Prognostic value of hepatitis B core antigen (HBcAg) expression in the liver of children with chronic hepatitis type B

Hepatitis B virus basal core promoter mutation and DNA load correlate with expression of hepatitis B core antigen in patients with chronic hepatitis B

BACKGROUND

Expression of intrahepatic hepatitis B core antigen (HBcAg) is related to the immunopathogenesis of hepatitis B virus (HBV) infection. This study investigated the role that HBV genotype and basal core promoter (BCP) mutation play in the expression of HBcAg.

METHODS

A total of 70 hepatitis B e antigen (HBeAg)-positive patients with chronic hepatitis (genotype B in 52 patients and genotype C in 18 patients; BCP mutation T1762/A1764 in 16 patients) were enrolled. Clinical, virologic, and histologic features were compared with regard to localization and expression of intrahepatic HBcAg. The effects that HBV genotype and BCP mutation T1762/A1764 had on expression of HBcAg were further evaluated by in vitro assays.

RESULTS

Cytoplasmic, mixed cytoplasmic/nuclear, and nuclear localization of intrahepatic HBcAg was found in 38 (56.7%), 25 (37.3%), and 4 (6.0%) patients, respectively; HBcAg was not discernible in 3 patients. A total of 58 (82.9%) of these patients expressed a high level of HBcAg. In multivariate analysis, cytoplasmic localization of HBcAg correlated only with a low HBV load in serum (P = .045) and BCP mutation (P = .04). A high expression level of HBcAg also correlated with a high HBV load in serum (P = .015) and with BCP wild-type sequence (P = .037). In vitro assays indicated that the HBV BCP mutant strain had lower subcellular expression of HBcAg than did the BCP wild-type strain.

CONCLUSIONS

HBV BCP mutation and HBV load, but not genotype, contribute to the expression of intrahepatic HBcAg.

The effects of hepatitis B virus core promoter mutations on hepatitis B core antigen distribution in hepatocytes as detected by laser-assisted microdissection

BACKGROUND/AIMS

The severity of liver damage in patients with chronic hepatitis B is dependent on several factors such as subcellular localization of hepatitis B core antigen (HBcAg) and mutation of hepatitis B virus (HBV) DNA. Here we studied the interrelationship between these two factors both in situ and in vitro.

METHODS

Hepatocytes from liver biopsies showing expression of HBcAg only in the cytoplasm (n=6), only in the nucleus (n=4) and in both cytoplasms or nucleus of different hepatocytes (n=5) were picked up by laser-assisted microdissection and were checked for nucleotide sequences of core promoter region of HBV DNA. HepG2 and Huh7 cell lines transfected with wild and mutant HBV DNA were checked for localization of HBcAg.

RESULTS

The frequencies of core promoter mutations at nucleotide (nt) 1762 and nt 1764 was significantly higher in hepatocytes with cytoplasmic expression of HBcAg compared to that of nuclear expression of HBcAg (P<0.05). Cytoplasmic expression of HBcAg was observed more frequently in HepG2 and Huh7 cells transfected with HBV mutant type (nt 1762 and 1764) than HBV wild type (P<0.05).

CONCLUSIONS

Cytoplasmic localization of HBcAg was associated with HBV DNA mutations at nt 1762 and 1764.

Factors predictive of response to interferon therapy in children with chronic hepatitis B

BACKGROUND/AIMS

The efficacy of interferon therapy in Caucasian children with chronic hepatitis B is similar to that in adults. However, little information is available about factors predicting response to this therapy in children. We have performed a univariate analysis to assess the strength of association between basal variables and response, and a multivariate analysis to determine the combination of basal variables which give the best prediction of response in terms of sensitivity and specificity.

METHODS

The basal parameters were studied in 50 children included in three different trials of interferon alpha therapy (360-700 MU/square meter of body surface, 2 or 3 times weekly for 12 to 24 weeks).

RESULTS

Of these, 18 (36%) were responders. In the univariate analysis, a higher histological activity (p < 0.05), a lower percentage of HBcAg-stained hepatocytes (p < 0.001), aspartate amino transferase and alanine aminotransferase levels (p < 0.05) and alanine aminotransferase peak prior to serum HBV-DNA clearance (p < 0.05), were associated to the response. In the multivariate analysis, the combinations of the percentage of HBcAg stained cells with alanine aminotransferase levels and with the histological activity index were the best variables for predicting response (sensitivity: 100% and specificity: 89% and 86%, respectively).

CONCLUSIONS

Factors predictive of response in children with chronic hepatitis B are similar to those found in adults, and may help in identifying those children with a better chance of responding.

Hepatitis B virus infection and primary hepatocellular carcinoma

For many years, epidemiological studies have demonstrated a strong link between chronic hepatitis B virus (HBV) infection and the development of primary hepatocellular carcinoma (PHC). Other hepatocarcinogens such as hepatitis C virus and aflatoxin also contribute to hepatocarcinogenesis either in conjunction with HBV infection or alone. Cellular and molecular biological studies are providing explanations for the HBV-PHC relationship, and models are now being formulated to further test the relative importance of various factors such as viral DNA integration, activation of oncogenes, genetic instability, loss of tumor suppressor genes, and trans-activating properties of HBV to the pathogenesis of PHC. Further research will probably define more than a single mechanism whereby chronic HBV infection results in PHC.

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.

Histology and virus expression in the liver: a prognostic puzzle in chronic hepatitis B

Forty chronic untreated paediatric carriers of hepatitis B virus (HBV) infection, with no other causes of liver disease, were biopsied on presentation, when the disease was in the active viral replication phase. After a period ranging from 1 to 13 years, all patients underwent a control biopsy. At the time of the last biopsy, 31 of the patients were anti-HBe positive, whereas 9 persisted in the active replication phase. In this latter phase, necrotic and inflammatory lesions and the presence of nuclear HBcAg were found significantly more frequently than when replication had terminated. The necrotic and inflammatory lesions detected in the first biopsy of patients who subsequently underwent anti-HBe seroconversion were significantly more severe than in patients failing to reach seroconversion. All patients who maintained viral replication showed generalized nuclear reactivity for HBcAg on presentation; such reactivity was also found in 16 of 31 (52%) patients who reached anti-HBeAg seroconversion. All these cases had piecemeal necrosis (PMN) in the biopsy. PMN may therefore be considered as a positive prognostic factor in that it identifies those patients who may seroconvert with significant remission of liver disease.

Detection of hepatitis B virus antigens in liver tissue. A relation to viral replication and histology in chronic hepatitis B infection

The expression of hepatitis B virus antigens was studied by double staining liver tissue with appropriate antisera and correlated with serum hepatitis B viral DNA and histology in 28 patients with disease related to chronic hepatitis B virus infection. The cellular localization of hepatitis B core and hepatitis B e antigens generally coincided, but there were important differences at a subcellular level. Thus, hepatitis B e antigen was detected in nuclei and/or cytoplasm but strong cytoplasmic hepatitis B e antigen was associated with a high serum hepatitis B viral DNA (P = 0.0017) but not with active liver disease. Hepatitis B core antigen could also be detected in nuclei and/or cytoplasm, but strong cytoplasmic hepatitis B core antigen expression, exceeding that of hepatitis B e antigen, was associated with active liver disease (P = 0.041) and not with serum hepatitis B virus DNA. The proportion of hepatocytes expressing hepatitis B surface antigen correlated inversely with the serum titer (P = 0.0017), whereas hepatitis B surface and nucleocapsid antigens were usually expressed independently. The data support the hypothesis that cytoplasmic hepatitis B core antigen and not hepatitis B e antigen is the target for immune system-mediated cytolysis of hepatocytes. Cytoplasmic hepatitis B e antigen is not associated with liver damage but is instead associated with high levels of hepatitis B virus replication.

Significance of hepatitis B core antigen in the liver in patients with chronic hepatitis B and its relation to hepatitis B virus DNA

Liver biopsies from 52 patients with chronic hepatitis B were investigated for the presence and distribution of HBcAg and the results were compared with the status of hepatitis B virus deoxyribonucleic acid (HBV-DNA). The patients consisted of 37 men and 15 women, aged 16-55 years (mean = 34 years). Serum alanine aminotransferase (ALT) was elevated in 50 patients (range: 18-969 U/L; mean = 290 U/L). Serological testing showed HBsAg in all, HBeAg in 45 (87%), and HBV-DNA in 28 (54%). Liver biopsies demonstrated HBcAg in 35 (67%) patients. HBcAg was not only present in 31 of 45 (69%) patients who were seropositive for HBeAg, but also in four of seven (57%) with antibody to HBeAg (anti-HBe). In 28 of 35 (80%) patients with HBcAg in the liver, serum HBV-DNA was detected. However, no serum HBV-DNA was detected in 17 patients who had no detectable HBcAg in the liver. The distribution of HBcAg in the liver was rather cytoplasmic and nuclear than nuclear alone. Among 33 patients with cytoplasmic HBcAg in the liver, 15 (45%) had an evidence of acute exacerbation of hepatitis with marked ALT elevation (range: 168-894 U/L; mean = 385 U/L) and nine patients showed severe chronic active hepatitis and confluent necrosis, histologically. These results indicate that the presence of HBcAg in the liver correlates with the amount of circulating hepatitis B virus as quantified by serum level of HBV-DNA. The predominant cytoplasmic HBcAg in the liver may suggest the possibility of multiple episodes of acute exacerbation and more severe ongoing hepatitis during the clinical course.

Serological and histological follow up of chronic hepatitis B infection

In order to study the clinical, serological, and morphological evolution of chronic hepatitis B virus infection in childhood, a prospective study has been carried out. A total of 90 children with a chronic infection were followed up for a mean (SD) of 3 (1.8) years. At the beginning of the study, 61 children were asymptomatic and 77 were household contacts of chronic carriers. Serologically 77 were hepatitis B e antigen (HBeAg) positive and 71 of them were positive to hepatitis B virus DNA. The mean alanine aminotransferase activities were higher among HBeAg positive patients than in antihepatitis B e (anti-HBe) positive ones. The most severe histological damage was also found among HBeAg positive patients. The annual seroconversion rate was 14%. A significant increase in the alanine aminotransferase activity was observed 13 (5.6) months before appearance of anti-HBe in the 85% of cases. Among anti-HBe positive patients, the alanine aminotransferase activities were normal in all except three (19%), two of whom had intrahepatic delta antigen. An increase in the histological activity was observed among patients who maintained HBeAg presence while an amelioration of liver damage was observed in anti-HBe carriers.

Serum markers of hepatitis B virus replication, liver histology and intrahepatic expression of hepatitis B core antigen

The presence and distribution of hepatitis B core antigen (HBcAg) was studied in the liver of 227 chronic carriers of hepatitis B surface antigen (HBsAg) to investigate its relationship with serum HBV-DNA, the status of hepatitis B 'e' antigen/antibody (HBeAg/anti-HBe) and the underlying liver disease. HBcAg was detected in 144 of the 227 (63%) liver specimens and HBV-DNA in 132 (58%) of the corresponding sera. Serum HBV-DNA showed a constant link with intrahepatic HBcAg. Out of 96 HBeAg-positive patients, 91 (95%) had HBcAg in the liver and 85 (89%) had HBV-DNA in serum. Overall there was a significant link between HBeAg and HBV-DNA in serum, but there was no correlation in 58 out of 227 (26%) cases. In HBeAg/HBV-DNA-positive carriers, HBcAg expression was predominantly nuclear. It was nuclear and cytoplasmic in patients with the highest levels of viremia. Eleven out of 13 (85%) HBV-DNA-positive patients who had only cytoplasmic HBcAg were HBcAg-negative and had low levels of HBV-DNA. Nine of 13 (69%) patients with exclusively cytoplasmic HBcAg had severe chronic liver disease. Neither the presence of HBV-DNA and HBeAg in serum nor the nuclear localization of HBcAg were associated with the severity of liver damage. In the group of HBV-DNA-positive patients (132), the presence of liver disease was significantly connected with the absence of HBeAg in serum (P less than 0.05; C.L. 3-35).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of factors predicting early seroconversion to anti-HBe in HBeAg-positive chronic hepatitis B

To investigate whether data obtained at the time of diagnosis may serve to predict early seroconversion to anti-HBe in chronic hepatitis B virus infection, we have compared the clinical, pathological and virological features of two groups of patients with untreated HBeAg-positive chronic hepatitis B who showed a markedly different outcome. One group (early seroconverters) included 20 patients who developed a typical seroconversion to anti-HBe within the first year of prospective follow-up. The other group (non-seroconverters) was formed by 21 patients who remained seropositive for HBeAg and still had raised aminotransferase serum levels after at least 2 years of follow-up. The serum aminotransferases, the degree of periportal and lobular lesions, the amount of liver fibrosis and the total score index of histological activity were significantly higher but the amount of HBcAg in liver was smaller in early seroconverters. Stepwise logistic regression analysis demonstrated that the alanine aminotransferase serum levels, the Knodell's index of histological activity and the amount of HBcAg in liver had significant value as independent predictors of early seroconversion. Calculation of the probability of seroconversion for individual cases showed marked differences between the two groups of patients, suggesting that early seroconversion to anti-HBe may be predicted in some patients with chronic hepatitis B.

Peroxidase-anti-peroxidase detection of hepatitis B surface and core antigen in liver biopsy specimens from patients with chronic type B hepatitis

Liver biopsy specimens from 58 American patients with chronic type B hepatitis were investigated for the presence and distribution of the hepatitis B core (HBcAg) and surface (HBsAg) antigens by peroxidase-anti-peroxidase techniques. HBsAg was detected in 43 (77%) and HBcAg in 52 (90%) patients. HBcAg was present in 50 of 51 (98%) patients with hepatitis B e antigen (HBeAg) but in only two of seven (29%) of patients with antibody to HBeAg (anti-HBe). There was no correlation between severity of hepatitis or height of aminotransferase activities and the amount of HBsAg or HBcAg in hepatocytes but there was a positive correlation between amount of HBcAg and height of HBV-DNA and DNA polymerase activity in serum. Follow-up liver biopsies, taken 1 to 3 yr later, were available from 39 patients. HBcAg remained detectable in 25 of 26 patients with persistence of HBeAg but disappeared in 12 patients who had lost HBeAg. In nine patients, HBcAg was cytoplasmic as well as nuclear in distribution. Seven of these patients had an intense lobular hepatitis with marked elevations in aminotransferase activities. These findings indicate that the amount of HBcAg in liver correlates with the amount of serum hepatitis B virus as quantified by serum levels of DNA polymerase and HBV-DNA. The amount of nuclear HBcAg does not correlate with the severity of the liver disease, but the presence of cytoplasmic HBcAg usually reflects an active and severe ongoing hepatitis.

IgM antibody to hepatitis B core antigen in children with chronic type B hepatitis

IgM antibody to hepatitis B core antigen (anti-HBc IgM) was investigated by an antibody-capture radioimmunoassay (serum dilution 1:4000) in serum samples from 31 untreated children with chronic hepatitis B who were followed prospectively for 1-7 years. At the start, all patients were positive for hepatitis B e antigen (HBeAg), and anti-HBc IgM was detected in 23 cases, including 15 out of 16 with chronic active hepatitis and 7 out of 14 with chronic persistent hepatitis. A significant positive correlation was found between anti-HBc IgM levels and severity of liver damage (P less than 0.05), while an inverse relationship was found between anti-HBc IgM levels and distribution of hepatitis B core (HBcAg) antigen in the liver as detected by immunofluorescence. In fact 75% of anti-HBc IgM positive patients showed a focal HBcAg pattern (less than 40% positive nuclei), whereas 87% of antibody negative cases exhibited a diffuse HBcAg expression (more than 60% stained nuclei). During follow-up, seroconversion from HBeAg to anti-HBe with subsequent remission of liver disease occurred in 82% of patients presenting with detectable levels of anti-HBc, including three out of seven cases with chronic persistent hepatitis, but in none of the cases that were initially negative (P less than 0.01). These results indicate that during the natural course of chronic hepatitis B in children, anti-HBc IgM levels in serum reflect the degree of host immune response to infected hepatocytes. The close correlation between anti-HBc IgM seropositivity and seroconversion from HBeAg to anti-HBe suggests that anti HBc IgM may have a prognostic value during the follow-up of children with chronic HBeAg positive hepatitis B.

Virological significance of HBeAg subtypes (HBeAg/1 and HBeAg/2) in patients with type B hepatitis

In order to establish the virological significance of HBeAg subtypes (HBeAg/1 and HBeAg/2) during hepatitis B virus infection, HBsAg, HBeAg and hepatitis B virus DNA in serum and HBcAg in liver were determined quantitatively in relation to the detection of HBeAg subtypes in agar gel diffusion. Thirty-eight chronic HBsAg carriers with HBeAg, including 16 non-specific reactive hepatitis, 8 chronic persistent hepatitis, 11 chronic active hepatitis and 3 liver cirrhosis, who were seen at Tohoku University Hospital from 1983 to 1985, were examined. Significantly larger amounts of HBsAg, HBeAg and hepatitis B virus DNA in serum and HBcAg in liver were found in patients positive for both HBeAg/1 and HBeAg/2 in serum than in those positive for only HBeAg/1 or negative for both subtypes. These results suggest that the presence of HBeAg/2 in serum may reflect the occurrence of active viral replication. When the detection pattern of HBeAg subtypes was examined during serial follow-up for at least 1 year, three groups of patients were classified with respect to the presence of HBeAg/2, i.e., Type I, consistently positive for HBeAg/2; Type II, consistently negative for HBeAg/2, and Type III, intermittently positive for HBeAg/2. More than 80% of Type I patients were histologically diagnosed having as nonspecific reactive hepatitis, while more than 80% of Type II and III patients had more progressive liver diseases such as chronic persistent hepatitis, chronic active hepatitis and liver cirrhosis. These results suggest that the serial examination of HBeAg subtypes in serum may be important for more detailed evaluations of type B hepatitis.

Chronic evolution of acute hepatitis type B: prevalence and predictive markers

During a prospective study of acute symptomatic viral hepatitis, started in 1978, 664 consecutive adult patients, including 223 drug abusers, fulfilled the diagnostic criteria (anti-HBc IgM positivity) for acute type B hepatitis. In order to evaluate the outcome of the disease, 443 patients were followed for up to 12 months after the onset. 2.4% of the infections became chronic; the rate did not significantly differ between drug addicts and non-drug abusers, suggesting that chronic hepatitis is a rare complication of acute symptomatic hepatitis type B. Ongoing liver damage after clearance of HBsAg from serum was observed in drug abusers only (14% of the cases). Clinical, biochemical and virological features of the acute phase in patients with ongoing infection were compared with those of uncomplicated cases. Anicteric hepatitis and lower transaminase values were significantly (p less than 0.05) associated to a chronic evolution of the disease, as well as a higher prevalence of HBV-DNA, DNA polymerase and HBcAg positivity in serum. Testing HBV-DNA and DNA polymerase early in the course of the infection appeared to be of high predictive value for the subsequent outcome of the illness.

Hepatitis B virus replication in acute glomerulonephritis with chronic active hepatitis

A 3 year old boy who had chronic active hepatitis type B with features of ongoing liver damage and active virus replication, developed acute membranous glomerulonephritis two years after the clinical onset of liver disease, when both hepatitis B e antigen and antibody were detectable in serum. After withdrawal of short term steroid treatment and resolution of hepatitis B virus replication, both glomerulonephritis and chronic hepatitis went into remission. Some months later hepatitis B surface antigen was no longer found in serum.