Clinical and virological studies on α-interferon treatment of chronic hepatitis type B

The positive results of a-interferon (IFN) therapy have generated an important change in the therapeutic approach of chronic hepatitis B patients. The studies presented in this thesis are directed to the question how the efficacy of a-IFN therapy for chronic hepatitis B could be improved (chapter 1). In particular we investigated whether patient selection, modification of the treatment schedule and new virological assessments could contribute to answer this question. For optimal management of the HBV-infected patients it is important to defme indications for new treatment modalities as a-IFN and liver transplantation. We followed a cohort of 98 patients with HBsAg-positive cirrhosis and determined which variables influenced the survival (chapter 2). High age, the presence of ascites and a high serum bilirubin level were indepently associated with a short duration survival. For the group with a compensated cirrhosis HBeAg-negative patients exhibited a significantly better prognosis than HBeAg-positive patients. In contrast we could not fmd a difference in survival in decompensated patients with a different HBeAg status. These fmdings suggest that there is an indication for antiviral therapy for patients with a compensated hepatitis B cirrhosis and active viral replication (HBeAg positive) whereas liver transplantation appears the major therapeutic option for patients with a decompensated chronic hepatitis B infection. The standard course of a-IFN therapy for chronic hepatitis B lasts 16 weeks and leads in about one third of the patients to cessation of virus replication. Intermittent a-IFN therapy of 24 weeks duration and prolongation of treatment in patients who already exhibited a partial response (HBV-DNA negative) could enhance the HBeAg serocvonversion rate (chapter 3). Another modification of the standard a-IFN treatment is combination therapy with zidovudine. In a randomized controlled study (chapter 4) we found that this combination was not more effective than a-IFN monotherapy. In patients treated with the combination of a-IFN and zidovudine side effects, in particular anemia and leucopenia, were more prominent than in those treated with a-IFN and placebo. In chapter 5 the benefit of a-IFN retreatment in chronic hepatitis B patients who previously failed to respond was evaluated. A response (HBeAg seroconversion) to therapy occurred in 2 of the 18 (11 %) investigated patients. This response rate may be comparable to the spontaneous HBeAg seroconversion incidence and therefore the efficacy of a-IFN retreatment in chronic hepatitis B appears limited. Variables with a known predictive value towards response for initial a-IFN courses (e.g. the level of inflammatory acitvity) did not influence the result of the retreatment

Antiviral treatment for chronic hepatitis B virus infection--immune modulation or viral suppression?

The availability of nucleoside analogues has broadened treatment options for chronic hepatitis B virus (HBV ) infection. Registered treatment for chronic hepatitis B currently consists of (pegylated) interferon, lamivudine and adefovir, while entecavir is expected to be licensed in the short term. Treatment is generally recommended for patients with high serum HBV DNA and elevated ALAT, indicating the host's immune response against HBV. Induction of an HBV -specific immune response seems crucial for persistent control of HBV infection. Currently available treatment strategies can be differentiated into those that provide sustained off-treatment response and those that provide therapy maintained response. A finite treatment course with immunomodulatory agents (interferon-based therapy) results in sustained response in about one third of patients, while nucleoside analogue treatment generally requires indefinite therapy without a clear stopping point. Since nucleoside analogues are well tolerated, prolonged therapy is feasible, but a major drawback is the considerable risk of developing antiviral resistance, which occurs most frequently in lamivudine treated patients and to a lesser extent during adefovir or entecavir therapy. In our opinion, treatment with peginterferon should therefore be considered first-line therapy in eligible patients with a high likelihood of response based on serum HBV DNA, ALAT and HBV genotype. Patients not responding to PEG-IF N therapy or not eligible for peginterferon therapy should be treated with nucleos(t)ide analogues

Immigration and viral hepatitis

WHO estimates reveal that the global prevalence of viral hepatitis may be as high as 500 million, with an annual mortality rate of up to 1.3 million individuals. The majority of this global burden of disease is borne by nations of the developing world with high rates of vertical and iatrogenic transmission of HBV and HCV, as well as poor access to healthcare. In 2013, 3.2% of the global population (231 million individuals) migrated into a new host nation. Migrants predominantly originate from the developing countries of the south, into the developed economies of North America and Western Europe. This mass migration of individuals from areas of high-prevalence of viral hepatitis poses a unique challenge to the healthcare systems of the host nations. Due to a lack of universal standards for screening, vaccination and treatment of viral hepatitis, the burden of chronic liver disease and hepatocellular carcinoma continues to increase among migrant populations globally. Efforts to increase case identification and treatment among migrants have largely been limited to small outreach programs in urban centers, such that the majority of migrants with viral hepatitis continue to remain unaware of their infection. This review summarizes the data on prevalence of viral hepatitis and burden of chronic liver disease among migrants, current standards for screening and treatment of immigrants and refugees, and efforts to improve the identification and treatment of viral hepatitis among migrants

Monocytes from chronic HBV patients react in vitro to HBsAg and TLR by producing cytokines irrespective of stage of disease

Individuals who are chronically infected with the hepatitis B virus (HBV) are highly heterogenous with respect to serum levels of HBV DNA, HBV particles and viral proteins. Since circulating leukocytes, such as monocytes, are constantly exposed to these viral components, it is likely that the functionality of these cells is affected. However, at present, little information is available on the consequences of the interaction between monocytes and viral components. Therefore, we examined the in vitro effects of HBV surface antigen (HBsAg) on monocytes and evaluated whether these effects were reflected in vivo. We observed that in vitro HBsAg exposure of monocytes induced robust production of IL-6 and TNF. However, between chronic HBV patients with distinct levels of serum HBsAg, HBV early antigen (HBeAg), and HBV DNA, TLR-induced monocyte cytokine production did not differ. Importantly, HBsAg-induced cytokine production by monocytes was similar between patients and healthy controls showing that earlier in vivo exposure to HBsAg does not affect the in vitro response. Additionally, we show that IL-10 is able to inhibit cytokine production by HBsAg-induced monocytes. In conclusion, we demonstrate that monocytes can recognize and respond to HBsAg, resulting in vigorous pro-inflammatory cytokine production in vitro. However, phenotype and function of the monocyte compartment in chronic HBV patients are not influenced by differences in levels of serum viral components, suggesting that regulatory mechanisms are active to avoid excessive in vivo monocyte activation

Negative Regulation of Hepatitis C Virus Specific Immunity Is Highly Heterogeneous and Modulated by Pegylated Interferon-Alpha/Ribavirin Therapy

Specific inhibitory mechanisms suppress the T-cell response against the hepatitis C virus (HCV) in chronically infected patients. However, the relative importance of suppression by IL-10, TGF-β and regulatory T-cells and the impact of pegylated interferon-alpha and ribavirin (PegIFN-α/ribavirin) therapy on these inhibitory mechanisms are still unclear. We revealed that coregulation of the HCV-specific T-cell responses in blood of 43 chronic HCV patients showed a highly heterogeneous pattern before, during and after PegIFN-α/ribavirin. Prior to treatment, IL-10 mediated suppression of HCV-specific IFN-γ production in therapy-naive chronic HCV patients was associated with higher HCV-RNA loads, which suggests that protective antiviral immunity is controlled by IL-10. In addition, as a consequence of PegIFN-α/ribavirin therapy, negative regulation of especially HCV-specific IFN-γ production by TGF-β and IL-10 changed dramatically. Our findings emphasize the importance of negative regulation for the dysfunctional HCV-specific immunity, which should be considered in the design of future immunomodulatory therapies

Genome-wide Association Study Identifies Genetic Variants Associated With Early and Sustained Response to (Pegylated) Interferon in Chronic Hepatitis B Patients: The GIANT-B Study

Background. (Pegylated) Interferon ([Peg]IFN) therapy leads to response in a minority of chronic hepatitis B (CHB) patients. Host genetic determinants of response are therefore in demand. Methods. In this genome-wide association study (GWAS), CHB patients, treated with (Peg)IFN for at least 12 weeks ± nucleos(t)ide analogues within randomized trials or as standard of care, were recruited at 21 centers from Europe, Asia, and North America. Response at 24 weeks after (Peg)IFN treatment was defined as combined hepatitis B e antigen (HBeAg) loss with hepatitis B virus (HBV) DNA <2000 IU/mL, or an HBV DNA <2000 IU/mL for HBeAg-negative patients. Results. Of 1144 patients, 1058 (92%) patients were included in the GWAS analysis. In total, 282 (31%) patients achieved the response and 4% hepatitis B surface antigen (HBsAg) loss. GWAS analysis stratified by HBeAg status, adjusted for age, sex, and the 4 ancestry components identified PRELID2 rs371991 (B= −0.74, standard error [SE] = 0.16, P = 3.44 ×10–6) for HBeAg-positive patients. Importantly, PRELID2 was cross-validated for long-term response in HBeAg-negative patients. G3BP2 rs3821977 (B = 1.13, SE = 0.24, P = 2.46 × 10–6) was associated with response in HBeAg-negative patients. G3BP2 has a role in the interferon pathway and was further examined in peripheral blood mononuclear cells of healthy controls stimulated with IFNα and TLR8. After stimulation, less production of IP-10 and interleukin (IL)-10 proteins and more production of IL-8 were observed with the G3BP2 G-allele. Conclusions. Although no genome-wide significant hits were found, the current GWAS identified genetic variants associated with (Peg)IFN response in CHB. The current findings could pave the way for gene polymorphism-guided clinical counseling, both in the setting of (Peg)IFN and the natural history, and possibly for new immune-modulating therapies

NK cells in self-limited HCV infection exhibit a more extensively differentiated, but not memory-like, repertoire

Natural killer (NK) cells have long been thought of as a purely innate immune cell population, but increasing reports have described developmental and functional qualities of NK cells that are commonly associated with cells of the adaptive immune system. Of these features, the ability of NK cells to acquire functional qualities associated with immunological memory and continuous differentiation resulting in the formation of specific NK cell repertoires has recently been highlighted in viral infection settings. By making use of a unique cohort of monitored, at-risk intravenous drug users in this study, we were able to dissect the phenotypic and functional parameters associated with NK cell differentiation and NK cell memory in patients 3 years after acute HCV infection and either the subsequent self-clearance or progression to chronicity. We observed increased expression of cytolytic mediators and markers CD56bright and NKp46+ of NK cells in patients with chronic, but not self-limited HCV infection. Patients with a self-limited infection expressed higher levels of differentiation-associated markers CD57 and KIRs, and lower levels of NKG2A. A more extensively differentiated NK cell phenotype is associated with self-clearance in HCV patients, while the NK cells of chronic patients exhibited more naïve and effector NK cell phenotypic and functional characteristics. The identification of these distinct NK cell repertoires may shed light on the role NK cells play in determining the outcome of acute HCV infections, and the underlying immunological defects that lead to chronicity