Inhibition of viral replication downregulates CD4(+)CD25(high) regulatory T cells and programmed death-ligand 1 in chronic hepatitis B

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

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

Immune checkpoints on T and NK cells in the context of HBV infection: Landscape, pathophysiology and therapeutic exploitation

In hepatitis B virus (HBV) infection, the interplay between the virus and the host immune system is crucial in determining the pathogenesis of the disease. Patients who fail to mount a sufficient and sustained anti-viral immune response develop chronic hepatitis B (CHB). T cells and natural killer (NK) cells play decisive role in viral clearance, but they are defective in chronic HBV infection. The activation of immune cells is tightly controlled by a combination of activating and inhibitory receptors, called immune checkpoints (ICs), allowing the maintenance of immune homeostasis. Chronic exposure to viral antigens and the subsequent dysregulation of ICs actively contribute to the exhaustion of effector cells and viral persistence. The present review aims to summarize the function of various ICs and their expression in T lymphocytes and NK cells in the course of HBV infection as well as the use of immunotherapeutic strategies targeting ICs in chronic HBV infection.

Regulatory T cells (Tregs) in liver fibrosis

The ability of the human liver to both synthesize extracellular matrix(ECM), as well as regulate fibrogenesis, are integral functions to maintaining homoeostasis. Chronic liver injury stimulates fibrogenesis in response to the imbalance between ECM accumulation and fibrosis resolution. Liver disease that induces fibrogenesis is associated with multiple risk factors like hepatitis infection, schistosomiasis, alcohol, certain drugs, toxicants and emerging aetiology like diabetes and obesity. The activation of hepatic stellate cells (HSCs), whose function is to generate and accumulate ECM, is a pivotal event in liver fibrosis. Simultaneously, HSCs selectively promote regulatory T-cells (Tregs) in an interleukin-2-dependent pattern that displays a dual relationship. On the one hand, Tregs can protect HSCs from NK cell attack, while on the other hand, they demonstrate an inhibitory effect on HSCs. This paper reviews the dual role of Tregs in liver fibrogenesis which includes its promotion of immunosuppression, as well as its activation of fibrosis. In particular, the balance between Tregs and the Th17 cell population, which produce interleukin (IL)-17 and IL-22, is explored to demonstrate their key role in maintaining homoeostasis and immunoregulation. The contradictory roles of Tregs in liver fibrosis in different immune microenvironments and molecular pathways need to be better understood if they are to be deployed to manage this disease.

A Review of Hepatitis B Virus and Hepatitis C Virus Immunopathogenesis

Despite the advances in therapy, hepatitis B virus (HBV) and hepatitis C virus (HCV) still represent a significant global health burden, both as major causes of cirrhosis, hepatocellular carcinoma, and death worldwide. HBV is capable of incorporating its covalently closed circular DNA into the host cell's hepatocyte genome, making it rather difficult to eradicate its chronic stage. Successful viral clearance depends on the complex interactions between the virus and host's innate and adaptive immune response. One encouraging fact on hepatitis B is the development and effective distribution of the HBV vaccine. This has significantly reduced the spread of this virus. HCV is a RNA virus with high mutagenic capacity, thus enabling it to evade the immune system and have a high rate of chronic progression. High levels of HCV heterogeneity and its mutagenic capacity have made it difficult to create an effective vaccine. The recent advent of direct acting antivirals has ushered in a new era in hepatitis C therapy. Sustained virologic response is achieved with DAAs in 85-99% of cases. However, this still leads to a large population of treatment failures, so further advances in therapy are still needed. This article reviews the immunopathogenesis of HBV and HCV, their properties contributing to host immune system avoidance, chronic disease progression, vaccine efficacy and limitations, as well as treatment options and common pitfalls of said therapy.

Association of T lymphocytes level and clinical severity in patients of COVID-19 in Shenzhen China

To explore the correlation between T lymphocytes and clinical severity in patients of COVID-19. A total of 183 COVID-19 patients were recruited in Shenzhen Third People’s Hospital from January 11 to February 16, 2020. According to the clinical classification criteria, they were divided into severe group (46 cases) and non-severe (137cases). T lymphocyte counts, lymphocyte subpopulation, IL-6 levels, and clinical outcomes were compared between the two groups. Compared with the non-severe group, the lymphocyte count, T lymphocyte count, T lymphocyte percentage, CD4+ T lymphocyte count, CD4+ T lymphocyte percentage, CD8+ T lymphocyte count, and CD8+ T lymphocyte percentage were lower in the severe group ( p < 0.05). Compared with the non-severe group, IL-6 were higher in the severe group ( p < 0.05). Compared with admission, the T lymphocyte count, CD4+ T lymphocyte count, and CD8+ T lymphocyte count were significantly increased upon discharge in severe patients, non-severe patients and all patients. Multivariate Logsitic regression analysis showed CD4+ T lymphocyte count (OR −0.011; 95% CI −0.041 to −0.001; p = 0.011), CD8+ T lymphocyte count (OR −0.14; 95% CI −0.048 to −0.003; p = 0.013) were closely correlated with the clinical severity in patients of COVID-19. Multivariate Logsitic regression analysis also showed CD4+ T lymphocyte count (OR −0.012; 95% CI −3.177 to 0.261; p = 0.021), CD8+ T lymphocyte count (OR −0.019; 95% CI −5.852 to 0.115; p = 0.004) were independent predictors of disease progressing to the composite endpoint. Subgroup analysis for critically ill patients: The T lymphocyte count, CD4+ T lymphocyte count, and CD8+ T lymphocyte count remained low in the death patients. The T lymphocyte count, CD4+ T lymphocyte count, and CD8+ T lymphocyte count recovered soon in the discharged patients. In the event of COVID-19 infection, the T-lymphoid system is the primary activated immune system. The T lymphocytes, CD4+ T lymphocytes, CD8+ T lymphocytes continued to be low may be significantly related to the deterioration of the disease, and may indicate a poor prognosis.

Treg/Th17 imbalance and its clinical significance in patients with hepatitis B-associated liver cirrhosis

BACKGROUND

Recent studies have shown that T cell-mediated cellular immune mechanisms play important roles in the progression of hepatitis B to liver cirrhosis, but the underlying mechanisms remain unclear. This present study was aimed to determine the relationship between Treg/Th17 and hepatitis B-associated liver cirrhosis.

METHODS

The Treg and Th17 cell frequencies in the peripheral blood of all participants, including 93 patients with hepatitis B-associated liver cirrhosis and 40 healthy subjects, were measured by flow cytometer. Cox regression model and receiver operating characteristic(ROC) curves were applied to investigate the prognostic significance of Treg/Th17 ratio in decompensated liver cirrhosis.

RESULTS

We observed the Treg/Th17 imbalance was present in patients with hepatitis B-associated liver cirrhosis, with reduced Treg cells in their peripheral blood, increased Th17 cells and decreased Treg/Th17 ratio. Treg and Th17 cells were negatively correlated. Treg/Th17 imbalance was closely related to the clinical stage of hepatitis B-associated liver cirrhosis. The Virus load, Treg frequencies and the Treg/Th17 ratio were independent factors predicting decompensated liver cirrhosis from a Cox regression model. The ROC analysis showed that the Treg/Th17 ratio was the best marker for predicting decompensated liver cirrhosis.

CONCLUSIONS

Treg/Th17 imbalance is involved in the pathogenesis of hepatitis B-associated liver cirrhosis and the Treg/Th17 ratio can be used as a potential marker for predicting decompensated liver cirrhosis.

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.

Vitamin E for the treatment of children with hepatitis B e antigen-positive chronic hepatitis: A systematic review and meta-analysis

AIM

To assess vitamin E efficacy, defined as its ability to induce hepatitis B e antigen (HBeAg) seroconversion, in children with HBeAg-positive persistent hepatitis.

METHODS

In July 2016, we extracted articles published in MEDLINE and the Cochrane Library using the following search terms: "chronic hepatitis B", "children", "childhood", "therapy", "treatment", "vitamin E", "tocopherols", "tocotrienols". Only randomized controlled trials (RCTs) published in English language were collected.

RESULTS

Three RCTs met inclusion criteria and were considered in the present meta-analysis. Overall, 23/122 children in the treatment group underwent HBeAg seroconversion vs 3/74 in the control group (OR = 3.96, 95%CI: 1.18-13.25, P = 0.025).

CONCLUSION

Although our meta-analysis has several limits, including the very small number of available studies and enrolled children with HBeAg positivity-related hepatitis, it suggests that vitamin E use may enhance the probability to induce HBeAg seroconversion in these patients. Further well designed and adequately sized trials are required to confirm or deny these very preliminary 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.

Serum Interleukin (IL)-9 and IL-10, but not T-Helper 9 (Th9) Cells, are Associated With Survival of Patients With Acute-on-Chronic Hepatitis B Liver Failure

CD4 T helper (Th) cells are reported to be essential for initiating and maintaining an effective immune response to hepatitis B virus (HBV) infection. Th9 cells are a new subset of CD4 Th cells that produce interleukin (IL)-9 and IL-10. The present study aimed to investigate the percentage of Th9 cells relative to the number of CD4 cells in peripheral blood. We also measured serum IL-9 and IL-10 levels in different stages of HBV infection and their relationship with progress and prognosis of liver disease. Whole blood samples from 111 patients with HBV infection, including 39 chronic hepatitis B (CHB), 25 HBV-liver cirrhosis (HBV-LC), 21 acute-on-chronic liver failure (ACLF) patients, and 26 healthy controls were collected. The percentage of Th9 cells and serum IL-9 and IL-10 levels were determined. There was no significant difference in the percentage of Th9 cells and serum IL-9 and IL-10 levels among different groups, nor were these related to hepatitis B e antigen status, complications of cirrhosis, inflammation index, or prognosis indexes. There was no change in the percentage of Th9 cells before and after antiviral treatment in CHB patients. There was no correlation of Th9 cells with survival of ACLF patients. However, IL-9 and IL-10 levels were significantly higher in the nonsurvived ACLF patients compared to survived ACLF patients. Furthermore, baseline IL-9 level predicted the prognosis of ACLF patients with 87.5% sensitivity and 61.5% specificity.Thus, our data indicate that Th9 cells were unlikely involved in the pathogenesis of HBV infection, but elevation in IL-9 and IL-10 may signal poor prognosis for ACLF.

A lack of Fas/FasL signalling leads to disturbances in the antiviral response during ectromelia virus infection

Ectromelia virus (ECTV) is an orthopoxvirus (OPV) that causes mousepox, the murine equivalent of human smallpox. Fas receptor-Fas ligand (FasL) signaling is involved in apoptosis of immune cells and virus-specific cytotoxicity. The Fas/FasL pathway also plays an important role in controlling the local inflammatory response during ECTV infection. Here, the immune response to the ECTV Moscow strain was examined in Fas (-) (lpr), FasL (-) (gld) and C57BL6 wild-type mice. During ECTV-MOS infection, Fas- and FasL mice showed increased viral titers, decreased total numbers of NK cells, CD4(+) and CD8(+) T cells followed by decreased percentages of IFN-γ expressing NK cells, CD4(+) and CD8(+) T cells in spleens and lymph nodes. At day 7 of ECTV-MOS infection, Fas- and FasL-deficient mice had the highest regulatory T cell (Treg) counts in spleen and lymph nodes in contrast to wild-type mice. Furthermore, at days 7 and 10 of the infection, we observed significantly higher numbers of PD-L1-expressing dendritic cells in Fas (-) and FasL (-) mice in comparison to wild-type mice. Experiments in co-cultures of CD4(+) T cells and bone-marrow-derived dendritic cells showed that the lack of bilateral Fas-FasL signalling led to expansion of Tregs. In conclusion, our results demonstrate that during ECTV infection, Fas/FasL can regulate development of tolerogenic DCs and Tregs, leading to an ineffective immune response.

CD4+CD25+ Regulatory T Cells Inhibit Natural Killer Cell Hepatocytotoxicity of Hepatitis B Virus Transgenic Mice via Membrane-Bound TGF-β and OX40

CD4+CD25+ regulatory T cells (Tregs) are involved in the regulation of physiological and pathological hepatic immune responses, but the roles are not well explored in natural killer (NK) cell-mediated liver diseases. In this study, using the NK cell-mediated oversensitive liver injury model of hepatitis B virus transgenic (HBs-Tg) mice triggered by a low dose of concanavalin A, it was observed that an increased number of CD4+CD25+Foxp3+ Tregs were accumulated in the liver, along with the recovery of liver injury. Adoptive transfer of hepatic Tregs from HBs-Tg mice but not wild B6 mice could significantly attenuate the oversensitive liver injury via inhibiting liver accumulation and decreasing NK cell group 2D-mediated activation of NK cells in the recipient HBs-Tg mice. Furthermore, upregulated expression of membrane-bound TGF-β (mTGF-β) and OX40 on hepatic Tregs were demonstrated to account for inhibiting the NK cell-mediated hepatic injury in HBs-Tg mice through cell-cell contact, confirmed by antibody blockade and cell Transwell experiments in vivo and in vitro. Our findings for the first time indicated that CD4+CD25+ Tregs directly suppressed NK cell-mediated hepatocytotoxicity through mTGF-β and OX40/OX40L interaction in a cell-cell contact manner in HBV-associated liver disease.

Efficacy of telbivudine in the treatment of chronic hepatitis b and liver cirrhosis and its effect on immunological responses

This study was aimed to evaluate the long-term effects of telbivudine (LdT) in the treatment of chronic hepatitis B (CHB) and HBV-related liver cirrhosis (LC) and to observe the changes of immunological responses during LdT treatment. Clinical data of 80 CHB and 28 HBV-related LC patients who were administered with LdT for 108 weeks and followed up were retrospectively analyzed. The liver function indicators including ALT, AST and γ-GT, HBV DNA copy number in serum and the rates of hepatitis B e antigen (HBeAg) seroconversion were analyzed before and 12, 24, 36, 48, 60, 72, 84, 96 and 108 weeks after LdT treatment in CHB and LC groups. Four serum fibrosis-related markers, including hyaluronic acid (HA), human laminin (LN), human type IV collagen (IV-C) and human N-terminal procollagen III peptide (PC-III), were detected before and after LdT treatment in LC group. The results showed favorable viral suppression and biochemical responses after treatment with LdT for 12 weeks, and a high rate of virological and biochemical control was maintained during the course of 108-week treatment in both CHB and LC groups. The four fibrosis-related markers, especially HA and LN, were down-regulated to some degrees in LC group. Moreover, LdT treatment led to the fluctuation of the circulating interferon-γ (IFN-γ) and interleukin-10 (IL-10) levels at different time points in CHB group. It was concluded that LdT could favorably lead to the virological suppression and biochemical remission. Besides, IFN-γ and IL-10 may represent a suitable and effective predictor of responsiveness during LdT therapy.

Significant roles of regulatory T cells and myeloid derived suppressor cells in hepatitis B virus persistent infection and hepatitis B virus-related HCCs

The adaptive immune system, including type1 helper T cells (Th1 cells), cytotoxic T lymphocytes (CTLs), and dendritic cells (DCs), plays an important role in the control of hepatitis B virus (HBV). On the other hand, regulatory T cells (Tregs) and myeloid derived suppressor cells (MDSCs) suppress the immune reaction in HBV and hepatocellular carcinoma (HCC). Excessive activation of immune suppressive cells could contribute to the persistent infection of HBV and the progression of HCC. The frequency and/or function of Tregs could affect the natural course in chronic hepatitis B patients and the treatment response. In addition to the suppressive function of MDSCs, MDSCs could affect the induction and function of Tregs. Therefore, we should understand in detail the mechanism by which Tregs and MDSCs are induced to control HBV persistent infection and HBV-related HCC. Immune suppressive cells, including Tregs and MDSCs, contribute to the difficulty in inducing an effective immune response for HBV persistent infection and HBV-related HCC. In this review, we focus on the Tregs and MDSCs that could be potential targets for immune therapy of chronic hepatitis B and HBV-related HCC.

Viral infection parameters not nucleoside analogue itself correlates with host immunity in nucleoside analogue therapy for chronic hepatitis B

AIM: To determine the relationship between host immunity and the characteristics of viral infection or nucleoside analogues (NAs) themselves in patients with chronic hepatitis B (CHB) receiving NA therapy.

METHODS: Fifty-two hepatitis B envelope antigen (HBeAg) positive CHB patients were enrolled and divided equally into two groups. One group received telbivudine (LDT, 600 mg/d), and the other group received lamivudine (LAM, 100 mg/d). Clinical, virological and immunological parameters were assessed at the baseline and at 4, 12, 24, 36 and 48 wk.

RESULTS: Both groups achieved significant hepatitis B virus (HBV) replication inhibition and alanine aminotransferase normalization at 48 wk. At the baseline, compared to healthy controls, CHB patients had a lower circulating CD8 T cell frequency (29.44% ± 11.55% vs 37.17% ± 7.30%, P = 0.03) and higher frequencies of programmed death 1 positive CD8 T cells (PD-1+ CD8 T) (16.48% ± 10.82% vs 7.02% ± 3.62%, P = 0.0001) and CD4+ CD25+ FoxP3+ T regulatory cells (Tregs) (23.64% ± 9.38% vs 13.60% ± 6.06%, P = 0.001). On therapy, at the beginning 24 wk with the levels of hepatitis B virus deoxyribonucleic acid (HBV DNA) and HBeAg declining, the frequencies of PD-1+ CD8 T cells and Treg cells gradually and significantly declined at 12 and 24 wk in both therapy groups. At treatment week 4, patients treated with LDT had a lower frequency of PD-1+ CD8 T cells compared to patients treated with LAM (10.08% ± 6.83% vs 20.51% ± 20.96%, P = 0.02). The frequency of PD-1+ CD8 T cells in all of the CHB patients was significantly correlated with both the HBV DNA level (r = 0.45, P = 0.01) and HBeAg level (r = 0.47, P = 0.01) at treatment week 24, but the frequency of Treg cells was only significantly correlated with the HBeAg level (r = 0.44,P = 0.02). Furthermore, the ability of CD8 T cells to secrete pro-inflammatory cytokines was partially restored after 24 wk of therapy.

CONCLUSION: NA-mediated HBV suppression could down-regulate the production of negative regulators of host immunity during the first 24 wk of therapy and could partially restore the ability of CD8 T cells to secrete pro-inflammatory cytokines. This immune modulating response may be correlated with the levels of both HBV DNA and HBeAg.

Advances in understanding relationship between peripheral blood CD4+CD25+ regulatory T cells and antiviral treatment in CHB patients

The immunosuppressive function of CD4⁺ CD25⁺ regulatory T cells may closely associate with the occurrence, development and prognosis of CHB patients. The change and function of CD4⁺CD25⁺ regulatory T cells in CHB patients undergoing antiviral treatment have aroused the attention of scholars. Here we review the types, immunophenotypes, and function of CD4⁺CD25⁺ regulatory T cells, as well as the relationship between peripheral blood CD4⁺CD25⁺ regulatory T cells and antiviral treatment in CHB patients.

CD4+CD25+ regulatory T cells and different states of HBV infection

CD4⁺CD25⁺ regulatory T cells are a recently discovered subset of CD4⁺ T cell population that mediates immune suppression. Recent studies suggested that regulatory T cells are closely associated with the prognosis of different states of HBV infection. Here we review the types, mechanisms of action and immunophenotypes of CD4⁺CD25⁺ regulatory T cells, as well as their relationship with different states of HBV infection.

Fallen angels or risen apes? A tale of the intricate complexities of imbalanced immune responses in the pathogenesis and progression of immune-mediated and viral cancers

Excessive immune responses directed against foreign pathogens, self-antigens, or commensal microflora can cause cancer establishment and progression if the execution of tight immuno-regulatory mechanisms fails. On the other hand, induction of potent tumor antigen-specific immune responses together with stimulation of the innate immune system is a pre-requisite for effective anti-tumor immunity, and if suppressed by the strong immuno-regulatory mechanisms can lead to cancer progression. Therefore, it is crucial that the inevitable co-existence of these fundamental, yet conflicting roles of immune-regulatory cells is carefully streamlined as imbalances can be detrimental to the host. Infection with chronic persistent viruses is characterized by severe immune dysfunction resulting in T cell exhaustion and sometimes deletion of antigen-specific T cells. More often, this is due to increased immuno-regulatory processes, which are triggered to down-regulate immune responses and limit immunopathology. However, such heightened levels of immune disruption cause a concomitant loss of tumor immune-surveillance and create a permissive microenvironment for cancer establishment and progression, as demonstrated by increased incidences of cancer in immunosuppressed hosts. Paradoxically, while some cancers arise as a consequence of increased immuno-regulatory mechanisms that inhibit protective immune responses and impinge on tumor surveillance, other cancers arise due to impaired immuno-regulatory mechanisms and failure to limit pathogenic inflammatory responses. This intricate complexity, where immuno-regulatory cells can be beneficial in certain immune settings but detrimental in other settings underscores the need for carefully formulated interventions to equilibrate the balance between immuno-stimulatory and immuno-regulatory processes.

Comparing the efficacy and clinical outcome of telbivudine and entecavir naïve patients with hepatitis B virus-related compensated cirrhosis

BACKGROUND AND AIM

There is limited data on the efficacy and outcome of telbivudine (LdT) therapy in patients with chronic hepatitis B and compensated cirrhosis. We evaluated LdT as first-line therapy in these patients and compared with those treated with entecavir (ETV).

METHODS

We consecutively enrolled 88 chronic hepatitis B patients with compensated cirrhosis primarily treated with LdT at least for 2 years or less than 2 years but developed resistance, and evaluated the efficacy and clinical outcomes. Meanwhile, we matched a control group who treated with ETV for comparison.

RESULTS

In LdT group, alanine aminotransferase normalization (65.8%), hepatitis B e antigen seroconversion (39.8%), hepatitis B virus (HBV) DNA undetectablility (71.6%), and virologic resistance (23.9%) were noted after 2 years treatment. Compared with ETV group, there were significant difference in HBV DNA undetectablility (P < 0.001) and virologic resistance (P < 0.001). In addition, the decline of serum hepatitis B surface antigen levels, hepatocellular carcinoma development, mortality, disease progression, and the change of renal function were similar. Cox regression analysis showed that pretreatment low albumin level and high model for end-stage liver disease scores were risk factors for disease progression.

CONCLUSIONS

These results indicated that although LdT and ETV are similar in clinical outcomes for patients with HBV-related compensated cirrhosis, LdT still had lower HBV undetectablility and higher resistant rate after 2 years treatment, which was a challenge for being as first-line therapy in these patients who need lifelong therapy.

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

Th17 cells and the secreting cytokines play an important role in the immune response and inflammation that is induced by hepatitis B virus (HBV). However, it remains not fully elucidated how the antiviral agents affect Th17 cytokines and signal pathway. Telbivudine therapy has been proved to inhibit HBV replication effectively and to improve clinical outcome of chronic hepatitis B (CHB). Thus, in this study, the effect of decrease in viral load and liver dysfunction resulting from telbivudine treatment on Th17 cells and the related cytokines IL-17, IL-22, and IL-23 were analyzed. Peripheral blood mononuclear cells and serum from twenty-four CHB patients were harvested at 0, 12, 24, 36, and 48 weeks after initiation of telbivudine treatment. In parallel to the reduction of HBV DNA and normalization of serum ALT, significant declines in circulating HBV-specific Th17 cells and IL-22 production were found during antiviral therapy. The expression of serum IL-22 and IL-23, but not IL-17 also decreased during therapy. Our findings suggest that antiviral effect of telbivudine may attribute to both direct virus inhibition and regulation of inflammation, which further improve the understanding of pathogenesis of HBV infection and develop antiviral strategy for controlling viral hepatitis.

CD69+NK cells contribute to the murine hepatitis virus strain 3-induced murine hepatitis

The role of hepatic CD69+ natural killer (NK) cells in virus-induced severe liver injury and subsequent hepatic failure is not well defined. In this study, a mouse model of fulminant liver failure (FHF) induced by murine hepatitis virus strain 3 (MHV-3) was used to study the role of hepatic CD69+NK cells in the development of FHF. The CD69 expression in NK cells in the liver, spleen, bone marrow and peripheral blood was detected by using flow cytometry. The correlation between the CD69 level in hepatic NK cells and liver injury was studied. The functional marker (CD107a), and activating and inhibitory receptor (NKG2D and NKG2A) expressed on CD69+NK cells and CD69-NK cells were detected by using flow cytometry. Pro-inflammatory cytokines (IL-9, IFN-γ and TNF-α) were also examined by using intracellular staining. After MHV-3 infection, the number of CD69+NK cells in the liver of BALB/cJ mice was increased markedly and peaked at 72 h post-infection. Similar changes were also observed in the spleen, bone marrow and peripheral blood. Meanwhile, the CD69 expression in hepatic NK cells was highly correlated with the serum level of ALT and AST. The expression of CD107a and NKG2D, as well as the production of TNF-α, IFN-γ and IL-9 in hepatic CD69+NK cells was all significantly up-regulated during 48-72 h post-infection. In contrast, the NKG2A expression was increased in hepatic CD69-NK cells but not in CD69+NK cells. These results suggested that hepatic CD69+NK cells play a pivotal role in the pathogenesis of FHF by enhancing degranulation and cytotoxic ability of NK cells and increasing the production of pro-inflammatory cytokines.

Liver FOXP3 and PD1/PDL1 Expression is Down-Regulated in Chronic HBV Hepatitis on Maintained Remission Related to the Degree of Inflammation

Background and Aim: T cell expression of PD1 and inhibition of T effector cells by Foxp3⁺-T regulatory cells are among the most powerful mechanisms for achieving a balanced immune response. Our aim was to investigate, how liver FOXP3 and PD1/PDL1 expression is regulated in chronic HBV hepatitis (CHB) on maintained long-term remission in comparison with active disease, and whether they are correlated to the expression of pro- and anti-inflammatory cytokines and apoptosis mediators, along with the degree of histological inflammation and markers of T cell effector restoration.

Methods: Fifty-three HBeAg-negative CHB patients with both active (30) and completely remitted disease on long-term antiviral treatment (23) and four controls (submitted to liver biopsy due to a mild increase of aminotransferases but without liver necroinflammatory and architecture changes) were enrolled in the study. Liver mRNA levels of immunoregulatory genes (FOXP3, IL10, TGFB1, and those of PD1/PDL1/PDL2 pathway), major apoptosis mediators (FAS, FASL, TNFA, TRAIL), cytokines of effector T cell restoration (IL2, IFNG), and those of IL1B, CD4, and CD8, were evaluated by quantitative real-time reverse-transcriptase PCR and were correlated with each other, along with the intensity of liver inflammation and fibrosis staging. The expression and localization of FOXP3, PD1, PDL1, CD4, and CD8 were also assessed by immunohistochemistry.

Results: The expression of FOXP3, IL10, TGFB1, PD1, PDL1, FASL, and CD8 was significantly down-regulated in the remission state. In contrast, liver expression of IL2 and IFNG, along with CD4, IL1B, TNFA, and FAS did not change significantly. Moreover, FOXP3, PD1, PDL1, and CD8 transcripts were positively correlated to the intensity of liver inflammation.

Conclusion: Our data indicate that in the CHB disease model, the immunosuppressive liver environment is down-regulated in the maintained on-treatment long-term remission state and correlates with the intensity of liver inflammation, but not liver T cell restoration.

High viral burden restricts short-lived effector cell number at late times postinfection through increased natural regulatory T cell expansion

Generating and maintaining a robust CD8(+) T cell response in the face of high viral burden is vital for host survival. Further, balancing the differentiation of effectors along the memory precursor effector cell pathway versus the short-lived effector cell (SLEC) pathway may be critical in controlling the outcome of virus infection with regard to clearance and establishing protection. Although recent studies have identified several factors that have the capacity to regulate effector CD8(+) T cell differentiation-for example, inflammatory cytokines-we are far from a complete understanding of how cells choose the memory precursor effector cell versus SLEC fate following infection. In this study, we have modulated the infectious dose of the poxvirus vaccinia virus as an approach to modulate the environment present during activation and expansion of virus-specific effector cells. Surprisingly, in the face of a high virus burden, the number of SLECs was decreased. This decrease was the result of increased natural regulatory T cells (Tregs) generated by high viral burden, as depletion of these cells restored SLECs. Our data suggest Treg modulation of differentiation occurs via competition for IL-2 during the late expansion period, as opposed to the time of T cell priming. These findings support a novel model wherein modulation of the Treg response as a result of high viral burden regulates late-stage SLEC number.

Telbivudine treatment is associated with high hepatitis B e antigen seroconversion and immune modulatory effects in chronic hepatitis B patients

Chronic hepatitis B (CHB) is characterized by an impaired immune response to hepatitis B virus. Among the nucleos(t)ides used in CHB treatment, telbivudine is associated with the highest rates of hepatitis B e antigen (HBeAg) seroconversion rates, which are similar to those observed with pegylated interferon (PegIFN). Besides direct antiviral effect, modulation of the immune system may be an additional benefit for telbivudine-treated patients. Indeed, there is much clinical data indicating an IFN-like behaviour for telbivudine in contrast to other oral nucleos(t)ides, such as high HBeAg seroconversion, similar hepatitis B surface antigen (HBsAg) decline and biphasic viral kinetics. Clinical studies, animal models and in vitro studies suggest that both the innate and adaptive immune system responses contribute to high HBeAg seroconversion during telbivudine treatment through modulation of the function and/or expression of CD4+/CD8+ T cells, Th1/Th2, Treg, PD-1/PD-L1, Th17, IL-21 and TFH. The results described in this review suggest that the antiviral effect of telbivudine may be attributable not only to direct suppression of hepatitis B virus, but also to immunoregulatory effects. Hypothetically, telbivudine shares some common signal pathways with IFN.

Effects of telbivudine and entecavir for HBeAg-positive chronic hepatitis B: a meta-analysis

AIM

To compare the effects of telbivudine (LDT) and entecavir (ETV) in treatment of hepatitis B e antigen (HBeAg)-positive chronic hepatitis B by meta-analysis.

METHODS

We conducted a literature search using PubMed, MEDLINE, EMBASE, the China National Knowledge Infrastructure, the VIP database, the Wanfang database and the Cochrane Controlled Trial Register for all relevant articles published before April 1, 2012. Randomized controlled trials (RCTs) comparing LDT with ETV for treatment of HBeAg-positive chronic hepatitis B were included. The data was analyzed with Review Manager Software 5.0. We used relative risk (RR) as an effect measure, and reported its 95% CI. Meta-analysis was performed using either a fixed-effect or random-effect model, based on the absence or presence of significant heterogeneity. Two reviewers assessed the risk of bias and extracted data independently and in duplicate. The analysis was executed using the main outcome parameters including hepatitis B virus (HBV) DNA undetectability, alanine aminotransferase (ALT) normalization, HBeAg loss, HBeAg seroconversion, drug-resistance, and adverse reactions. Meta-analysis of the included trials and subgroup analyses were conducted to examine the association between pre-specified characteristics with the therapeutic effects of the two agents.

RESULTS

Thirteen eligible trials (3925 patients in total) were included and evaluated for methodological quality and heterogeneity. In various treatment durations of 4 wk, 8 wk, 12 wk, 24 wk, 36 wk, 48 wk, 52 wk, 60 wk and 72 wk, the rates of HBV DNA undetectability and ALT normalization in the two groups were similar, without statistical significance. At 4 wk and 8 wk of the treatment, no statistical differences were found in the rate of HBeAg loss between the two groups, while the rate in the LDT group was higher than in the ETV group at 12 wk, 24 wk, 48 wk and 52 wk, respectively (RR 2.28, 95% CI 1.16, 7.03, P = 0.02; RR 1.45, 95% CI 1.16, 1.82, P = 0.001; RR 1.45, 95% CI 1.11, 1.89, P = 0.006; and RR 1.86, 95% CI 1.04, 3.32, P = 0.04). At 4 wk, 8 wk, 60 wk and 72 wk of the treatment, there were no significant differences in the rate of HBeAg seroconversion between the two groups, while at 12 wk, 24 wk, 48 wk and 52 wk, the rate in the LDT group was higher than in the ETV group (RR 2.10, 95% CI 1.36, 3.24, P = 0.0008; RR 1.71, 95% CI 1.29, 2.28, P = 0.0002; RR 1.86, 95% CI 1.36, 2.54, P < 0.0001; and RR 1.87, 95% CI 1.21, 2.90, P = 0.005). The rate of drug-resistance was higher in the LDT group than in the ETV group (RR 3.76, 95% CI 1.28, 11.01, P = 0.02). In addition, no severe adverse drug reactions were observed in the two groups. And the rate of increased creatine kinase in the LDT group was higher than in the ETV group (RR 5.58, 95% CI 2.22, 13.98, P = 0.0002).

CONCLUSION

LDT and ETV have similar virological and biomedical responses, and both are safe and well tolerated. However, LDT has better serological response and higher drug-resistance.

Regulatory T cells in HIV infection: can immunotherapy regulate the regulator?

Regulatory T cells (Tregs) have a dominant role in self-tolerance and control of autoimmune diseases. These cells also play a pivotal role in chronic viral infections and cancer by limiting immune activation and specific immune response. The role of Tregs in HIV pathogenesis remains poorly understood as their function, changes according to the phases of infection. Tregs can suppress anti-HIV specific responses and conversely can have a beneficial role by reducing the deleterious impact of immune activation. We review the frequency, function and homing potential of Tregs in the blood and lymphoid tissues as well as their interaction with dendritic cells in the context of HIV infection. We also examine the new insights generated by recombinant IL-2 and IL-7 clinical trials in HIV-infected adults, including the immunomodulatory effects of Tregs. Based on their detrimental role in limiting anti-HIV responses, we propose Tregs as potential targets for immunotherapeutic strategies aimed at decreasing Tregs frequency and/or immunosuppressive function. However, such approaches require a better understanding of the time upon infection when interfering with Treg function may not cause a deleterious state of hyperimmune activation.

Effects of telbivudine treatment on the circulating CD4⁺ T-cell subpopulations in chronic hepatitis B patients

CD4⁺ T cells serve as master regulators of the adaptive immune response to HBV. However, CD4⁺ T-cell subsets are heterogeneous, and it remains unknown how the antiviral agents affect the different CD4⁺ T cell subtypes. To this end, the expressions of signature transcription factors and cytokines of CD4⁺ T-cell subtypes were examined in hepatitis B patients before and after treatment with telbivudine. Results showed that, upon the rapid HBV copy decrease induced by telbivudine treatment, the frequencies and related cytokines of Th17 and Treg cells were dramatically decreased, while those for Th2 cells were dramatically increased. No obvious changes were observed in Th1 cell frequencies; although, IFN-γ expression was upregulated in response to telbivudine treatment, suggesting another cell source of IFN-γ in CHB patients. Statistical analyses indicated that Th17 and Tr1 (a Treg subtype) cells were the most sensitive subpopulations of the peripheral blood CD4⁺ T cells to telbivudine treatment over 52 weeks. Thus, Th17 and Tr1 cells may represent a suitable and effective predictor of responsiveness during telbivudine therapy. These findings not only improve our understanding of hepatitis pathogenesis but also can aid in future development of appropriate therapeutic strategies to control viral hepatitis.