Cellular immune response to hepatitis B virus antigens. An overview

Liver Damage and microRNAs: An Update

One of the major organs in the body with multiple functions is the liver. It plays a central role in the transformation of macronutrients and clearance of chemicals and drugs. The serum biomarkers often used to indicate liver damage are not specifically for drug-induced liver injury (DILI) or liver injury caused by other xenobiotics, nor for viral infection. In this case, microRNAs (miRNAs) could play an exciting role as biomarkers of specific liver damage. In this review, we aimed to update the current literature on liver damage induced by drugs, as acute conditions and viral infections mediated by the hepatitis B virus (HBV) linked these two conditions to advanced research, with a focus on microRNAs as early biomarkers for liver damage. The undoubtable evidence that circulating miR-122 could be used as a human biomarker of DILI came from several studies in which a strong increase of it was linked with the status of liver function. In infancy, there is the possibility of an early miRNA detection for hepatitis B virus infection, but there are a lack of solid models for studying the HVB molecular mechanism of infection in detail, even if miRNAs do hold unrealized potential as biomarkers for early detection of hepatitis B virus infection mediated by HBV.

The woodchuck as an animal model for pathogenesis and therapy of chronic hepatitis B virus infection

This review describes the woodchuck and the woodchuck hepatitis virus (WHV) as an animal model for pathogenesis and therapy of chronic hepatitis B virus (HBV) infection and disease in humans. The establishment of woodchuck breeding colonies, and use of laboratory-reared woodchucks infected with defined WHV inocula, have enhanced our understanding of the virology and immunology of HBV infection and disease pathogenesis, including major sequelae like chronic hepatitis and hepatocellular carcinoma. The role of persistent WHV infection and of viral load on the natural history of infection and disease progression has been firmly established along the way. More recently, the model has shed new light on the role of host immune responses in these natural processes, and on how the immune system of the chronic carrier can be manipulated therapeutically to reduce or delay serious disease sequelae through induction of the recovery phenotype. The woodchuck is an outbred species and is not well defined immunologically due to a limitation of available host markers. However, the recent development of several key host response assays for woodchucks provides experimental opportunities for further mechanistic studies of outcome predictors in neonatal- and adult-acquired infections. Understanding the virological and immunological mechanisms responsible for resolution of self-limited infection, and for the onset and maintenance of chronic infection, will greatly facilitate the development of successful strategies for the therapeutic eradication of established chronic HBV infection. Likewise, the results of drug efficacy and toxicity studies in the chronic carrier woodchucks are predictive for responses of patients chronically infected with HBV. Therefore, chronic WHV carrier woodchucks provide a well-characterized mammalian model for preclinical evaluation of the safety and efficacy of drug candidates, experimental therapeutic vaccines, and immunomodulators for the treatment and prevention of HBV disease sequelae.

Detection of hepatitis B virus genome in hepatocellular carcinoma tissues with PCR-in situ hybridization

The detection is described of hepatitis B virus (HBV)-DNA in preserved hepatocellular carcinoma tissues, which were derived from 14 HBV-seropositive patients. Detection was by polymerase chain reaction (PCR) amplification of the target sequence, followed by specific localization of the PCR product with in situ hybridization. PISH (PCR-in situ hybridization) yielded strong positive signals in most of the tumor tissues despite very low copy numbers of chromosome-integrated HBV genome, whereas no signal was detected in control samples, indicating that the signals were specific for HBV. Positive signals were sometimes detected in cirrhotic nodules surrounding the tumor regions, indicating that HBV had infected non-transformed liver cells. HBV-DNA was detected in both nucleus and cytoplasm in some specimens, possibly representing HBV at different stages of the life cycle. In one case, a gradient of viral DNA was revealed, with the highest DNA signal centered at the site of viral antigen expression. Taken together, PISH is shown to be a highly sensitive molecular detection method that is capable of detecting the presence of a low copy number viral genome in situ.

Concurrent emergence of hepatitis B e antigen-negative hepatitis B virus variant and autoimmune hepatitis cured by adenine arabinoside monophosphate

We report the case of a hepatitis B virus chronic carrier in whom features of severe autoimmune hepatitis developed concurrently with the emergence of a hepatitis Be antigen-negative variant. Corticosteroid administration failed to normalize serum transaminase activity and resulted in increased viral multiplication. Adenine arabinoside monophosphate treatment allowed simultaneous inhibition of hepatitis B virus multiplication and remission of autoimmune features. This observation indicates that hepatitis Be antigen-negative variants can induce autoimmune hepatitis and adds support to the hypothesis that autoimmune hepatitis can be triggered by hepatotropic viruses. Patients with both features should first be treated with adenine arabinoside monophosphate. This observation indicates that hepatitis Be antigen-negative variants can induce autoimmune hepatitis and adds support to the hypothesis that autoimmune hepatitis can be triggered by hepatotropic viruses. Patients with both features should first be treated with adenine arabinoside monophosphate.

LEA-1/ICAM-1 interaction is essentially involved in the pathogenesis of delayed-type hypersensitivity-induced liver injury to picryl chloride

The kinetics of lymphocyte function associated antigen 1 (LFA-1) expression on spleen cells (SPC) and liver non-parenchymal cells (NPC), and intercellular adhesion molecule 1 (ICAM-1) expression on hepatocytes (HC) was examined in acute liver injury mice induced by a DTH reaction to picryl chloride (PCl). The peak expression of LFA-1 on SPC was seen at 6 hr after eliciting liver injury, and then that of LFA-1 on NPC and ICAM-1 on HC appeared at 12 hr. Thereafter, the serum ALT elevation reached to a peak at 18 hr. A splenectomy before the PCl elicitation significantly reduced the ALT elevation. Both SPC and NPC from liver injury mice induced a remarkable release of ALT from HC in vitro, in parallel with their LFA-1 expression. The pre-treatment of NPC or SPC with anti-LFA-1 mAb, irrespective of the presence of complement, completely blocked the ALT release. Also, when HC was prebound with anti-ICAM-1 mAb, neither NPC nor SPC showed a cytotoxicity against the HC. Furthermore, the treatment of NPC with either anti-Thy1.2 or anti-CD4 mAb in the presence but not absence of complement, showed a complete abolishment of ALT release. Anti-CD8 mAb plus complement also tended to inhibit ALT release. The twofold increase in CD4+ LFA-1+ and mild increase in CD8+ LFA-1+ populations were also confirmed in NPC at 12 hr. These results suggest that PCl elicitation in liver may trigger an increased expression of LFA-1 on SPC and NPC and ICAM-1 on HC. LFA-1/ICAM-1 interaction between liver-infiltrating NPC, mainly including CD4+ and CD8+ T cells, and HC may be an essential step for the hepatocyte damage in PCl-DTH liver injury.

Restriction of V beta gene usage of liver-derived lymphocytes in chronic hepatitis B and C

T lymphocytes have been reported to be the predominant inflammatory cells in the liver of patients with chronic viral hepatitis. Their presence may reflect either nonspecific inflammation or a virus-specific immune response. To assess the repertoire of intra-hepatic T cells, we investigated the TCR V beta gene usage of T cells in 10 patients with chronic hepatitis B and 15 with chronic hepatitis C. Liver-derived lymphocytes and peripheral blood lymphocytes were analyzed by flow cytometry. Five out of the 10 hepatitis B patients were found to have an accumulation of certain V beta T cells in the liver (V beta 6.7; V beta 6.7; V beta 3.1, V beta 5.1, and V beta 6.7; V beta 3.1; V beta 12.1, respectively). Four out of the 15 hepatitis C patients were found to have an accumulation of certain V beta T cells in the liver (V beta 5.1; V beta 8 and V beta 5.2 and 5.3; V beta 3.1 and V beta 5.2 and 5.3; V beta 3.1 and V beta 12.1, respectively). Despite a limited screening of V beta subfamilies, this study indicates that, in patients with chronic hepatitis B and C, T cells using a certain V beta gene may accumulate in the liver. This suggests that intra-hepatic T cells are oligoclonal and possibly virus specific. Our results argue against the role of a superantigen in perpetuating liver disease. In addition, this study supports a role for T lymphocytes in the pathogenesis of chronic hepatitis C.

The interaction of human immunodeficiency virus infection and hepatitis B virus infection in infected homosexual men

A retrospective analysis of 99 hepatitis B-positive homosexual men with known human immunodeficiency virus (HIV) status was conducted to study the interaction of concurrent HIV infection on the course of their chronic hepatitis B virus (HBV) infection. All 99 subjects had chronic hepatitis B, 43 of whom were HIV antibody negative and 56 of whom were HIV antibody positive at the time of their initial presentation. Serial serum aminotransferase levels were used as an indirect estimate of the severity of hepatic inflammation. Factors that may influence the course of hepatitis B, HIV status, hepatitis B e antigen (HBeAg)/hepatitis B e antibody (HBeAb) status, alcohol intake, and zidovudine (AZT) therapy were correlated with aminotransferase values. Overall, there was no difference in mean serum alanine aminotransferase (ALT) levels between HIV antibody-negative and HIV antibody-positive patients. There is a higher prevalence rate of HBeAg in HIV antibody-positive patients (p < 0.05), and the seroconversion rate from HBeAg to HBeAb was lower in HIV antibody-positive patients compared with HIV antibody-negative patients (p < 0.05). However, reactivation rates from HBeAb to HBeAg were no different in the HIV antibody-positive and negative hepatitis B carriers. With mild, moderate, or heavy alcohol intake, we observed no statistically significant difference in mean serum alanine aminotransferase levels and no mean serum aspartate aminotransferase levels between HIV antibody-negative patients versus HIV antibody-positive patients. Similarly, there was no significant difference in the pattern of serum aminotransferase in those subjects treated with or without AZT. The mortality rates were higher in HIV antibody-positive patients (n = 8) compared with in HIV antibody-negative patients (n = 2). Seventy-five percent (n = 6) of the HIV antibody-positive patients died from acquired immunodeficiency syndrome (AIDS), and overall only two patients died of liver disease, one in each group. We conclude that there is no overt influence by HIV or the treatment thereof on the course of chronic HBV infection in a population of homosexual men. In HIV-infected patients, death from AIDS predominated; hence, the main target for therapy should be HIV rather than HBV.

Activation of a heterogeneous hepatitis B (HB) core and e antigen-specific CD4+ T-cell population during seroconversion to anti-HBe and anti-HBs in hepatitis B virus infection

Overcoming hepatitis B virus infection essentially depends on the appropriate immune response of the infected host. Among the hepatitis B virus antigens, the core (HBcAg) and e (HBeAg) proteins appear highly immunogenic and induce important lymphocyte effector functions. In order to investigate the importance of HBcAg/HBeAg-specific T lymphocytes in patients with acute and chronic hepatitis B and to identify immunodominant epitopes within the HBcAg/HBeAg, CD4+ T-cell responses to hepatitis B virus-encoded HBcAg and HBcAg/HBeAg-derived peptides were studied in 49 patients with acute and 39 patients with chronic hepatitis B. The results show a frequent antigen-specific CD4+ T-cell activation during acute hepatitis B infection, a rare HBcAg/HBeAg-specific CD4+ T-cell response among HBeAg+ chronic carriers, and no response in patients with anti-HBe+ chronic hepatitis. An increasing CD4+ T-cell response to HBcAg/HBeAg coincides with loss of HBeAg and hepatitis B virus surface antigen (HBsAg). Functional analysis of peptide-specific CD4+ T-cell clones revealed a heterogeneous population with respect to lymphokine production. Epitope mapping within the HBcAg/HBeAg peptide defined amino acids (aa) 1 to 25 and aa 61 to 85, irrespective of the HLA haplotype, as the predominant CD4+ T-cell recognition sites. Other important sequences could be identified in the amino-terminal part of the protein, aa 21 to 45, aa 41 to 65, and aa 81 to 105. The immunodominant epitopes are expressed in both proteins, HBcAg and HBeAg. Our findings lead to the conclusion that activation of CD4+ T lymphocytes by HBcAg/HBeAg is a prerequisite for viral elimination, and further studies have to focus on the question of how to enhance or induce this type of T-cell response in chronic carriers. The immunodominant viral sequences identified may have relevance to synthetic vaccine design and to the use of peptide T-cell sites as immunotherapeutic agents in chronic infection.

Establishment of a T cell-dependent nude mouse liver injury model induced by Propionibacterium acnes and LPS

Normal ICR mice developed severe liver injury when they were given intravenous injections of Propionibacterium acnes and lipopolysaccharide (LPS) with a 7 day interval. In contrast, T cell-deficient ICR nude mice were resistant to P. acnes and LPS-induced liver injury. However, athymic ICR nude mice, which were treated with cell transfer of normal ICR mouse spleen cells (10(8) cells) or ICR mouse nylon-wool passed splenic T-enriched cells (over 10(7) cells), showed severe liver injury as assessed by elevation of serum transaminase activities. Histological analyses also demonstrated that the transferred cells migrated into the liver of nude mice to induce liver injury. However, depletion of both CD4+ T cells and CD8+ T cells from transferred cell populations caused a marked decrease in the elevation of serum transaminase, indicating the actual involvement of T cells in liver injury. Moreover, in vivo administration of anti-LFA-1 mAb blocked P. acnes and LPS-induced liver injury in nude mice following T cell transfer. Thus, this model will provide a new strategy to investigate T cell-dependent cell-cell interaction during the induction of liver damage.

An increased number of circulating gamma/delta TCR + T cells in patients with chronic viral hepatitis

There is evidence that gamma/delta TCR+T cells are specialized in recognizing different antigens, but their immunologic role as a second TCR is still unclear. The aim of this study was to investigate the percentage of absolute numbers of circulating gamma/delta TCR + T cells in patients with chronic viral hepatitis (CVH) and to compare with HBsAg+, HCV healthy carriers and healthy subjects. Forty nine patients with CVH-24 with chronic active (CAH) and 25 with chronic persistent hepatitis (CPH)-, 21 HBsAg+, 20 HCV asymptomatic carriers and 20 healthy subjects were enrolled in the study. Lymphocyte subsets were determined after incubation with monoclonal antibodies to T total (CD5) and T gamma/delta cells (TCR-gamma/delta-1) using immunofluorescence microscopy. An increased number of circulating gamma/delta TCR + T cells was found in patients with CVH in comparison with asymptomatic carriers and normal controls: this increase was more profound in patients with CAH, compared to CPH patients. These results indicate a correlation between circulating gamma/delta TCR + T cells in CVH patients and activity and chronicity of the disease.

Alterations in intrahepatic expression of duck hepatitis B viral markers with ganciclovir chemotherapy

Ducks congenitally infected with duck hepatitis B virus (DHBV) were treated with the guanosine analogue, ganciclovir, and the effect on serum and intrahepatic expression of DHBV DNA and viral proteins was examined. After 21 days of ganciclovir treatment, a substantial reduction in viraemia occurred; in contrast, the level of circulating DHBV surface antigen was unchanged. Ganciclovir therapy also substantially reduced the level of DHBV DNA replicative intermediates and the expression of viral core and surface antigen in hepatocytes. However, despite the antiviral treatment some liver cells, including the bile duct epithelial cells and putative oval cells, maintained their intense staining for the viral proteins. Furthermore, DHBV-infected cells in extrahepatic sites such as the pancreas, kidney and spleen were also unaffected by ganciclovir treatment. These results suggest that monotherapy with nucleoside analogues is unlikely to eliminate chronic hepadnaviral infection, and antiviral programs should be designed to target all cell populations infected by the virus.

Heterogeneity of hepatitis B virus C-gene sequences: implications for amplification and sequencing

Occasionally direct sequencing of amplified hepatitis B virus DNA leads to weak signals on autoradiograms. Using amplified C-gene sequences we investigated whether this is due to sequence heterogeneity of virus populations and use of inappropriate primers for direct sequencing. High C-gene sequence heterogeneity (point mutations, stop codons and a one codon deletion) was observed in HBV genomes from serum of a chronic carrier who underwent interferon treatment. The type of C-gene mutations detected by direct sequencing depended on the type of primers used. Cloning and sequencing of amplified C-gene sequences demonstrated that this was due to mutations in the region complementary to the sequencing primer. These data demonstrate the existence of novel HBV C-gene mutants and imply that multiple or degenerate sequencing and amplification primers are essential for accurate evaluation of the extent of HBV C-gene heterogeneity. Based on comparative sequence analysis of all available completely or incompletely sequenced C-genes, guidelines for optimal primer design are proposed for similar studies.

Interleukin 6 production by peripheral blood mononuclear cells in patients with chronic hepatitis B virus infection and primary biliary cirrhosis

IL-6 production by peripheral blood mononuclear cells (PBMC) was studied in patients with chronic hepatitis B virus (HBV) infection and primary biliary cirrhosis (PBC) using the ELISA method. Spontaneous production of IL-6 was significantly increased in patients with HBeAg+ chronic hepatitis (CH). The cultures stimulated with lipopolysaccharide and lectin-free interleukin-2 (IL-2) showed enhanced IL-6 production both in controls and all patient groups compared with culture without any stimulation. IL-6 production in response to IL-2 was higher in patients with HBeAg+ CH and PBC than in controls. In PBMC with increased IL-6 production, monocyte function was increased in patients with HBeAg+ CH and PBC, while B cells from PBC showed elevated response to Staphylococcus aureus Cowan 1. IL-6 production in the presence of HBeAg was greater in anti-HBe+ patients than in HBeAg+ ones. These results suggest that IL-6 response is involved in the immune response in patients with chronic liver disease.

Molecular mimicry of hepatitis B surface antigen by an anti-idiotype-derived synthetic peptide

Monoclonal antibody 2F10 is an "internal-image" anti-idiotype (anti-id) antibody capable of mimicking the group-specific "a" determinant of human hepatitis B surface antigen (HBsAg). By mRNA sequencing and computer-assisted molecular modeling of monoclonal antibody 2F10, we identified a 15-amino acid region of the heavy-chain hypervariable region that has partial residue homology with sequences of the "a" determinant epitopes of HBsAg. We have established that a linear 15-mer peptide from a contiguous region on the anti-id antibody can (i) generate anti-HBsAg-specific antibodies when injected into mice, (ii) prime murine lymph node cells for in vitro HBsAg-specific T-cell proliferative responses, and (iii) stimulate in vitro human CD4+ T cells that were primed in vivo to HBsAg by natural infection with hepatitis B virus or vaccination with a commercially available HBsAg vaccine. Significantly, this peptide could also stimulate CD4+ T cells of human hepatitis B virus carriers. We conclude that a 15-mer peptide derived from the anti-id sequence can duplicate the B- and T-cell stimulatory activity of the intact anti-id antibody and the antigen that is mimicked, HBsAg.

Electron microscopic study of hepatitis B virus-associated antigens on the infected liver cell membrane in relation to analysis of immune target antigens in chronic hepatitis B

To clarify the characteristics of cell surface Pre-S2 Ag, HBcAg and HBeAg immunohistochemically and to explore their relationship with a cellular immune target antigen, 31 liver biopsy specimens from chronic HBV carriers were examined by immunoperoxidase staining. By immune light microscopy, Pre-S2 Ag was detected on the liver cell membrane in 18 (58%) of the 31 cases, HBcAg in 4 cases (13%) and HBeAg in 4 cases (13%). Pre-S2 Ag frequently showed a honeycomb-like membrane expression pattern which was present regardless of liver inflammation, whereas HBcAg and HBeAg exhibited a scattered membrane expression pattern detected in areas of marked inflammation. Of the 18 cases showing a honeycomb-like Pre-S2 Ag expression, 3 concomitantly showed a scattered membrane expression pattern. Immunoelectron microscopy revealed these two distinct membrane expression patterns. In areas showing a honeycomb-like membrane expression pattern, Pre-S2 Ag was demonstrated in the intercellular space and on the basolateral membranes of hepatocytes, but was not detected on the cell membranes in areas of the intercellular space lacking an immunoreaction. Cytoplasmic expression of Pre-S2 Ag was less extensive in these hepatocytes. These findings suggest that the honeycomb-like membrane expression of Pre-S2 Ag results from attachment of extracellular antigen to the liver cell membrane. In contrast, in areas showing a scattered membrane expression pattern, Pre-S2 Ag, HBcAg and HBeAg were each detected as single-layered linear deposits along the cell membrane, but were absent in the intercellular space. Each antigen was also expressed abundantly in the cytoplasm, and the immunoproducts appeared to fuse with the cell membrane. These findings suggest that the scattered membrane expression of these antigens results from intrahepatic transfer of antigen synthesized in the liver cell to the cell membrane, possibly serving as a target for the host immune-mediated response in connection with inflammation.

Immune response of peripheral blood mononuclear cells to antigenic determinants within hepatitis B core antigen in HB virus-infected man

Residues 72-146 within hepatitis B core Ag (HBcAg) represent T-cell recognition site in HB-virus-infected man. This study was undertaken to define critical residues involved in the immunogenicity of dominant T-cell determinants of HBcAg. For this purpose, p120-131 and its analog (p120-131 [A] containing alanine substitutions at residues 122 and 125, which were identified as epitopic residues in mice, were synthesized. These peptides and recombinant HBcAg were analyzed for their ability to stimulate peripheral blood mononuclear cells (PBMC) from 25 patients with chronic HBV infection and three patients with acute hepatitis B. PBMC from 18 out of 28 patients showed significantly increased IFN-gamma production and proliferative response in the presence of recombinant HBcAg. Eight patients responded to the two peptides, while 12 patients did not. Four patients responded only to p120-131, and four displayed a response only to p120-131 [A]. The responses to the two peptides were similar among HBeAg-positive and anti-HBe-positive patients, and did not depend on disease activity, except for HBeAg-positive asymptomatic carriers in whom there was no response to any additive. These results indicate that immune responses to p120-131 and its analog were similar in our patient groups. The dominant epitopic residues in this region of HBcAg may differ between man and mouse.

Effect of duration of hepatitis B virus infection on the association between human immunodeficiency virus type-1 and hepatitis B viral replication

This study examined the effect of duration of hepatitis B virus infection on the association between human immunodeficiency virus type-1 infection and hepatitis B viral replication. Twenty-five chronic HBsAg carriers were studied. Presence of hepatitis B virus DNA and expression of HBeAg were more frequent among 20 chronic HBsAg carriers positive for human immunodeficiency virus type-1 antibody compared with five chronic HBsAg carriers negative for human immunodeficiency virus type-1 antibody, but the associations were not statistically significant. Hepatitis B virus DNA and HBeAg were inversely related to duration of hepatitis B virus infection (p less than 0.001). Stratifying for duration of hepatitis B virus infection, the presence of viral replication was similar among patients negative and positive for antibody to human immunodeficiency virus type-1. Hepatitis B virus DNA levels did not increase with the decline of cellular immunity over time. In conclusion, hepatitis B virus replication among chronic carriers may be a function of duration of hepatitis B virus infection rather than of an effect of human immunodeficiency virus type-1.

Detection of pre-C and core region mutants of hepatitis B virus in chronic hepatitis B virus carriers

We analyzed the pre-C and core region of hepatitis B virus (HBV) DNA by a polymerase chain reaction in 22 chronic carriers. In 9 hepatitis B e antigen-positive asymptomatic carriers, a single DNA band was detected at the expected size, whereas additional shorter DNA bands were observed in 7 out of 11 patients with chronic hepatitis. The smaller-sized DNAs from one chronic hepatitis patient had various lengths of deletions spanning from 105 to 183 bp in the middle of the core gene, and all deletions included common nucleotide sequences. All of the smaller-sized DNAs from the other patients proved to be variant core genes. They were deleted in similar regions by Southern analysis using oligonucleotide probes. A follow-up study revealed that four out of seven chronic hepatitis patients with a short core gene seroconverted to antibody to hepatitis B e antigen, but those with only a "wild type" did not. In another set of sequence studies, clones isolated from two chronic carriers displayed heterogeneity of the pre-C and core gene which was more often present in sera with normal alanine aminotransferase levels than with abnormal levels. These results suggest that mutant HBV alters the host immune response, and may modulate the clinical course of HBV infection. An alternative possibility is that chronic hepatitis selects for mutant forms.

Hepatitis B virus antigen-specific T-cell activation in patients with acute and chronic hepatitis B

Since the hepatitis B virus is noncytopathic, it is generally believed that the individual specific immune response determines the course of infection. The lack of data about hepatitis B virus-specific T-cell reactions in acute infection led us to investigate the specific cellular immune response of infected individuals in terms of proliferation, and gamma-interferon and lymphotoxin production. Our results demonstrate that peripheral blood mononuclear cells (PBMNC) from patients with acute and chronic hepatitis B respond weakly to HBsAg. In contrast, patients with acute hepatitis show a vigorous response to the nucleocapsid antigen (HBcAg) in terms of proliferation and lymphokine production, while only few chronic virus carriers gave a proliferative response. Either of the antigens could activate lymphocytes to produce gamma-interferon and lymphotoxin, cytokines which may modulate antiviral immune response.

Interferon alfa therapy in patients with chronic hepatitis B virus infection. Effects on hepatitis B virus DNA in the liver

Pretrial and posttrial liver biopsy samples from 124 adult patients who participated in two randomized, controlled trials of interferon alfa therapy for chronic hepatitis B virus (HBV) infection were analyzed to determine the effects of interferon on the replication of HBV in the liver. Replicative forms of HBV DNA were detected in the pretrial biopsy samples from all and posttrial biopsy samples from 74% treated patients and 86% controls. Replicative forms of HBV DNA were detected in the posttrial biopsy samples from all patients who remained positive for hepatitis B e antigen and HBV DNA in the serum, in 77% treated patients and 80% controls who cleared HBV DNA in the serum but who remained positive for hepatitis B e antigen, but in only 19% treated patients and 40% controls who cleared HBV DNA as well as hepatitis B e antigen in the serum. Serum alanine aminotransferase levels were significantly lower in patients whose posttrial biopsies did not contain replicative forms of HBV DNA. In summary, we demonstrated that in most patients with chronic HBV infection treated with interferon alfa, serological response was associated with the disappearance of replicative forms of HBV DNA in the liver.

Trans-activation of HLA-DR gene by hepatitis B virus X gene product

Hepatocellular injury during hepatitis B virus (HBV) infection has been postulated to result from a human leukocyte antigen (HLA)-restricted T-lymphocyte host immune response against HBV antigens. Although HLA expression is enhanced in the presence of hepatic inflammation, whether HBV itself can induce HLA expression on infected hepatocytes is unknown. In this study, we demonstrate the induction of HLA-DR expression on human hepatoma cell lines transfected with HBV DNA sequences. The HBV X gene alone was capable of inducing HLA-DR expression. This induction correlated with elevated HLA-DR RNA, and this resulted directly from transcriptional trans-activation of the HLA-DR gene by the HBV X protein. These studies suggest that the HBV X protein can regulate the expression of HLA-DR and thus raise the possibility of participation by the X gene in the immunopathogenesis of HBV infection.

Hepatic expression of intercellular adhesion molecule-1 (ICAM-1) in viral hepatitis B

The in situ distribution patterns of intercellular adhesion molecule-1 and human leukocyte antigen-DR antigens were studied in serial sections of 61 liver biopsy specimens from patients with hepatitis B virus infection using immunohistochemical techniques. In addition, the topographical relationship between the display of HBcAg on one hand and the expression of intercellular adhesion molecule-1 by hepatocytes on the other was analyzed with a double-staining immunohistochemical procedure in 14 selected liver biopsy samples showing chronic persistent or chronic active hepatitis and signs of active hepatitis B virus replication as reflected by the presence of variable amounts of HBcAg in a nuclear or cytoplasmic pattern of immunoreactivity. Coexpression of intercellular adhesion molecule-1 and human leukocyte antigen-DR antigens by hepatocytes correlated positively with the site and extent of the inflammatory infiltrate, which was composed of lymphocytes expressing lymphocyte function-associated antigen-1. In healthy HBsAg-positive carriers without inflammatory liver disease, no intercellular adhesion molecule-1 or human leukocyte antigen-DR expression was found on hepatocytes; in acute hepatitis, intercellular adhesion molecule-1 and human leukocyte antigen-DR were strongly expressed throughout the liver parenchyma on liver cell membranes and on sinusoidal lining cells. In chronic persistent and chronic active hepatitis and in active cirrhosis, intercellular adhesion molecule-1 and human leukocyte antigen-DR showed membranous positivity on focal clusters of hepatocytes in areas of periportal or intraacinar inflammation.(ABSTRACT TRUNCATED AT 250 WORDS)

Neoexpression of sialyl oligomeric Lewis X by Kupffer cells in chronic hepatitis

The expression of a carbohydrate antigen, sialyl oligomeric Lewis X (SOLex), by Kupffer cells was examined in liver biopsy specimens from patients with chronic hepatitis. The antigen was expressed by Kupffer cells from these patients but not by those from normal controls. Expression of the antigen did not correlate with the histological type of chronic hepatitis, nor with SOLex expression in liver cells, which did correlate with severity of hepatic necrosis and inflammation. Treatment of patients with interferon-alpha increased SOLex expression by Kupffer cells, but not by liver cells, which suggests different means of regulation of SOLex expression in these two cell types. SOLex and HLA class II antigens were expressed simultaneously by Kupffer cells. Expression of SOLex by Kupffer cells (HLA class II antigen-positive) and liver cells (HLA class I antigen-positive) suggests a possible autoimmune response against this carbohydrate antigen in chronic hepatitis.

Distribution of non-lymphoid, inflammatory cells in chronic HBV infection

Non-lymphoid cells play a key role in the initiation and maintenance of cellular immune responses. Using in-situ immunohistochemical techniques and a panel of monoclonal antibodies (mcabs) reactive with B5-fixed, paraffin-embedded liver biopsies, we analysed the non-lymphoid cell component in inflammatory infiltrates in 20 cases of chronic hepatitis B virus (HBV) infection. In addition, lymphocyte subsets and HLA-DR antigens were studied. Mcab KP1 labelled scattered Kupffer cells, which variably expressed HLA-DR antigens. Their random distribution and lack of significant topographical association with lymphocytes suggest that classical Kupffer cells do not play a major role in cell-mediated immune reactions. On the other hand, mcab Mac387 was unreactive with normal liver tissue but labelled HLA-DR+ dendritic cells in areas of intralobular inflammation. On (immuno)electron microscopy, these Mac387+ dendritic cells were situated in the Disse space, where they formed close contacts with lymphocytes. Similar dendritic cells were situated at the edge of portal tracts in cases of chronic active, but not chronic persistent hepatitis. Immunostaining on serial frozen sections revealed their close topographical association with cytotoxic/suppressor T-cells, suggesting that Mac387+ HLA-DR+ dendritic cells play an immunomodulatory role in the effector arm of the cellular immune response that takes place in the periphery of portal tracts and the lobular parenchyma, and that involves activation and proliferation of cytotoxic T cells. Finally, large Mac387- HLA-DR+ dendritic cells expressing the LN2 marker were situated amidst helper/inducer T-cells in the centre of severely inflamed portal tracts.(ABSTRACT TRUNCATED AT 250 WORDS)

Randomised controlled trial of lymphoblastoid interferon alfa in Europid men with chronic hepatitis B virus infection

OBJECTIVE

To confirm the findings of pilot studies that interferon alfa is an effective treatment of Europid men with chronic hepatitis B virus infection.

DESIGN

Randomised controlled trial of three months treatment with interferon alfa followed by 12 months of observation.

SETTING

Outpatient clinic of a tertiary referral centre.

PATIENTS

37 Treated men (six anti-HIV positive) and 34 untreated men (nine anti-HIV positive) who met the criteria for the trial. Four controls failed to complete follow up.

INTERVENTIONS

The treated group received subcutaneous injections of 5-10 MU interferon alfa/m2 daily for five days, then 10 MU/m2 thrice weekly for 11 weeks. Follow up continued at monthly intervals for 12 months. Untreated controls were monitored over the same period.

MAIN OUTCOME MEASURE

Hepatitis B e antigen and hepatitis B virus DNA state after 15 months of observation.

RESULTS

12 Of the 37 treated patients cleared hepatitis B e antigen and hepatitis B virus DNA, whereas only one of 30 untreated controls seroconverted over the same period--an increased response rate of 29% (95% confidence interval 13% to 45%). The life table estimate of response at 15 months was 35% in treated patients, an increase of 32% above controls (95% confidence interval 16% to 48%). The response rates in groups by predictive pretreatment variables were 12 of 31 anti-HIV negative patients (excess response 34%; 95% confidence interval 14% to 54%), 12 of 26 with chronic active hepatitis before treatment (excess response 46%; 27% to 65%), and 12 of 21 with a pretreatment serum aspartate aminotransferase activity greater than 70 IU/l (excess response 46%; 16% to 76%). The combination of these factors predicted response with a sensitivity of 100% and a specificity of 80%. Four of the 12 responders, who had all been infected for less than two years, also lost hepatitis B surface antigen. Treatment was well tolerated.

CONCLUSIONS

Interferon alfa is effective in the treatment of a proportion of Europid men with chronic hepatitis B virus infection, who might be identified before treatment. Additional strategies are required to improve the rate of response.

In vitro amplification of hepatitis B virus sequences from liver tumour DNA and from paraffin wax embedded tissues using the polymerase chain reaction

A 185 base pair fragment from the core-polymerase overlap region of the hepatitis B virus (HBV) genome was amplified using the polymerase chain reaction (PCR). The results were compared with those of Southern blotting on extracted DNA from eight hepatocellular carcinomata. The data agreed with those of Southern blotting in six cases (two positive, four negative) but in two other positive cases PCR failed to amplify HBV sequences. This suggests deletion or mutation, or both, of this viral region in these cases. PCR was also used to amplify HBV sequences from formalin fixed, paraffin wax embedded tissue. Tissue inhibition of PCR occurred which increased with the number of tissue sections. It was present in tissues from different organs and species and fixed by different procedures, thus highlighting the need for a positive control during amplification. Use of formalin fixed Alexander cells, however, showed a sensitivity of one viral copy per 5000 cells. Confirmation of the identity of the PCR products was carried out using PCR-generated biotinylated probes, and suggested the insertion of extra nucleotide sequences or infection with an HBV variant in one case.