Functional impairment of myeloid and plasmacytoid dendritic cells of patients with chronic hepatitis B

Metabolic deficiencies underlie reduced plasmacytoid dendritic cell IFN-I production following viral infection

Type I Interferons (IFN-I) are central to host protection against viral infections, with plasmacytoid dendritic cells (pDC) being the most significant source, yet pDCs lose their IFN-I production capacity following an initial burst of IFN-I, resulting in susceptibility to secondary infections. The underlying mechanisms of these dynamics are not well understood. Here we find that viral infection reduces the capacity of pDCs to engage both oxidative and glycolytic metabolism. Mechanistically, we identify lactate dehydrogenase B (LDHB) as a positive regulator of pDC IFN-I production in mice and humans; meanwhile, LDHB deficiency is associated with suppressed IFN-I production, pDC metabolic capacity, and viral control following infection. In addition, preservation of LDHB expression is sufficient to partially retain the function of otherwise exhausted pDCs, both in vitro and in vivo. Furthermore, restoring LDHB in vivo in pDCs from infected mice increases IFNAR-dependent, infection-associated pathology. Our work thus identifies a mechanism for balancing immunity and pathology during viral infections, while also providing insight into the highly preserved infection-driven pDC inhibition.

HBV and HBsAg strongly reshape the phenotype, function, and metabolism of DCs according to patients' clinical stage

BACKGROUND

Hepatitis B is a liver infection caused by HBV. Infected individuals who fail to control the viral infection develop chronic hepatitis B and are at risk of developing life-threatening liver diseases, such as cirrhosis or liver cancer. Dendritic cells (DCs) play important roles in the immune response against HBV but are functionally impaired in patients with chronic hepatitis B. The underlying mechanisms involved in HBV-induced DC dysfunctions remain to be elucidated.

METHODS

We explored DC modulations by HBV and HBsAg by exposing blood-derived cDC1s, cDC2s, and plasmacytoid DCs from healthy donors to HBV or HBsAg and stimulating them with toll-like receptor ligand. Their phenotypic and functional features, as well as their metabolic profile, were analyzed through multiparametric flow cytometry and multiplex assays and further explored on patients' samples.

RESULTS

We found that HBV deeply reshaped the DC secretome in response to toll-like receptor ligand. Strikingly, we observed that HBV-exposed DCs secrete high levels of CX3CL1 (fractalkine), a chemokine responsible for attracting antiviral effectors to the site of infection. HBsAg exposure favored DC activation while drastically altering TRAIL expression in response to toll-like receptor ligand and increasing the secretion of cytokines/chemokines involved in immune tolerance. HBsAg further dampened the metabolism of DC subsets while driving metabolic switches. Notably, the relevance of the CX3CL1/CX3CR1 axis, TGF-β, and metabolic disturbances was demonstrated within intrahepatic DC subsets in patients according to disease stage.

CONCLUSIONS

Our work brings new insights into the immunomodulation induced by HBV on DCs, which contribute to impaired antiviral responses and progression toward chronicity.

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.

Rupestonic Acid Derivative YZH-106 Promotes Lysosomal Degradation of HBV L- and M-HBsAg via Direct Interaction with PreS2 Domain

Hepatitis B surface antigen (HBsAg) is not only the biomarker of hepatitis B virus (HBV) infection and expression activity in hepatocytes, but it also contributes to viral specific T cell exhaustion and HBV persistent infection. Therefore, anti-HBV therapies targeting HBsAg to achieve HBsAg loss are key approaches for an HBV functional cure. In this study, we found that YZH-106, a rupestonic acid derivative, inhibited HBsAg secretion and viral replication. Further investigation demonstrated that YZH-106 promoted the lysosomal degradation of viral L- and M-HBs proteins. A mechanistic study using Biacore and docking analysis revealed that YZH-106 bound directly to the PreS2 domain of L- and M-HBsAg, thereby blocking their entry into the endoplasmic reticulum (ER) and promoting their degradation in cytoplasm. Our work thereby provides the basis for the design of a novel compound therapy to target HBsAg against HBV infection.

Early application of IFNγ mediated the persistence of HBV in an HBV mouse model

The antiviral activity of interferon gamma (IFNγ) against hepatitis B virus (HBV) was demonstrated both in vivo and in vitro in a previous study. IFNγ can suppress HBV replication by accelerating the decay of replication-competent nucleocapsids of HBV. However, in this study, we found that the direct application of the mouse IFNγ (mIFNγ) expression plasmid to the liver of an HBV hydrodynamic injection (HI) mouse model led to the persistence of HBV, as indicated by sustained HBsAg and HBeAg levels in the serum as well as an increased percentage of the HBsAg positive mice, whereas the level of HBV DNA in the serum and the expression of HBcAg in the liver were inhibited at the early stage after HI. Meanwhile, we found that the productions of both HBcAb and HBsAb were suppressed after the application of mIFNγ. In addition, we found that HBV could be effectively inhibited in mice immunized with HBsAg expression plasmid before the application of mIFNγ. Furthermore, mIFNγ showed antiviral effect and promoted the production of HBsAb when the mice subjected to the core-null HBV plasmid. These results indicate that the application of mIFNγ in the HBV HI mouse model, the mice showed defective HBcAg-specific immunity that impeded the production of HBcAb and HBsAb, finally allowing the persistence of the virus. Moreover, IFNγ-induced negative immune regulatory factors also play an important role in virus persistence.

Modulation of plasmacytoid dendritic cell and CD4+ T cell differentiation accompanied by upregulation of the cholinergic anti-inflammatory pathway induced by enterovirus 71

Enterovirus 71 (EV71) is a neurotropic enterovirus associated with hand, foot, and mouth disease (HFMD) fatalities. In this study, we investigated the impact of EV71 on plasmacytoid dendritic cells (pDCs) and CD4+ T cells. The results showed that pDCs were promptly activated, secreting interferon (IFN)-α and inducing CD4+ T cell proliferation and differentiation during early EV71 infection. This initiated adaptive immune responses and promoted proinflammatory cytokine production by CD4+ T cells. Over time, viral nucleic acids and proteins were synthesized in pDCs and CD4+ T cells. Concurrently, the cholinergic anti-inflammatory pathway (CAP) was activated, exhibiting an anti-inflammatory role. With constant viral stimulation, pDCs and CD4+ T cells showed reduced differentiation and cytokine secretion. Defects in pDCs were identified as a key factor in CD4+ T cell tolerance. CAP had a more significant regulatory effect on CD4+ T cells than on pDCs and was capable of inhibiting inflammation in these cells.

Metabolic Deficiencies Underlie Plasmacytoid Dendritic Cell Exhaustion After Viral Infection

Type I Interferons (IFN-I) are central to host protection against viral infections 1 . While any cell can produce IFN-I, Plasmacytoid Dendritic Cells (pDCs) make greater quantities and more varieties of these cytokines than any other cell type 2 . However, following an initial burst of IFN- I, pDCs lose their exceptional IFN-I production capacity and become "exhausted", a phenotype that associates with enhanced susceptibility to secondary infections 3-5 . Despite this apparent cost for the host, pDC exhaustion is conserved across multiple species and viral infections, but the underlying mechanisms and the potential evolutionary advantages are not well understood. Here we characterize pDC exhaustion and demonstrate that it is associated with a reduced capacity of pDCs to engage both oxidative and glycolytic metabolism. Mechanistically, we identify lactate dehydrogenase B (LDHB) as a novel positive regulator of pDC IFN-I production in mice and humans, show that LDHB deficiency is associated with suppressed IFN-I production, pDC metabolic capacity, and viral control following a viral infection, and demonstrate that preservation of LDHB expression is sufficient to partially restore exhausted pDC function in vitro and in vivo . Furthermore, restoring LDHB in vivo in exhausted pDCs increased IFNAR dependent infection- associated pathology. Therefore, our work identifies a novel and conserved mechanism for balancing immunity and pathology during viral infections, while also providing insight into the highly preserved but previously unexplained phenomenon of pDC exhaustion.

The role of Traditional Chinese medicine in anti-HBV: background, progress, and challenges

Chronic hepatitis B (CHB) remains a major world's most serious public health issues. Despite the remarkable effect of nucleos(t)ide analogues (NAs) in inhibiting hepatitis B virus (HBV) deoxyribonucleic acid (DNA) as the first-line drug, there are several limitations still, such as poor antigen inhibition, drug resistance, low-level viremia, restricting patients' functional cure. Due to the constraints of NAs, traditional medicines, such as traditional Chinese medicine (TCM), have become more prevalently used and researched in the clinical treatment of CHB as complementary alternative therapies. As a consequence, the review focuses on the background based on HBV's life cycle as well as the NAs' limitations, progress based on direct and indirect pathway of targeting HBV of TCM, and challenges of TCM. We found TCMs play an increasingly important role in anti-HBV. In a direct antiviral way, they regulate HBV infection, replication, assembly, and other aspects of the HBV life cycle. As for indirect way, TCMs can exert anti-HBV effects through targeting the host, including immune regulation, apoptosis, autophagy, oxidative stress, etc. Especially, TCMs have the advantages of strong antigenic inhibition compared to NAs. Specifically, we can combine the benefits of TCMs in strong HBV antigen inhibition with the benefits of NAs in targeted antiviral effects, in order to find a suitable combination of "TCM + NAs" to contribute to Chinese knowledge of the realisation of the "global elimination of HBV by 2030" goal of the World Health Organization.

Function and autophagy of monocyte-derived dendritic cells is affected by hepatitis B virus infection

BACKGROUND

The role of dendritic cells and the autophagy state of dendritic cells in the immune response of hepatitis B virus (HBV) infection was still controversial. In this study, we carefully examined the phenotype, function and autophagy pathway of dendritic cells in HBV infection.

METHODS

Monocyte-derived dendritic cells from healthy blood donors and patients with chronic HBV infection were stimulated by lipopolysaccharide, supernatant of HepG2.2.15 cells or supernatant of HepG2 cells respectively. Phenotype of dendritic cells was examined by flow cytometry and cytokines secretion was detected by enzyme-linked immunosorbent assay. Autophagy related proteins were detected by western blot and immunofluorescence analysis.

RESULTS

Our results showed that the expression of both major histocompatibility complex II molecules and co-stimulated molecules including cluster of differentiation antigen 80, cluster of differentiation antigen 86 in the monocyte-derived dendritic cells from patients with chronic HBV infection was significantly higher than that from healthy donors when cultured with supernatant of HepG2.2.15 cells. The amount of cytokines, including tumour necrosis factor-α, interleukin-10 and interleukin-12, secreted by monocyte-derived dendritic cells from patients with chronic HBV infection was also significantly higher than that from healthy donors when stimulate by HBV. Interestingly, the expression level of autophagy-related proteins including autophagy-related protein5 and associated protein 1 light chain in dendritic cells from patients with chronic HBV infection was significantly increased when compared with that from healthy donors when re-exposed to HBV.

CONCLUSIONS

Our results indicated that dendritic cells from patients with chronic HBV infection could intensively present antigen and express co-stimulatory molecules. The increased activation of dendritic cells might be related to the enhanced autophagy of dendritic cells in HBV infection.

Treated chronic hepatitis B is a good prognostic factor of diffuse large B-cell lymphoma

BACKGROUND/AIMS

Chronic hepatitis B (CHB) is a risk factor for non-Hodgkin lymphoma (NHL). Our recent study suggested that antiviral treatment may reduce the incidence of NHL in CHB patients. This study compared the prognoses of hepatitis B virus (HBV)-associated diffuse large B-cell lymphoma (DLBCL) patients receiving antiviral treatment and HBV-unassociated DLBCL patients.

METHODS

This study comprised 928 DLBCL patients who were treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) at two referral centers in Korea. All patients with CHB received antiviral treatment. Time-to-progression (TTP) and overall survival (OS) were the primary and secondary endpoints, respectively.

RESULTS

Among the 928 patients in this study, 82 were hepatitis B surface antigen (HBsAg)-positive (the CHB group) and 846 were HBsAg-negative (the non-CHB group). The median follow-up time was 50.5 months (interquartile range [IQR]=25.6-69.7 months). Multivariable analyses showed longer TTP in the CHB group than the non-CHB group both before inverse probability of treatment weighting (IPTW; adjusted hazard ratio [aHR]=0.49, 95% confidence interval [CI]=0.29-0.82, p=0.007) and after IPTW (aHR=0.42, 95% CI=0.26-0.70, p<0.001). The CHB group also had a longer OS than the non-CHB group both before IPTW (HR=0.55, 95% CI=0.33-0.92, log-rank p=0.02) and after IPTW (HR=0.53, 95% CI=0.32-0.99, log-rank p=0.02). Although liver-related deaths did not occur in the non-CHB group, two deaths occurred in the CHB group due to hepatocellular carcinoma and acute liver failure, respectively.

CONCLUSION

Our findings indicate that HBV-associated DLBCL patients receiving antiviral treatment have significantly longer TTP and OS after R-CHOP treatment than HBV-unassociated DLBCL patients.

Acute-on-chronic liver failure: far to go-a review

Acute-on-chronic liver failure (ACLF) has been recognized as a severe clinical syndrome based on the acute deterioration of chronic liver disease and is characterized by organ failure and high short-term mortality. Heterogeneous definitions and diagnostic criteria for the clinical condition have been proposed in different geographic regions due to the differences in aetiologies and precipitating events. Several predictive and prognostic scores have been developed and validated to guide clinical management. The specific pathophysiology of ACLF remains uncertain and is mainly associated with an intense systemic inflammatory response and immune-metabolism disorder based on current evidence. For ACLF patients, standardization of the treatment paradigm is required for different disease stages that may provide targeted treatment strategies for individual needs.

Antigen Recognition and Immune Response to Acute and Chronic Hepatitis B Virus Infection

The antigen recognition and immune response to acute and chronic hepatitis B virus (HBV) infections are the result of both the innate and adaptive immune response. The innate immune response comprises Dendritic Cells (DCs), which served as professional antigen-presenting cells and a bridge between innate and adaptive immunity, Kupffer cells and inflammatory monocytes for the continuous inflammation of hepatocyte, neutrophils for hepatic tissue damage due to acute inflammation, type I interferons (IFN), which induce an antiviral state on infected cells, directs natural killer (NK) cells to kill virally infected cells, reduces the population of infected cells, and promotes the effective maturation and site recruitment of adaptive immunity through the production of pro-inflammatory cytokines and chemokines. Through stimulating B cells, T-helper, and cytotoxic T cells, the adaptive immune system also protects against hepatitis B infection. During HBV infection, a network of cell types that can either play protective or harmful functions creates the anti-viral adaptive immune response. These many elements, such as ‎Cluster of differentiation four (CD4) T cells (traditionally known as helper T cells), are potent cytokine producers and necessary for the effective maturation of effector cytotoxic cluster of differentiation eight (CD8) T cells and B cell antibody production. By cytolytic and non-cytolytic processes, CD8 T cells are able to eliminate HBV-infected hepatocytes and directly detect virus-infected cells, and circulating CD4+ CD25+ regulatory T cells for the modulation of immune system. In order to avoid reinfection, B cells can produce antibodies that destroy free viral particles. Moreover, by presenting HBV antigens to helper T cells, B cells may also influence how well these cells operate.

Activation of CD4 T cells during prime immunization determines the success of a therapeutic hepatitis B vaccine in HBV-carrier mouse models

BACKGROUND & AIMS

We recently developed a heterologous therapeutic vaccination scheme (TherVacB) comprising a particulate protein prime followed by a modified vaccinia-virus Ankara (MVA)-vector boost for the treatment of HBV. However, the key determinants required to overcome HBV-specific immune tolerance remain unclear. Herein, we aimed to study new combination adjuvants and unravel factors that are essential for the antiviral efficacy of TherVacB.

METHODS

Recombinant hepatitis B surface and core antigen (HBsAg and HBcAg) particles were formulated with different liposome- or oil-in-water emulsion-based combination adjuvants containing saponin QS21 and monophosphoryl lipid A; these formulations were compared to STING-agonist c-di-AMP and conventional aluminium hydroxide formulations. Immunogenicity and the antiviral effects of protein antigen formulations and the MVA-vector boost within TherVacB were evaluated in adeno-associated virus-HBV-infected and HBV-transgenic mice.

RESULTS

Combination adjuvant formulations preserved HBsAg and HBcAg integrity for ≥12 weeks, promoted human and mouse dendritic cell activation and, within TherVacB, elicited robust HBV-specific antibody and T-cell responses in wild-type and HBV-carrier mice. Combination adjuvants that prime a balanced HBV-specific type 1 and 2 T helper response induced high-titer anti-HBs antibodies, cytotoxic T-cell responses and long-term control of HBV. In the absence of an MVA-vector boost or following selective CD8 T-cell depletion, HBsAg still declined (mediated mainly by anti-HBs antibodies) but HBV replication was not controlled. Selective CD4 T-cell depletion during the priming phase of TherVacB resulted in a complete loss of vaccine-induced immune responses and its therapeutic antiviral effect in mice.

CONCLUSIONS

Our results identify CD4 T-cell activation during the priming phase of TherVacB as a key determinant of HBV-specific antibody and CD8 T-cell responses.

IMPACT AND IMPLICATIONS

Therapeutic vaccination is a potentially curative treatment option for chronic hepatitis B. However, it remains unclear which factors are essential for breaking immune tolerance in HBV carriers and determining successful outcomes. Our study provides the first direct evidence that efficient priming of HBV-specific CD4 T cells determines the success of therapeutic hepatitis B vaccination in two preclinical HBV-carrier mouse models. Applying an optimal formulation of HBV antigens that activates CD4 and CD8 T cells during prime immunization provided the foundation for an antiviral effect of therapeutic vaccination, while depletion of CD4 T cells led to a complete loss of vaccine-induced antiviral efficacy. Boosting CD8 T cells was important to finally control HBV in these mouse models. Our findings provide important insights into the rational design of therapeutic vaccines for the cure of chronic hepatitis B.

Toll-like receptor-mediated innate immunity orchestrates adaptive immune responses in HBV infection

Chronic hepatitis B virus (HBV) infection remains to be a substantial global burden, especially for end-stage liver diseases. It is well accepted that HBV-specific T and B cells are essential for controlling HBV infection. Toll-like receptors (TLRs) represent one of the major first-line antiviral defenses through intracellular signaling pathways that induce antiviral inflammatory cytokines and interferons, thereby shaping adaptive immunity. However, HBV has evolved strategies to counter TLR responses by suppressing the expression of TLRs and blocking the downstream signaling pathways, thus limiting HBV-specific adaptive immunity and facilitating viral persistence. Recent studies have stated that stimulation of the TLR signaling pathway by different TLR agonists strengthens host innate immune responses and results in suppression of HBV replication. In this review, we will discuss how TLR-mediated responses shape HBV-specific adaptive immunity as demonstrated in different experimental models. This information may provide important insight for HBV functional cure based on TLR agonists as immunomodulators.

Toll-Like Receptor 7 Agonist RG7854 Mediates Therapeutic Efficacy and Seroconversion in Woodchucks With Chronic Hepatitis B

Conventional treatment of chronic hepatitis B (CHB) is rarely curative due to the immunotolerant status of patients. RG7854 is an oral double prodrug of a toll-like receptor 7 (TLR7) agonist that is developed for the treatment of CHB. The therapeutic efficacy, host immune response, and safety of RG7854 were evaluated in the woodchuck model of CHB. Monotreatment with the two highest RG7854 doses and combination treatment with the highest RG7854 dose and entecavir (ETV) suppressed viral replication, led to loss of viral antigens, and induced seroconversion in responder woodchucks. Since viral suppression and high-titer antibodies persisted after treatment ended, this suggested that a sustained antiviral response (SVR) was induced by RG7854 in a subset of animals. The SVR rate, however, was comparable between both treatment regimens, suggesting that the addition of ETV did not enhance the therapeutic efficacy of RG7854 although it augmented the proliferation of blood cells in response to viral antigens and magnitude of antibody titers. The induction of interferon-stimulated genes in blood by RG7854/ETV combination treatment demonstrated on-target activation of TLR7. Together with the virus-specific blood cell proliferation and the transient elevations in liver enzymes and inflammation, this suggested that cytokine-mediated non-cytolytic and T-cell mediated cytolytic mechanisms contributed to the SVR, in addition to the virus-neutralizing effects by antibody-producing plasma cells. Both RG7854 regimens were not associated with treatment-limiting adverse effects but accompanied by dose-dependent, transient neutropenia and thrombocytopenia. The study concluded that finite, oral RG7854 treatment can induce a SVR in woodchucks that is based on the retrieval of antiviral innate and adaptive immune responses. This supports future investigation of the TLR7 agonist as an immunotherapeutic approach for achieving functional cure in patients with CHB.

Expression of Functional Molecule on Plasmacytoid Dendritic Cells Is Associated With HBsAg Loss in HBeAg-Positive Patients During PEG-IFN α-2a Treatment

Objective

The ideal endpoint of antiviral therapy in chronic hepatitis B (CHB) patients is to clear hepatitis B surface antigen (HBsAg). This study aimed to evaluate whether the expression of functional molecules on plasmacytoid dendritic cells (pDCs) is associated with HBsAg loss in HBeAg-positive patients during peginterferon alpha-2a (PEG IFN α-2a) therapy.

Methods

A single-center prospective cohort study was performed in HBeAg-positive CHB patients who were treated with PEG-IFN α-2a and followed up for 4 years. HBsAg clearance, HBeAg loss and undetectable HBV DNA achieved by PEG-IFN α-2a therapy was considered as functional cure. The frequencies of pDC and CD86⁺ pDC in peripheral blood, and the mean fluorescence intensity of CD86 (CD86MFI) on the surface of pDC were measured at starting therapy, after 12 and 24 weeks of therapy.

Results

Of 63 patients enrolled, 17 patients achieved HBsAg loss. The baseline HBV DNA load in Non-functional-cure group was significantly higher than that in Functional cure group, and the CD86⁺ pDC% was significantly lower in patients without functional cure. HBV DNA load (OR=0.146, P = 0.002) and CD86⁺ pDC% (OR=1.183, P = 0.025) were independent factors associated with functional cure confirmed by binary logistic regression analysis. In the Functional cure group, HBsAg, HBeAg, and HBV DNA loads decreased remarkably after 12 weeks and 24 weeks of treatment compared to baseline. In Non-functional-cure group, CD86⁺ pDC% and CD86MFI increased significantly from baseline after 12 weeks of treatment. In the Functional cure group, compared with baseline, pDC% increased significantly at 24 weeks, while CD86MFI increased significantly after 24 weeks of treatment.

Conclusion

The lower the baseline HBV DNA load and the more the baseline CD86⁺ pDC%, the easier it is for patients to obtain functional cure.

Underlying Co-Morbidity Reveals Unique Immune Signatures in Type II Diabetes Patients Infected With SARS-CoV2

Background

SARS-CoV2 infection in patients with comorbidities, particularly T2DM, has been a major challenge globally and has been shown to be associated with high morbidity and mortality. Here, we did whole blood immunophenotyping along with plasma cytokine, chemokine, antibody isotyping, and viral load from oropharyngeal swab to understand the immune pathology in the T2DM patients infected with SARS-CoV2.

Methods

Blood samples from 25 Covid-19 positive patients having T2DM, 10 Covid-19 positive patients not having T2DM, and 10 Covid-19 negative, non-diabetic healthy controls were assessed for various immune cells by analyzing for their signature surface proteins in mass cytometry. Circulating cytokines, chemokines, and antibody isotypes were determined from plasma while viral copy number was determined from oropharyngeal swabs. All our representative data corroborated with laboratory findings.

Results

Our observations encompass T2DM patients having elevated levels of both type I and type II cytokines and higher levels of circulating IgA, IgM, IgG1, and IgG2 as compared to NDM and healthy volunteers. They also displayed higher percentages of granulocytes, mDCs, plasmablasts, Th2-like cells, CD4⁺ EM cells, and CD8⁺ TE cells as compared to healthy volunteers. T2DM patients also displayed lower percentages of pDCs, lymphocytes, CD8⁺ TE cells, CD4⁺, and CD8⁺ EM.

Conclusion

Our study demonstrated that patients with T2DM displayed higher inflammatory markers and a dysregulated anti-viral and anti-inflammatory response when compared to NDM and healthy controls and the dysregulated immune response may be attributed to meta inflammation.

Association of Chronic Hepatitis B Infection and Antiviral Treatment With the Development of the Extrahepatic Malignancies: A Nationwide Cohort Study

PURPOSE

Epidemiologic studies suggest that chronic hepatitis B (CHB) is a risk factor for various primary extrahepatic malignancies. Our aim was to evaluate the associations of CHB and nucleos(t)ide analog (NA) treatment with the risk of the development of extrahepatic malignancies.

PATIENTS AND METHODS

We conducted an 18-month landmark analysis using nationwide claims data from the National Health Insurance Service of South Korea. Patients newly diagnosed with CHB in 2012-2014 (n = 90,944) and matched-controls (n = 685,436) were included. Patients with CHB were further classified as the NA-treated (CHB+/NA+, n = 6,539) or the NA-untreated (CHB+/NA-, n = 84,405) group. Inverse probability of treatment weighting analysis was applied to balance the treatment groups. Time-varying Cox analysis was performed to evaluate time-varying effect of NA treatment. The primary outcome was the development of any primary extrahepatic malignancy. Development of intrahepatic malignancy and death were considered as competing events.

RESULTS

During the study period (median = 47.4 months), 30,413 patients (3.9%) developed any extrahepatic malignancy. The CHB+/NA- group had a higher overall risk of extrahepatic malignancy than the CHB+/NA+ group (adjusted subdistribution hazard ratio [aSHR] = 1.28; 95% CI, 1.12 to 1.45; P < .001) or controls (aSHR = 1.22; 95% CI, 1.18 to 1.26; P < .001). There was no difference in the risk of extrahepatic malignancy between the CHB+/NA+ group and the controls (CHB+/NA+ v control: aSHR = 0.96; 95% CI, 0.84 to 1.08; P = .48). In time-varying Cox analysis, the CHB+/NA- patients were associated with a higher risk of extrahepatic malignancy than the CHB+/NA+ patients (aSHR = 1.37; 95% CI, 1.23 to 1.52; P < .001).

CONCLUSION

Patients with CHB have an elevated risk of developing primary extrahepatic malignancy. Long-term NA treatment was associated with a lower risk of extrahepatic malignancy development among patients with CHB.

Immune therapies against chronic hepatitis B

Patients with chronic hepatitis B (CHB) represent a living and permanent reservoir of hepatitis B virus (HBV). Millions of these CHB patients will eventually develop complications such as liver cirrhosis, hepatic failure, and hepatocellular carcinoma if they are not treated properly. Accordingly, several antiviral drugs have been developed for the treatment of CHB, but these drugs can neither eradicate all forms of HBV nor contain the progression of complications in most patients with CHB. Thus, the development of new and novel therapeutics for CHB remains a pressing need. The molecular and cellular mechanisms underlying the pathogenesis of CHB indicate that immune dysregulations may be responsible for HBV persistence and progressive liver damage in CHB. This provided the scientific and ethical basis for the immune therapy of CHB patients. Around 30 years have passed since the initiation of immune therapies for CHB in the early 1990s, and hundreds of clinical trials have been accomplished to substantiate this immune treatment. Despite these approaches, an acceptable regimen of immune therapy is yet to be realized. However, most immune therapeutic agents are safe for human usage, and many of these protocols have inspired considerable optimism. In this review, the pros and cons of different immune therapies, observed in patients with CHB during the last 30 years, will be discussed to derive insights into the development of an evidence-based, effective, and patient-friendly regimen of immune therapy for the treatment of CHB.

Type I Interferon Induction and Exhaustion during Viral Infection: Plasmacytoid Dendritic Cells and Emerging COVID-19 Findings

Type I Interferons (IFN-I) are a family of potent antiviral cytokines that act through the direct restriction of viral replication and by enhancing antiviral immunity. However, these powerful cytokines are a caged lion, as excessive and sustained IFN-I production can drive immunopathology during infection, and aberrant IFN-I production is a feature of several types of autoimmunity. As specialized producers of IFN-I plasmacytoid (p), dendritic cells (DCs) can secrete superb quantities and a wide breadth of IFN-I isoforms immediately after infection or stimulation, and are the focus of this review. Notably, a few days after viral infection pDCs tune down their capacity for IFN-I production, producing less cytokines in response to both the ongoing infection and unrelated secondary stimulations. This process, hereby referred to as "pDC exhaustion", favors viral persistence and associates with reduced innate responses and increased susceptibility to secondary opportunistic infections. On the other hand, pDC exhaustion may be a compromise to avoid IFN-I driven immunopathology. In this review we reflect on the mechanisms that initially induce IFN-I and subsequently silence their production by pDCs during a viral infection. While these processes have been long studied across numerous viral infection models, the 2019 coronavirus disease (COVID-19) pandemic has brought their discussion back to the fore, and so we also discuss emerging results related to pDC-IFN-I production in the context of COVID-19.

Human Hepatitis B Virus Negatively Impacts the Protective Immune Crosstalk Between Natural Killer and Dendritic Cells

BACKGROUND AND AIMS

Natural killer (NK) cells play a crucial role in the clearance of human viruses but their activity is significantly impaired in patients infected with chronic hepatitis B (CHB). Cooperation with dendritic cells (DCs) is pivotal for obtaining optimal NK cell antiviral function; thus, we investigated whether HBV might impact the ability of DCs to sustain NK cell functions.

APPROACH AND RESULTS

Human DCs were poor stimulators of interferon-gamma (IFN-γ) production by NK cells when exposed to HBV, while maintaining the capability to trigger NK cell cytotoxicity. HBV prevented DC maturation but did not affect their expression of human leukocyte antigen class I, thus allowing DCs to evade NK cell lysis. Tolerogenic features of DCs exposed to HBV were further supported by their increased expression of IL-10 and the immunosuppressive enzyme indoleamine 2,3-dioxygenase, which contributed to the impairment of DC-mediated NK cell IFN-γ production and proliferation, respectively. HBV could also inhibit the expression of inducible immunoproteasome (iP) subunits on DCs. In fact, NK cells could induce iP subunit expression on DCs, but they failed in the presence of HBV. Remarkably, circulating blood DC antigen1 (BDCA1)⁺ DCs isolated from patients with CHB were functionally compromised, hence altering, in turn, NK cell responses.

CONCLUSIONS

The abnormal NK-DC interplay caused by HBV may significantly impair the efficacy of antiviral immune response in patients with CHB.

Molecular Mechanisms during Hepatitis B Infection and the Effects of the Virus Variability

The immunopathogenesis and molecular mechanisms involved during a hepatitis B virus (HBV) infection have made the approaches for research complex, especially concerning the patients’ responses in the course of the early acute stage. The study of molecular bases involved in the viral clearance or persistence of the infection is complicated due to the difficulty to detect patients at the most adequate points of the disease, especially in the time lapse between the onset of the infection and the viral emergence. Despite this, there is valuable data obtained from animal and in vitro models, which have helped to clarify some aspects of the early immune response against HBV infection. The diversity of the HBV (genotypes and variants) has been proven to be associated not only with the development and outcome of the disease but also with the response to treatments. That is why factors involved in the virus evolution need to be considered while studying hepatitis B infection. This review brings together some of the published data to try to explain the immunological and molecular mechanisms involved in the different stages of the infection, clinical outcomes, viral persistence, and the impact of the variants of HBV in these processes.

Review of Lambda Interferons in Hepatitis B Virus Infection: Outcomes and Therapeutic Strategies

Hepatitis B virus (HBV) chronically infects over 250 million people worldwide and causes nearly 1 million deaths per year due to cirrhosis and liver cancer. Approved treatments for chronic infection include injectable type-I interferons and nucleos(t)ide reverse transcriptase inhibitors. A small minority of patients achieve seroclearance after treatment with type-I interferons, defined as sustained absence of detectable HBV DNA and surface antigen (HBsAg) antigenemia. However, type-I interferons cause significant side effects, are costly, must be administered for months, and most patients have viral rebound or non-response. Nucleos(t)ide reverse transcriptase inhibitors reduce HBV viral load and improve liver-related outcomes, but do not lower HBsAg levels or impart seroclearance. Thus, new therapeutics are urgently needed. Lambda interferons (IFNLs) have been tested as an alternative strategy to stimulate host antiviral pathways to treat HBV infection. IFNLs comprise an evolutionarily conserved innate immune pathway and have cell-type specific activity on hepatocytes, other epithelial cells found at mucosal surfaces, and some immune cells due to restricted cellular expression of the IFNL receptor. This article will review work that examined expression of IFNLs during acute and chronic HBV infection, the impact of IFNLs on HBV replication in vitro and in vivo, the association of polymorphisms in IFNL genes with clinical outcomes, and the therapeutic evaluation of IFNLs for the treatment of chronic HBV infection.

Identification of miRNAs associated with dendritic cell dysfunction during acute and chronic hepatitis B virus infection

The uptake or expression of hepatitis B virus (HBV) proteins by dendritic cells (DCs) is considered important for disease outcome. Differential expression of microRNA (miRNA) may have a role in viral persistence and hepatocellular injury. The miRNA expression was investigated by microarray in DCs from different stages of HBV infection and liver disease namely, immune active (IA; n = 20); low replicative (LR; n = 20); HBeAg negative (n = 20); acute viral hepatitis (AVH, n = 20) and healthy controls (n = 20). miRNA levels were analyzed by unsupervised hierarchical clustering and principal component analyses and validated by quantitative polymerase Chain Reaction (qPCR). The miRNA-messenger RNA (mRNA)regulatory networks identified 19 miRNAs and 12 target gene interactions in major histocompatibility complex and other immune pathways. miR-2278, miR-615-3p, and miR-3681-3p were downregulated in the IA group compared to healthy control, miR-152-3p and miR-3613-3p in the LR group compared to IA group and miR-152-3p and miR-503-3p in HBe negative compared to LR group. However, miR-7-1-1-3p, miR-192-5p, miR-195-5p, and miR-32-5p in LR, miR-342-3p, and miR-940 in HBe negative, and miR-34a-5p, miR-130b-3p, miR-221-3p, miR-320a, miR-324-5p, and miR-484 in AVH were upregulated. Further, qPCR confirmed changes in miRNA levels and their target genes associated with antigen processing and presentation. Thus, a deregulated network of miRNAs-mRNAs in DCs seems responsible for an impaired immune response during HBV pathogenesis.

Innate immunity and HBV persistence

Hepatitis B virus (HBV) causes chronic infections that are associated with immune dysfunction. Though T cell impairment is perhaps the most prominent immune change contributing to viral persistence, HBV interaction with the innate immune system is also likely key, as the lack of effective innate immunity has functional consequences that promote chronic infection. In addition to an intrinsic ability to fight viral infections, the innate immune system also impacts T cell responses and other adaptive immune mechanisms critical for HBV control. Therefore, it is essential to understand the relationships between HBV and innate immunity, as these interactions may be useful immunotherapeutic targets to manage the infection.

Treatment with the Immunomodulator AIC649 in Combination with Entecavir Produces Antiviral Efficacy in the Woodchuck Model of Chronic Hepatitis B

As current interventions for chronic hepatitis B (CHB) rarely induce cure, more effective drugs are needed. Short-term treatment of woodchucks with the novel immunomodulator AIC649, a parapoxvirus-based stimulator of toll-like receptor 9 dependent and independent pathways, has been shown to reduce viral DNA and surface antigen via a unique, biphasic response pattern. The present study evaluated long-term AIC649 treatment in combination with Entecavir for potency and safety in woodchucks. AIC649 monotreatment induced modest reductions in serum viral DNA and surface and e antigens that were associated with the same biphasic response pattern previously observed. Entecavir monotreatment reduced transiently viremia but not antigenemia, while AIC649/Entecavir combination treatment mediated superior viral control. Undetectability of viral antigens and elicitation of antibodies in AIC649/Entecavir-treated woodchucks correlated with the expression of interferons and suppression of viral replication in liver. Combination treatment was well tolerated, and liver enzyme elevations were minor and transient. It was concluded that the AIC649-mediated effects were most likely based on an improvement and/or reconstitution of antiviral immune responses that are typically deficient in CHB. As a combination partner to Entecavir, the antiviral efficacy of AIC649 was markedly enhanced. This preclinical study supports future evaluation of AIC649 for treatment of human CHB.

Designing the next-generation therapeutic vaccines to cure chronic hepatitis B: focus on antigen presentation, vaccine properties and effect measures

In the mid‐90s, hepatitis B virus (HBV)‐directed immune responses were for the first time investigated in detail and revealed suboptimal T‐cell responses in chronic HBV patients. Based on these studies, therapeutic vaccination exploiting the antigen presentation capacity of dendritic cells to prime and/or boost HBV‐specific T‐cell responses was considered highly promising. Now, 25 years later, it has not yet delivered this promise. In this review, we summarise what has been clinically tested in terms of antigen targets and vaccine forms, how the immunological and therapeutic effects of these vaccines were assessed and what major clinical and immunological findings were reported. We combine the lessons learned from these trials with the most recent insights on HBV antigen presentation, T‐cell responses, vaccine composition, antiviral and immune‐modulatory drugs and disease biomarkers to derive novel opportunities for the next generation of therapeutic vaccines designed to cure chronic HBV either alone or in combination therapy.

Hepatitis B-related hepatocellular carcinoma and stress: untangling the host immune response from clinical outcomes

Chronic hepatitis B virus (HBV) infection is a major public health challenge on the global scale. Affecting hundreds of millions worldwide, HBV is a leading risk factor for hepatocellular carcinoma (HCC). Clinical outcomes from chronic HBV infection are varied and appear to be influenced by a complex and dysregulated host immune response. In turn, much attention has been given to the immunologic response to HBV in an effort to identify host factors that lead to the development of HCC. However, the role of nonimmunologic host factors, such as chronic stress, in HBV-related HCC is poorly defined. Indeed, a growing appreciation for the effects of stress on chronic liver diseases raises the question of its role in chronic HBV infection. In this light, the present review will untangle the roles of key host factors in HBV-related HCC with an emphasis on chronic stress as a viable contributor. First discussed is the interplay of stress, inflammation and chronic liver disease. The host immune response's role as a driver of HBV-related HCC is then reviewed, allowing for a close exploration of the effects of stress on immune function in chronic hepatitis B and as a potential risk factor for HBV-related HCC.

Hepatitis B virus exploits C-type lectin receptors to hijack cDC1s, cDC2s and pDCs

Objectives

C‐type lectin receptors (CLRs) are key receptors used by DCs to orchestrate responses to pathogens. During infections, the glycan–lectin interactions shape the virus–host interplay and viruses can subvert the function of CLRs to escape antiviral immunity. Recognition of virus/viral components and uptake by CLRs together with subsequent signalling cascades are crucial in initiating and shaping antiviral immunity, and decisive in the outcome of infection. Yet, the interaction of hepatitis B virus (HBV) with CLRs remains largely unknown. As HBV hijacks DC subsets and viral antigens harbour glycan motifs, we hypothesised that HBV may subvert DCs through CLR binding.

Methods

We investigated here the pattern of CLR expression on BDCA1⁺ cDC2s, BDCA2⁺ pDCs and BDCA3⁺ cDC1s from both blood and liver of HBV‐infected patients and explored the ability of HBsAg to bind DC subsets through specific CLRs.

Results

We highlighted for the first time that the CLR repertoire of circulating and intrahepatic cDC2s, cDC1s and pDCs was perturbed in patients with chronic HBV infection and that some CLR expression levels correlated with plasma HBsAg and HBV DNA levels. We also identified candidate CLR responsible for HBsAg binding to cDCs (CD367/DCIR/CLEC4A, CD32/FcɣRIIA) and pDCs (CD369/DECTIN1/CLEC7A, CD336/NKp44) and demonstrated that HBsAg inhibited DC functions in a CLR‐ and glycosylation‐dependent manner.

Conclusion

HBV may exploit CLR pathways to hijack DC subsets and escape from immune control. Such advances bring insights into the mechanisms by which HBV subverts immunity and pave the way for developing innovative therapeutic strategies to restore an efficient immune control of the infection by manipulating the viral glycan–lectin axis.

The Multiple Functions of B Cells in Chronic HBV Infection

Chronic hepatitis B virus (HBV) infection is one of the main causes of liver diseases, of which the natural history and clinical outcomes are associated with the role of B cells. As humoral immune cells, B cells play a critical role in the process of anti-HBV antibody production. In addition, some studies have also characterized other B cell subsets involved in antigen presentation and regulating the immune response beyond antibody secretion. However, not all B cell subsets play a positive role in the immune response to chronic HBV infection, and various B cell subsets jointly mediate persistent HBV infection, tolerance, and liver damage. Thus, we further sought to elucidate the multiple functions of B cells to gain novel insight into the understanding of chronic hepatitis B (CHB) pathogenesis. We also reviewed the current immunotherapies targeting B cells to explore novel therapeutic interventions for the treatment of chronic HBV infection.

Infection and cancer suppress pDC derived IFN-I

Plasmacytoid dendritic cells (pDCs) are specialized producers of Type I interferon (IFN-I) that promote anti-viral and anti-tumor immunity. However, chronic infections and cancer inhibit pDC-derived IFN-I. While the mechanisms of this inhibition are multifarious they can be classified broadly into two categories: i) reduction or ablation of pDC IFN-I-production capacity (functional exhaustion) and/or ii) decrease in pDC numbers (altered population dynamics). Recent work has identified many processes that contribute to suppression of pDC-derived IFN-I during chronic infections and cancer, including sustained stimulation through Toll Like Receptors (TLRs), inhibitory microenvironments, inhibitory receptor ligation, and reduced development from bone marrow progenitors and apoptosis. Emerging success leveraging pDCs in treatment of disease through TLR activation illustrates the therapeutic potential of targeting pDCs. Deeper understanding of the systems that limit pDC-derived IFN-I has the potential to improve these emerging therapies as well as help devising new approaches that harness the outstanding IFN-I-production capacity of pDCs.

Pathological Change of Chronic Hepatitis B Patients with Different Tongue Coatings by Circular Multi-Omics Integrated Analysis

OBJECTIVE

To compare the circular pathological changes of chronic hepatitis B (CHB) patients according to the tongue diagnosis.

METHODS

Totally 41 CHB patients with typical white tongue coating (WTC) or yellow tongue coating (YTC) were enrolled and 14 healthy volunteers with normal tongue manifestation served as controls. The mRNA expression of peripheral leukocytes was detected by GeneChips, and 9 genes were randomly selected for expression validation. Circular metabolites were detected by gas chromatographymass spectrometry. Biological information was analyzed based on ingenuity pathways analysis or metabolomics database and the integrated networks were constructed by ClueGO.

RESULTS

A total of 945 and 716 differentially expressed genes were found in patients with WTC and YTC relative to healthy volunteers respectively. The biological information analysis indicated that CHB patients had obviously increased functions in cell death, apoptosis and necrosis (Z-score ⩾2, P<0.05) and decreased activation in T lymphocytes (Z-score ⩽-2, P<0.05), regardless of the tongue manifestation. Compared to patients with WTC, the YTC patients were predicted to be more active in functions related to virus replication (Z-score ⩾2, P<0.05), and the content of circular fatty acids, such as oleic acid (P=0.098) and lauric acid (P=0.035), and citric acid cycle-related metabolites were higher in the YTC patients (P<0.1). The integrated analysis based on differential genes and metabolites indicated that the most difference in the biological function network between the WTC and YTC patients was tumor necrosis factor receptor associated factor 6 mediated-nuclear factor kappa-B activation process.

CONCLUSIONS

CHB patients with YTC had more severe inflammation and fatty acids metabolism aberrant than patients with WTC. The results facilitate the modern pathological annotation of Chinese medicine tongue diagnosis theory and provide a reference for the interpretation of pharmacological mechanisms of Chinese medicine treatment.

HBVsvp-Pulsed Dendritic Cell Immunotherapy Induces Th1 Polarization and Hepatitis B Virus-Specific Cytotoxic T Lymphocytes Production

Background

In chronic hepatitis B virus (CHB) patients, both dendritic cells (DCs) and T cells are functionally impaired and consequently the HBV-specific cellular immune responses are downregulated. The present study aims to investigate whether monocyte-derived DC (MoDCs)-pulsed-HBV subviral particles (HBVsvp) can polarize Th1 cells to induce HBV-specific cytotoxic T-lymphocytes (CTL) responses in CHB patients.

Methods and Materials

To this end, the human hepatoma HepG2.2.15 cell line was used to produce HBVsvp as a culturing system, and HBVsvp were concentrated for highly virus titer using the polyethylene glycol protocol. Peripheral blood mononuclear cells (PBMCs), collected from CHB patients and healthy donors, were differentiated into MoDCs and T cells. PBMCs-derived MoDCs were first pulsed with HBVsvp and then cultured with PBMCs-derived T cells. MoDCs and/or T subsets cells were identified for phenotypic activation by FACS analysis. The cytokine secretion of IL-4, IL-12, and IFN-γ in the culture supernatants was detected.

Results

The MoDCs were restored for their activation upon pulsing with HBVsvp in vitro, as identified by significantly overexpression of both CD86 and HLA-DR, and overproduction of IL-4 and IL-12. Furthermore, MoDCs-pulsed-HBVsvp induced Th1 frequencies and activated HBV-specific CTL to produce significantly highest amount of IFN-γ. Enhanced HBV-specific CTL led to strong cytolytic capacity against HepG2.2.15.

Conclusion

Overall, our data suggest that in vitro activation of MoDCs with HBVsvp overcomes the functionally impaired DCs and T cells in CHB patients offering a promising tool for therapeutic or vaccine-based approaches against HBV.

Hepatitis B surface antigen seroclearance: Immune mechanisms, clinical impact, importance for drug development

HBsAg seroclearance occurs rarely in the natural history of chronic hepatitis B (CHB) infection and is associated with improved clinical outcomes. Many factors are associated with HBsAg seroconversion, including immune and viral factors. However, the immune mechanisms associated with HBsAg seroclearance are still difficult to elucidate. HBsAg seroclearance is the ideal aim of HBV treatment. Unfortunately, this goal is rarely achieved with current treatments. Understanding the mechanisms of HBsAg loss appears to be important for the development of curative HBV treatments. While studies from animal models give insights into the potential immune mechanisms and interactions occurring between the immune system and HBsAg, they do not recapitulate all features of CHB in humans and are subject to variability due to their complexity. In this article, we review recent studies on these immune factors, focusing on their influence on CHB progression and HBsAg seroconversion. These data provide new insights for the development of therapeutic approaches to partially restore the anti-HBV immune response. Targeting HBsAg will ideally relieve the immunosuppressive effects on the immune system and help to restore anti-HBV immune responses.

Quantative HBsAg level correlates dendritic cells maturation in chronic hepatitis B patients

BACKGROUND

In order to better understand the role of Dendritic cells (DCs) in Chronic Hepatitis B (CHB), we investigated the frequencies and maturation markers on DCs in CHB patients and its change during entecavir treatment.

METHODS

Twenty-six CHB patients on anti-virus treatment for 48 weeks were included in this study. Patients' blood samples were collected on every 3 months since starting treatment. Samples on baseline and after 48 weeks treatment were examined using flow-cytometry to investigate frequencies and maturation markers of DCs.

RESULTS

The frequencies of myeloid DCs (mDCs) and plasmacytoid DCs (pDCs) were lower in CHB patients than healthy controls on baseline. pDCs frequencies and mDCs maturation markers expression were increased after entecavir (ETV) treatment. Patients with higher baseline HBsAg levels showed a poorer maturation status than those with low baseline HBsAg levels, regardless of changes in HBsAg levels after treatment.

CONCLUSIONS

Entecavir treatment could restore the decreased DCs frequencies in CHB patients and improve DCs maturation levels. Baseline HBsAg level is an important factor that affecting DCs.

Mechanisms of HBV immune evasion

The concept of immune evasion is a longstanding topic of debate during chronic Hepatitis B Virus infection. The 292 million individuals chronically infected by HBV are clear evidence that the virus avoids elimination by the immune system. The exact mechanisms of immune evasion remain undefined and are distinct, but likely interconnected, between innate and adaptive immunity. There is a significant body of evidence that supports peripheral tolerance and exhaustion of adaptive immunity but our understanding of the role that central tolerance plays is still developing. Innate immunity instructs the adaptive immune response and subversion of its functionality will impact both T and B cell responses. However, literature around the interaction of HBV with innate immunity is inconsistent, with reports suggesting that HBV avoids innate recognition, suppresses innate recognition, or activates innate immunity. This complexity has led to confusion and controversy. This review will discuss the mechanisms of central and peripheral tolerance/exhaustion of adaptive immunity in the context of chronic HBV infection. We also cover the interaction of HBV with cells of the innate immune system and propose concepts for the heterogeneity of responses in chronically infected patients.

Quantitation of Plasmacytoid Dendritic Cells in Chronic Hepatitis B Patients with HBeAg Positivity During PEG-IFN and Entecavir Therapy

Plasmacytoid dendritic cells (pDCs) are crucial for control of chronic hepatitis B (CHB) virus infection. In this study, we evaluated the frequencies of pDCs and expression of functional molecules on pDCs in patients treated with PEG-IFN-α-2a or entecavir (ETV) and investigated changes during treatment. The mean fluorescence intensity of CD86 (CD86MFI) on the surface of pDCs and frequencies of pDCs and CD86⁺ pDCs in peripheral blood were measured. Compared with baseline, CD86⁺ pDC% and CD86MFI increased obviously after PEG-IFN-α-2a treatment for 12 and 24 weeks. For patients treated with ETV, only pDC% increased observably after treatment weeks 12 and 24 (P < 0.001) compared with baseline. Hepatitis B surface antigen (HBsAg) decline was significantly associated with elevated CD86⁺ pDC% (r = 0.348, P = 0.015) during PEG-IFN-α-2a treatment. In the HBsAg response group, CD86⁺ pDC% and CD86MFI (P < 0.001) increased observably after PEG-IFN-α-2a therapy, whereas only CD86MFI had a statistically significant difference after therapy compared with baseline (12 weeks versus 0 weeks, P = 0.022; 24 weeks versus 0 weeks, P = 0.015) in the HBsAg nonresponse group. CD86⁺ pDC% between the 2 groups had statistically significant differences at baseline (P = 0.001) and at the treatment time points of 12 and 24 weeks (P < 0.001), respectively. For patients receiving ETV therapy, pDC% increased observably, but CD86⁺ pDC% decreased significantly (P < 0.001) in the HBV DNA nonresponse group during early treatment with ETV. In CHB patients, HBsAg response in PEG-IFN-α-2a therapy correlated with the increase of CD86⁺ pDC% and HBV DNA nonresponse in ETV treatment correlated with the decrease of CD86⁺ pDC%.

Characterization Of The Interaction Between Subviral Particles Of Hepatitis B Virus And Dendritic Cells - In Vitro Study

Background

During an infection with hepatitis B virus (HBV), infectious particles (Dane particles) can be detected in addition to aggregates of the subviral particles (SVP) which is considered an immune escaping mechanism for the virus. Dendritic cells (DCs) are a specialized type of antigen-presenting cell (APC) that can activate native T-cells to prime an immune response controlling HBV infection. The aim of this study was to characterize the interaction between HBVsvp and DCs in vitro.

Methods

HBVsvp that comprises surface and core proteins were produced in vitro by HepG2.2.15 as a culturing system; DCs derived from the bone marrow of mice were pulsed by HBVsvp. A different pattern of cytokines secreted by bone-marrow-derived dendritic cells from C56BL/6 mice pulsed with HBVsvp were analyzed. The interactions between HBVsvp and DCs were characterized using FACS analysis, protein assay, Western blot, and immunofluorescence staining.

Results

Pulsation of DCs with HBVsvp resulted in strong activation and higher secretion of DC cytokines including INF-α, INF-γ, TNF-α, IL-1α, IL-10, and IL-12; but not for IL-1β, IL-2, IL-6, and IL-15. The production of CXCL-10/IP-10 was increased during the observation period and reached the maximal secretion after 24 hrs (p < 0.001). In total protein assay, we found significantly higher protein concentration in HBVsvp stimulated DC groups compared to not activated DCs (p < 0.001). Both 24 kDa small surface antigen (HBVs) and the 21 kDa core protein (HBVc) were detected in activated DCs. For DCs immunofluorescence staining, our data showed clear differences in the morphology of DCs between negative control and those pulsed with HBVsvp.

Conclusion

Result demonstrates a significant complex interaction between HBVsvp and DCs, in vitro.

Liver DCs in health and disease

Hepatic dendritic cells represent a unique and multifaceted subset of antigen-presenting leukocytes that orchestrate specified immune responses in the liver. They are constantly exposed to antigens and signals derived not only from the hepatic microenvironment and the systemic circulation but also from the portal vein draining the gut and conveying food antigens as well as microbial compounds. Modulated by these various factors they shape intrahepatic immune responses during acute and chronic liver diseases, hepatocellular carcinoma and allograft tolerance as well as systemic responses to gut-derived components. Hence, hepatic DC are central targets to decipher and fine-tune innate and adaptive hepatic immune responses as well as tolerance. This review focuses on the origin of hepatic DC, the different DC subsets present in the liver and their functionality during different acute and chronic liver diseases in mice and men and will discuss potential DC directed therapeutic interventions in liver disease.

Immune suppression in chronic hepatitis B infection associated liver disease: A review

Hepatitis B virus (HBV) infection is one the leading risk factors for chronic hepatitis, liver fibrosis, cirrhosis and hepatocellular cancer (HCC), which are a major global health problem. A large number of clinical studies have shown that chronic HBV persistent infection causes the dysfunction of innate and adaptive immune response involving monocytes/macrophages, dendritic cells, natural killer (NK) cells, T cells. Among these immune cells, cell subsets with suppressive features have been recognized such as myeloid derived suppressive cells(MDSC), NK-reg, T-reg, which represent a critical regulatory system during liver fibrogenesis or tumourigenesis. However, the mechanisms that link HBV-induced immune dysfunction and HBV-related liver diseases are not understood. In this review we summarize the recent studies on innate and adaptive immune cell dysfunction in chronic HBV infection, liver fibrosis, cirrhosis, and HCC, and further discuss the potential mechanism of HBV-induced immunosuppressive cascade in HBV infection and consequences. It is hoped that this article will help ongoing research about the pathogenesis of HBV-related hepatic fibrosis and HBV-related HCC.

Characteristics of Impaired Dendritic Cell Function in Patients With Hepatitis B Virus Infection

Dendritic cells (DCs) are antigen-presenting cells with a central role in host immune response. This study analyzed gene expression and DC function in hepatitis B virus (HBV) patients, functions impaired because of HBV, and identified the genes related to these functions. Peripheral blood mononuclear cells from 64 HBV patients and 19 healthy controls were analyzed. Peripheral blood DCs were stained with antibodies against human leukocyte antigen-DR/Lin-1/CD123/CD11c and separated into plasmacytoid DCs (pDCs) and myeloid DCs by fluorescence-activated cell sorting. Using an interferon-gamma enzyme-linked immunospot assay, we analyzed antigen-specific response in HBV-infected patients. Regarding DC function, we analyzed antigen-presenting capacity, cell migration capacity, phagocytic capacity, and cytokine production capacity. DC gene expression was analyzed by microarray to identify genes related to DC function. No difference was found in the number of DCs in peripheral blood between healthy participants and HBV patients. In cell-surface marker analysis, CD80, CD83, CD86, CD40, and C-C motif chemokine receptor 7 expression levels in pDCs were related to the HBV-specific T-cell response. DCs from HBV patients exhibited decreases in antigen-presenting capacity, migration capacity, and cytokine production capacity. In gene expression analysis, immune-related genes with greatly reduced expression levels in chronic hepatitis B patients were identified. Of these genes, interleukin (IL)-6 signal transducer (IL6ST) expression level positively correlated with DC surface marker expression level. Adjustment of IL6ST expression level in DCs and treatment with oncostatin M resulted in recovery of DC function. Conclusion: IL6ST expression was identified as one cause of decline in DC function in HBV patients. Adjustment of IL6 family cytokine signaling may be useful for recovering reduced DC function in HBV infection.

Stimulating DDX3 expression by serotonin 5-HT receptor 7 through phosphorylation of p53 via the AC-PKA-ERK signaling pathway

DDX3 is a host viral factor that can inhibit the hepatitis B virus-induced innate immune responses. In this study, the 20 bioactive compounds have screened the effects on DDX3 and we found that 5-HT upregulated DDX3 promoter activity via the 5-HT₇ receptor on liver hepatocellular cells (HepG2 cells) by using a luciferase assay, reverse transcription-polymerase chain reaction analysis, and Western blot analysis. Furthermore, we are trying to elucidate the pathways involved in the stimulating effect of 5-HT on DDX3 expression to induce innate immune responses against hepatitis B virus infection. A knockdown of the 5-HT₇ receptor by transfection si-5-HT₇ receptors or si-control into HepG2 cells treated by 5-HT (or 5-HT plus agonist) confirmed the role of the 5-HT₇ receptor in DDX3 expression. The IFN-β-Luc expression and level of hepatitis B virus surface Antigen (HBsAg) showed that DDX3 mediated by the 5-HT₇ agonist (AS-19) increased IFN-β expression and inhibited HBV replication. Luciferase assays showed the involvement of 5-HT₇ receptors in DDX3 expression via cAMP/AC/PKA pathways by using protein kinase A (PKA) and adenylyl cyclase inhibitor (MDL 12330A). AS-19 mediated DDX3 promoter activated PKA extracellular signal-regulated kinase ERK signaling the p53 phosphorylation (-1080/-1070) resulted in upregulation of DDX3 promoter transactivation via the 5-HT₇ receptors agonist. Overall, 5-HT₇ was found to be a new potential target to inhibit hepatitis B infection by activating AC/PKA/ERK pathways by phosphorylating p53 via the 5-HT₇ agonist response by mediating DDX3 expression.

Plasmacytoid dendritic cells and their role in the immunopathogenesis of viral infections for example hepatitis B

A new approach in understanding the mechanisms of immune response in viral hepatitis is the discovery of a unique type of immune cells – plasmocytoid dendritic cells (pDCs). Plasmocytoid dendritic cells (pDCs) are cells of lymphoid origin and morphologically resemble plasma cells. Functionally, they are professional IFN-a-producing cells that play an important role in antiviral immune response. Data on the mechanisms of PDCs participation in hepatitis B virus infection are few and contradictory. In chronic HBV infection, the role of pDCs remains mysterious and poorly understood with conflicting circulating blood pDCs results that show differently that they are not affected or reduced. However, functional disorders of pDCs were observed in patients with chronic HBV infection. The establishment of these mechanisms, as well as the search for the cause of hepatitis B virus latency and the formation of chronic infection remains one of the important and promising areas of scientific activities today.

Plasmacytoid Dendritic Cell Function and Cytokine Network Profiles in Patients with Acute or Chronic Hepatitis B Virus Infection

Background:

Plasmacytoid dendritic cells (pDCs) and cytokines play an important role in occurrence and recovery of hepatitis B virus (HBV) infection. The aim of this study was to explore the frequency and function of pDC and serum cytokine network profiles in patients with acute or chronic HBV infection.

Methods:

The healthy individuals (HI group), hepatitis B envelope antigen (HBeAg)-positive chronic HBV patients in immune tolerance (IT) phase (IT group), HBeAg-positive chronic HBV patients (CHB group), and acute HBV patients (AHB group) were enrolled in this study. The frequency of cluster of differentiation antigen 86 (CD86) + pDC and the counts of CD86 molecular expressed on surface of pDC were tested by flow cytometer. The quantitative determinations of cytokines, including Fms-like tyrosine kinase 3 ligand (Flt-3L), interferon (IFN)-α2, IFN-γ, interleukin (IL)-17A, IL-6, IL-10, transforming growth factor (TGF)-β1 and TGF-β2, were performed using Luminex multiplex technology.

Results:

In this study, there were 13 patients in HI group, 30 in IT group, 50 in CHB group, and 32 in AHB group. Compared with HI group, HBV infected group (including all patients in IT, CHB and AHB groups) had significantly higher counts of CD86 molecular expressed on the surface of pDC (4596.5 ± 896.5 vs. 7097.7 ± 3124.6; P < 0.001). The counts of CD86 molecular expressed on the surface of pDC in CHB group (7739.2 ± 4125.4) was significantly higher than that of IT group (6393.4 ± 1653.6, P = 0.043). Compared with IT group, the profile of cytokines of Flt-3L, IFN-γ, and IL-17A was decreased, IFN-α2 was significantly increased (P = 0.012) in CHB group. The contents of IL-10, TGF-β1, and TGF-β2 in AHB group were significantly increased compared with IT and CHB groups (all P < 0.05).

Conclusions:

This study demonstrated that the function of pDC was unaffected in HBV infection. The enhanced function of pDC and IFN-α2 might involve triggering the immune response from IT to hepatitis active phase in HBV infection. Acute patients mainly presented as down-regulation of the immune response by enhanced IL-10 and TGF-β.

Maternal Immunity Influences Vertical Transmission of Hepatitis B to Newborns

Vertical transmission of hepatitis B virus (HBV) from the mother to the newborn often results in viral persistence. To understand mechanisms of maternofetal HBV transmission, we studied maternal immunity and peripheral blood mononuclear cell (PBMC) transcriptome in mothers and newborns. We included 50 mothers and babies who were hepatitis B surface antigen (HBsAg) positive: 22 HBV transmitting mothers (group [Gr.] I) and 28 HBV nontransmitting mothers (Gr. II) to newborns and 10 healthy mother-baby pairs (Gr. III). PBMCs were analyzed for HBV-specific dendritic cells (DCs), T cells, T follicular helper (TFh) cells, B cells, functional immune responses, and cytokine levels as well as transcriptome signatures to identify immune gene expression correlates for protective immunity. Group II mothers had lower HBsAg levels (3.82 × 10³ versus 1.493 × 10⁴; P < 0.0001) with greater HBV-specific responses of DCs, T cells, TFh cells, and B cells than Gr. I mothers. Frequencies of TFh cells were lower in Gr. I mothers, with reduced interleukin-21 (IL-21) levels, and these inversely correlated with HBV DNA levels. Cut-off levels of 9.5% and 8.93% from the receiver operating curve predicted the involvement of TFh cells and B cells in HBV transmission. Transcriptome signatures revealed that maternal gene imprints were reflected in the newborns. Genes related to DCs, TFh cells, and B cells were increased in Gr. II, and Gr. II newborns showed a boost in cellular and humoral responses after vaccination. Conclusion: In mothers infected with HBV, low serum IL-21 levels and decreased TFh-cell and plasma B-cell frequencies are associated with vertical transmission of HBV to newborns. These features are indicative of low protective maternal immunity.

Mycobacterium Tuberculosis infection among the elderly in 20 486 rural residents aged 50-70 years in Zhongmu County, China

OBJECTIVES

Elderly individuals in rural China have been known to be at increased risk of contracting tuberculosis (TB) and developing active disease. This study aims to estimate the burden of mycobacterium tuberculosis (MTB) infection and to identify potential targeted subgroups for infection control.

METHODS

As part of the investigation of an interventional study, 50- to 70-year-old rural residents in Zhongmu County were targeted for MTB infection testing using QuantiFERON-TB Gold In-Tube (QFT). Questionnaires and physical examinations were conducted to acquire their demographic information and health status.

RESULTS

A total of 20 486 individuals were included in the analysis. The prevalence of QFT positivity was 20.79% (4259/20 486) and 50 participants (0.24%) had indeterminate results. A positive dose-response relation was found for QFT positivity with smoking intensity. Compared with non-drinkers, the risk of MTB infection was lower among participants with moderate alcohol consumption (<10 g/day) with adjusted odds ratio (OR) of 0.82 (95% CI 0.71-0.94). In addition, gender of male, with a history of previous TB or silicosis, and hepatitis B/C virus infection were associated with increased risk of MTB infection. An indeterminate QFT result was related to being underweight (adjusted OR 3.18; 95% CI 1.09-9.26).

CONCLUSIONS

Our results indicate a high burden of MTB infection among the elderly in this rural area. Smokers, individuals with a history of previous TB or silicosis, and those with hepatitis B/C virus infection should be prioritized for MTB infection control to reduce the risk of disease development from a new infection.

Circulating and Hepatic BDCA1+, BDCA2+, and BDCA3+ Dendritic Cells Are Differentially Subverted in Patients With Chronic HBV Infection

Background and aims: Chronic hepatitis B virus (HBV) infection is a major health burden potentially evolving toward cirrhosis and hepatocellular carcinoma. HBV physiopathology is strongly related to the host immunity, yet the mechanisms of viral evasion from immune-surveillance are still misunderstood. The immune response elicited at early stages of viral infection is believed to be important for subsequent disease outcome. Dendritic cells (DCs) are crucial immune sentinels which orchestrate antiviral immunity, which offer opportunity to pathogens to subvert them to escape immunity. Despite the pivotal role of DCs in orientating antiviral responses and determining the outcome of infection, their precise involvement in HBV pathogenesis is not fully explored.

Methods: One hundred thirty chronically HBV infected patients and 85 healthy donors were enrolled in the study for blood collection, together with 29 chronically HBV infected patients and 33 non-viral infected patients that were included for liver biopsy collection. In a pioneer way, we investigated the phenotypic and functional features of both circulating and intrahepatic BDCA1+ cDC2, BDCA2+ pDCs, and BDCA3+ cDC1 simultaneously in patients with chronic HBV infection by designing a unique multi-parametric flow cytometry approach.

Results: We showed modulations of the frequencies and basal activation status of blood and liver DCs associated with impaired expressions of specific immune checkpoints and TLR molecules on circulating DC subsets. Furthermore, we highlighted an impaired maturation of circulating and hepatic pDCs and cDCs following stimulation with specific TLR agonists in chronic HBV patients, associated with drastic dysfunctions in the capacity of circulating DC subsets to produce IL-12p70, TNFα, IFNα, IFNλ1, and IFNλ2 while intrahepatic DCs remained fully functional. Most of these modulations correlated with HBsAg and HBV DNA levels.

Conclusion: We highlight potent alterations in the distribution, phenotype and function of all DC subsets in blood together with modulations of intrahepatic DCs, revealing that HBV may hijack the immune system by subverting DCs. Our findings provide innovative insights into the immuno-pathogenesis of HBV and the mechanisms of virus escape from immune control. Such understanding is promising for developing new therapeutic strategies restoring an efficient immune control of the virus.

Interferon-α Up-Regulates the Expression of PD-L1 Molecules on Immune Cells Through STAT3 and p38 Signaling

Interferon-α (IFNα) has one of the longest histories of use amongst cytokines in clinical oncology and has been applied for the treatment of many types of cancers. Due to its immune-activating properties, IFNα is also an attractive candidate for combinatory anti-cancer therapies. Despite its extensive use in animal tumor models as well as in several clinical trials, the different mechanisms underlying patient responses and affecting desirable clinical benefits are still under investigation. Here we show that in addition to its immune-activating properties, IFNα induces the expression of a key negative regulator, immunosuppressive PD-L1 molecule, in the majority of the specific immune cell populations, particularly in the dendritic cells (DC). DC can modulate immune responses by a variety of mechanisms, including expression of T-cell regulatory molecules and cytokines. Our results showed that treatment of DC with IFNα-2b led to pronounced up-regulation of surface expression of PD-L1 molecules, increased IL-6 and decreased IL-12 production. Moreover, we present evidence that IFNα-treated DC exhibited a reduced capacity to stimulate interferon-γ production in T cells compared to control DC. This T-cell response after treatment of DC with IFNα was recovered by a pre-treatment with an anti-PD-L1 blocking antibody. Further analyses revealed that IFNα regulated PD-L1 expression through the STAT3 and p38 signaling pathways, since blocking of STAT3 and p38 activation with specific inhibitors prevented PD-L1 up-regulation. Our findings underline the important roles of p38 and STAT3 in the regulation of PD-L1 expression and prove that IFNα induces STAT3/p38-mediated expression of PD-L1 and thereby a reduced stimulatory ability of DC. The augmentation of PD-L1 expression in immune cells through IFNα treatment should be considered by use of IFNα in an anti-cancer therapy.

Hepatitis B virus-persistent infection and innate immunity defect: Cell-related or virus-related?

The outcomes of hepatitis B virus (HBV) infection are closely related to the age at which infection was acquired. Infection acquired in adult life tends to be self-limited, in contrast to perinatal acquirement, for which chronic persistence of the HBV is a general outcome. Innate immunity plays an indispensable role in early virus infection, facilitating virus clearance. However, it has been reported that HBV is under-recognized and poorly eliminated by the innate immune system in the early stages of infection, possibly explaining the long-lasting persistence of viremia afterwards. Furthermore, due to the existence of covalently closed circular DNA, chronic HBV clearance is very difficult, even when patients are given interferon-α and nucleotide/nucleoside analogs for antiviral therapy. The mechanism by which HBV evades innate immune recognition and establishes persistent infection remains a subject of debate. Besides, some researchers are becoming more interested in how to eradicate chronic HBV infection by restoring or boosting innate immunity. This review aimed to summarize the current knowledge on how intrahepatocyte signaling pathways and innate immune cells act after the onset of HBV infection and how these actions are related to the persistence of HBV. We anticipate the insights presented herein to be helpful for future development of novel immune therapeutic strategies to fight HBV infection.