Role of immunohistochemistry for hepatitis D and hepatitis B virus in hepatitis delta

BACKGROUND & AIMS

Immunohistochemical assessment of liver tissue in chronic delta hepatitis (CDH) is underinvestigated. Aim of the study was (i) to assess variables associated with hepatitis D antigen (HDAg), hepatitis B surface antigen (HBsAg) and hepatitis B core antigen (HBcAg) staining in the liver.

METHODS

Demographic, biochemical and virologic data collected from the HIDIT 1 study were used. HBsAg, HBcAg and HDAg immunohistochemical (IHC) staining was semiquantitatively assessed.

RESULTS

Hepatitis D antigen immunohistochemical staining displayed positive correlations with age and alanine aminotransferase (ALT) and negative correlations with serum HBsAg (P = 0.01 for all). HBsAg IHC displayed a negative correlation with gamma glutamyl transferase and positive correlations with serum HBV DNA, serum HBsAg levels and HBeAg serology (P < 0.001, P = 0.02 and P = 0.007 respectively). HBcAg staining was mainly nuclear and displayed negative correlations with serum HBsAg and histologic activity (P = 0.002 and P = 0.02 respectively). Pegylated IFN based treatment led to a decline of all IHC markers, however, these markers had no impact on treatment outcome.

CONCLUSIONS

These data suggest an association of liver injury with HDAg expression in CDH whereas the negative correlation between HBcAg expression and liver injury and the overall nuclear localization of HBcAg suggest that HBcAg does not contribute to liver injury in CDH. HDV cases with high level of HBV replication, high serum HBsAg levels, HBeAg positivity, that are probably in the earlier stages of disease (low gamma-glutamyl transferase), had a more intense HBsAg staining profile. Overall, the data enforce the importance of HDAg and HBsAg in different phases of CDH infection.

Decreased hepatocyte membrane potential differences and GABAA-beta3 expression in human hepatocellular carcinoma

To determine whether hepatocyte membrane potential differences (PDs) are depolarized in human HCC and whether depolarization is associated with changes in GABAA receptor expression, hepatocyte PDs and gamma-aminobutyric acid (GABA)A receptor messenger RNA (mRNA) and protein expression were documented in HCC tissues via microelectrode impalement, real-time reverse-transcriptase polymerase chain reaction, and Western blot analysis, respectively. HCC tissues were significantly depolarized (-19.8+/-1.3 versus -25.9+/-3.2 mV, respectively [P<0.05]), and GABAA-beta3 expression was down-regulated (GABAA-beta3 mRNA and protein expression in HCC; 5,693+/-1,385 and 0.29+/-0.11 versus 11,046+/-4,979 copies/100 mg RNA and 0.62+/-0.16 optical density in adjacent tumor tissues, respectively [P=0.002 and P<0.0001, respectively]) when compared with adjacent nontumor tissues. To determine the physiological relevance of the down-regulation, human malignant hepatocytes deficient in GABAA-beta3 receptor expression (Huh-7 cells) were transfected with GABAA-beta3 complementary DNA (cDNA) or vector alone and injected into nu/nu nude mice (n=16-17 group). Tumors developed after a mean (+/-SD) of 51+/-6 days (range: 41-60 days) in 7/16 (44%) mice injected with vector-transfected cells and 70+/-12 days (range: 59-86 days) in 4/17 (24%) mice injected with GABAA-beta3 cDNA-transfected cells (P<0.005).

CONCLUSION

The results of this study indicate that (1) human HCC tissues are depolarized compared with adjacent nontumor tissues, (2) hepatic GABAA-beta3 receptor expression is down-regulated in human HCC, and (3) restoration of GABAA-beta3 receptor expression results in attenuated in vivo tumor growth in nude mice.

Expression of mutated hepatitis B virus X genes in human hepatocellular carcinomas

To explore the role of hepatitis B virus (HBV) X protein in liver carcinogenesis, independently from its role in viral replication, we have analyzed X gene structure and expression in tumorous and non-tumorous tissues obtained from 9 hepatitis B surface antigen (HBsAg)-negative, HBV DNA-positive patients. HBV replication was undetectable in tumorous tissues. HBV X gene was truncated at its 3' end in 5 of 9 tumorous tissues and 1 of 8 non-tumorous livers. Sequence analysis performed on uninterrupted X genes from 3 tumors and 3 surrounding non-tumorous tissues showed a high rate of mutations, selectively in the tumorous livers. In 1 of the 3 tumors, a frameshift mutation induced a new stop at codon 129. HBV RNAs were tested by reverse transcriptase-polymerase chain reaction (RT-PCR) with surface (S), core (C) and X specific primers. X, but not S and C, RNA expression was found in 6 of 8 tumors and in 6 of 7 non-tumorous tissues. This finding was consistent with immunohistochemical detection of X, but not S and C, antigens in all tumors also expressing X RNA. Our results provide evidence for selective expression of HBV X, but not S and C, RNA and protein in the tumorous and non-tumorous tissue of HBsAg-negative, HBV DNA-positive patients. It also shows that the structure of the X gene is modified (interrupted or highly mutated) in the majority of tumorous livers. Taken together, our findings are consistent with a potential role of mutated X proteins in HBV-related liver oncogenesis.

Expression of mutated hepatitis B virus X genes in human hepatocellular carcinomas

To explore the role of hepatitis B virus (HBV) X protein in liver carcinogenesis, independently from its role in viral replication, we have analyzed X gene structure and expression in tumorous and non-tumorous tissues obtained from 9 hepatitis B surface antigen (HBsAg)-negative, HBV DNA-positive patients. HBV replication was undetectable in tumorous tissues. HBV X gene was truncated at its 3' end in 5 of 9 tumorous tissues and 1 of 8 non-tumorous livers. Sequence analysis performed on uninterrupted X genes from 3 tumors and 3 surrounding non-tumorous tissues showed a high rate of mutations, selectively in the tumorous livers. In 1 of the 3 tumors, a frameshift mutation induced a new stop at codon 129. HBV RNAs were tested by reverse transcriptase-polymerase chain reaction (RT-PCR) with surface (S), core (C) and X specific primers. X, but not S and C, RNA expression was found in 6 of 8 tumors and in 6 of 7 non-tumorous tissues. This finding was consistent with immunohistochemical detection of X, but not S and C, antigens in all tumors also expressing X RNA. Our results provide evidence for selective expression of HBV X, but not S and C, RNA and protein in the tumorous and non-tumorous tissue of HBsAg-negative, HBV DNA-positive patients. It also shows that the structure of the X gene is modified (interrupted or highly mutated) in the majority of tumorous livers. Taken together, our findings are consistent with a potential role of mutated X proteins in HBV-related liver oncogenesis.

Expression of mutated hepatitis B virus X genes in human hepatocellular carcinomas

To explore the role of hepatitis B virus (HBV) X protein in liver carcinogenesis, independently from its role in viral replication, we have analyzed X gene structure and expression in tumorous and non-tumorous tissues obtained from 9 hepatitis B surface antigen (HBsAg)-negative, HBV DNA-positive patients. HBV replication was undetectable in tumorous tissues. HBV X gene was truncated at its 3' end in 5 of 9 tumorous tissues and 1 of 8 non-tumorous livers. Sequence analysis performed on uninterrupted X genes from 3 tumors and 3 surrounding non-tumorous tissues showed a high rate of mutations, selectively in the tumorous livers. In 1 of the 3 tumors, a frameshift mutation induced a new stop at codon 129. HBV RNAs were tested by reverse transcriptase-polymerase chain reaction (RT-PCR) with surface (S), core (C) and X specific primers. X, but not S and C, RNA expression was found in 6 of 8 tumors and in 6 of 7 non-tumorous tissues. This finding was consistent with immunohistochemical detection of X, but not S and C, antigens in all tumors also expressing X RNA. Our results provide evidence for selective expression of HBV X, but not S and C, RNA and protein in the tumorous and non-tumorous tissue of HBsAg-negative, HBV DNA-positive patients. It also shows that the structure of the X gene is modified (interrupted or highly mutated) in the majority of tumorous livers. Taken together, our findings are consistent with a potential role of mutated X proteins in HBV-related liver oncogenesis.