Sequential immunological analysis of HBV/HCV co-infected patients during Peg-IFN/RBV therapy

Lower frequency of MDSCs was significantly related to functional cure in CHB patients treated with peginterferon

BACKGROUND AND AIMS

Myeloid-derived suppressor cells (MDSCs) and CD4⁺ regulatory T cells (Tregs) expand during chronic hepatitis B virus (HBV) infection and inhibit antiviral immunity. However, the relationship between antiviral effect and the frequencies of those immune suppressive cells after pegylated interferon α-2a (PegIFNα-2a) therapy is not clearly understood. This study aimed to investigate the contribution of monocytic MDSCs (mMDSCs) and CD4⁺ Tregs to functional cure (HBsAg seroclearance) after PegIFNα-2a therapy and evaluate the effect of PegIFNα-2a therapy on these cells.

METHODS

Flow cytometry analysis was performed along with longitudinal immune monitoring of 97 hepatitis B e antigen (HBeAg) negative chronic hepatitis B (CHB) patients receiving PegIFNα-2a weekly for 48 weeks.

RESULTS

The frequencies of mMDSCs and CD4⁺ Tregs increased in all HBV patients, and they were higher in the HBsAg persistence group than in the HBsAg seroclearance group. A significant decline in the frequency of mMDSCs was found in patients who realized functional cure after PegIFNα-2a treatment. In contrast, the frequency of CD4⁺ Tregs in both the HBsAg seroclearance and persistence groups significantly increased. Multivariate analyses indicated that the baseline serum HBsAg levels (p < .001) and mMDSCs frequency (p = .027) were independently associated with the HBsAg clearance, and the combined marker (HBsAg plus mMDSCs) displayed the highest specificity (93.1%) than any other markers in predicting HBsAg seroclearance.

CONCLUSIONS

These results suggest that a poor response to PegIFNα-2a treatment in CHB patients may be related to the frequencies of immune suppressive cells, while the therapeutic targeting of these cells might be effective in boosting anti-HBV immunity.

HBV coinfection with HCV alters circulating Tfh cell distribution and impairs HCV neutralizing antibody responses

Hepatitis C virus (HCV) and hepatitis B virus (HBV) coinfection reciprocally influences viral replication and host defence responses. This study aimed to investigate the impact of HBV coinfection on circulating T follicular helper cell (cTfh) distribution and the HCV neutralizing antibody (nAb) response. HCV neutralizing antibody responses were measured in individuals with HCV monoinfection (n = 83) and HBV/HCV coinfection (n = 78) using the HCV pseudoparticle neutralization assay. The frequencies of cTfh cells and their subsets in HCV monoinfection (n = 34) and HBV/HCV coinfection (n = 30) were analysed by flow cytometry. The correlations of clinical parameters, cTfh cells and neutralizing antibody responses were analysed. Compared with HCV monoinfection, the HBV coinfection group showed significantly lower HCV neutralizing antibody responses (P < 0.001) and a decreased frequency of circulating Th1-like Tfh cells (Tfh1) (P = 0.004). In HCV monoinfection, the frequency of the Tfh1 subset was positively correlated with HCV neutralizing antibody responses (R = 0.378, P = 0.03), but this correlation was lost under HBV/HCV coinfection (R = 0.115, P = 0.551). In contrast, the frequency of circulating Th2-like Tfh cells (Tfh2) was negatively correlated with the HCV neutralizing antibody responses (R = 0.404, P = 0.003). Further analysis showed that HBV coinfection enhanced the Tfh2 subset composition within cTfh cells (P < 0.001), which was associated with serum HBsAg in HBV/HCV coinfection (R = 0.521, P = 0.003). As expected, HBsAg also exhibited an inverse association with HCV neutralizing antibody responses in HBV/HCV coinfection (R = 0.59, P < 0.001). In contrast to HCV monoinfection, HBV/HCV coinfection leads to altered cTfh cell distribution and impaired HCV neutralizing antibody responses, which are associated with HBsAg. These findings will be helpful for better understanding the immunopathogenesis of HBV/HCV coinfection.

The Role of Immune Cells in Chronic HBV Infection

Hepatitis B virus (HBV) infection is a major cause of chronic liver diseases that may progress to liver cirrhosis and hepatocellular carcinoma. Host immune responses are important factors that determine whether HBV infection is cleared or persists. After infection, viral replication occurs inside hepatocytes, and the secretion of infectious virions can take place at high rates for decades. Consequently, HBV DNA and viral proteins, like HBV early antigen (HBeAg) and HBV surface antigen (HBsAg), can be easily detected in serum. Chronic infection with HBV is the result of an ineffective antiviral immune response towards the virus. In this review, we discuss the role of immune cells in chronic HBV infection.

Significant biomarkers for the management of hepatocellular carcinoma

Surveillance of hepatocellular carcinoma (HCC) is important for early detection. Imaging tests including computed tomography, magnetic resonance imaging and ultrasonography with or without various kinds of contrast medium are important options for detecting HCC. In addition to the imaging tests, various kinds of biomarkers including alpha-fetoprotein (AFP), lectin-bound AFP (AFP-L3) and protein induced by vitamin K absence or antagonist II (PIVKA-II) have been widely used to detect HCC and analyze treatment response. Recently, various kinds of novel biomarkers (proteins and miRNA) have been found to predict the malignancy potential of HCC and treatment response to specific therapies. Moreover, various combinations of well-established biomarkers and novel biomarkers have been tested to improve sensitivity and specificity. In practical terms, biomarkers that can be analyzed using peripheral blood samples might be more useful than immunohistochemical techniques. It has been reported that quantification of cytokines in peripheral blood and the analysis of peripheral immune subsets could be good biomarkers for managing HCC. Here, we describe the usefulness of and update well-established and novel biomarkers for the management of HCC.

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

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

Poly(I:C) treatment leads to interferon-dependent clearance of hepatitis B virus in a hydrodynamic injection mouse model

We have previously shown that poly(I:C) activates murine hepatic cells to produce interferon (IFN) and suppresses hepatitis B virus (HBV) replication in vitro. Therefore, we addressed whether poly(I:C) is able to induce the clearance of HBV in vivo. The chronic HBV replication mouse model was established by the hydrodynamic injection (HI) of pAAV-HBV1.2 into the tail veins of wild-type and IFN-α/βR-, IFN-γ-, and CXCR3-deficient C57BL/6 mice. Fourteen days post-HI of pAAV-HBV1.2, mice were administered poly(I:C) by intraperitoneal injection, intramuscular injection, or HI. Only treatment of poly(I:C) by HI led to HBV clearance in wild-type C57BL/6 mice. Serum HBsAg disappeared within 40 days postinfection (dpi) in mice that received poly(I:C) by HI, and this was accompanied by the appearance of anti-HBs antibodies. HBV-specific T-cell and antibody responses were significantly enhanced by HI of poly(I:C). HBV replication intermediates and HBcAg-positive hepatocytes were eliminated in the liver. HI of poly(I:C) induced the production of IFNs in mice and enhanced the levels of cytokines, IFN-stimulated genes, and T-cell markers in the liver. Importantly, poly(I:C)-induced HBV clearance was impaired in IFN-α/βR-, IFN-γ-, and CXCR3-deficient mice, indicating that the induction of type I IFN and the stimulation and recruitment of T cells into the liver are essential for HBV clearance in this model. Taken together, the application of poly(I:C) by HI into the liver enhances innate and adaptive immune responses and leads to HBV clearance in an HBV mouse model, implicating the potential of intrahepatic Toll-like receptor 3 (TLR3) activation for the treatment of chronic hepatitis B patients.

IMPORTANCE

It has become well accepted that immunomodulation is a potentially useful approach to treat chronic viral infection. Recently, combinations of antiviral treatment and therapeutic vaccinations were evaluated for therapies of chronic hepatitis B virus (HBV) infection. Activation of the innate immune branch may also be important for viral control and contributes to HBV clearance. Our present study demonstrated that hepatic TLR3 activation led to clearance of hepatitis B virus in an HBV mouse model. For the first time, we showed that HBV clearance in this model is dependent not only on type I interferon (IFN) but also on type II IFN, indicating a coordinated action of innate and adaptive immune responses. T-cell recruitment appeared to be critical for the success of TLR3-mediated antiviral action. These findings implicate the potential of intrahepatic TLR3 activation for the treatment of chronic HBV infection.