Cells In Chronic Hepatitis B Patients Research Articles

Insights into Immune Exhaustion in Chronic Hepatitis B: A Review of Checkpoint Receptor Expression.

Hepatitis B, caused by the hepatitis B virus (HBV), often progresses to chronic infection, leading to severe complications, such as cirrhosis, liver failure, and hepatocellular carcinoma. Chronic HBV infection is characterized by a complex interplay between the virus and the host immune system, resulting in immune cell exhaustion, a phenomenon commonly observed in chronic viral infections and cancer. This state of exhaustion involves elevated levels of inhibitory molecules, cells, and cell surface receptors, as opposed to stimulatory counterparts. This review aims to elucidate the expression patterns of various co-inhibitory and co-stimulatory receptors on immune cells isolated from chronic hepatitis B (CHB) patients. By analyzing existing data, the review conducts comparisons between CHB patients and healthy adults, explores the differences between HBV-specific and total T cells in CHB patients, and examines variations between intrahepatic and peripheral immune cells in CHB patients. Understanding the mechanisms underlying immune exhaustion in CHB is crucial for developing novel immunotherapeutic approaches. This detailed analysis sheds light on the immune exhaustion observed in CHB and lays the groundwork for future combined immunotherapy strategies aimed at leveraging checkpoint receptors to restore immune function and improve clinical outcomes.

Single-cell RNA sequencing reveals the immunoregulatory roles of PegIFN-α in patients with chronic hepatitis B.

Chronic hepatitis B (CHB) is caused by HBV infection and affects the lives of millions of people worldwide by causing liver inflammation, cirrhosis, and liver cancer. Interferon-alpha (IFN-α) therapy is a conventional immunotherapy that has been widely used in CHB treatment and achieved promising therapeutic outcomes by activating viral sensors and interferon-stimulated genes (ISGs) suppressed by HBV. However, the longitudinal landscape of immune cells of CHB patients and the effect of IFN-α on the immune system are not fully understood. Here, we applied single-cell RNA sequencing (scRNA-seq) to delineate the transcriptomic landscape of peripheral immune cells in CHB patients before and after PegIFN-α therapy. Notably, we identified three CHB-specific cell subsets, pro-inflammatory (Pro-infla) CD14+ monocytes, Pro-infla CD16+ monocytes and IFNG+ CX3CR1- NK cells, which highly expressed proinflammatory genes and positively correlated with HBsAg. Furthermore, PegIFN-α treatment attenuated percentages of hyperactivated monocytes, increased ratios of long-lived naive/memory T cells and enhanced effector T cell cytotoxicity. Finally, PegIFN-α treatment switched the transcriptional profiles of entire immune cells from TNF-driven to IFN-α-driven pattern and enhanced innate antiviral response, including virus sensing and antigen presentation. Collectively, our study expands the understanding of the pathological characteristics of CHB and the immunoregulatory roles of PegIFN-α, which provides a new powerful reference for the clinical diagnosis and treatment of CHB.

Increased Non-MAIT CD161+CD8+ T Cells Display Pathogenic Potential in Chronic HBV Infection

CD161-expressing CD8+ T cells consist of mucosal-associated invariant T cells with semi-invariant T-cell receptor (TCR) use and non-mucosal-associated invariant T CD161+CD8+ T cells with polyclonal TCR repertoire. Although CD161+CD8+ T cells are enriched in liver and embrace hepatitis B virus (HBV)-specific T cells in chronic hepatitis B (CHB) patients, their roles in disease progression remain poorly understood. This study aimed to decipher their profiling and dynamic changes during chronic HBV infection. Blood samples from 257 CHB patients and nontumor liver specimens from 73 HBV-positive patients were analyzed for CD161+CD8+ T-cell characterization by flow cytometry, TCR repertoire determination, transcriptomic analyses, and cell experiments. CD161+CD8+ T cells were increased and hyperactivated in patients, while positive correlation between the CD161+CD8+ T-cell ratio and HBV-DNA level suggested this was insufficient to control HBV replication. The overlap of complementarity determining region 3 sequences supported the switch between CD161-CD8+ and CD161+CD8+ populations. Although CD161+CD8+ T cells were endowed with innateness phenotype and enhanced antiviral capacity, the population from patients had impaired type I cytokine production, and increased interleukin 17 and granzyme B secretion. The increased CD161+CD8+ T cells and their increased granzyme B secretion correlated positively with inflammation-associated liver injury. Hepatic CD161+CD8+ T cells showed neutrophil-related pathogenic potential because they had increased transcript signatures and proinflammatory cytokine production in neutrophil recruitment- and response-related pathways that changed consistently in the injured liver. Our results highlight the reduced antiviral potency but increased pathogenic potential of CD161+CD8+ T cells in CHB patients, supporting CD161 expression as a marker of pathogenic CD8+ T subset and the intervention target for liver injury.

Increased ILT2 expression contributes to dysfunction of CD56dimCD16+NK cells in chronic hepatitis B virus infection

Natural killer (NK) cells play a crucial role in the control of human viral infections but their activity is significantly impaired in patients infected with chronic hepatitis B (CHB). The mechanism that contributes to NK cell dysfunction in CHB needs further elucidation. In this study, we analyzed the expression and function of the novel inhibitory receptor immunoglobulin-like transcript-2 (ILT2) on NK cells from 131 CHB patients and 36 healthy controls. We observed that ILT2 expression on circulating CD56dimCD16+NK cells was increased in immune-tolerant, immune-active and HBeAg-negative hepatitis patients compared with inactive carriers and controls. The frequency of ILT2+CD56dimNK cells was positively correlated with serum viral load in immune-tolerant patients. The percentage of ILT2+CD56dimNK cells decreased along with HBV load in CHB patients who received antiviral therapy. Functional analysis showed that ILT2+CD56dimNK cells in CHB patients had significantly reduced degranulation and IFN-γ production. Upregulation of ILT2 was associated with high levels of apoptosis in CD56dimCD16+NK cells from CHB patients. ILT2 blockade was shown to increase the cytotoxicity and IFN-γ production of CD56dimNK cells in some CHB patients. Finally, ILT2 was found to be moderately upregulated by TGF-β1, which was increased in immune-tolerant, immune-active and HBeAg-negative hepatitis patients. Our results show that chronic HBV infection increases the levels of the inhibitory receptor ILT2 on CD56dimNK cells and inhibits their functions, providing a new mechanism of NK-cell disability in CHB patients.

HBV-Specific CD8+ T-Cell Tolerance in the Liver.

Hepatitis B virus (HBV) remains a leading cause of liver-related morbidity and mortality through chronic hepatitis that may progress to liver cirrhosis and cancer. The central role played by HBV-specific CD8+ T cells in the clearance of acute HBV infection, and HBV-related liver injury is now well established. Vigorous, multifunctional CD8+ T cell responses are usually induced in most adult-onset HBV infections, while chronic hepatitis B (CHB) is characterized by quantitatively and qualitatively weak HBV-specific CD8+ T cell responses. The molecular basis of this dichotomy is poorly understood. Genomic analysis of dysfunctional HBV-specific CD8+ T cells in CHB patients and various mouse models suggest that multifaceted mechanisms including negative signaling and metabolic abnormalities cooperatively establish CD8+ T cell dysfunction. Immunoregulatory cell populations in the liver, including liver resident dendritic cells (DCs), hepatic stellate cells (HSCs), myeloid-derived suppressor cells (MDSCs), may contribute to intrahepatic CD8+ T cell dysfunction through the production of soluble mediators, such as arginase, indoleamine 2,3-dioxygenase (IDO) and suppressive cytokines and the expression of co-inhibitory molecules. A series of recent studies with mouse models of HBV infection suggest that genetic and epigenetic changes in dysfunctional CD8+ T cells are the manifestation of prolonged antigenic stimulation, as well as the absence of co-stimulatory or cytokine signaling. These new findings may provide potential new targets for immunotherapy aiming at invigorating HBV-specific CD8+ T cells, which hopefully cures CHB.

Mechanism of gamma-chain cytokines in regulating the expression of T-cell immunoglobulin and mucin domain-containing molecule 3 in CD8 + T cells of chronic hepatitis B patients

Objective To investigate the mechanism of gamma-chain (γC) cytokines in regulating the expression of T-cell immunoglobulin and mucin domain-containing molecule 3 (TIM-3) in CD8+ T cells of chronic hepatitis B (CHB) patients. Methods A total of 23 CHB patients who attended Tangdu Hospital, Fourth Military Medical University, from January to May, 2017, were enrolled. Peripheral blood was collected from all patients, and Ficoll density gradient centrifugation was used to isolate peripheral blood mononuclear cells (PBMCs). PBMCs were stimulated with interleukin-7 (IL-7), interleukin-15 (IL-15), and interleukin-21, respectively, and then anti-γC antibody and/or anti-IL-7Rα, anti-IL-2Rβ, and anti-IL-21R were added to the culture solution. After 96 hours of culture, flow cytometry was used to measure the expression of TIM-3, interleukin-2 (IL-2), interleukin-10 (IL-10), and interferon-γ (IFNγ) and the phosphorylation level of signal transducer and activator of transcription (STAT) in CD8+ T cells. A one-way analysis of variance and the least significant difference t-test were used for comparison of continuous data. Results The CD8+ T cells stimulated by IL-7 and IL-15 had a significantly higher percentage of TIM-3-positive CD8+ T cells than those without stimulation (t=9.966 and 9.074, P Conclusion IL-7 and IL-15 can upregulate the expression of TIM-3 in CD8+ T cells of CHB patients, possibly via the γC receptor-mediated STAT-cytokine signaling pathway.

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

Little is known about the mechanisms of IL-17 secreting T cells accumulation in HBV-transfected livers. Here, we investigated the role of the chemokines CCL17, CCL20 and CCL22 in this process. Peripheral blood and liver tissues were obtained from 30 chronic hepatitis B (CHB) patients and 15 healthy volunteers and were evaluated by flow cytometric analysis and immunohistochemistry. Chemokine production by monocyte-derived dendritic cells (MoDCs) cocultured with HBV-transfected or untransfected Huh7 cells was measured by quantitative real-time PCR and enzyme-linked immunosorbent assay. The chemotactic activity of the culture supernatants was also tested. The proportions of IL-17 secreting CD4 (Th17) and CD8 (Tc17) T cells were both increased in liver and peripheral blood mononuclear cells of CHB patients compared to those in HVs. CHB patients showed higher intrahepatic levels of CCL17 mRNA, CCL22 mRNA, CCR6 mRNA and CCR4 mRNA than HVs. The expression of CCR6 and CCR4 on the surface of Th17 and Tc17 cells in CHB patients was also significantly higher than that in HVs. Significant correlations existed between the CCR4/CCR6 levels and both the alanine transaminase levels and HBV DNA loads. Contact between MoDCs and pBlue-HBV-transfected Huh7 cells induced the expression of CCL17 and CCL22 dependent on the dose of HBV DNA. However, CCL20 expression was lower in CHB patients than in HVs. Transwell experiments showed that upregulation of CCL17 and CCL22 enhanced the migration of IL-17 secreting T cells. Contact of HBV-transfected cells with MoDCs induces CCL17 and CCL22 chemokine production, which may favour the recruitment of Th17 and Tc17 cells to liver tissue in CHB. Our results reveal the mechanism of IL-17 secreting T cells recruitment to liver tissue and thus provide new immunotherapy targets for CHB patients.

CD8+CD28- T cells: key cytotoxic players impacting disease pathogenesis in chronic HBV infection.

During chronic hepatitis B (CHB), CD8+ T cells down-regulate CD28, the primary co-stimulation molecule for T-cell activation. Diverse functional attributes of CD8+CD28- T cells are suggested in various disease contexts. The present study aimed to characterize CD8+CD28- T cells in different phases of chronic Hepatitis B virus (HBV) infection (CHI)- Immune-tolerance (IT), Hepatitis B e-antigen-positive CHB (EP-CHB), Inactive carriers (IC) and Hepatitis B e-antigen-negative CHB (EN-CHB), to appraise their contribution in HBV-related disease pathophysiology. Flow cytometry analysis of T cells in peripheral blood of study subjects revealed enhanced CD8+CD28- T-cell accumulation in EP-/EN-CHB, compared with IT/IC and they expanded equivalently in HBV-specific and non-specific CD8+ T-cell compartments. Profound increase in CD8+CD28- T cells expressing perforin/granzyme-B/CD57/IFN-γ/TNF-α and markers of terminal differentiation were observed exclusively in EP-/EN-CHB. Further, activation with anti-NKG2D resulted in heightened IFN-γ/TNF-α production selectively from CD8+CD28- T cells, suggesting NKG2D-mediated alternative co-stimulation. CD8+CD28- T cells sorted from CHB patients induced enhanced apoptosis of peripheral blood mononuclear cells (PBMC), including CD4+ T cells. However, NKG2D-ligand (major histocompatibility complex class I chain-related molecule A/B (MICA/B)) was preferentially expressed by HBV-specific CD4+ T cells of CHB patients, making these cells a potential target to NKG2D-dependent CD8+CD28- T-cell killing. Both CD28+ and CD28- T cells in CHB expressedCXCR3 at similar levels and thus capable of homing to the liver. A positive correlation was seen between CD8+CD28- T-cell frequency and serum-alanine transaminase (ALT) levels and CHB-derived CD8+CD28- T cells caused pronounced cell death in HBV-transfected Huh7 cells. Immunofluorescence staining identified greater intrahepatic incidence of CD8+CD28- T cells but decline in CD4+ T cells in CHB than IC. Collectively, CD8+CD28- T cells demonstrated differential distribution and phenotypic/functional skewing in different CHI phases and contribute to disease progression by Perforin-Granzyme- or IFN-γ-TNF-α-mediated cytotoxicity while restraining antiviral immunity through NKG2D-dependent HBV-specific CD4+ T-cell depletion.

Differential Expression of Immune Inhibitory Checkpoint Signatures on Antiviral and Inflammatory T Cell Populations in Chronic Hepatitis B.

Virus-specific T cells are critical in mediating the pathogenesis of hepatitis B virus (HBV) infection. Interferon gamma (IFNγ)-producing T cells are associated with resolution; in contrast, interleukin-17 (IL-17)-producing T cells are linked to exacerbation of liver inflammation and injury. Checkpoint receptors stringently regulate T cell functions, with their expression profiles varying on different T cell subsets. Blockade of checkpoint receptors may be an effective therapeutic strategy for chronic hepatitis B (CHB); however, blockade may also inadvertently exacerbate proinflammatory responses. In this study, we sought to determine the balance of inflammatory and antiviral T cells and determine their inhibitory receptor profile. The frequency of total and HBV antigen-specific Th17 and Tc17 cells was higher in CHB patients compared with healthy controls (HCs). Th17 and Tc17 cells in CHB patients had significantly lower expression of T cell immunoglobulin and mucin domain protein-3 (TIM-3) compared with HCs, with no difference in programmed death-1 (PD-1) or CD244 expression. Conversely, Th1 and Tc1 cells in CHB patients hyperexpressed PD-1 and CD244, while TIM-3 expression was comparable in both cohorts. During CHB, antiviral IFNγ T cells hyperexpress multiple immune inhibitory receptors driving their functional impairment. In contrast, inflammatory Th17/Tc17 cells hypoexpress TIM-3, but not PD-1 or CD244. Checkpoint inhibitors for CHB should target PD-1 or CD244 to allow restoration of IFNγ responses without affecting inflammatory IL-17 production.

Correlation between toll-like receptor 9 expression in peripheral blood dendritic cells and interferon-α antiviral sustained virological response in patients with chronic hepatitis B

Purpose: To investigate the link between dendritic cells (DC cells), toll-like receptor 9 (TLR9) and tumor necrosis factor-α (TFN-α) expressions in peripheral blood of patients with chronic hepatitis B (CHB).Methods: Peripheral blood mononuclear cells (PBMC) and CD cells were prepared from CHB patients and healthy volunteers, and the cell proliferation was assessed. The surface expressions of CD83, CD86, CD40 and human leukocyte antigen DR (HLA-DR) on DC cells were assayed by flow cytometry, while the expressions of mRNAs of TLR9, MyD88 and NF-κB in each cell-group were determined by fluorescent quantitation PCR. Protein expressions of TLR9, MyD88 and NF-κB were analyzed by Western blot.Results: The rate of proliferation of DC cells in the CHB patients was slower than the rate in healthy volunteers (p < 0.05), and the expression of co-stimulatory molecules was significantly lower in CHB patients than in healthy volunteers (p < 0.05). The ability to stimulate T-lymphocyte proliferation of the CHB-DC group was much weaker than that of the D-NC group (p < 0.05). In fluorescent quantitation assays, the relative expressions of mRNAs of TLR9, MyD88 and NF-κB in cells of CpG-Stimulate ODN (CpG-S ODN) group were higher than those of the control group (p < 0.05), but the relative expressions of mRNAs of TLR9, MyD88 and NF-κB in the cells of the CpG-S ODN group were significantly lower (p < 0.05). Moreover, IFN-α level in the CpG-S ODN group was much higher than that in the control group (t = 6.633, p = 0.014 < 0.05). However, results from Western blot showed that the relative expressions of TLR9, MyD88 and NF-κB in the CpG-S ODN group were lower than in the control group (p < 0.05).Conclusion: These results indicate that TLR9 on the surface of DC cells of CHB patients can eliminate HBV by generating IFN-α via regulation of MyD88 and NF-κB.Keywords: Chronic hepatitis B, Dendritic cells, TLR9, IFN-α

Elevated Hepatic CD1d Levels Coincide with Invariant NKT Cell Defects in Chronic Hepatitis B Virus Infection.

Activation of invariant NKT (iNKT) cells manifests antiviral immune responses in vivo. However, clinical trials have failed to show consistent hepatitis B virus (HBV) DNA reduction postadministration of iNKT cell-specific agonist α-galactosylceramide (α-GalCer). In this study, we aimed to investigate HBV infection-related iNKT cell defects and explore iNKT cell-based therapeutic potential for chronic hepatitis B (CHB). Liver specimens from 30 HBV-infected hepatocellular carcinoma patients were collected for CD1d/hepatitis B surface Ag (HBsAg) staining and/or intrahepatic iNKT cell assay. Two hundred and six chronic HBV-infected patients (including 130 CHB patients) were enrolled in the study of circulating iNKT cell frequency and function. We found that liver and hepatoma tissue that positively stained for HBsAg had higher CD1d expression as compared with HBsAg negatively stained counterparts. The elevated CD1d expression in infected tissue is supposed to facilitate the iNKT cell-based antiviral effects locally. However, iNKT cell defects that related with disease progression suggested iNKT cells attenuated their effects during chronic HBV infection. The residual iNKT cells in CHB patients showed aberrant activation and hyporesponsiveness to α-GalCer. Exogenous IL-2 fully rescued α-GalCer-induced expansion of iNKT cells from CHB patients, and synergistic effects of IL-2 and IL-15 helped to recover the CD1d-dependent IFN-γ production. In conclusion, our results highlight the increased CD1d expression in HBV-infected liver and differential iNKT cell defects associated with disease progression during chronic HBV infection. The reversibility of iNKT cell defects suggests protective immune responses could be partially recovered in CHB.

Recovery of NK(CD56+CD3-) Cells after One Year of Tenofovir Therapy for Chronic Hepatitis B Infection.

Natural killer (NK) cells have been reported to be dysfunctional in chronic hepatitis B (CHB) infection. However, the functional recovery of NK cells under antiviral therapeutic agents in CHB was not clearly understood. In this study, we investigated the phenotypic changes of NK(CD56+CD3-) cells in terms of their functional markers (CD16, NKG2A, NKG2D) during tenofovir therapy in CHB. The frequency of NK(CD56+CD3-) cells in CHB patients was significantly increased after 12 months of tenofovir therapy when compared with baseline. The expression levels of CD16+/CD56+CD3- and NKG2A+/CD56+CD3- cells were also affected by tenofovir treatment. In addition, there was a positive correlation between the proportion of NK(CD56+CD3-) cells and HBV DNA (log copies/ml) in CHB patients.

CXCR5+CD8+T Cells Indirectly Offer B Cell Help and Are Inversely Correlated with Viral Load in Chronic Hepatitis B Infection

Treatment options for chronic hepatitis B (CHB) infection are extremely limited. CXCR5+ CD8+ T cell is a novel cell subtype and could possess strong cytotoxic properties in HIV infection. In this study, we investigated the role of CXCR5+ CD8+ T cells in CHB patients. Compared to healthy individuals, both CHB patients and hepatitis B virus (HBV)-infected hepatocellular carcinoma patients presented significant upregulation of CXCR5+ CD8+ T cells in peripheral blood, in which CXCR5+ CD8+ T cells were negatively correlated with the frequency of CXCR5+ CD4+ T cells in CHB patients. After PMA+ionomycin stimulation, CXCR5+ CD8+ T cells from CHB patients presented significantly higher transcription level of interferon gamma (IFN-γ), interleukin 10 (IL-10), and IL-21, as well as higher IL-10 and IL-21 protein secretion, than CXCR5- CD8+ T cells. Unlike CXCR5+ CD4+ T cells, when incubated with naive CD19+CD27- B cells, CXCR5+ CD8+ T cells alone did not upregulate IgM, IgG, and IgA secretion. However, addition of CXCR5+ CD8+ T cells in B cell-CXCR5+ CD4+ T cell coculture significantly increased the levels of secreted IgG and IgA, demonstrating that CXCR5+ CD8+ T cell could indirectly offer B cell help. Furthermore, high frequencies of CXCR5+ CD8+ T cells tended to associate with low HBV DNA load, and the frequency of CXCR5+ CD8+ T cells was negatively correlated with alanine aminotransferase (ALT) level. Together, these results suggested that CXCR5+ CD8+ T cells were involved in the antiviral immune responses in CHB and could potentially serve as a therapeutic candidate.

Changes of hepatitis B core antigen-specific cytotoxic T lymphocytes in chronic hepatitis B patients during antiviral treatment and relapse after withdrawal of treatment

Objective To explore the potential mechanism of severe liver injury shortly after withdrawal of antiviral therapy in chronic hepatitis B (CHB) patients. Methods Forty-nine patients with chronic hepatitis B virus (HBV) infection from the Department of Infectious Diseases of the First Affiliated Hospital of Nanchang University and 8 healthy volunteers from August 2014 to March 2015 were included in this study. All of them were human leukocyte antigen (HLA)-A2-positive. CHB patients were classified into three groups, including 15 cases in immune-tolerance group, 20 cases in sustained antiviral treatment group, and 14 cases in recurrence of drug withdrawal group. The frequency of peripheral HLA-A0201-restricted hepatitis B core antigen (HBcAg)18-27 pentamer complex specific CD8+ T cells in CHB patients was analyzed by flow cytometry. Enzyme linked immunospot assay(ELISPOT) was used to detect interferon-gamma (IFN-γ) and tumor necrosis factor-α (TNF-α) secretions of HBcAg18-27-specific CD8+ T cells. The experimental data were analyzed using non-parametric U tests. Results In healthy control group, immune-tolerance group, sustained antiviral treatment group and recurrence of drug withdrawal group, the frequencies of HBcAg-specific CD8+ T cells were (0.17±0.16)%, (1.46±0.72)%, (3.24±1.60)% and (4.67±2.43)%, respectively. Compared with healthy control group, the difference were all statistically significant in the three groups (Z=-3.583, -4.018 and -3.823, respectively; all P<0.01). The frequencies of HBcAg-specific CD8+ T cells in immune-tolerance group or recurrence of drug withdrawal group were both significantly different from that in sustained antiviral therapy group (Z=-3.400 and -2.030, respectively; both P<0.05). The difference between immune-tolerance group and recurrence of drug withdrawal group was also significant (Z=-3.230, P<0.01). The secretion levels of IFN-γ of HBcAg-specific CD8+ T cells in healthy control group, immune-tolerance group, sustained antiviral treatment group and recurrence of drug withdrawal group were 2 (0-6), 16 (2-53), 106 (14-254) and 156 (28-395) spot forming cell (SFC)/106 peripheral blood mononuclear cell (PBMC), respectively. The differences between healthy control group and immune-tolerance group, sustained antiviral treatment group or recurrence of drug withdrawal group were all statistically significant (Z=-3.585, -4.069 and -3.824, respectively; all P<0.01). The IFN-γ level of HBcAg-specific CD8+ T cells in recurrence of drug withdrawal group was significantly higher than that in sustained antiviral therapy group (Z=-2.205, P=0.027), and that in sustained antiviral therapy group was significantly higher than that in immune-tolerance group (Z=-4.700, P<0.01). The TNF-α levels secreted by HBcAg-specific CD8+ T cells in each group were 2 (0—5), 16 (2—32), 112 (15—283), and 195 (55—537) SFC/106 PBMC, respectively. The differences between healthy control group and immune-tolerance group, sustained antiviral treament group or recurrence of drug withdrawal group were all statistically significant (Z=-3.619, -4.069 and -3.824, respectively; all P<0.01). The TNF-α level secreted by HBcAg-specific CD8+ T cells in recurrence of drug withdrawal group was significantly higher than that in sustained antiviral therapy group (Z=-2.449, P=0.014), and that in sustained antiviral therapy group was significantly higher than that in immune-tolerance group (Z=-4.350, P<0.01). Conclusions The changes of frequency and immune function of HBcAg-specific CD8+ T cells in CHB patients may be one of the reasons causing severe liver damage after irregular withdrawal of nucleoside analogues. Key words: Hepatitis B; T-lymphocytes, cytotoxic; Antiviral treatment; Recurrence

Altered Immune Profiles of Natural Killer Cells in Chronic Hepatitis B Patients: A Systematic Review and Meta-Analysis.

BackgroundNatural killer (NK) cells are the main effective component of the innate immune system that responds to chronic hepatitis B (CHB) infection. Although numerous studies have reported the immune profiles of NK cells in CHB patients, they are limited by inconsistent results. Thus, we performed a meta-analysis to characterize reliably the immune profiles of NK cells after CHB infection, specifically frequency, phenotype, and function.MethodsA literature search of the computer databases MEDLINE, PUBMED, EMBASE, and Cochrane Center Register of Controlled Trails was performed and 19 studies were selected. The standard mean difference (SMD) and 95% confidence interval (CI) of each continuous variable was estimated with a fixed effects model when I2 < 50% for the test for heterogeneity, or the random effects model otherwise. Publication bias was evaluated using Begg’s and Egger’s tests.ResultsThe meta-analysis of publications that reported frequency of peripheral NK cells showed that NK cell levels in CHB patients were significantly lower compared with that of healthy controls. A higher frequency of CD56bright NK subsets was found in CHB patients, but the CD56dim NK subsets of CHB patients and healthy controls were similar. CHB patients before and after antiviral therapy with nucleotide analogues (NUCs) showed no statistical difference in NK frequency. The activating receptors were upregulated, whereas inhibitory receptors were comparable in the peripheral NK cells of CHB individuals and healthy controls. NK cells of CHB patients displayed higher cytotoxic potency as evidenced by CD107a protein levels and conserved potency to produce interferon-gamma (IFNγ), compared with their healthy counterparts.ConclusionOur results revealed that CHB patients had a lower frequency of NK cells compared with healthy individuals not treatable with antiviral NUC therapy. With an activating phenotype, NK cells in CHB patients showed better cytotoxic potency and conserved IFNγ production.

Roles of the programmed cell death 1, T cell immunoglobulin mucin-3, and cluster of differentiation 288 pathways in the low reactivity of invariant natural killer T cells after chronic hepatitis B virus infection.

One of the main responses of invariant natural killer T (iNKT) cells to antigen stimulation is the rapid production of interleukin (IL)-4 and interferon (IFN)-γ cytokines. There is a decline in the function of iNKT cells in chronic hepatitis B (CHB) patients. In this study, we explored the impact of programmed cell death 1 (PD-1), T cell immunoglobulin mucin-3 (Tim-3), and cluster of differentiation 28 (CD28) expression on iNKT cell functions in CHB patients. Flow cytometry was used to test iNKT frequencies and levels of PD-1, Tim-3, CD28, IL-4, and IFN-γ secreted by iNKT cells. An enzyme-linked immunosorbent assay (ELISA) was used to measure IL-4 and IFN-γ secretion upon α-galactosylceramide (α-GalCer) activation ex vivo. We found that the levels of expression of PD-1 and Tim-3 from iNKT cells in CHB patients were significantly higher than in healthy donors (p<0.05), but there was lower expression of CD28 (p<0.05) and an impaired capability to produce IL-4 and IFN-γ (p<0.05). In vitro α-GalCer stimulation upregulated the expression of PD-1(+) iNKT cells (p<0.05), Tim-3(+) iNKT cells (p<0.05), and CD28(+) iNKT cells (p<0.05). In response to combination therapies consisting of α-GalCer and anti-PDL1 monoclonal antibody (mAb) and/or anti-Tim-3 mAbs and/or anti-CD80/anti-CD28 mAbs, IL-4(+) and IFN-γ(+) iNKT cells demonstrated different degrees of growth (p<0.05). The functional decline of iNKT cells was closely related to the decrease in CD28 expression and the increases of Tim-3 and PD-1. In addition, clinical antiviral treatment with lamivudine could partially restore the immune function of iNKT cells in CHB patients.

IL-35 expression in peripheral blood CD4+ T cells from chronic hepatitis B virus-infected patients directly correlates with virus load

Interleukin 35 (IL-35) functions in an anti-inflammatory fashion by inhibiting T-cell proliferation, whereas CD4+ T cells play an important role in cellular immunity. In a hepatitis B virus (HBV) infection, the viral proteins stimulate the immune system to generate antiviral molecules, which correlate to HBV DNA load. We investigated the impact of HBV DNA load on the expression of IL-35 mRNA in CD4+ T cells, and the expression of IL-35 cytokine in serum of the patients with chronic HBV infection. Here we report that the frequency of circulating CD4+ T cells correlates with the HBV DNA load in the serum of chronic hepatitis B (CHB) patients. An increased number of CD4+ T cells were found in those patients with higher levels of HBV DNA. Regulatory T cells (T regs) also showed this trend, but circulating cytotoxic lymphocytes (CTLs) showed a negative correlation with serum HBV DNA load. In addition, significantly more IL-35 mRNA was found in the CD4+ T cells of CHB patients, compared to healthy controls. Patients in the high viral load group showed increased levels of IL-35 mRNA, compared with those in the low viral load group. The level of IL-35 cytokine in the serum of CHB patients was significantly higher than in the healthy controls and in those infected with HBV, the patients with a higher viral load had more serum IL-35 cytokines, compared to those with a lower viral load. Our study suggests that increased serum IL-35 could be directly related to increased levels of IL-35 mRNA in CD4+ T cells and HBV DNA load in CHB patients. The possible role of IL-35 as an immune regulator in chronic HBV infection should be investigated further.

Tim‐3 expression on peripheral monocytes and CD3+CD16/CD56+natural killer‐like T cells in patients with chronic hepatitis B

Hepatitis B virus (HBV) infection is one of the major causes of chronic liver inflammation. Tim-3 acts as a negative regulatory molecule and plays a critical role in immune tolerance. In the current study, we investigated Tim-3 expression on peripheral monocytes and CD3+CD16/CD56+ natural killer like T (NKT-like) cells in chronic hepatitis B (CHB) patients. Peripheral blood mononuclear cells (PBMCs) were isolated from 52 CHB patients and 60 healthy controls. Tim-3+CD14+ cells and Tim-3+CD3+CD16/CD56+ cells were analyzed by flow cytometry. Results showed that expression of Tim-3 was significantly increased on both the monocytes and NKT-like cells in CHB patients than in controls (P = 0.002 and P < 0.001, respectively). Tim-3 levels on monocytes and NKT-like cells were further upregulated in patients with acute-on-chronic liver failure (ACLF). In addition, we assessed the correlation of Tim-3 expression with levels of alanine aminotransferase (ALT) and tumor necrosis factor alpha (TNF-α). Data revealed that Tim-3 expression on both monocytes and NKT-like cells was positively correlated with level of ALT (r = 0.59, P < 0.001, and r = 0.60, P < 0.001, respectively), whereas Tim-3 expression on NKT-like cells was negatively correlated with serum level of TNF-α (r = -0.54, P < 0.001) in CHB patients. Our results suggest that Tim-3 may play important roles in the pathogenesis of CHB.

B and T lymphocyte attenuator is highly expressed on intrahepatic T cells during chronic HBV infection and regulates their function

T cell antiviral function is impaired during chronic hepatitis B (CHB). Programmed death-1 (PD-1) impairs antiviral T cell responses, but dysfunction is not always reversed by blockade of PD-1 pathway. Whether distinct T cell populations expressing different sets of inhibitory molecules exist has not been determined. We studied the expression of the B and T lymphocyte attenuator (BTLA) on both peripheral blood mononuclear cells (PBMC) and intrahepatic lymphocytes, and the effects of blocking BTLA on circulating and intrahepatic T cells in CHB patients. Sixty-three CHB patients who underwent liver biopsy were enrolled. The expression of BTLA and PD-1 on PBMC and intrahepatic T cells was assessed by flow cytometry with antibodies to T cell differentiation molecules. Functional recovery was evaluated by analyzing production of interferon (IFN)-γ and interleukin (IL)-2 after incubation of T cells with anti-CD3 and irradiated mature dendritic cells in the presence of anti-BTLA, anti-PD-1, or both. Intrahepatic T cells expressed higher levels of BTLA than their peripheral counterparts. A significant fraction of intrahepatic T cells coexpressed BTLA and PD-1 and showed deep exhaustion of T cell responses. Blockade of the BTLA pathway enhanced both intrahepatic and PBMC T cell proliferation and cytokine secretion, and exhibited an additive effect upon blockage of PD-1. Upregulation of inhibitory receptor BTLA restricts T cell responses in CHB. T cell exhaustion by high antigen concentrations exacerbates dysfunction of peripheral and intrahepatic T cells. Blockage of BTLA is a potential therapeutic approach for chronic HBV infection that may act by restoring antiviral T cell responses.

Treatment with telbivudine positively regulates antiviral immune profiles in Chinese patients with chronic hepatitis B.

Chronic infection with hepatitis B virus (HBV) is associated with impairment of T and NK cell immunity. This study was aimed at investigating the impact of treatment with telbivudine (LDT) on T and NK cell immunity in patients with chronic hepatitis B (CHB). A total of 54 CHB patients and 30 healthy controls (HC) were recruited. Individual patients were treated orally with 600 mg LDT daily for 13 months. The serum HBV DNA loads, the levels of the HBV-related biomarkers alanine aminotransferase (ALT) and aspartate transaminase (AST), and the numbers of different subsets of peripheral T and NK cells in subjects were measured before and longitudinally after LDT treatment. Following treatment with LDT, the serum HBV DNA loads and the percentages of HBsAg- or HBeAg-seropositive cases were gradually reduced, accompanied by decreased levels of serum ALT and AST. In comparison with the HC, fewer CD3(-) CD56(+) and CD244(+) NK cells and CD3(+) CD8(+) T cells, lower frequencies of cytokine(+) CD4(+) T cells, and more CD3(+) CD4(+), CD4(+) CD25(+) Foxp3(+), CD4(+) CD25(+) CD127(low), and CD8(+) PD-1(+) T cells were detected in CHB patients. Treatment with LDT increased the numbers of NK and CD8(+) cells and the frequencies of cytokine(+) CD4(+) T cells but reduced the numbers of CD4(+) CD25(+) Foxp3(+), CD4(+) CD25(+) CD127(low), and CD8(+) PD-1(+) T cells in CHB patients. The frequencies of cytokine(+) CD4(+) T cells were negatively associated with the levels of serum HBV DNA, ALT, and AST. Thus, treatment with LDT inhibits HBV replication, modulates T and NK cell immunity, and improves liver function in Chinese patients with CHB.