Risks associated with hepatitis A and hepatitis B in patients with hepatitis C.

Individuals with hepatitis C virus (HCV) are at risk for acquiring hepatitis A virus (HAV) or hepatitis B virus (HBV) because of shared risk factors. A number of organizations recommend vaccination against HAV and HBV for patients with HCV. The rationale for vaccinating these patients is to prevent hepatic superinfections. Acute HAV superinfection causes more severe disease, acute hepatic failure, and higher fatality rates in patients with underlying chronic liver disease, specifically chronic HBV infection and chronic HCV infection. Available data, although limited, suggest that HBV coinfection with HAV and HCV causes more severe hepatic injury than infection with HAV or HCV alone. At standard doses, hepatitis A and hepatitis B vaccines are safe and immunogenic in patients with mild-to-moderate hepatitis C or chronic liver disease. Regardless of disease severity, vaccination should be routinely administered to patients upon diagnosis of HCV infection. Early vaccination is important because response to vaccination is reduced as liver disease progresses. Prevaccination and postvaccination serology testing is recommended in specific populations. A new combination hepatitis A and hepatitis B vaccine has been shown to be as safe and effective as monovalent hepatitis A and B vaccines and is currently under review by the United States Food and Drug Administration. A combination vaccine would offer ease of administration and convenience and could increase compliance in patients with hepatitis C or other chronic liver disease: two groups that should be more aggressively targeted by healthcare professionals.     

Suppression of hepatitis B virus replication mediated by hepatitis A‐induced cytokine production

Abstract: Background: Acute hepatitis A virus (HAV) infection can cause severe hepatitis especially in patients with underlying chronic liver disease. In patients with pre‐existing chronic hepatitis B (HBV) acute HAV infection can suppress HBV replication. The exact mechanism of HBV suppression during acute HAV infection is still a subject of debate. One mechanism may be the production of HAV infection‐induced cytokines leading to suppression of HBV replication and viral clearance. Aim: To evaluate cytokine production and HBV‐specific lympho‐proliferative responses (LPR) during acute HAV infection in a patient with chronic HBV infection‐clearing markers of active HBV replication. Design: Early detection of a case of acute HAV infection in an HBeAg‐positive, HBV DNA‐positive chronic HBV patient treated with lamivudine. Results: At the time of HAV infection a sharp peak in the gamma‐interferon (IFN‐γ) level occurred just before the rise in serum transaminase activity. This was subsequently followed by a decrease in HBV DNA and HBeAg below the limit of detection of the assay. However the HBV‐specific T‐cell response was not modified. After resolution of the acute HAV infection and withdrawal of antiviral therapy HBV replication relapsed. Conclusion: The sharp rise in IFN‐γ production mediated by the acute HAV infection may be pivotal in the suppression of HBV replication in chronic hepatitis B.     

Suppression of hepatitis B virus replication mediated by hepatitis A-induced cytokine production

BACKGROUND: Acute hepatitis A virus (HAV) infection can cause severe hepatitis especially in patients with underlying chronic liver disease. In patients with pre-existing chronic hepatitis B (HBV) acute HAV infection can suppress HBV replication. The exact mechanism of HBV suppression during acute HAV infection is still a subject of debate. One mechanism may be the production of HAV infection-induced cytokines leading to suppression of HBV replication and viral clearance. AIM: To evaluate cytokine production and HBV-specific lympho-proliferative responses (LPR) during acute HAV infection in a patient with chronic HBV infection-clearing markers of active HBV replication. DESIGN: Early detection of a case of acute HAV infection in an HBeAg-positive, HBV DNA-positive chronic HBV patient treated with lamivudine. RESULTS: At the time of HAV infection a sharp peak in the gamma-interferon (IFN-gamma) level occurred just before the rise in serum transaminase activity. This was subsequently followed by a decrease in HBV DNA and HBeAg below the limit of detection of the assay. However the HBV-specific T-cell response was not modified. After resolution of the acute HAV infection and withdrawal of antiviral therapy HBV replication relapsed. CONCLUSION: The sharp rise in IFN-gamma production mediated by the acute HAV infection may be pivotal in the suppression of HBV replication in chronic hepatitis B.     

6 Immunopathogenesis of viral hepatitis

More than 500 million people world-wide suffer from viral hepatitis which can be caused by a variety of distinct infectious agents. The spectrum of disease, which ranges from acute self-limited hepatitis to liver cirrhosis, not only reflects the different biological properties and pathogenicity of the hepatitis viruses, but is also the result of the specific interaction between each virus and the immune system of the infected host. The immune response plays a crucial role in the elimination of the infecting virus as well as in disease pathogenesis and is described in detail for acute and chronic hepatitis B and C virus infection. Acute hepatitis B virus infection is characterized by a vigorous, polyclonal cytotoxic T lymphocyte response against HBV that is not readily detectable in patients with chronic hepatitis B, suggesting that resolution of disease is mediated by the HBV-specific CTL response in these patients. Because traces of virus as well as HBVspecific CTL can perist for decades after clinical recovery, continuous priming of new CTL by minute traces of virus is thought to protect from reactivation of disease. In contrast, the hepatitis C virus causes chronic liver disease despite a polyclonal and multispecific immune response, suggesting that distinct immunological and viral mechanisms determine the different clinical outcome of HBV and HCV infection. Their implications for the development of immunomodulatory vaccines to cure patients with chronic viral hepatitis are discussed.     

Management of HBV, HCV, and HDV coinfection

Worldwide, chronic hepatitis B virus (HBV) infection is the most common cause of chronic liver disease. Concurrent hepatitis C (HCV) or hepatitis D (HDV) infection is common because of their shared routes of transmission. Studies show that concurrent HBV/HCV or HBV/HDV infections may be associated with a fulminant course of acute hepatitis, more severe forms of chronic liver disease, and higher risk for development of hepatocellular carcinoma. Virologic markers in HBV patients coinfected with HCV or HDV are dynamic and have different patterns. The replication of one virus may dominate the other and antiviral therapeutic strategies should target the dominant virus. Standard interferon-α or pegylated interferon is usually the treatment of choice for HBV/HCV and HBV/HDV coinfection. Adding ribavirin or lamivudine may benefit HBV patients coinfected with HCV but is ineffective against HDV. Treatment guidelines have not been established for chronic HBV coinfection with either HCV or HDV; therefore, management decisions usually depend on the clinical experience of the treating physician and the sparse data available regarding treatment options.     

Hepatitis B virus infection and alcohol consumption

Hepatocellular carcinoma(HCC) is the most common type of primary liver cancer, and the second most common cause of cancer deaths worldwide. The top three causes of HCC are hepatitis B virus(HBV),hepatitis C virus(HCV), and alcoholic liver disease. Owing to recent advances in direct-acting antiviral agents, HCV can now be eradicated in almost all patients. HBV infection and alcoholic liver disease are expected, therefore, to become the leading causes of HCC in the future. However, the association between alcohol consumption and chronic hepatitis B in the progression of liver disease is less well understood than with chronic hepatitis C. The mechanisms underlying the complex interaction between HBV and alcohol are not fully understood, and enhanced viral replication, increased oxidative stress and a weakened immune response could each play an important role in the development of HCC. It remains controversial whether HBV and alcohol synergistically increase the incidence of HCC. Herein, we review the currently available literature regarding the interaction of HBV infection and alcohol consumption on disease progression.     

Current issues in the management of paediatric viral hepatitis

Viral hepatitis poses important problems for children. In preschoolers, hepatitis A virus (HAV) infection frequently causes acute liver failure. Vaccinating toddlers against HAV in countries with high endemicity is expected to decrease mortality. HAV vaccine demonstrates efficacy (comparable to immunoglobulin) as post‐exposure prophylaxis. A recently developed vaccine against hepatitis E virus (HEV) may benefit fetal health, because pregnant women are most prone to acute liver failure as a result of HEV. Hepatitis B vaccine continues to demonstrate value and versatility for preventing serious liver disease. With chronic infection, undetectable levels of serum HBV DNA complement e‐seroconversion as the preferred outcome measure; suppressed viral load correlates with long‐term complications better than HBeAg status. Among Taiwanese children, low pretreatment HBV DNA (<2 × 10⁸ copies/ml) strongly predicted response to interferon‐α. Future paediatric studies must incorporate HBV DNA levels. The rationale for routine treatment of immunotolerant hepatitis B during childhood remains uncertain. Any treatment of chronic hepatitis B in childhood requires consideration of the risks and benefits. Childhood hepatitis C virus (HCV) infection results mainly from mother‐to‐infant transmission. Babies of HCV‐infected women should be tested for serum HCV RNA at 1 month of age. If negative, confirmatory anti‐HCV antibody testing may be performed between 12 and 15 months of age. Children with chronic hepatitis C may develop progressive fibrosis/cirrhosis, particularly in the setting of obesity and insulin resistance. Treatment of children chronically infected with genotype 2 or 3 is highly successful: combination therapy of pegylated interferon‐α and ribavirin is well tolerated and superior to pegylated interferon‐α alone.     

The role of the virus specific T-cell response in acute and chronic HBV and HCV infection

Infections with hepatitis B (HBV) and hepatitis C virus (HCV) are worldwide one of the most frequent causes for chronic liver disease, liver cirrhosis and hepatocellular carcinoma. The mechanisms responsible for the elimination or the persistence of the virus are not well understood. The immunopathogenesis of HBV and HCV infection is primarily mediated by virus specific CD4+- and CD8+-T-cells. During acute infection a strong and multispecific T-cell response against different viral epitopes can be detected and is associated with the clearance of the virus. In case of viral persistence virus specific T-cells contribute to liver inflammation. In this article we summarize the current concepts about the role of the virus specific T-cell response in acute and chronic HBV and HCV infection.     

Viral hepatitis: virus/host interaction

Abstract   Hepatitis A virus is considered directly cytopathic to the liver cell. Severity of the liver damage is dictated by viral load. Acute infection is followed by sustained immunity to the virus. Hepatitis B (HBV) and C (HCV) viruses are noncytopathic, hepatotropic viruses that cause acute and chronic hepatitis and hepatoma. Cellular and humoral immune responses are responsible not only for viral clearance but also for hepatocyte damage. T-cell response to HBV is vigorous, polyclonal, and multispecific in acutely infected patients who clear the virus while it is weak and narrowly focused in chronically infected patients. It is mainly executed by cytotoxic T lymphocytes (CTL), which destroy infected hepatocytes and secrete antiviral cytokines that interrupt the HBV life cycle. T-cell response to HCV is strong and multispecific in both acutely and chronically infected patients. Whether HCV is susceptible to a cytokine-mediated type of control is unknown. The ability of HCV to persist despite a strong CTL response suggests that HCV is either less visible to the CTL or less responsive to cytokine-mediated antiviral signals than HBV. Both viruses, but especially HCV, have a high mutation rate, leading to the occurrence of variant viral genomes with growth advantage and the ability of escaping immune recognition.     

What did we learn from the Shanghai hepatitis A epidemic?

A major outbreak of hepatitis A (HAV), associated with consumption of raw clams, occurred in Shanghai, China in 1988. Over 300 000 cases were reported, of which 47 (0.015%) were fatal. An elevated mortality rate was observed in hepatitis B surface antigen (HBsAg)-positive patients (0.05%). The majority of these patients were also hepatitis B e antigen (HBeAg)-positive, indicating active liver disease and high viral replication rates. The increased mortality in hepatitis B virus (HBV)/HAV coinfected individuals is hypothesized to be the result of T-cell-mediated destruction of HBV-infected hepatocytes, enhanced by acute HAV infection. Following recovery from HAV there is an increase in HBV expression and activated cytotoxic cells and subsequent cytolysis. Patients with chronic HBV infection are clearly at considerable risk of severe disease and increased mortality in the event of HAV infection. The period of greatest risk is during the immunoeliminative phase of HBV infection, which generally occurs in early adulthood. With the prevalence of HBV approaching 10% in this group, there is a clear opportunity for benefit from vaccination.     

Management of chronic hepatitis B virus infection: a new era of disease control

When assessing patients with chronic hepatitis B virus (HBV) infection, consider the state of viral replication, the immune response and whether viral mutations could be present, as well as evidence for liver disease or extrahepatic manifestations. In wild-type infections, loss of hepatitis B e antigen (HBeAg), gain of anti-HBe and disappearance of HBV DNA from serum indicate immunosuppression of viral replication, or 'nonreplicative chronic HBV infection'. This 'healthy carrier' state must be distinguished from HBeAg-negative chronic hepatitis B (CHB) resulting from precore and core promoter mutations. HBeAg-negative CHB is common with genotypes D (Mediterranean region, south Asia) and C (north Asia) infections. Age, disease activity (alanine aminotransferase level) and severity (fibrosis stage, cirrhosis) influence treatment decisions. Following the marginal effectiveness of interferon and often temporary effectiveness of lamivudine due to drug resistance, treatment of CHB is entering a new era. Adefovir, entecavir, tenofovir, telbivudine and clevudine have equal or superior antiviral efficacy to lamivudine, whereas several agents are effective against lamivudine-resistant HBV. Pegylated-interferon (peginterferon) is superior to conventional interferon for obtaining sustained immunosuppression of HBV without drug resistance. Antiviral suppression of HBV replication for 2-5 years reverses hepatic fibrosis, prevents cirrhosis and, when cirrhosis is established, improves liver function, prevents hepatic decompensation and lowers the risk of liver cancer. Before embarking on immunosuppressive chemotherapy or organ transplantation in patients with chronic HBV infection, it is important to start antiviral therapy to prevent hepatitis flares. Antiviral therapy can be effective against membranous glomerulonephritis and polyarteritis nodosa caused by HBV. Further improvements in treatment of CHB are needed to prevent drug resistance and permanently suppress viral replication by eradicating viral templates or stimulating host immune responsiveness to HBV.     

Does antiviral therapy for hepatitis B and C prevent hepatocellular carcinoma?

Approximately 75% to 80% of hepatocellular carcinomas (HCC) worldwide are attributed to chronic hepatitis B virus (HBV) and chronic hepatitis C virus (HCV) infection. Thus, effective prevention of HBV and HCV infection and progression from acute HBV and HCV infection to chronic hepatitis, cirrhosis and HCC might prevent as many as 450,000 deaths from HCC each year. The most effective approach to preventing HCC is to prevent HBV and HCV infection through vaccination. Indeed HBV vaccine is the first vaccine demonstrated to prevent cancers. However, a vaccine for HCV is not available and for persons who are chronically infected with HBV or HCV, antiviral therapy is the only option for preventing HCC. Direct evidence supporting a benefit of antiviral therapy on the prevention of HCC has been shown in a few randomized controlled trials. There is abundant evidence that antiviral therapy, in patients with long-term virological response, can improve liver histology, providing indirect support that antiviral therapy may prevent HCC by slowing progression of liver disease and possibly even reversing liver damage. Nevertheless, the risk of HCC remains in patients with chronic HBV or chronic HCV infection if treatment is initiated after cirrhosis is established. These data indicate that treatment might be of greater benefit if instituted earlier in the course of chronic hepatitis B or C. Safer, more effective, and more affordable antiviral therapies are needed for both hepatitis B and hepatitis C so more patients can benefit from treatment and more HCCs can be prevented.     

The presence of an intrahepatic cytotoxic T lymphocyte response is associated with low viral load in patients with chronic hepatitis C virus infection

BACKGROUND/AIMS: The role of cytotoxic T lymphocytes (CTL) in limiting viral replication and producing hepatocellular injury in patients with chronic hepatitis C virus (HCV) infection is controversial. METHODS: Intrahepatic and peripheral blood HCV-specific CTL activity against the entire HCV polyprotein was assessed in 26 patients. CTL responses were assessed after effector lymphocytes were re-stimulated for 6 days in vitro using HCV-vaccinia virus-infected autologous cells expressing HCV antigens. Serum and hepatic viral loads were measured and immunohistochemistry for CD3 and CD8 was performed to localise and enumerate effector cells in liver. RESULTS: A positive CTL response was detected in 39/52 (75%) of assays conducted with intrahepatic mononuclear cells and 21/52 (40%) of peripheral blood assays (P<0.001). The presence of an intrahepatic CTL response was associated with low hepatic viral load (P=0.004). Hepatic lobular infiltration by CD8(+)T cells correlated weakly with serum alanine aminotransferase levels (r=0.42, P=0.04) and no relationship was demonstrated between CTL activity and histological evidence of liver damage. CONCLUSIONS: HCV-specific CTL activity is found more commonly in liver than in blood. An inverse relationship between CTL responses and viral load supports the hypothesis that HCV-specific CTL limit viral replication in patients with chronic HCV infection.     

Chronic viral hepatitis in kidney transplantation

Chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infection in potential kidney transplant candidates-once considered absolute contraindications to kidney transplantation-no longer creates overt barriers to transplantation. Advances in the medical management of HBV and HCV infection have created opportunities for a substantial number of patients to be effectively treated with antiviral therapy before transplantation. For HBV infection, a number of new drugs enable clearance of the virus with minimal adverse effects and drug resistance. Pretransplantation antiviral therapy is advisable for patients with HCV infection, but adverse effects are common and viral eradication remains challenging. Regardless of viral clearance, pretransplant patients without bridging fibrosis (as confirmed by liver biopsy) or clinical stigmata of cirrhosis should be considered for kidney transplantation as survival is superior when compared to treatment with dialysis, and progression of liver disease is unlikely. For patients with advanced liver disease, simultaneous liver-kidney transplantation is an important consideration. These treatment advances further increase the burden of organ donor shortage; however, organs from deceased donors with chronic HBV or HCV infection could be efficiently allocated to certain individuals with a viral infection of the same type to increase the pool of available transplant organs.     

Epidemiology, natural history, and treatment of hepatitis B virus and hepatitis C virus coinfection

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are important global public health problems. Coinfection with HBV and HCV is not uncommon due to the shared route of parenteral transmission. The interaction between HBV and HCV in coinfected individuals is complex, and viral interference has been well described. Patients who are coinfected with HBV and HCV have faster rates of fibrosis progression, more severe liver disease, and are at markedly increased risk of developing hepatocellular carcinoma as compared to those with HBV or HCV monoinfection. Therefore, treatment of HBV-HCV coinfection is important, but it is a challenging and evolving field. Hepatitis A virus (HAV) superinfection is associated with a high risk of liver failure and death in patients with underlying chronic liver disease, and all individuals with HBV-HCV coinfection should receive the HAV vaccine.     

Analysis of serum α‐fetoprotein concentration in patients with viral hepatitis

OBJECTIVE: To investigate serum α‐fetoprotein (AFP) concentrations in patients with viral hepatitis. METHODS: Serum concentrations of total bilirubin (TB), alanine aminotransferase (ALT), aspartate amino­transferase (AST), albumin, globulin, AFP and viral markers were determined in 310 patients with pathologically proven viral hepatitis. The relation between the concentration of AFP and clinical manifestation, pathology, family history of liver malignant disease and virus type was studied. RESULTS: Serum AFP concentrations were elevated in 115 of the 310 patients (37.1%). According to the pathological diagnosis, the lowest positive rate of AFP was in acute hepatitis (11.7%), the highest was in chronic severe hepatitis (66.7%), the second highest in liver cirrhosis (57.5%), and chronic hepatitis was intermediate (34.2%). If the diagnosis was based on the clinical manifestation, the highest positive rate was found in chronic severe hepatitis, the lowest in chronic hepatitis, and acute hepatitis was intermediate. The positive rate of serum AFP by virus type was 35.5% for hepatitis B (HBV), superinfected with HAV or with HEV was 62.8%, and with HCV was 27.3%. Only one in six patients with HCV infection and none with simple HAV or HEV infection were positive for AFP. In patients with a family history of liver cancer, the positive rate of AFP was higher than in those without such a history (57.9%vs 38.2%; P = 0.75). CONCLUSIONS: The results indicate that AFP positivity is not uncommon in patients with viral hepatitis and if the patient has an elevated concentration, it is highly likely to be HBV infection or HBV super­infected with HAV or HEV.     

Pathogenesis of chronic hepatitis C: immunological features of hepatic injury and viral persistence.

The immune response to viral antigens is thought to be responsible for viral clearance and disease pathogenesis during hepatitis C virus (HCV) infection. In chronically infected patients, the T-cell response to the HCV is polyclonal and multispecific, although it is not as strong as the response in acutely infected patients who display a more vigorous T-cell response. Importantly, viral clearance in acutely infected patients is associated with a strong CD4(+) helper T-cell response. Thus, the dominant cause of viral persistence during HCV infection may be the development of a weak antiviral immune response to the viral antigens, with corresponding inability to eradicate infected cells. Alternatively, if clearance of HCV from the liver results from the antiviral effect of T-cell-derived cytokines, as has been demonstrated recently for the hepatitis B virus, chronic HCV infection could occur if HCV is not sensitive to such cytokines or if insufficient quantities of cytokines are produced. Liver cell damage may extend from virally infected to uninfected cells via soluble cytotoxic mediators and recruitment and activation of inflammatory cells forming the necroinflammatory response. Additional factors that could contribute to viral persistence are viral inhibition of antigen processing or presentation, modulation of the response to cytotoxic mediators, immunological tolerance to HCV antigens, mutational inactivation of cytotoxic T lymphocyte (CTL) epitopes, mutational conversion of CTL epitopes into CTL antagonists, and infection of immunologically privileged tissues. Analysis of the basis for viral persistence is hampered because the necessary cell culture system and animal model to study this question do not yet exist.     

Management of hepatitis C in HIV and/or HBV co-infected patients

Co-infection with either HIV or HBV in chronic hepatitis C patients is common, since all these viruses share transmission routes and geographical distribution. Interaction between these viruses generally amplifies liver damage, increasing the risk of developing end-stage liver disease and hepatocellular carcinoma. HIV–HCV co-infection is associated with poorer response to antiviral therapy. New antivirals against HCV are eagerly awaited for this population. HBV–HCV dual infections are less common. The principles guiding indication of therapy in monoinfected patients should be followed considering which virus replicates in persons with serological markers of dual HBV–HCV infection. Although there is growing evidence supporting the use of direct acting antivirals (DAA) in dually infected patients with active HCV replication, prospective trials should be conducted to demonstrate their benefit, assessing carefully the rate and clinical consequences of HBV rebounds.     

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.     

Chronic hepatitis B reactivation following infliximab therapy in Crohn's disease patients: need for primary prophylaxis

BACKGROUND: There is little information about the effect of infliximab on the clinical course of liver disease in Crohn's disease patients with concomitant hepatitis B virus (HBV) infection. Theoretically, immunosuppression induced by infliximab will facilitate viral replication which could be followed by a flare or exacerbation of disease when therapy is discontinued. There are no specific recommendations on surveillance and treatment of HBV before infliximab infusion. Two cases of severe hepatic failure related to infliximab infusions have been described in patients with rheumatic diseases. PATIENTS AND METHODS: Hepatitis markers (C and B) and liver function tests were prospectively determined to 80 Crohn's disease patients requiring infliximab infusion in three hospitals in Spain. RESULTS: Three Crohn's disease patients with chronic HBV infection were identified. Two of the three patients with chronic HBV infection suffered severe reactivation of chronic hepatitis B after withdrawal of infliximab therapy and one died. A third patient, who was treated with lamivudine at the time of infliximab therapy, had no clinical or biochemical worsening of liver disease during or after therapy. From the remaining 80 patients, six received the hepatitis B vaccine. Three patients had antibodies to both hepatitis B surface antigen (anti-HBs) and hepatitis B core protein (anti-HBc) with normal aminotransferase levels, and one patient had positive anti-hepatitis C virus (HCV) antibodies, negative HCV RNA, and normal aminotransferase levels. Except for the patients with chronic HBV infection, no significant changes in hepatic function were detected. CONCLUSIONS: Patients with Crohn's disease who are candidates for infliximab therapy should be tested for hepatitis B serological markers before treatment and considered for prophylaxis of reactivation using antiviral therapy if positive.