Chronic viral hepatitis B in infancy

Rethinking the pathogenesis of hepatitis B virus (HBV) infection

Chronic hepatitis B virus (HBV) infection affects approximately 375 million people worldwide. Current antiviral treatment effectively controls, but rarely clears chronic HBV infection. In addition, a significant portion of chronic HBV infected patients are not suitable for currently available antiviral therapy, and still face higher risk for cirrhosis and hepatocellular carcinoma. The poorly understood pathogenesis of HBV infection is the main barrier for developing more effective treatment strategies. HBV has long been viewed as non-cytopathic and the central hypothesis for HBV pathogenesis lies in the belief that hepatitis B is a host specific immunity-mediated liver disease. However, this view has been challenged by the accumulating experimental and clinical data that support a model of cytopathic HBV replication. In this article we systematically review the pathogenic role of HBV replication in hepatitis B and suggest possible HBV replication related mechanisms for HBV-mediated liver injury. We propose that a full understanding of HBV pathogenesis should consider the following elements. I. Liver injury can be caused by high levels of HBV replication and accumulation of viral products in the infected hepatocytes. II. HBV infection can be either directly cytopathic, non-cytopathic, or a mix of both in an individual patient depending upon accumulation levels of viral products that are usually associated with HBV replication activity in individual infected hepatocytes.

Hepatitis B "by proxy": an emerging presentation of chronic hepatitis B in children

We report on 6 adopted asymptomatic children in whom chronic HBV infection was identified through the occurrence of an acute hepatitis B in a family member. All of the children had serum HBV-DNA >2000 pg/mL. Acute hepatitis B in a family should alert the physician regarding the possibility of existing chronic HBV infection in other members of the family, especially newly adopted children, leading to a quick evaluation of their HBV status and to an efficacious protection of susceptible family members.

Outcome of liver disease and response to interferon treatment are not influenced by hepatitis B virus core gene variability in children with chronic type B hepatitis

BACKGROUND/AIMS

Hepatitis B virus (HBV) core gene heterogeneity may influence the outcome of liver disease and the response to interferon (IFN) therapy in adult HBV carriers. The aim of this study was to evaluate the possible association between HBV core gene variability and evolution of chronic hepatitis in children.

METHODS

We examined serum samples from 25 children with HBV chronic hepatitis and HBe antigen (HBeAg) positivity who were followed-up for a mean of 7.4 years. Seven cases spontaneously seroconverted to anti-HBe, becoming HBV healthy carriers; nine cases were successfully treated with IFN; nine cases were non-responders to IFN therapy. HBV-DNA was extracted from one serum sample ("I") collected during the HBeAg positive phase, and from a second sample ("II") collected after the anti-HBe seroconversion or, in non-responders, after stopping therapy. The entire core gene of the HBV isolates was amplified and sequenced.

RESULTS

Each isolate showed single or no missense mutation independently of the clinical behavior of the patients. HBeAg-defective viruses were detected in one case in both samples and in two cases only in sample "II".

CONCLUSIONS

Core gene variability does not seem to be involved either in the outcome of infection or in the response to IFN treatment in children with HBV chronic hepatitis. Considering that most of the HBV carriers in our area acquire the infection in childhood, our data suggest that core gene heterogeneity is not a major cause of progression to chronicity.

Chronic viral hepatitis in children

Hepatitis B virus is the most common causative agent of chronic viral hepatitis in children. The disease may take an aggressive course, but remains mostly asymptomatic. HDV infection occurs in about 13% of those children who are chronic carriers and are HBsAg positive. HCV infection is generally related to parenteral risk and generally remains asymptomatic. In addition to describing the course of the various diseases, treatment and control measures are discussed.

Incidence of cirrhosis in children with chronic hepatitis

To determine the incidence of liver cirrhosis in children with chronic hepatitis, we investigated 92 children (64 were girls; mean age was 8 years 2 months) with chronic hepatitis for the presence of cirrhosis by the combined use of laparoscopy and needle liver biopsy, between 1975 and 1985. Forty-six children had hepatitis B virus-related chronic hepatitis; cirrhosis was present in 13 (32%). Cirrhosis was diagnosed by laparoscopy in 14 children and by needle liver biopsy in eight. In six patients, cirrhosis was diagnosed within the first 12 months after the clinical onset of liver disease. Forty-six children had autoimmune hepatitis; cirrhosis was present in 41 (89%). Cirrhosis was diagnosed by laparoscopy in all 41 children and by needle liver biopsy in 23 children. Cirrhosis was already present in all 10 children studied 2 to 5 months after the first sign of liver disease. Our results indicate that the incidence of cirrhosis is high in children with chronic hepatitis, especially of the autoimmune type, and that cirrhosis may occur early, irrespective of cause. A combination of laparoscopy and biopsy is more reliable than biopsy alone for the diagnosis of cirrhosis in children with chronic hepatitis.

Chronic hepatitis B in male and female children of HBsAg carrier mothers

We have studied a group of children born to HBsAg+ mothers, resident in the English West Midlands; none of the children had sought medical attention for hepatitis B-related problems. Forty-two out of 48 children born to HBeAg+ mothers were HBsAg+. Among these children, the mean age of the HBeAg+ girls was significantly lower than that of the HBeAg+ boys (P = 0.05), suggesting that girls eradicate HBeAg at a younger age than boys. Among all children born to HBsAg+ mothers, liver function tests were normal except in 2 HBsAg+ boys who had elevated serum aminotransferase activities. Excluding these boys, serum alanine aminotransferase activity, while within the normal range, was significantly higher in HBeAg+ and anti-HBe+ children than in their immune (anti-HBs+) and non-infected siblings (P less than 0.01 and P less than 0.05). Waning infectivity was observed in many HBsAg+ mothers, giving rise to a typical pattern of infection within a family: older children, born to the still HBeAg+ mother, being HBeAg+ carriers, while younger siblings, born when the mother had become anti-HBe+, had no markers of infection. These younger children are vulnerable to 'horizontal' transmission.

A longitudinal follow-up of asymptomatic hepatitis B surface antigen-positive Chinese children

Fifty-one asymptomatic Chinese hepatitis B surface antigen (HBsAg) carrier children (34 boys, 17 girls), age 1 to 15 years (median: 10 years), were prospectively followed for up to 4 years (median: 30 months) to determine the natural evolution of clinical, biochemical and virological features during the early phase of chronic hepatitis B virus infection. Hepatomegaly was the only abnormal finding on examination, being present in five children initially and four at follow-up. Serum ALT levels were normal in 80% of the children at presentation and remained within the normal range during the study in 60%. Fluctuations in ALT levels were mild. In four of 12 instances, transient elevations in ALT levels were associated with a fall in serum hepatitis B virus DNA levels. At presentation, 43 (84%) children were hepatitis B e antigen (HBeAg) positive; only two (7%) cleared HBeAg on follow-up. None of the eight children who were initially positive for the antibody to HBeAg reverted back to HBeAg positivity. All the children remained HBsAg positive. In this study, we demonstrated that chronic hepatitis B virus infection in asymptomatic Chinese children is usually associated with a mild and stable liver disease despite high levels of hepatitis B virus replication. This may reflect an immunological tolerance to the hepatitis B virus induced by early exposure to the virus and accounts for the persistently high levels of hepatitis B virus replication on follow-up.

Pathology of chronic hepatitis B virus infection in children: with special reference to the intrahepatic expression of hepatitis B virus antigens

The clinical, virologic and pathologic features of chronic hepatitis B virus infection were studied in 66 children, of whom 29 were symptomatic and 37 asymptomatic. The majority (79%) of symptomatic children had histologically aggressive diseases: 11 had chronic active hepatitis and 10 had cirrhosis. In contrast, most asymptomatic children had nonaggressive diseases (35 cases); only 2 had chronic active hepatitis. Nine of the 10 children with cirrhosis were under 6 years of age, and the cirrhosis was often advanced, indicating that hepatitis B virus infection can cause the rapid development of cirrhosis in early life. HBcAg was present in 71% of 62 cases examined and correlated well with the status of HBeAg in serum. Cytoplasmic HBcAg was more frequently associated with aggressive disease than was nuclear HBcAg expression alone or no detectable HBcAg in the liver. A male predominance (75%) was found, particularly in children with aggressive diseases (91%) compared to those with nonaggressive forms of disease (67%). Sera from mothers of 43 of these children were tested for HBsAg, and 51% were positive. HBsAg was particularly common among mothers of children with symptomatic disease (69%) or cirrhosis (100%). These findings suggest that male sex and perinatal infection are important factors in the development of overt chronic hepatitis B and cirrhosis in children.

Prospective study of asymptomatic HBsAg carrier children infected in the perinatal period: clinical and liver histologic studies

Liver histologic findings were studied in 18 children who were 4 to 9 years old, and who had been HBsAg carriers since having been infected by their mothers in the perinatal period. All were born to HBeAg-HBsAg carrier mothers; the children were followed periodically from birth. Throughout their entire course, none developed symptoms or signs suggestive of liver disease. All of the 18 children showed mild but definite liver histologic changes: 15 had nonspecific histologic changes, and three had chronic persistent hepatitis. In 13 of 18 children, follow-up aminotransferase activities were abnormal, but none exceeded 100 KU. At the time of biopsy, ALTs on four children were above the upper limit of normal. All children were HBeAg-positive in early infancy, but five lost this antigen and developed antibody during follow-up. The histologic findings in HBeAg-positive children did not differ from those in children with antibody. Perinatal hepatitis B virus infection has been thought to play an important role in chronic liver disease, including hepatocellular carcinoma. This study indicates that some pathologic changes following perinatal infection begin very early.

Liver cirrhosis associated with chronic hepatitis B virus infection in childhood

We evaluated the prevalence and the clinical features of liver cirrhosis associated with chronic hepatitis B virus (HBV) infection in a prospective study of 292 consecutive children who were chronic HBsAg carriers with increased aminotransferase activity. Liver histologic changes at presentation were consistent with cirrhosis in 10 (3.4%) patients (100% boys, mean age 4.0 +/- 3.3 years). In none of the remaining children, including 166 with histologic evidence of chronic active hepatitis, did the condition progress to cirrhosis during an observation period of 1 to 10 years. This lack of progression suggests that cirrhosis is an early complication of chronic HBV disease in some patients. A higher prevalence of delta infection and increased incidence of blood transfusions were observed in patients with cirrhosis, supporting the hypothesis that superinfection with delta or non-A, non-B agents may play a synergistic role. Eight of 10 patients had histologic features of disease activity at presentation, although only two had symptoms. During follow-up, persistence of disease activity was observed only in the three delta antigen-positive patients. None of the patients with inactive cirrhosis have developed signs of liver failure or portal hypertension.

A retrospective study of the role of delta agent infection in children with HBsAg-positive chronic hepatitis

The prevalence of intrahepatic delta antigen and/or anti-delta antibody was retrospectively investigated in 102 children with chronic HBsAg-positive hepatitis who were seen consecutively in three medical institutions between 1974 and 1982. Delta infection markers were found in 13 patients (12.7%) who exhibited high serum titers of anti-delta antibody; intrahepatic delta antigen was detected in ten. Eleven of the 13 children had severe progressive liver disease associated in all but one with absence of hepatitis B virus replication as evaluated by analysis of serum hepatitis B virus DNA. The factors which seem to increase the risk of delta infection in children who are hepatitis B virus carriers are geographic origin, a history of exposure to blood derivatives and age. A further 37 of 102 children had chronic active hepatitis (20 patients) or cirrhosis (17 patients) without evidence of delta infection. These results indicate that delta infection occurs in children with chronic hepatitis. This possibility should be considered in investigation of children with HBsAg-positive chronic liver disease. Although the delta agent is an important cause of progressive liver disease in children who are chronic HBsAg carriers, severe liver injury and especially cirrhosis can occur without evidence of delta infection.