Defective natural killer cell anti-viral capacity in paediatric HBV infection

Peripheral Mononuclear Cells Surface Markers Evaluation in Different Stages of Hepatocellular Carcinoma; in a Trial for Early and Accurate Diagnosis in Patients with Post-Hepatitis Liver Cirrhosis and Unremarkable Raised AFP

Introduction

HCC is frequently diagnosed late, when only palliative treatment is available. So, we try to use different immunological markers to identify early HCC in patients with unremarkable raised AFP.

Methods

This study was conducted on 112 participants divided into two equal groups: Group I, 56 patients with liver cirrhosis and different stages of HCC; Group II, 56 patients with liver cirrhosis. The diagnosis of HCC was based on AASLD guidelines. TNM and BCLC classification systems are used for staging of HCC.

Results

A significant reduction in the median percentage of lymphocyte subset (CD3⁺, CD4⁺, CD8⁺, CD19⁺) and NK cell percentage (CD56⁺) has been detected in HCC patients (all P < 0.001). In the HCC group the median monocyte subpopulations CD14⁺ CD16^- Classical, CD14⁺⁺ CD16⁺ Intermediate, and CD14^-+ CD16⁺⁺ Non-Classical were 11.7, 4.0, and 3.5, respectively, with marked reduction compared with liver cirrhosis group (all P < 0.001). Patients with advanced stages (BCLC C and D) were more likely to have significantly higher median CD33⁺ than patients with early stages (BCLC A and B) (P = 0.05); also, the median levels of HLA DR⁺ lymphocytes % in the HCC case group were 21.8 in patients with advanced disease (BCLC C and D) and 13.1 in patients with early stages of the disease (P = 0.04). Patients with late stage (TNM III) were more likely to have significantly higher median CD14⁺ CD16^- Classical monocyte subset, CD36⁺ HLA DR⁺, and CD36⁺ CD16^- than patients with early stages (TNM I and II).

Conclusion

Patients with HCC with unremarkable raised AFP showed marked reduction in lymphocytes, natural killer cells, and all monocyte subpopulations. In addition, patients with advanced HCC showed increased CD33⁺ and HLA DR⁺ lymphocytes %, CD14⁺ CD16^- Classical monocyte subset, CD36⁺ HLA DR⁺, and CD36⁺ CD16^- compared with patients with early stages of HCC.

Advances in Immunotherapy for Hepatitis B

Hepatitis B virus (HBV) is a hepatotropic virus with the potential to cause chronic infection, and it is one of the common causes of liver disease worldwide. Chronic HBV infection leads to liver cirrhosis and, ultimately, hepatocellular carcinoma (HCC). The persistence of covalently closed circular DNA (cccDNA) and the impaired immune response in patients with chronic hepatitis B (CHB) has been studied over the past few decades. Despite advances in the etiology of HBV and the development of potent virus-suppressing regimens, a cure for HBV has not been found. Both the innate and adaptive branches of immunity contribute to viral eradication. However, immune exhaustion and evasion have been demonstrated during CHB infection, although our understanding of the mechanism is still evolving. Recently, the successful use of an antiviral drug for hepatitis C has greatly encouraged the search for a cure for hepatitis B, which likely requires an approach focused on improving the antiviral immune response. In this review, we discuss our current knowledge of the immunopathogenic mechanisms and immunobiology of HBV infection. In addition, we touch upon why the existing therapeutic approaches may not achieve the goal of a functional cure. We also propose how combinations of new drugs, and especially novel immunotherapies, contribute to HBV clearance.

Transforming growth factor β as a possible independent factor in chronic hepatitis B

To investigate the association between immune-cell-related cytokines and the development of chronic hepatitis B (CHB), patients with chronic hepatitis B virus (HBV) infection in the immunotolerant (IT) phase (n = 30) or hepatitis B envelope antigen (HBeAg)-positive CHB (n = 250) were enrolled in this study. Serological indicators and plasma cytokine levels were measured at the time of enrollment. The results showed that there were significant differences in the median age of the patients (27 vs. 31 years), alanine aminotransferase levels (ALT, 29.85 vs. 234.70 U/L), alanine aminotransferase levels (AST, 23.40 vs. 114.90 U/L), HBsAg levels (4.79 vs. 3.88 log₁₀ IU/ml), HBeAg levels (1606.36 vs. 862.47 S/CO), and the HBV DNA load (8.17 vs. 6.71 log₁₀ IU/ml) between the IT and CHB groups (all P < 0.01). The median values of Fms-like tyrosine kinase 3 ligand (FLT3-L), interferon-gamma (IFN-γ), interleukin- 17A (IL-17A), and transforming growth factor beta (TGF-β1) were significantly higher in the IT group than in the CHB group (FLT3-L, 41.62 vs. 27.47 pg/ml; IFN-γ, 42.48 vs. 33.18 pg/ml; IL-17A, 15.66 vs. 8.90 pg/ml; TGF-β1, 4921.50 vs. 2234 pg/ml; all P < 0.01). The median IFN-α2, TGF-β3 and IL-10 levels in the IT group were significantly lower than those in the CHB group (IFN-α2, 15.24 vs. 35.78 pg/ml, P = 0.000; TGF-β3, 131.69 vs. 162.61 pg/ml, P = 0.025; IL-10, 5.02 vs. 7.9 pg/ml, P = 0.012). Multivariate logistic regression analysis indicated that TGF-β 1 (OR = 0.999, 95% CI 0.999-1.000, P < 0.001) and TGF-β2 levels (OR = 1.008, 95%CI 1.004-1.012, P < 0.001) were modestly but significantly associated with the incidence of CHB. The results suggest that TGF-β level might be an independent factor related to the occurrence of CHB.

Peripheral natural killer cells in chronic hepatitis B patients display multiple molecular features of T cell exhaustion

Antiviral effectors such as natural killer (NK) cells have impaired functions in chronic hepatitis B (CHB) patients. The molecular mechanism responsible for this dysfunction remains poorly characterised. We show that decreased cytokine production capacity of peripheral NK cells from CHB patients was associated with reduced expression of NKp30 and CD16, and defective mTOR pathway activity. Transcriptome analysis of patients NK cells revealed an enrichment for transcripts expressed in exhausted T cells suggesting that NK cell dysfunction and T cell exhaustion employ common mechanisms. In particular, the transcription factor TOX and several of its targets were over-expressed in NK cells of CHB patients. This signature was predicted to be dependent on the calcium-associated transcription factor NFAT. Stimulation of the calcium-dependent pathway recapitulated features of NK cells from CHB patients. Thus, deregulated calcium signalling could be a central event in both T cell exhaustion and NK cell dysfunction occurring during chronic infections.

Pharmacotherapy options for managing hepatitis B in children

INTRODUCTION

To eliminate viral hepatitis by 2030, the World Health Organization (WHO) launched the first global health sector strategy on viral hepatitis, with particular focus given to hepatitis B and C in 2016. To achieve the reduction of mortality in children, it is indispensable to know which children should be treated and how to treat them.

AREA COVERED

In this article, the authors review the antiviral treatment of children with chronic hepatitis B virus (HBV) infection including antivirals available for children with chronic HBV infection.

EXPERT OPINION

The approvals of nucleos(t)ide analogues (NAs) and pegylated interferon (PEG-IFN) for children have lowered a hurdle to the initiation of antiviral treatment in children. The international guidelines use nearly the same criteria of antiviral treatment for children with chronic HBV infection, but the WHO guidelines provide a cautious stance on the antiviral treatment of children. Not only PEG-IFN but also NAs with a high genetic barrier to drug resistance should be the first-line treatment for children. In settings with limited medical resources, NAs can be the first-line treatment for children. Although the concept of an 'immune-tolerant phase' is challenged, evidence is not sufficient to recommend the treatment of HBeAg-positive immune-tolerant children.

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.

Peripheral blood lymphocyte subset levels differ in patients with hepatocellular carcinoma

We investigated the levels of target lymphocyte subsets in peripheral blood lymphocyte samples from patients with hepatocellular carcinoma (HCC). A total of 715 high-risk patients with primary HCC were recruited in Guangxi, China as the case group. The control group included 100 patients who received health examinations at the same hospital during the same period. Fasting elbow venous blood (10 mL) was collected from each participant, and flow cytometry was used to detect the levels of NK cells and CD3⁺, CD4⁺ and CD19⁺ T cells in peripheral blood samples. All included patients with prmary HCC were treated by surgical resection, and followed up for one year. The levels of CD19⁺ and NK cells were lower in cases than in controls (both P < 0.05). In addition, the level of CD8⁺ cells was greater in the case group than in the control group (P < 0.05). In the high-HCC-risk population, CD8⁺, CD19⁺ and NK cell levels all differed between male and female patients, patients in TNM stages I–II and stages III–IV, patients with and without extrahepatic metastasis, and patients with and without HBV infection (all P < 0.05). After follow-up, detected recurrence and survival rate was 33.71% and 83.64%, respectively. CD8⁺ levels was reduced following surgical resection, whereas the levels of CD19⁺ and NK cells were increased (all P < 0.05). In conclusion, altered levels of CD8⁺, CD19⁺ and NK cell levels may be used as reference values for monitoring immune function in certain populations with high HCC risk, and as potential evidence for the clinical diagnosis and treatment of HCC.

Veritable antiviral capacity of natural killer cells in chronic HBV infection: an argument for an earlier anti-virus treatment

Background

There is limited information on innate immunity, especially natural killer (NK) cell function, in different chronic hepatitis B (CHB) stages. Therefore, we examined whether the clinical staging strategy accurately reflects veritable NK cell immunity.

Methods

A total of 237 eligible CHB patients and 22 healthy controls were enrolled in our study. Demographic and clinical data were collected, and the CHB phases (immune active-IA, immune tolerant phase-IT, inactive CHB-IC, and grey zone-GZ) were classified according to the latest American Association for the Study of Liver Disease guidelines. Peripheral blood mononuclear cells from patients and healthy controls were tested for NK cell frequency, phenotype and function using flow cytometry.

Results

A significant decrease in activating receptor NKp44 and NKp46 expression and significant increase of exhaustion molecule Tim-3 expression were observed in NK cells from CHB patients. Reduced cytokine secretion and preserved or elevated cytotoxic function were also observed. Patients in the IT group exhibited comparable cytokine secretion and cytolytic capacity as age-matched IA patients. NK cell anti-viral functions were preserved in GZ patients. Some of the NK cell function in patients who were excluded from treatment by the current treatment guidelines was less compromised than patients who qualified for treatment.

Conclusion

Our findings provide evidence of veritable NK cell immunity during different natural history phases in treatment-naïve patients with chronic HBV Infection. Chronic HBV infection hindered NK cell function in CHB patients. However, the presumed IT and GZ statuses of CHB patients based on the clinical parameters may not accurately reflect the inner immune status of these patients and should be reconsidered. Some patients excluded from treatment by the current treatment guidelines may be able to be selected as candidates for treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-017-1318-1) contains supplementary material, which is available to authorized users.

Immune balance in Hepatitis B Infection: Present and Future Therapies

Chronic hepatitis B virus (HBV) infection affects millions of people worldwide and about half a million people die every year. India represents the second largest pool of chronic HBV infections with an estimated 40 million chronically infected patients. Persistence or clearance of HBV infection mainly depends upon host immune responses. Chronically infected individuals remain in immune tolerant phase unless HBV flares and leads to the development of chronic active hepatitis or acute-on-chronic liver failure. Strategies based on inhibition of viral replication (nucleoside analogues) or immune modulation (interferons) as monotherapy, or in combination in sequential therapies, are currently being used globally for reducing HBV viral load and mediating HBsAg clearance. However, the immune status and current therapies for promoting sustained virological responses in HBV-infected patients remain suboptimal. Elimination of cccDNA is major challenge for future therapies, and new molecules such as NTCP, Toll-like receptor (TLR)7 agonist (GS9620) and cyclophilin have emerged as potential targets for preventing HBV entry and replication. Other than these, HBV cccDNA elimination is the major target for future therapies.

Different antiviral effects of IFNα subtypes in a mouse model of HBV infection

Interferon alpha (IFNα) is commonly used for the treatment of chronic hepatitis B (CHB) patients. There are 13 different IFNα subtypes in humans, but only the subtype IFNα2 is used for clinical treatment. The antiviral activities of all other IFNα subtypes against HBV have not been studied. To obtain basic knowledge about the direct antiviral as well as the immunomodulatory effects of IFNα subtypes, we used the HBV hydrodynamic injection (HI) mouse model. Application of most IFNα subtype proteins inhibited HBV replication in vivo, with IFNα4 and IFNα5 being the most effective subtypes. Decreased viral loads after therapeutic application of IFNα4 and IFNα5 correlated with expanded effector cell populations of NK cells and T cells in both liver and spleen. Hydrodynamic injection of plasmids encoding for the effective IFNα subtypes (pIFNα) was even more potent against HBV than injecting IFNα proteins. The combination of pIFNα4 and pIFNα5 showed a synergistic antiviral effect on HBV replication, with a strong increase in NK cell and T cell activity. The results demonstrate distinct anti-HBV effects of different IFNα subtypes against HBV in the mouse model, which may be relevant for new therapeutic approaches.

NKG2D modulates aggravation of liver inflammation by activating NK cells in HBV infection

Hepatitis B virus (HBV) infection is thought to be an immune-mediated liver disease. The mechanisms underlying natural killer (NK) cell group 2D receptor (NKG2D) that activates NK cells and participates in anti-HBV immunity and immunopathology has not been thoroughly elucidated. Peripheral NKG2D+ and IFN-γ+ NK cells frequencies and intrahepatic NKG2D and IFN-γ mRNA and protein expressions were determined in HBV-infected patients. Levels of NKG2D and IFN-γ mRNA and protein in NK cells, co-cultured with HBV-replicating HepG2 cells with or without NKG2D blockade, were analyzed. Serum and supernatant IFN-γ, TNF-α, perforin and granzyme B were measured. In results, peripheral NKG2D+ and IFN-γ+ NK cells frequencies, intrahepatic NKG2D and IFN-γ mRNA and protein levels, and serum IFN-γ, TNF-α, perforin and granzyme B levels were all highest in HBV-related acute-on-chronic liver failure group, followed by chronic hepatitis B and chronic HBV carrier groups. In vitro, NKG2D and IFN-γ mRNA and protein levels were higher in NK cells with IFN-α stimulation than without stimulation. Supernatant IFN-γ, TNF-α, perforin and granzyme B levels were increased under co-culture or IFN-α stimulating conditions, but were partially blocked by NKG2DmAb. In conclusion, NKG2D regulates immune inflammation and anti-viral response partly through activation of NK cells during HBV infection.

Gene copy number variations in the leukocyte genome of hepatocellular carcinoma patients with integrated hepatitis B virus DNA

Integration of hepatitis B virus (HBV) DNA into the human liver cell genome is believed to promote HBV-related carcinogenesis. This study aimed to quantify the integration of HBV DNA into the leukocyte genome in hepatocellular carcinoma (HCC) patients in order to identify potential biomarkers for HBV-related diseases. Whole-genome comparative genomic hybridization (CGH) chip array analyses were performed to screen gene copy number variations (CNV) in the leukocyte genome, and the results were confirmed by quantitative polymerase chain reaction (qPCR). The commonly detected regions included chromosome arms 19p, 5q, 1q and 15p, where 200 copy number gain events and 270 copy number loss events were noted. In particular, gains were observed in 5q35.3 (OR4F3) and 19p13.3 (OR4F17) in 90% of the samples. Successful homologous recombination of OR4F3 and the HBV P gene was demonstrated, and the amplification at 5q35.3 is potentially associated with the integration of HBV P gene into natural killer cells isolated from peripheral blood mononuclear cells (PBMCs). Receiver operating characteristic (ROC) curve analysis indicated that the combination of OR4F3 and OR4F17 a novel potential biomarker of HBV-related diseases.

Natural Killer Cells in Viral Hepatitis

Natural killer (NK) cells are traditionally regarded as first-line effectors of the innate immune response, but they also have a distinct role in chronic infection. Here, we review the role of NK cells against hepatitis C virus (HCV) and hepatitis B virus (HBV), two agents that cause acute and chronic hepatitis in humans. Interest in NK cells was initially sparked by genetic studies that demonstrated an association between NK cell-related genes and the outcome of HCV infection. Viral hepatitis also provides a model to study the NK cell response to both endogenous and exogenous type I interferon (IFN). Levels of IFN-stimulated genes increase in both acute and chronic HCV infection and pegylated IFNα has been the mainstay of HCV and HBV treatment for decades. In chronic viral hepatitis, NK cells display decreased production of antiviral cytokines. This phenotype is found in both HCV and HBV infection but is induced by different mechanisms. Potent antivirals now provide the opportunity to study the reversibility of the suppressed cytokine production of NK cells in comparison with the antigen-induced defect in IFNγ and tumor necrosis factor-α production of virus-specific T cells. This has implications for immune reconstitution in other conditions of chronic inflammation and immune exhaustion, such as human immunodeficiency virus infection and cancer.