects. More importantly, the B-cell hyperactivation, co-stimulatory molecule downregulation and HBsAg-specific B-cell impairment were reversed in RP patients. The reversal of B-cell hyperactivation and functional impairment is associated with HBsAg seroconversion in chronic hepatitis B patients.

Telbivudine therapy may shape CD4(+) T-cell response to prevent liver fibrosis in patients with chronic hepatitis B

BACKGROUND & AIMS

Nucleos(t)ide analogues (NAs) can indirectly restore host immunity against hepatitis B virus (HBV) by inhibiting virus replication. We aimed to investigate whether telbivudine could prevent HBV-related fibrosis progression by their influence on CD4(+) T-cell response.

METHODS

Thirty-six HBeAg-positive patients with chronic hepatitis B (CHB) were enrolled for 52-week telbivudine monotherapy and were followed at treatment week (TW)-0, 4, 12, 24 and 52. By TW-52, the patients were classified into a complete-response group (CR, n = 10) with both negative HBV-DNA and HBeAg, or a part-response group (PR, n = 11) only with negative DNA, or a non-response group (NR, n = 15) still with positive DNA. The peripheral blood mononuclear cells (PBMCs) were prepared for further flow cytometric and real-time PCR analyses, and also for the in vitro experiments with primary hepatic stellate cells (HSCs).

RESULTS

Peripherally, all chronic HBV-infected subjects showed the involvement of CD4(+) T-cell responses, among whom the inactive carriers (IC) had Th1 (CD4(+) IFNγ(+) ) dominated, CHB had Th17 (CD4(+) IL-17(+) ) dominated, while the immune tolerant (IT) subjects had Treg (CD4(+) CD25(high) Foxp3(+) ) dominated. Besides, we found the therapeutic responses to telbivudine were especially associated with up-regulation of Th1 and Th17, and down-regulation of Treg. Furthermore, compared to CD4(+) cells from CR, those from NR could in vitro significantly exacerbate cell activation, proliferation and cytokine production of HSCs, which were partly mediated by IL-4 and TGF-β1.

CONCLUSIONS

Telbivudine might slow down HBV-related liver fibrosis progression by restoring CD4(+) T-cell responses against HBV.

Treating Immune-tolerant Hepatitis B

Hepatitis B virus (HBV) infection is a major cause of cirrhosis and hepatocellular carcinoma worldwide. On the basis of virus-host interactions, the natural history of HBV carriers can be divided into four chronological phases. In the first immune tolerance phase, HBV carriers are positive for hepatitis B e antigen (HBeAg) and have high HBV replication activity, normal ALT levels as well as minimal liver disease. Ample evidence has shown that patients in the immune tolerance phase have very low viral evolution and minimal risk of fibrosis progression. However, recent immunological studies argued that HBV-specific immune responses already exist in a proportion of immune-tolerant patients and the immune activities are comparable to those in the immune clearance phase. Regarding antiviral therapy, whether these immune-tolerant patients are indicated for treatment remains debated. Previous studies showed that HBeAg-positive patients with normal or near-normal ALT levels, who are assumed to be in the immune tolerance phase, have a lower HBeAg seroconversion rate receiving either pegylated interferon or nucleos(t)ide analogue treatment. The latest clinical trial focusing on-treatment response of immune-tolerant patients with tenofovir disoproxil fumarate-based therapy also confirmed the results. The HBeAg seroconversion rates are <5% at 4 years of treatment. Considering the minimal risk of disease progression and low treatment response rates in immune-tolerant patients, current antiviral therapy should not be recommended unless the patients have advanced liver fibrosis. In addition, novel agents targeting the HBV template known as covalently closed circular DNA and aiming to reduce or eliminate it are urgently required.

Decline in intrahepatic cccDNA and increase in immune cell reactivity after 12 weeks of antiviral treatment were associated with HBeAg loss

Viral load reduction facilitates recovery of antiviral T-cell responses. Dynamic alterations in intrahepatic viraemia clearance and immune cell reactivity during the early phase of nucleoside analogue (NA) therapy and the impact of these changes on HBeAg seroconversion are unknown. Fifteen HBeAg-positive chronic hepatitis B (CHB) patients were treated with adefovir dipivoxil. T-cell reactivity to HBV core and surface antigens were tested using ELISPOT assay from baseline to week 48 post-treatment (at 4-week intervals). Before and at week 12 of treatment, paired liver biopsies were analysed for intrahepatic HBV-DNA and cccDNA via real-time fluorescent PCR. In situ detection of CD4(+) , CD8(+) T cells and NK cells was analysed by immunohistochemistry. With viral load reduction, HBV-specific IFN-γ-producing CD4(+) T cells in patients with HBeAg loss were greatly enhanced and reached the highest level at week 12, with further increase observed between week 36 and week 48. After 12 weeks of treatment, total intrahepatic HBV-DNA and cccDNA had significantly decreased; however, there was no difference in the viral loads or extent of reduction between patients with and without HBeAg loss. Paralleling reduction in viral load, intrahepatic CD8(+) T lymphocytes increased in patients with HBeAg loss compared with baseline values. Only one patient without HBeAg loss exhibited similar results. Increased immune cells were observed in certain patients along with reduced hepatic viral loads during the second phase of HBV-DNA decline, which could promote the recovery of antiviral immunity and facilitate HBeAg loss.

Myeloid-derived suppressor cells regulate immune response in patients with chronic hepatitis B virus infection through PD-1-induced IL-10

Although myeloid-derived suppressor cells (MDSCs) are well known for their immunosuppressive function in several pathological conditions, the role of MDSCs in hepatitis B virus infection remains obscure. In this study, we investigated the frequency and function of MDSCs in the peripheral blood and liver of 91 chronic hepatitis B (CHB) patients. A higher percentage of MDSCs, defined as CD14(+)HLA-DR(-/low), was detected in peripheral blood of CHB patients than that of the healthy controls. Moreover, high expression of programmed death 1 (PD-1) and secretion of IL-10 in this population were determined. The frequency of MDSCs was positively correlated with serum viral load, but it was negatively correlated with liver inflammatory injury. These cells were also abundant in liver tissue of CHB patients and were related to necroinflammatory activity. Furthermore, we found that these cells could suppress hepatitis B virus-specific CD8(+) T cell response, including reduced proliferation and IFN-γ production, and inhibit degranulation of CD8(+) T cells, including reduced production of granzyme B and perforin. Importantly, PD-1-induced IL-10 production by MDSCs was responsible for the suppressive activity. To our knowledge, for the first time our study proved that CD14(+)HLA-DR(-/low)PD-1(+) MDSCs in CHB patients contribute to an inadequate immune response against the virus and lead to chronic infection, which represents a potential target for therapeutic intervention.

Inhibition of SATB1 expression in regulatory T cells contributes to hepatitis B virus-related chronic liver inflammation

Regulatory T cells (Tregs) contribute to the pathogenesis of chronic hepatitis B (CHB). Special AT-rich sequence-binding protein 1 (SATB1) may be a key component of this process. In the present study, Tregs and conventional T cells (Tconvs) were isolated by magnetic cell sorting of peripheral blood from CHB patients (n=57), individuals with resolved hepatitis B virus (HBV) infections (n=15), and healthy controls (n=29). SATB1 expression was studied by reverse transcription-quantitative PCR, flow cytometry and immunofluorescence microscopy, and the correlation of SATB1 expression to the expression of liver inflammation serum markers and the HBV DNA load was assessed. CHB patients showed significantly reduced SATB1 expression in Tregs than healthy controls and individuals with resolved HBV infections. Moreover, SATB1 expression in Tregs was significantly lower than in Tconvs of patients with chronic HBV infection. Serum HBV DNA and liver inflammation markers were inversely correlated to the SATB1 mRNA level in Tregs. Antiviral treatment was accompanied by increased expression of the SATB1 gene in Tregs. Thus, Tregs from CHB patients have reduced levels of SATB1, which is resolved with antiviral therapy. Inhibition of SATB1 expression may impair the hepatic inflammatory response and contribute to HBV persistence.

Interleukin-21 mediates hepatitis B virus-associated liver cirrhosis by activating hepatic stellate cells

AIM

Interleukin-21 (IL-21) is involved in effective primary hepatic immune response against hepatitis B virus (HBV) and profibrotic function. However, the role of IL-21 in HBV-associated liver cirrhosis is poorly understood. This study aimed to investigate the role of IL-21 in HBV-associated liver cirrhosis and possible mechanisms.

METHODS

The study subjects included 10 healthy controls and 30 patients with HBV-associated liver cirrhosis that categorized into three subgroups based on Child-Pugh score (A, 13; B, 10; C, 7). The frequencies of IL-21(+) CD4(+) T cells were detected by flow cytometry, and the level of IL-21 in plasma was measured by enzyme-linked immunoassay. The distribution of IL-21(+) cells in situ in liver was observed by immunohistochemistry. In addition, the in vitro expression of α-smooth muscle actin (α-SMA), apoptosis and proliferation markers of LX-2 cells were examined by flow cytometry and Cell Counting Kit-8 kit. Finally, the collagen levels in the supernatant were measured by chemiluminescence.

RESULTS

Increased peripheral number of IL-21(+) CD4(+) cells, elevated plasma level of IL-21 and IL-21(+) cell accumulation in liver were observed in patients with HBV-associated liver cirrhosis. In vitro administration of IL-21 was accompanied with increased expression of α-SMA, inhibited LX-2 cells apoptosis and upregulated collagen production by LX-2 cells.

CONCLUSION

IL-21 may contribute to the fibrogenesis of HBV-associated liver cirrhosis by activating the hepatic stellate cells. Therefore, neutralization of IL-21 could be a favorable new therapeutic strategy for liver cirrhosis treatment.

Changes of costimulatory molecule CD28 on circulating CD8+ T cells correlate with disease pathogenesis of chronic hepatitis B

Costimulatory signals are critical for antiviral immunity. The aim of this study was to evaluate the change of costimulatory molecule CD28 on circulating CD8⁺ T cells in chronic hepatitis B patients (CHB). Seventy CHB patients and fifty-six healthy controls were included, and forty-eight CHB patients were recruited for 52 weeks of longitudinal investigation. The proportions of circulating CD8⁺CD28⁺ and CD8⁺CD28⁻ subpopulations were determined by flow cytometry, and the CD8⁺CD28⁺/CD8⁺CD28⁻ T cells ratio was calculated. Compared with the subpopulation in healthy controls, high proportions of CD8⁺CD28⁻ subpopulation were observed in CHB patients. Similarly, the CD8⁺CD28⁺/CD8⁺CD28⁻ T cells ratio was significantly decreased in CHB patients compared with healthy controls and correlated significantly with hepatitis B virus (HBV) loads. High proportions of CD8⁺CD28⁻ subpopulation and low CD8⁺CD28⁺/CD8⁺CD28⁻ T cells ratio were observed in hepatitis B e antigen- (HBeAg-) positive individuals as compared with that in HBeAg-negative subjects. A significant decrease in CD8⁺CD28⁻ subpopulation, increase in CD8⁺CD28⁺ subpopulation, and CD8⁺CD28⁺/CD8⁺CD28⁻ T cells ratio were seen in those patients who received efficient antiviral therapy. Thus, aberrant CD28 expression on circulating CD8⁺ T cells and the CD8⁺CD28⁺/CD8⁺CD28⁻ T cells ratio reflect the dysregulation of T cell activation and are related to the pathogenesis of chronic HBV infection.

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.

Incidence and risk factors for incomplete HBV DNA suppression in HIV/HBV-co-infected patients initiating tenofovir-based therapy

Suppression of hepatitis B virus (HBV)-DNA to undetectable levels is an important goal for HIV/HBV-co-infected patients receiving anti-HBV-active antiretroviral therapy (ART), and current guidelines recommend that this outcome should be reached by 1 year of treatment. However, the proportion of patients that fail to achieve an undetectable HBV DNA at this time point and its determinants remain unknown in clinical practice. The objective of this study was to determine the incidence and risk factors for incomplete HBV suppression following 1 year of tenofovir-based ART. We performed a cohort study among tenofovir-treated HIV/HBV-co-infected patients. Patients had HBV viraemia, initiated tenofovir-based ART and had HBV DNA measured at 1 year of therapy. The primary outcome was incomplete HBV suppression (HBV DNA ≥2.6 log IU/mL) at 1 year. Logistic regression determined odds ratio (ORs) of incomplete HBV suppression for risk factors of interest. Among 133 patients, 54% (95% CI, 46-63%) had incomplete HBV suppression at 1 year. Incomplete suppression was associated with higher baseline HBV DNA (OR, 1.46 per log IU/mL increase; 95% CI, 1.1-1.94) and detectable HIV viraemia at 1 year (OR, 2.52; 95% CI, 1.19-5.32). Among 66 patients with suppressed HIV RNA at 1 year, 28 (42%) failed to achieve an undetectable HBV DNA. Failure to suppress HBV DNA by 1 year occurred in a sizeable proportion of tenofovir-treated HIV/HBV-co-infected patients. Higher HBV DNA and detectable HIV viraemia were risk factors for incomplete HBV suppression.

Enhanced high-mobility group box 1 (HMGB1) modulates regulatory T cells (Treg)/T helper 17 (Th17) balance via toll-like receptor (TLR)-4-interleukin (IL)-6 pathway in patients with chronic hepatitis B

High-mobility group box 1 (HMGB1) proteins are substantially up-regulated in acute and chronic hepatitis. However, the immunopathogenic role of HMGB1 in patients with chronic hepatitis B (CHB) has not been elucidated. In this study, using a cohort of 36 CHB patients, we demonstrated a crucial role for HMGB1 to modulate balance between regulatory T (Treg) and T helper 17 (Th17) cells via the toll-like receptor (TLR)-4-interleukin (IL)-6 pathway. Serum HMGB1 levels were dramatically higher in CHB patients and increased along with liver injury, inflammation and fibrosis. Notably, HMGB1 increased along with decreased Treg/Th17 cells ratios in the periphery or intrahepatic microenvironment, which provides a clue for HMGB1 to favour Th17 responses whereas inhibit Treg responses. For in vitro studies, serum pools were constructed with serum from CHB patients at an advanced stage, whereas peripheral blood mononuclear cells (PBMC) pools were constructed with cells from those at an early stage. CHB-serum significantly enhanced retinoic acid-related orphan receptor-γt (RORγt), whereas they inhibited forkhead box P3 (Foxp3) expression in CHB-PBMC, which could be reversed by blocking of HMGB1, TLR4, or IL-6. Besides, recombinant HMGB1 (rHMGB1) dose-dependently up-regulated RORγt whereas down-regulated Foxp3 expression in CHB-PBMC, and meanwhile, rHMGB1 enhanced TLR4 and IL-6 expression in CHB-PBMC. Moreover, the axis of HMGB1-TLR4-IL-6-Treg/Th17 required noncontact interactions between CD4 and non-CD4 cells. In addition, rHMGB1 down-regulated anti-inflammatory proteins on CD4(+) CD25(+) cells whereas up-regulated pro-inflammatory cytokines in CD4(+) CD25(-) cells. In summary, enriched HMGB1 in CHB patients shifts Treg/Th17 balance to Th17 dominance via the TLR4-IL-6 pathway, which exacerbates liver injury and inflammation.

Baseline CD4+ T-cell counts predict HBV viral kinetics to adefovir treatment in lamivudine-resistant HBV-infected patients with or without HIV infection

BACKGROUND

Coinfection with HIV and hepatitis B virus (HBV) substantially alters the course of HBV. Directly acting anti-HBV agents suppress HBV viral levels; however, the kinetics of HBV decline in mono- and coinfected persons have not been evaluated. We investigated the role of baseline CD4+ T-cell counts as a predictor of HBV response to adefovir (ADV) therapy in chronic HBV with and without HIV coinfection.

METHODS

We conducted a double-blind, randomized, placebo-controlled study of HIV-infected (n = 12) and uninfected (n = 5) chronic HBV patients treated with ADV. Five HIV uninfected patients received ADV; the HIV+ patients received ADV or placebo for a total of 48 weeks. At the end of 48 weeks, all patients received open-label ADV for an additional 48 weeks. HBV, HIV viral loads, CD4+ T-cell counts, and safety labs were performed on days 0, 1, 3, 5, 7, 10, 14, and 28 and then every 4 weeks.

RESULTS

Lower HBV slopes were observed among coinfected compared to monoinfected patients (P = .027 at 4 weeks, P = .019 at 24 weeks, and P = .045 at 48 weeks). Using a mixed model analysis, we found a significant difference between the slopes of the 2 groups at 48 weeks (P = .045). Baseline CD4+ T-cell count was the only independent predictor of HBV decline in all patients.

CONCLUSION

HIV coinfection is associated with slower HBV response to ADV. Baseline CD4+ T-cell count and not IL28B genotype is an independent predictor of HBV decline in all patients, emphasizing the role of immune status on clearance of HBV.

Peripheral type I interferon receptor correlated with oxidative stress in chronic hepatitis B virus infection

Type I interferon receptor (IFNAR) has been involved in the progression of chronic hepatitis B (CHB). Oxidative stress is also associated with hepatitis B virus (HBV) infection and might contribute to the structure and function of protein synthesis including the IFNAR family. This study was aimed to determine the possible associations between oxidative stress and peripheral IFNAR expression in chronic HBV infection. Fifty-four CHB patients and 31 liver cirrhosis (LC) patients were consecutively collected, as well as 11 healthy subjects as controls. Expression levels of IFNAR1 and IFNAR2 in peripheral blood lymphocytes and monocytes were measured by flow cytometry. IFNAR1 and IFNAR2c mRNA were detected by real-time reverse transcription-polymerase chain reaction. Levels of plasma-soluble IFNAR and oxidative stress parameters, including xanthine oxidase (XOD), malondialdehyde (MDA), glutathione (GSH), glutathione S-transferase (GST), and glutathione peroxidase (GSH-Px) were detected by enzyme linked immunosorbent assay (ELISA). The frequencies of IFNAR1 and IFNAR2 in lymphocytes and monocytes were significantly increased in CHB and LC patients than in healthy controls. Expression levels of IFNAR1 and IFNAR2c mRNA and plasma-soluble IFNAR level in CHB and LC patients were upregulated compared with healthy controls. Mean fluorescence intensity (MFI) of IFNAR2 in monocytes of CHB patients was higher than that in LC patients. Levels of plasma XOD, MDA, and GST were significantly increased in CHB and LC patients compared with healthy controls. Meanwhile, GSH and GSH-Px in CHB and LC patients were decreased than that in healthy controls. Furthermore, plasma MDA, GSH, and GST levels in CHB patients were higher than that in LC patients. In CHB patients, plasma GST level was negatively correlated with MFI of IFNAR2 in lymphocytes. Our results suggested that oxidative stress play an important role in the regulation of IFNAR in chronic HBV infection.

Non-antigen-specific and antigen-specific immune therapies for chronic hepatitis B: evidences from laboratory benches and patient's bedsides

INTRODUCTION

Due to unsatisfactory therapeutic efficacy and considerable side effects of antiviral drugs in patients with chronic hepatitis B (CHB), immunotherapy has emerged as an alternative approach. CHB immunotherapy may be categorized into two main types: i) non-antigen-specific immune therapy and ii) hepatitis B virus (HBV) antigen-specific immune therapy. Although different immune modulators have been used in CHB patients for the last two to three decades, the nature and design of ongoing regimens of immunotherapeutic approaches need considerable modifications.

AREAS COVERED

In this review, the authors have outlined the relevant immunotherapies for CHB patients that have been used for the last two to three decades. The mechanisms underlying the limited therapeutic efficacy of available therapeutic agents for CHB patients have been discussed to aid in the development of an effective therapeutic approach for these patients.

EXPERT OPINION

Circumstantial evidence indicates that a better regimen of immunotherapy may be developed using different HBV-related antigens or combinations of two or more HBV-related antigens, or combinations of HBV-related antigens and antiviral drugs. However, the capacity of 'inducible immunity' by immune modulators to cure or block progression of liver diseases in CHB patients needs to be addressed.

Natural killer cells are characterized by the concomitantly increased interferon-γ and cytotoxicity in acute resolved hepatitis B patients

Natural killer (NK) cells are abundant in the liver and have been implicated in inducing hepatocellular damage in patients with chronic hepatitis B virus (HBV) infection. However, the role of NK cells in acute HBV infection remains to be elucidated. We comprehensively characterized NK cells and investigated their roles in HBV clearance and liver pathology in 19 chronic hepatitis B (CHB) patients and 21 acute hepatitis B (AHB) patients as well as 16 healthy subjects. It was found that NKp46⁺ NK cells were enriched in the livers of AHB and CHB patients. We further found that peripheral NK cells from AHB patients expressed higher levels of activation receptors and lower levels of inhibitory receptors than those from CHB patients and HC subjects, thus displaying the increased cytolytic activity and interferon-γ production. NK cell activation levels were also correlated positively with serum alanine aminotransferase levels and negatively with plasma HBV DNA levels in AHB patients, which is further confirmed by the longitudinal follow-up of AHB patients. Serum pro-inflammatory cytokine and chemokine levels were also increased in AHB patients as compared with CHB and HC subjects. Thus, the concomitantly increased interferon-γ and cytotoxicity of NK cells were associated with liver injury and viral clearance in AHB patients.

Association of TAP1 and TAP2 polymorphisms with the outcome of persistent HBV infection in a northeast Han Chinese population

OBJECTIVE

Transporter associated with antigen processing (TAP) plays a central role in a cellular immune response against HBV. Polymorphisms exist at the coding region of TAP and alter its structure and function. The aim of this study was to evaluate the potential relationship between polymorphisms of TAP and different outcomes of persistent HBV infection in a Han population in northeastern China.

MATERIAL AND METHODS

189 HBV spontaneously recovered (SR) subjects, 571 HBV-infected patients including 180 chronic hepatitis B (CHB), 196 liver cirrhosis (LC) and 195 hepatocellular carcinoma (HCC) individuals were included in this study. TAP1-333 Ile/Val and -637 Asp/Gly, TAP2-651 Arg/Cys and -687 Stop/Gln were genotyped in all the samples by using a PCR-RFLP method.

RESULTS

The frequency of TAP1-637-Gly (allele G) was significantly higher in persistently HBV-infected individuals (CHB and LC) than that of SR subjects (OR = 1.58, 95% CI 1.12-2.45, p = 0.024; OR = 1.78, 95% CI 1.27-2.68, p = 0.002) by a logistic regression analysis. In addition, the statistically significant difference in the distribution of TAP2-651-Cys (allele T) was observed between HCC cases and SR controls (OR = 2.30, 95% CI 1.51-3.72, p < 0.001), and TAP2-687-Gln (allele C) in CHB patients was more common than that in SR subjects (OR = 1.41, 95% CI 1.13-1.97, p = 0.021). The data also revealed that haplotype 687 Gln-651 Cys-637 Gly-333 Ile was strongly associated with persistent HBV infection (CHB, LC and HCC) (p < 0.001, < 0.05 and < 0.001, respectively).

CONCLUSION

These results suggested that TAP variants were likely to play a substantial role in different outcomes of persistent HBV infection in the studied population.

Multiple cytokine expression profiles reveal immune-based differences in occult hepatitis B genotype H-infected Mexican Nahua patients

A high prevalence of occult hepatitis B (OHB) genotype H infections has been observed in the native Mexican Nahua population. In addition, a low incidence of hepatitis B virus (HBV)-associated hepatocellular carcinoma has been described in Mexico. The immune response to infection among OHB-infected patients has been poorly evaluated in vivo. Therefore, we assessed the expression profiles of 23 cytokines in OHB genotype H-infected Nahua patients. A total of 41 sera samples from natives of the Nahua community were retrospectively analysed. Based on their HBV antibody profiles, patients were stratified into two groups: OHB patients (n = 21) and patients that had recovered from HBV infection (n = 20). Herein, we report distinctive cytokines profiles in OHB-infected individuals. Compared to healthy controls (n = 20) and patients who resolved HBV infection, OHB-infected patients displayed an increase in interleukin (IL)-2 secretion in addition to a characteristic inflammation profile (decrease in IL-8 and tumour necrosis factor-alpha levels and increased levels of tumour growth factor-beta). IL-15 and interferon-gamma levels were reduced in OHB-infected individuals when compared to those patients who resolved HBV infection. In contrast, OHB patients showed an increase in monocyte chemoattractant protein (MCP)-1 and MCP-2 compared to healthy controls and patients who resolved HBV infection. These findings suggest that cytokine expression can influence the severity of OHB disease and could lead to new investigation into the treatment of liver and other infectious diseases.

The role of innate immunity in HBV infection

Hepatitis B virus (HBV) infection is one of the main causes of chronic liver diseases. Whether HBV infection is cleared or persists is determined by both viral factors and host immune responses. It becomes clear that innate immunity is of importance in protecting the host from HBV infection and persistence. However, HBV develops strategies to suppress the antiviral immune responses. A combined therapeutic strategy with both viral suppression and enhancement of antiviral immune responses is needed for effective long-term clearance and cure for chronic HBV infection. We and others confirmed that bifunctional siRNAs with both gene silencing and innate immune activation properties are beneficial for inhibition of HBV and represent a potential approach for treatment of viral infection. Understanding the nature of liver innate immunity and their roles in chronic HBV progression and HBV clearance may aid in the design of novel therapeutic strategies for chronic HBV infection.

Increased Th17 cells contribute to disease progression in patients with HBV-associated liver cirrhosis

T helper (Th) 17 cells have been demonstrated to participate in the pathogenesis of HBV-associated liver damage. However, little is known regarding the immunopathogenic role of liver fibrosis in patients with HBV-associated liver cirrhosis. The aims of this study were to evaluate whether Th17 cells are related to disease progression in patients and to explore the possible mechanisms. The frequencies of circulating Th17 cells were analysed in 78 patients with hepatitis B and cirrhosis (Child A: 34; Child B: 22; Child C 22) and matched controls. Liver samples were collected from 13 patients with HBV-associated cirrhosis, 23 patients with chronic hepatitis B and 12 healthy controls for immunohistochemical analysis. IL-17 receptor expression was studied on liver biopsies and in human hepatic stellate cells as well as their response to recombinant IL-17 by flow cytometry. Patients with hepatitis B-associated cirrhosis with more severe disease displayed significant increases in peripheral numbers of Th17 cells as well as in IL-17 plasma levels. The increased intrahepatic IL-17(+) cells correlated positively with fibrotic staging scores and clinical progression from CHB to cirrhosis. Moreover, many IL-17(+) cells were located in fibrotic areas in the liver of patients with cirrhosis. In vitro, IL-17 together with IL-17-activated monocytes, could promote the activation of stellate cells, which, in turn, aggravated liver fibrosis and the inflammatory response. In summary, increased peripheral and intrahepatic Th17 cells are enriched in patients with hepatitis B and cirrhosis and contribute further to the severity of disease progression through induction of stellate cell activation.

Identification of HLA-A*0201-restricted CD8+ T-cell epitope C₆₄₋₇₂ from hepatitis B virus core protein

The efficacy of a potential therapeutic vaccine against chronic hepatitis B virus (HBV) infection depends on the development of strong and multi-specific T cell responses. The potency of CD8+ cytotoxic T lymphocyte (CTL) responses toward HBV core antigen (HBcAg) has been shown to be critical for the outcomes of HBV chronic infection. In this study we have identified a previously undescribed HLA-A*0201-restricted HBcAg-specific CTL epitope (HBcAg₆₄₋₇₂, C₆₄₋₇₂, ELMTLATWV). T2 binding assay showed that C₆₄₋₇₂ had high affinity to HLA-A*0201 molecule. Functionally, the peptide C₆₄₋₇₂ could induce peptide-specific CTLs both in vivo (HLA-A2.1/K(b) transgenic mice) and in vitro (PBLs of healthy HLA-A2.1+ donors), as demonstrated by interferon-γ (IFN-γ) secretion upon stimulation with C₆₄₋₇₂-pulsed T2 cells or autologous human dendritic cells (DCs) respectively. HLA-A*0201-C₆₄₋₇₂ tetramer staining revealed the presence of a significant population of C₆₄₋₇₂-specific CTLs in C₆₄₋₇₂-stimulated CD8+ T cells. Furthermore, the peptide-specific cytotoxic reactivity and the production of perforin and granzyme B of CTLs also increased after stimulation with C₆₄₋₇₂-pulsed autologous DCs. These results indicate that the newly identified epitope C₆₄₋₇₂ has potential to be used in the development of immunotherapeutic approaches to HBV infection.

Design of therapeutic vaccines: hepatitis B as an example

Therapeutic vaccines are currently developed for chronic viral infections, such as human papillomavirus (HPV), human immunodeficiency virus (HIV), herpesvirus and hepatitis B (HBV) and C (HCV) virus infections. As an alternative to antiviral treatment or to support only partially effective therapy a therapeutic vaccine shall activate the patient's immune system to fight and finally control or ideally even eliminate the virus. Whereas the success of prophylactic vaccination is based on rapid neutralization of the invading pathogen by antibodies, virus control and elimination of infected cells require T cells. Therefore, induction of a multi-specific and multifunctional T-cell response against key viral antigens is a paradigm of therapeutic vaccination--besides activation of a humoral immune response to limit virus spread. In this review, we describe options to develop a therapeutic vaccine for chronic viral infections using HBV as a promising example.

Immunopathogenesis and prognostic immune markers of chronic hepatitis B virus infection

Host immune responses induced by hepatitis B virus (HBV) infection not only substantially drive disease progression, but also significantly influence efficacy of antiviral treatments in HBV-infected individuals. Therefore, it is important to fully understand the course of immune pathogenesis and to find efficient immunological markers that can predict the disease progression of chronic HBV infection. This review introduces the current progress in clinical immunology and analyzes the mechanisms of antiviral effects and liver injury, which are induced by both innate and adaptive immune responses. The recently identified immunological markers indicated to be closely correlated with disease progression and antiviral efficacy during HBV infection are also summarized. Careful monitoring of these immune markers may help physicians to make decisions on when to begin or withdraw antiviral drugs, or to formulate the prognosis of acute-on-chronic liver failure (ACLF) patients in the clinic. Finally, this review highlights some novel therapeutic strategies to modulate host immunity that have been proposed to sustain antiviral control of chronic HBV infection, as well as the challenges that we are presently facing in the field.

Reversal of hepatitis B virus-induced immune tolerance by an immunostimulatory 3p-HBx-siRNAs in a retinoic acid inducible gene I-dependent manner

It is extensively accepted that hepatitis B virus (HBV) escapes from innate immunity by inhibiting type I interferon (IFN) production, but efficient intervention to reverse the immune tolerance is still not achieved. Here, we report that 5'-end triphosphate hepatitis B virus X gene (HBx)-RNAs (3p-HBx-short interfering [si]RNAs) exerted significantly stronger inhibitory effects on HBV replication than regular HBx-siRNAs in stably HBV-expressing hepatoplastoma HepG2.2.15 cells through extremely higher expression of type I IFNs, IFN-induced genes and proinflammatory cytokines, and retinoic acid inducible gene I (RIG-I) activation. Also, 3p-HBx-siRNA were more efficient to stimulate type I IFN response than HBx sequence-unrelated 3p-scramble-siRNA in HepG2.2.15 cells, indicating that a stronger immune-stimulating effect may partly result from the reversal of immune tolerance through decreasing HBV load. In RIG-I-overexpressed HepG2.2.15 cells, 3p-HBx-siRNAs exerted stronger inhibitory effects on HBV replication with greater production of type I IFNs; on the contrary, in RIG-I-silenced HepG2.2.15 cells or after blockade of IFN receptor by monoclonal antibody, inhibitory effect of 3p-HBx-siRNAs on HBV replication was largely attenuated, indicating that immunostimulatory function of 3p-HBx-siRNAs was RIG-I and type I IFN dependent. Moreover, in HBV-carrier mice, 3p-HBx-siRNA more strongly inhibited HBV replication and promoted IFN production than HBx-siRNA in primary HBV(+) hepatocytes and, therefore, significantly decreased serum hepatitis B surface antigen and increased serum IFN-β.

CONCLUSION

3p-HBx-siRNAs may not only directly inhibit HBV replication, but also stimulate innate immunity against HBV, which are both beneficial for the inversion of HBV-induced immune tolerance.

Kinetics of immune responses to hepatitis B virus infection

The pathogenesis of hepatitis B is mainly triggered by the host's cellular immune responses to hepatitis B virus (HBV) infection, and the immune responses against the virus depends on the interaction of various immune cells. Current research of immunity to hepatitis B infection mainly focuses on understanding the differences between patients who can control HBV infection and those with persistent infection. In this paper, we analyze how immunological events influence the development of innate and adaptive immunity needed to control HBV infection and explore the mechanisms by which high levels of viral antigens, CD4⁺ T cells, programmed death 1 (PD-1), the presence of regulatory T cells, and impaired dendritic cell functions maintain the HBV-specific immunological failure.

Hyper-activated pro-inflammatory CD16 monocytes correlate with the severity of liver injury and fibrosis in patients with chronic hepatitis B

BACKGROUND

Extensive mononuclear cell infiltration is strongly correlated with liver damage in patients with chronic hepatitis B virus (CHB) infection. Macrophages and infiltrating monocytes also participate in the development of liver damage and fibrosis in animal models. However, little is known regarding the immunopathogenic role of peripheral blood monocytes and intrahepatic macrophages.

METHODOLOGY/PRINCIPAL FINDINGS

The frequencies, phenotypes, and functions of peripheral blood and intrahepatic monocyte/macrophage subsets were analyzed in 110 HBeAg positive CHB patients, including 32 immune tolerant (IT) carriers and 78 immune activated (IA) patients. Liver biopsies from 20 IA patients undergoing diagnosis were collected for immunohistochemical analysis. IA patients displayed significant increases in peripheral blood monocytes and intrahepatic macrophages as well as CD16(+) subsets, which were closely associated with serum alanine aminotransferase (ALT) levels and the liver histological activity index (HAI) scores. In addition, the increased CD16(+) monocytes/macrophages expressed higher levels of the activation marker HLA-DR compared with CD16(-) monocytes/macrophages. Furthermore, peripheral blood CD16(+) monocytes preferentially released inflammatory cytokines and hold higher potency in inducing the expansion of Th17 cells. Of note, hepatic neutrophils also positively correlated with HAI scores.

CONCLUSIONS

These distinct properties of monocyte/macrophage subpopulations participate in fostering the inflammatory microenvironment and liver damage in CHB patients and further represent a collaborative scenario among different cell types contributing to the pathogenesis of HBV-induced liver disease.

Decreased ratio of Treg cells to Th17 cells correlates with HBV DNA suppression in chronic hepatitis B patients undergoing entecavir treatment

Background

Treatment with nucleotide analogs is known to be effective in inhibiting HBV replication; however, patients with chronic hepatitis B (CHB) often show a wide range of clinical responses to these drugs. Therefore, the identification of an early immunologic marker associated with the clinical outcomes in such cases is critical for the improved clinical management. In our study, we aimed to investigate whether the viral load in CHB patients affected the ratio of the number of regulatory T cells (Tregs) to the number of interleukin-17-producing helper (Th17) cells. Further, we evaluated the clinical implications of the alterations in this ratio.

Methodology/Principal Findings

Nine patients seropositive for hepatitis B e antigen received entecavir monotherapy for 12 months and the percentages of Tregs and Th17 cells as well as the HBV-specific IL-17 productions in these patients were longitudinally analyzed. The entecavir-induced suppression of HBV replication was accompanied by a rapid increase in the number of Th17 cells, together with a decrease in Treg cells, which lead to a significant reduction of Treg/Th17 ratios. In addition, peripheral blood mononuclear cells (PBMCs) exhibited a decreased IL-17 production upon stimulation with the HBV core antigen in vitro.

Conclusions

The inhibition of viral replication results in an increase in Th17 cells and concomitant decrease in Treg cells. This imbalance of Treg cells to Th17 cells might have an important role in HBV persistence during entecavir treatment.

Hepatitis B e antigen seroconversion: a critical event in chronic hepatitis B virus infection

BACKGROUND

Replication of hepatitis B virus (HBV) is the primary driver of disease progression and clinical outcomes in patients with chronic hepatitis B (CHB), but other factors, such as hepatitis B e antigen (HBeAg) status, also influence disease course. The importance of HBeAg seroconversion is underscored by current CHB treatment guidelines that recommend limiting the duration of antiviral therapy in HBeAg-positive patients who achieve seroconversion.

AIMS

A 2-day meeting of leading hepatologists with extensive experience managing patients with CHB in the Asia-Pacific region was held with the overall goals of reviewing and evaluating (1) available data on the relationship between HBeAg seroconversion and clinical outcomes for patients with HBeAg-positive CHB, and (2) the ways in which seroconversion should influence patient management.

CONCLUSIONS

It was agreed that HBeAg seroconversion is an important serologic end point for patients with CHB and that achieving this goal should be an important consideration in treatment selection. Patients with HBeAg-positive CHB should consider pegylated interferon if they are aged < 40 years (especially women), have lower HBV DNA levels, can afford this treatment, and have a lifestyle that would support adherence to injection therapy. Alternatively, nucleos(t)ide analogs are recommended in patients with alanine aminotransferase levels ≥ 2 × the upper limit of normal, HBV DNA levels < 9 log(10) IU/ml, and compensated CHB. Entecavir, telbivudine, and tenofovir may be used as first-line therapy; they can be administered as a finite therapeutic course in HBeAg-positive patients who seroconvert. Telbivudine and tenofovir should be considered in women of child-bearing potential.

Unique hepatitis B virus subgenotype in a primitive tribal community in eastern India

Hepatitis B virus (HBV) strains isolated from members of the primitive Paharia ethnic community of Eastern India were studied to gain insight into the genetic diversity and evolution of the virus. The Paharia tribe has remained quite separate from the rest of the Indians and differs culturally, genetically, and linguistically from the mainstream East Indian population, whose HBV strains were previously characterized. Full-length HBV DNA was PCR amplified, cloned, and sequenced. Phylogenetic relationships between the tribal sequences and reference sequences from the mainstream population were assessed, and divergence times of subgenotypes of HBV genotype D were estimated. HBV was found in 2% of the Paharias participating in the study. A predominance of hepatitis B e antigen-negative infection (73%) was observed among the Paharias, and the genome sequences of the HBV strains exhibited relative homogeneity, with a very low prevalence of mutations. The novel feature of Paharia HBV was the exclusive presence of the D5 subgenotype, which was recently identified in Eastern India. Analysis of the four open reading frames (ORFs) of these tribal HBV D5 sequences and comparison with previously reported D1 to D7 sequences enabled the identification of 27 specific amino acid residues, including 6 unique ones, that could be considered D5 signatures. The estimated divergence times among subgenotypes D1 to D5 suggest that D5 was the first to diverge and hence is the most ancient of the D subgenotypes. The presence of a specific, ancient subgenotype of HBV within an ethnically primitive, endogamous population highlights the importance of studies of HBV genetics in well-separated human populations to understand viral transmission between communities and genome evolution.