[Natural history of hepatitis B infection]

Hepatitis B virus (HBV) is transmitted by parenteral, sexual and perinatal routes. While fulminant hepatitis may occur in 1% of cases of symptomatic acute hepatitis, the principal problem of HBV infection is that it may become chronic, classically defined by carriage of HB surface antigens (HBsAg) for more than 6 months. This occurs in only 0.5 to 3% of immunocompetent adults but more frequently in children (up to 90%) and in immune-compromised patients (30 to 100%). The course of chronic HBV infection is characterized by variations in viral replication with spontaneous reactivation or discontinuation, and potential exacerbations observed clinically or by laboratory testing. The pathogenesis of HBV infection is mainly immune-mediated, resulting from host-virus interactions but also from the complexity of the virus itself (integration, mutation, occult replication). These factors explain the variety of presentations of chronic HBV infection, which range from immune tolerance to inactive carriage of HBsAg, passing through a stage of immune clearance, where chronic active hepatitis which may lead to cirrhosis (yearly incidence of 1.3 to 5.9%). Cirrhosis may be complicated by portal hypertension, liver failure, or hepatocellular carcinoma, which together explain 80% of the morbidity and mortality associated with HBV. The 5-year survival rate for HBV-related cirrhosis ranges from 52 to 82%. Immunosuppression, hepatitis D virus superinfection, and chronic alcohol consumption are the principal factors that modify this natural history. Chronic HBV infection is a major public health problem, particularly in developing countries, and it requires that efforts to make HBV vaccination universal be intensified.

Molecular epidemiology of hepatitis B and C virus infections in Asia

The present paper provides a review of the current literature regarding the molecular-based epidemiology of hepatitis B virus (HBV) and hepatitis C virus (HCV), which are very important viruses underlying the etiology of blood-borne infectious diseases worldwide. Particularly, both HBV and HCV are widespread on the Asian continent and are associated with acute and chronic liver diseases, including hepatocellular carcinoma. HBV has been classified into genotypes A through G and shown to have a distinct geographic distribution. In Asia, genotypes B and C of HBV prevail, and genotype C has been shown to cause more serious liver disease than genotype B. High prevalence of HBV mutants with various forms, such as the pre-S mutant, basal core promoter mutant, YMDD motif mutant and vaccine escape mutant, were seen in Asia and these were found to be related to the severity of liver disease and sensitivity to therapy. HCV has also been classified into multiple genotypes and associated with geographic distribution. HCV genotype 1 is less sensitive to interferon therapy and may be associated with the presence of more serious liver disease than the other genotypes. Data on the relation among the HBV/HCV genotypes, their pathogenicity in chronic liver diseases including hepatocellular carcinoma and their effect on therapy are awaited with great interest, especially in Asia, which is an endemic region of blood-borne hepatitis viruses.

High prevalence of hepatitis B virus pre-s mutant in countries where it is endemic and its relationship with genotype and chronicity

It has been reported that hepatitis B virus (HBV) mutants carrying mutations in the pre-S region can be found in infected patients. In this study, we investigated the prevalence of the HBV variant with the pre-S mutant in different geographic regions, including countries with low and high levels of endemic HBV infection, and analyzed the correlation with clinical findings. We examined 387 HBV DNA-positive serum samples from individuals among 12 countries, consisting of Vietnam, Myanmar, Thailand, China, Korea, Nepal, Japan, Russia, Spain, United States, Bolivia, and Ghana. HBV pre-S mutants were detected in 71 (18.3%) of 387 serum samples tested. This mutant was the most prevalent in Vietnam (36%), followed by Nepal (27.3%), Myanmar (23.3%), China (22.4%), Korea (14.3%), Thailand (10.5%), Japan (7.7%), and Ghana (4.3%). In contrast, no case with this mutation was found in Russia, Spain, United States, and Bolivia. Among the HBV deletion mutations, 15.5% (11 of 71) occurred in the pre-S1 and 46.5% (33 of 71) in the pre-S2 regions. Eight (11.3%) cases had a mutation in both the pre-S1 and pre-S2 regions. In addition, a point mutation at the pre-S2 starting codon was observed in 19 (26.7%) cases. The detection rate of the HBV mutant in patients with hepatocellular carcinoma was significantly higher than in other patients (P < 0.05). Furthermore, these mutants were found more frequently in genotype B (25%) and genotype C (24.5%) than in the other genotypes (P < 0.05). Our results indicated that there was a high prevalence of HBV pre-S mutation in regions of endemic HBV infection in Asia. Furthermore, the pre-S mutation appeared to be correlated with hepatocellular carcinoma and HBV genotypes.

Vaccination of chronic hepatitis B virus carriers with preS2/S envelope protein is not associated with the emergence of envelope escape mutants

PreS2/S vaccination of chronic hepatitis B virus (HBV) carriers led to a reduction in HBV replication or clearance of virus in 30% of treated patients. This study assessed whether vaccinotherapy of chronic HBV carriers induced the selection of escape mutants in the envelope 'a' determinant and whether envelope genetic variability might affect the response to vaccination. No amino acid differences were observed in the 'a' determinant between sequences obtained before and after treatment (five responders and seven non-responders). However, alignment with HBV prototype sequences revealed seven amino acid changes. Two mutations (T140S and P127L) diverged from subtype variations. In the complete envelope sequence (five non-responders and five responders), ten amino acid modifications were detected between sequences obtained before and after treatment. The absence of any common mutations did not enable the definition of a hot spot of mutations implicated in the response to vaccination. Moreover, vaccinotherapy does not induce the selection of escape mutants in the 'a' determinant.

HBV viral load within subpopulations of peripheral blood mononuclear cells in HBV infection using limiting dilution PCR

Extrahepatic viral load in peripheral blood mononuclear cells (PBMCs) of patients with hepatitis B virus (HBV) is still under debate. In this study, HBV infection rates and viral titers were examined within all PBMC subpopulations using limiting dilution-PCR (LD-PCR). PBMCs of patients with acute or chronic hepatitis B were separated by magnetic beads in monocytes, B-cells, CD4+ T-cells, CD8+ T-cells, and NK cells. Using two-round nested PCR, HBV-DNA sequences were detected in all patients examined within each PBMC subpopulation. The frequencies of HBV-positive cells and viral loads were calculated by Poisson analysis of HBV PCR results from serial dilutions of cells and cell lysates. Highest infection rates were found in monocytes and B-cells followed by CD8 + T-cells, NK cells, and CD4+ T-cells. Concerning all subsets, frequencies of HBV-positive cells were 50- to 500-fold higher in chronic than in acute hepatitis B. Viral loads were mostly estimated at about one HBV genome per HBV-positive cell. Moreover, slightly elevated HBV titers were seen in B-cells, CD4+ T-cells, and NK cells in both acute and chronic hepatitis B. It was demonstrated that beside a generally more latent HBV infection in PBMCs, elevated HBV titers point to replication or selective viral uptake within particular PBMC subsets. Therefore, the data suggest that HBV-infected PBMCs may participate in persistence of HBV.

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.

Clinical evaluation and applications of the Amplicor HBV Monitor test, a quantitative HBV DNA PCR assay

Viral load has emerged recently as a reliable marker of disease progression and therapeutic efficacy in chronic infections, including AIDS and hepatitis C. The clinical management of type B hepatitis could also be improved by monitoring viremia levels in patients with chronic liver disease undergoing anti-viral treatment. To address this question we evaluated the performance of a newly developed, quantitative PCR assay (Amplicor HBV Monitor test, Roche Diagnostic Systems) in the assessment of viremia changes over time in a group of 45 patients with chronic active hepatitis (CAH) who received interferon treatment. Of the 45 patients, 14 were HBsAg and anti-HBeAg positive and 31 HBsAg, HBeAg positive. Follow-up extended up to 24 months. An average of ten samples per patient were analyzed for levels of ALT, IgM anti-HBc (Abbott Laboratories), HBV DNA by in-house dot-blot hybridization and hybridization-capture assays (HBV-DNA hybrid capture kit, Murex Diagnostics) and by Amplicor HBV Monitor. A sustained biochemical response was observed at the end of treatment in 12 HBeAg-positive and in seven anti-HBeAg positive patients. This was accompanied by the disappearance of HBeAg and of HBV DNA (hybridization assays) in all cases and by the clearance of IgM anti-HBc in 70% of the cases. Viremia (quantitative PCR assay) became undetectable only in 25-30% of cases and was associated with the loss of HBsAg. A good correlation was observed between the time course of IgM anti-HBc, quantitative PCR and dot-blot hybridization although the latter missed 33% of viremic samples. Together, these results indicate that the Amplicor HBV Monitor test is a robust and standardized assay for quantifying HBV viremia levels in the range from 10(2) to 10(7) copies/ml. Compared to other current markers, viral load may provide additional clinical information by predicting long term virologic response and HBsAg clearance in patients with normal ALT at the end of interferon therapy.

Frequent chronic hepatitis B virus infection in HIV-infected patients positive for antibody to hepatitis B core antigen only. Swiss HIV Cohort Study

Persons with immune deficiency may present with atypical results in serological tests for hepatitis B virus (HBV). Frozen serum specimens that were sequentially obtained over time from a cohort of 57 HIV-infected patients, all of whom tested positive only for antibody to hepatitis B core antigen (anti-HBcAg), were therefore retested for HBV markers, including HBV DNA. The results were assessed for their time course and correlated with clinical data and alanine aminotransferase (ALT) values. Forty-eight patients were male; intravenous drug users constituted the principal risk group (n = 30), followed by homosexual men (n = 22). Thirty-three persons tested positive for antibody to hepatitis C virus (anti-HCV). During a median of 31 months from the first to the last serum, anti-HBcAg remained the sole marker of HBV infection in 98.2% of the patients. Polymerase chain reaction (PCR) to detect DNA for HBV core and HBV surface gene was positive in 126 (62.4%) and 121 (59.9%) of all 202 serum samples, respectively. Over time, HBV DNA was detected at least once in 51 (89.5%) patients. In contrast, decomplexed hepatitis B surface antigen (HBsAg) was detected at least once in 14 (24.6%) patients. Among patients positive for HBV DNA and negative for anti-HCV, eight (36.4%) of 22 had chronic hepatitis (ALT elevation > or = 6 months) that was attributable only to persisting HBV infection. Similarly, 12 (41.4%) of 29 patients positive for both HBV DNA and anti-HCV had chronic viral hepatitis, but their ALT values were significantly higher. In HIV-infected patients, anti-HBcAg as the sole serological HBV marker detected must be considered indicative of chronic HBV infection and is in part associated with chronic hepatitis and ALT elevation.

Chronic hepatitis C: the viral load per liver cell before treatment as a new marker to predict long-term response to IFN-alpha therapy

BACKGROUND/AIMS

So far, there are no reliable parameters that can predict the long-term sustained response to treatment with interferon-alpha in patients with chronic hepatitis C. In this study, we have developed a semi-quantitative method to determine the viral load per liver cell and have correlated this factor with the outcome of hepatitis C patients treated with interferon-alpha.

METHODS

Hepatitis C virus RNA levels were measured in serum, peripheral blood mononuclear cells and liver cells of randomly chosen hepatitis C patients before treatment with interferon-alpha (n=37). The number of cells present in the liver biopsies was determined by a polymerase chain reaction-based quantitation of the housekeeping gene beta-globin. The patients were divided into a responder ("R", n=15, 41%) and a non-responder ("NR", n=22, 59%) group, as defined by normal liver enzymes and negative hepatitis C virus-polymerase chain reaction 6 months after treatment.

RESULTS

Long-term sustained responders had a significantly lower viral load per liver cell (median: 5 vs. 650 copies/1000 liver cells, p-value: 0.0001), lower age (median: 32 vs. 54 years, p-value: 0.006) and lower percentage of geno- or serotype 1 (46% vs. 91%). Regarding viral load in serum and peripheral blood mononuclear cells, alanine aminotransferase levels, gamma-globulin levels and histological changes, no statistically significant differences were observed.

CONCLUSIONS

In chronic hepatitis C infection, a high viral load per liver cell represents a new marker to predict long-term response to therapy with IFN-alpha.

HLA-DRB1*1301 and *1302 protect against chronic hepatitis B

BACKGROUND/AIMS

The outcome of acute hepatitis B infection may be influenced by host factors like the major histocompatibility complex (MHC). We have investigated MHC class I and class II antigens in patients with chronic hepatitis B compared to a healthy control population. To confirm the findings of this first study we performed a second study in a group of subjects who had spontaneously recovered from acute hepatitis B infection.

METHODS

Frequencies of MHC class I and class II antigens were analyzed in patients with chronic hepatitis B virus infection and in control subjects. MHC class I typing was done by standard microlymphocytotoxicity assays. DRB1 and DQA1 genotypes were determined by polymerase chain reaction based typing methods.

RESULTS

In the first study the class II allele HLA-DRB1*1301-02 was found in 4 of 70 subjects with chronic hepatitis B virus infection (5.7%) compared to 27 of 101 healthy controls (26.7%, relative risk 0.17; p=0.001; p(corr)=0.025). This protective effect of the DRB1*1301-02 allele was confirmed in the second study. Eight of 24 patients (33.3%) who cleared hepatitis B virus spontaneously were positive for DRB1*1301-02 (relative risk of developing chronic infection compared to chronic hepatitis B subjects 0.12; p=0.004). Subtyping confirmed that 1301 and 1302 were both decreased in frequency in patients with chronic hepatitis B.

CONCLUSIONS

The MHC class II allele DRB1* 1301-02 is associated with protection from chronic hepatitis B in Caucasian patients.

Pre-core mutants of hepatitis B virus in patients receiving immunosuppressive treatment after orthotopic liver transplantation

Orthotopic liver transplantation (OLT) is a possible treatment for acute or chronic liver failure due to hepatitis B virus (HBV) infection, but reinfection of the graft can be a serious complication. The aim of this study was to monitor HBV markers, to analyse pre-core-/core-mutations as well as to identify the viral population causing reinfection after OLT, and to investigate the emergence or disappearance of these mutants in patients receiving immunosuppressive treatment. Fifty-four pre-and posttransplant serum samples of 17 patients were analysed. All patients underwent OLT for HBV-related liver disease and had HBV-DNA before and after OLT. Total DNA was extracted from all sera and a 240 bp fragment comprising the pre-core region of HBV was amplified by polymerase chain reaction (PCR). Pre-core mutants of HBV were determined by direct sequencing of these PCR products and by sequencing of PCR clones. Eight of 17 patients were infected with pre-core wildtype HBV before OLT (group A). Seven of eight patients of group A were reinfected by pre-core wildtype HBV after OLT. In one of eight patients in addition to wildtype HBV a mutant strain (nt. 1899 G-->A) was detected. Nine of 17 patients were infected with pre-core mutant HBV before OLT (group B). Six of nine patients of group B were reinfected with the same mutant population; in one, an additional pre-core mutation emerged; two patients lost pre-core mutant HBV (nt. 1896 and 1899 G-->A). In one of the latter two, a pre-core start-codon mutant (nt. 1816 G-->T), not detectable before OLT, emerged, in the other a nt. 1897 G-->A stop-codon mutant persisted. Five patients of each group were followed-up for more than 24 (25 to 58) months on immunosuppressive therapy. In all five patients of group A, pre-core wildtype of HBV persisted during long-term follow up. Two of five patients of group B were infected stably with a stop-codon HBV-mutant nt. 1896. In three patients, the nt. 1896 stop-codon mutant disappeared during immunosuppressive therapy. However, in one of the latter three, an HBV stop-codon mutant nt. 1897 persisted. In conclusion, most patients who underwent OLT for HBV-related disease were reinfected with the same virus population that existed before OLT. In rare cases, new mutants emerged after OLT or preexisting mutants were lost. During long-term follow-up on immunosuppressive therapy, in the majority of patients pre-core mutants disappeared and wildtype HBV became the predominant virus strain.

Quantitative assay of PCR-amplified hepatitis B virus DNA using a peroxidase-labelled DNA probe and enhanced chemiluminescence

We have developed a sensitive and quantitative assay for hepatitis B virus (HBV) DNA in serum or plasma in which PCR and then microtiter hybridization analysis are used. Assay of HBV DNA in serum or plasma is important for demonstrating viral replication, indicating and monitoring antiviral therapy, determining the infectivities of virus carriers, and ensuring the safety of blood products. Under optimum conditions PCR can amplify one HBV DNA molecule to 10(8) copies, but detection of this amount of DNA still requires hybridization with labelled probes or a nested PCR. We labelled one strand of the PCR product with a biotinylated primer. The double-stranded amplicon was incubated in streptavidin-coated microplate wells. The nonlabelled strand was removed after denaturation of the double-stranded DNA with alkali, and the bound strand was hybridized with a peroxidase-coupled single-stranded probe. The amount of bound peroxidase was measured in a luminometer. Four picograms of amplicon was detectable in this system, whereas conventional ethidium bromide staining requires a 1,000 times higher amplicon concentration. The performance of the new assay was compared with those of nested PCR and a PCR system that uses a digoxigenin label, hybridization to a solid-phase adsorbed probe, and colorimetric detection. The chemiluminescence assay was found to be almost as sensitive as nested PCR and approximately five times more sensitive than the colorimetric test.

PCR analysis of hepatitis B virus DNA in paraffin-embedded liver tissue from patients with chronic liver disease

We described a nested polymerase chain reaction protocol to detect hepatitis B viral DNA in paraffin-embedded liver tissue and tried to determine whether this virus was associated with non-B chronic liver disease. Fifty-five samples were obtained from 28 patients with B, and 27 patients with non-B chronic liver disease (35 cirrhosis, 4 hepatocellular carcinoma and 16 chronic hepatitis). The two sets of primers amplify a sequence located in a conserved polymerase/surface region of the viral genome. Reaction products were analysed using a nonisotopic hybridization method. None of the 27 (0%) seronegative samples and 20 of the 28 (71%) seropositive specimens were positive for hepatitis B virus DNA. There were 4 false negatives in which beta-globin PCR was positive. Although its sensitivity is reduced in formalin-fixed paraffin-embedded tissue, nested PCR allows rapid detection of HBV DNA sequences and can be a useful tool if no frozen tissue is available.

Quantitative molecular methods in virology

During the past few years, significant technical effort was made to develop molecular methods for the absolute quantitation of nucleic acids in biological samples. In virology, semi-quantitative and quantitative techniques of different principle, complexity, and reliability were designed, optimized, and applied in basic and clinical researches. The principal data obtained in successful pilot applications in vivo are reported in this paper and show the real usefulness of these methods to understand more details of the natural history of viral diseases and to monitor specific anti-viral treatments in real time. Theoretical considerations and practical applications indicate that the competitive polymerase chain reaction (cPCR) and competitive reverse-transcription PCR (cRT-PCR) assay systems share several advantages over other quantitative molecular methodologies, thus suggesting that these techniques are the methods of choice for the absolute quantitation of viral nucleic acids present in low amounts in biological samples. Although minor obstacles to a wide use of these quantitative methods in clinical virology still remain, further technical evolution is possible, thus making the quantitative procedures easier and apt to routine applications.

Contribution of HEV and HCV in causing fulminant non-A, non-B hepatitis in western India

During 1990, 38 patients with fulminant non-A, non-B hepatitis (NANB) died in Government Medical College Hospital, Aurangabad. Serum samples from these patients were tested for antibodies to hepatitis C virus (anti-HCV) and IgM antibodies to hepatitis E virus (IgM-anti-HEV). All samples were also subjected to polymerase chain reaction (PCR) for the detection of HBV DNA, HCV RNA and HEV RNA. None of the patients had circulating anti-HCV antibodies; three had HCV RNA. Based on anti-HEV-IgM positivity 14 patients (37%) could be diagnosed as suffering from hepatitis E. None was positive for HEV RNA. In the absence of serological markers, HBV DNA was present in three cases. None of the HBV DNA positive patients had anti-delta antibodies. Dual infections (HBV with HEV, and HBV with HCV) were seen in two cases. The aetiology of half of the NANB cases could not be assigned to the known hepatitis viruses using current techniques.

Evidence of non-A, non-B, non-C infection in chronic hepatitis by polymerase chain reaction testing for hepatitis B and C viruses

BACKGROUND/AIMS

Although hepatitis C virus is clearly the major cause of non-A, non-B acute and chronic hepatitis, there is a group of patients with histologically documented chronic hepatitis with no serological marker of hepatitis B and C, nor any other risk factors for liver disease.

METHODS

We have investigated 17 well-characterized patients with chronic active hepatitis. HBV-DNA and HCV-RNA were tested by polymerase chain reaction in 17 serum samples and in six liver biopsies.

RESULTS

Four of the 17 patients had serum HCV-RNA detectable by polymerase chain reaction, while none had HBV-DNA detectable by polymerase chain reaction. Three of the six liver samples gave a positive signal by cyclin A and HLA, and only these were considered for the study. One of the three was HCV-RNA positive, while none was HBV-DNA positive.

CONCLUSIONS

Our results, obtained through careful elimination of all known risk factors for liver disease, strongly suggest that non-A, non-B, non-C hepatotropic virus(es) could be involved in some cases of chronic active liver disease.

Microwave treatment of serum facilitates detection of hepatitis B virus DNA by the polymerase chain reaction. Results of a study in anti-HBe positive chronic hepatitis B

Investigation by polymerase chain reaction of HBV-DNA in serum from chronic hepatitis B virus carriers is not widely used for routine diagnosis because polymerase chain reaction assays are complex and may be too sensitive. We investigated the sensitivity, the specificity and the possible value for clinical use of a simplified polymerase chain reaction method in which a single, 30 cycles round of polymerase chain reaction is performed using only 10 microliters of serum treated with microwaves. The efficiency of the polymerase chain reaction in amplifying HBV-DNA was greater after microwave irradiation of serum than after alkaline extraction, but lower than after protein digestion and phenol chloroform precipitation. Despite its simplicity and high sensitivity, the assay was very specific. Studies in anti-HBe positive chronic hepatitis B virus carriers demonstrated HBV-DNA sequences in 1/15 (7%) healthy carriers, in 4/20 (20%) patients with slight alanine aminotransferase elevation, in 16/18 (89%) with marked alanine aminotransferase elevation and in all 20 with fluctuating alanine aminotransferase levels. In the latter, HBV-DNA was detected either at exacerbation (two cases), during remission (one case) or both (17 cases). HBV-DNA was detected by classical dot-blot hybridization in only 24/58 (41%) samples that were positive by the simplified polymerase chain reaction method. Although extremely high sensitivity is not achieved, microwave irradiation of serum simplifies considerably the detection of small amounts of HBV-DNA and makes polymerase chain reaction suitable for monitoring patients in whom weak hepatitis B virus replication is associated with ongoing liver disease.

Evidence for hepatitis B virus infection in patients with chronic hepatitis C with and without serological markers of hepatitis B

To assess the influence of HBV infection on anti-HCV-positive chronic liver disease, we performed a prospective case-control study comparing 19 HBsAg-positive, anti-HCV-positive patients with 38 HBsAg-negative, anti-HCV-positive patients, pair-matched for age, sex, and ALT levels. HBV and HCV infections were investigated by standard serology and polymerase chain reaction. HCV RNA was found in all patients with CAH and in 90.0% with cirrhosis (33% HBsAg-positive). HBV DNA sequences were found, in the HBsAg-positive subjects, in 71.4% of CAH and in 83.3% of cirrhotics; in the HBsAg-negative ones, only 10% of CAH but 77.7% of cirrhotics had demonstrable HBV DNA sequences. Consequently, 80.0% of cirrhotics had evidence of both HBV and HCV infection. Conventional serology gives partial information on the true occurrence of HBV infection in HBsAg-negative patients, while PCR defines more accurately the HBV status. When the rate of double infection is defined in this way, it correlates with the presence of cirrhosis.

Detection of hepatitis B virus DNA in the serum of Canadian hepatitis B surface antigen negative, anti-HBc positive individuals, using the polymerase chain reaction

Continuing hepatitis B virus (HBV) infection is normally associated with the presence of hepatitis B surface antigen (HBsAg) in the serum. In spite of sensitive screening assays for HBsAg, rare cases of post-transfusion HBV infection are still observed. Antibody to hepatitis B core antigen (anti-HBc) often indicates remote HBV infection but DNA hybridisation and more sensitive polymerase chain reaction (PCR) assays have demonstrated that some HBsAg negative individuals, positive for anti-HBc, have continuing HBV replication. To determine the incidence of ongoing HBV infection in a Canadian HBsAg negative, anti-HBc positive population we studied three groups with this combination of HBV markers: Group A, 36 patients referred for investigation of raised serum aminotransferases; Group B, 21 Canadian Red Cross blood donors; Group C, seven vaccinees in an Ottawa Health Care Student hepatitis B vaccination programme. The PCR was carried out using a nested PCR reaction with primers specific for the pre-core region of HBV. Seven of 36 (19%) patients in Group A had detectable HBV DNA whereas none of Group B or C were positive. This data indicates that in some HBsAg negative patients with ongoing hepatic inflammation, continuing HBV replication may persist. This was not observed in any healthy blood donors or health care students investigated. Larger studies are required, but this data would suggest that, in Canada, the addition of anti-HBc testing for all blood donors for detection of low level HBV replication would not be indicated.

Quantitative detection of hepatitis B virus DNA in serum using chemiluminescence: comparison with radioactive solution hybridization assay

A quantitative, non-radioactive hybrid capture HBV DNA assay (Digene Diagnostics), which uses an efficient solution hybridization procedure coupled to a sensitive chemiluminescent signal amplification system, was compared with the quantitative, radioactive solution hybridization assay (Genostics, Abbott Laboratories), in hepatitis B virus carriers, particularly in those undergoing antiviral therapy. The qualitative reproducibility of the chemiluminescent method, tested on 30 sera, was acceptable, with a reproducibility rate of 93.3%. A comparison of this hybrid capture HBV DNA assay with the radioactive test on 113 sera obtained from 48 patients (39 HBsAg-positive patients) gave a sensitivity of 87.2%, a specificity of 100% and an agreement between the two tests of 89.4% (101 sera including 82 HBV DNA positive and 19 negative samples). Changes in HBV DNA levels measured by the two assays showed a good correlation with each other during interferon therapy. However, the hybrid capture values were higher than the radioactive assay values, with the ratio of the two values being variable in the same patient during the course of treatment. The Genostics assay therefore seems to be a more accurate procedure for evaluating changes in viral replication, particularly at high HBV DNA levels. However, the hybrid capture method is faster and has the advantage of being a non-radioactive procedure. This chemiluminescent assay is easy to perform as a routine diagnostic procedure and may be a useful alternative to the radioactive solution hybridization method.

Detection of hepatitis C virus replication in ovarian metastases of a patient with hepatocellular carcinoma

Hepatocellular carcinoma is one of the most common human cancers with an annual incidence of about 1,000,000 cases worldwide. Although hepatocellular carcinoma is predominant in hepatitis B virus endemic areas, it has also become a major problem in Europe, Japan and North America in close association with the increasing incidence of hepatitis C virus infection. The pathogenetic role of hepatitis C virus infection in the development of HBsAg-negative hepatocellular carcinoma needs to be clarified. In this paper the case of a 66-year-old HBsAg-negative and anti-HCV positive female who developed hepatocellular carcinoma in a cirrhotic liver is reported. After 1 year of follow up, urgent laparotomy had to be performed due to highly differentiated ovarian metastases of the hepatocellular carcinoma. Plus- and minus-stranded HCV-RNA was detected by reverse transcription and "nested" polymerase chain reaction in both the patient's serum and in the metastatic ovarian tissue.

A long-term follow-up study of asymptomatic hepatitis B surface antigen-positive carriers in Montreal

BACKGROUND/AIMS

Prospective studies from the Far East and Alaska have shown an increased mortality from cirrhosis and/or hepatocellular carcinoma in asymptomatic hepatitis B virus (HBV) carriers. The magnitude of this risk in apparently healthy North American carriers remains undefined.

METHODS

The outcomes of 317 asymptomatic hepatitis B surface antigen-positive carriers from the Montreal area were examined after 16 years of follow-up. A majority of carriers were of French Canadian origin, were positive for antibody to hepatitis B e antigen, and had normal serum transaminase levels; institutionalization in orphanages as infants or children was the most important epidemiological risk factor, suggesting horizontal transmission of HBV during childhood.

RESULTS

At follow-up, mean age was 46 +/- 8 years; 3 carriers had died of HBV-related cirrhosis, 1 of alcoholic cirrhosis, and 9 of causes unrelated to liver disease. No carrier died of hepatocellular carcinoma; had the risk of hepatocellular carcinoma been similar to that reported from the Far East and Alaska, 17 cases of hepatocellular carcinoma-related deaths would have been expected. During follow-up, the annual negativation rate for hepatitis B surface antigen was 0.7%.

CONCLUSIONS

In asymptomatic HBV carriers from Montreal, a majority are "healthy" carriers and remain asymptomatic after 16 years of follow-up and the risk of death from HBV-related cirrhosis and/or hepatocellular carcinoma is low.

Competitive polymerase chain reaction and analysis of viral activity at the molecular level

Due to the high sensitivity level (which can be pushed to the limit of one molecule) and its extraordinary flexibility, the polymerase chain reaction (PCR) is the method of choice for the detection of nucleic acids present in very low concentration in biological samples. Since the qualitative features of PCR amplification have limited its use, several PCR-based approaches for the quantitation of low-abundance nucleic acid species have been planned and proposed in the last few years. Recently, different lines of evidence have indicated that competitive PCR and competitive reverse-transcription-PCR share several advantages over other quantitative approaches. This evidence opens up unexpected possibilities in many biological fields, including virology; in fact, availability of reliable techniques for the absolute quantitation of DNA and RNA species may be the key to a better understanding of the pathogenic steps of most viral diseases and for a more precise monitoring of patients treated with specific antiviral compounds. In this review article, we summarize the procedures adopted for this quantitative molecular approach; additionally, several important technical aspects to plan novel competitive PCR-based applications are analyzed, and early results obtained using cPCR for the direct evaluation of viral activity in vivo are discussed.

Quantitative assessment of hepatitis B virus DNA in chronic hepatitis B: comparison of two solution hybridization assays

We compared two solution hybridization assays, the AffiProbe assay (Orion Corporation) and the Abbott HBV-DNA assay (Abbott), for quantitative measurement of hepatitis B virus (HBV) DNA in serum samples obtained from chronic hepatitis B surface antigen (HBsAg) carriers. Forty transversally collected (group 1) and 83 serially collected (group 2) serum samples from chronic hepatitis B patients were tested with both assays. The serial serum samples were obtained from 6 patients who underwent alpha-interferon therapy with different outcomes (nonresponse, hepatitis B e antigen [HBeAg] seroconversion, HBeAg and HBsAg seroconversion). In group 1 a good correlation (r = 0.91; P < 0.001) was found between the HBV-DNA results of the two assays. Two samples (5%) were HBV-DNA positive according to the Abbott but negative according to the AffiProbe assay; for all other samples the HBV-DNA status corresponded. In group 2 the assays gave colinear HBV-DNA results during follow-up of 5 of the 6 patients (correlation for the total group: r = 0.90; P < 0.001). Nevertheless, in both groups the AffiProbe assay yielded about 5-10 times higher HBV-DNA levels than the Abbott HBV-DNA assay (P < 0.001). These discordant results were most probably due to standardization differences of the positive control samples of the two test systems. This observation underlines the need for international standardization of HBV-DNA and uniform reference panels.

Toward routine diagnosis of hepatitis B virus desoxyribonucleic acid

Although a multitude of hepatitis B markers are available to discriminate different states of hepatitis B virus (HBV) infection, there remains a need to detect the HBV DNA itself. The HBV DNA test is the only test that can quantify the number of complete virions. As shown in this review, the diagnostic value of testing for HBV DNA depends on quantification, and there are situations in which in vitro amplification is necessary and others in which testing for HBV DNA without preamplification is best. Indications for analysis of HBV DNA include the early recognition of chronic hepatitis B, discrimination of different HBsAg carrier states, recognition of the evolution of variants, indication and follow-up of anti-viral therapy with interferon, and assessment of blood products for infectivity. In each of these cases quantification of HBV DNA improves the diagnosis of HBV infection and will become an important tool in the routine diagnosis of hepatitis B virus infection in the future.

Correlation of HBeAg/anti-HBe, ALT levels, and HBV DNA PCR results in HBsAg-positive patients

A highly sensitive polymerase chain reaction (PCR) was used to analyse serum samples from HBsAg-positive patients in Sweden. Forty-two chronic carriers were tested, five of whom were of Swedish origin. Of the total, there were 13 HBeAg-positive and 27 anti-HBe-positive patients, while 1 patient was negative for both HBeAg and anti-HBe and one was positive for both markers. Nine of the 13 HBeAg-positive carriers and only 7 of the 27 anti-HBe-positive carriers had elevated alanine transaminase (ALT) levels (P = 0.01). Two PCR tests of marginally different sensitivity were used on all patient samples. All 13 HBeAg-positive patients and the patients with and lacking both HBeAg and anti-HBe markers, respectively, were positive in both PCR tests. One HBeAg-positive patient was shown to shed hepatitis B virus (HBV) DNA in both saliva and urine. Twelve of the 27 anti-HBe-positive carriers, 6 of whom had elevated ALT levels, were PCR positive. The remaining 15 had no evidence of HBV DNA and all but 1 had normal ALT levels. A positive PCR result was more common in those anti-HBe-positive patients with elevated ALT levels (P < 0.02). The precore gene from 18 samples was sequenced and, with a few exceptions, showed a high degree of conservation. We suggest that in the absence of optimal tests for infectivity of serum from HBsAg-positive patients, and until PCR becomes more widely available, all anti-HBe-positive patients with elevated ALT levels be considered highly infectious.

Delayed clearance of HBV-DNA detected by PCR in the absence of viral replication

The polymerase chain reaction (PCR) was used to study the in vivo persistence and clearance of HBV-DNA in the serum of a monkey (Macaca mulatta) known to be naturally resistant to the HBV infection. Total infectious plasma, virus pellet, and viral DNA were inoculated into 3 different monkeys. Degradation of infectious particles and clearance of HBV-DNA were analyzed by detecting HBV-DNA sequences in serial dilutions of serum by dot blot hybridization and PCR. Semi-quantitation was carried out by comparison with minimal positive dilutions of known HBV-DNA. The presence of hepatitis B surface antigen (HB-sAg) and hepatitis B e antigen (HBeAg) in serum was also investigated. PCR assays were found positive in serial samples of the 3 monkeys, and passively transmitted viral DNA remained detectable for 3 months after inoculation. HBsAg and HBeAg were detectable for 3 weeks and 2 weeks, respectively, in a monkey inoculated with total infectious plasma. Semi-quantitation of HBV viremia showed that the amount of virus detected 1 day after injection was markedly decreased and persisted at a low level, showing a rapid and important sequestration of viral particles. Since replication can be excluded in these monkeys, the data show that HBV-DNA sequences can remain detectable at a low level in the serum for long periods. It is thus conceivable that PCR may also detect the HBV genome, eventually degraded in vivo, and a weakly positive result does not always mean ongoing viral replication.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis C virus associated primary hepatocellular carcinoma in a noncirrhotic liver

The case of a 71-year-old man with a primary hepatocellular carcinoma in a non-cirrhotic liver is reported. There were no risk factors of hepatocellular carcinoma (HCC)-like liver cirrhosis, alcohol drinking, tobacco smoking, exposure to vinyl chloride, thorotrast, aflatoxin or alpha 1-antitrypsin deficiency. Serologically, the patient was positive for antibodies to the hepatitis B virus (anti-HBc, anti-HBs) and for anti-hepatitis C virus (HCV) antibodies. Virologically, positive and negative strands of HCV RNA could be detected in the patient's serum and tumorous liver tissue by reverse transcription polymerase chain reaction as a sign of persistent HCV replication. Histologically, the HCC was completely surrounded by liver tissue which showed the signs of nodular regenerative hyperplasia. Indeed, the mechanism of hepatocarcinogenesis remains to be clarified. However, this case supports the observation that HCC may also develop in patients with HCV infection without preexisting liver cirrhosis.

Polymerase chain reaction for the diagnosis of hepatitis B and C viral hepatitis

The detection of HBV, HCV, and HDV genomes through the use of the polymerase chain reaction (PCR) has made possible a new step in viral diagnosis. The main advantages of PCR are its extreme sensitivity and the possibility to develop rapid assays using non-radioactive probes. Several studies have now clearly shown its usefulness for the demonstration of viremias, the identification of seronegative viral carriers, and studies on mother-to-child transmission. Several limitations, however, still hamper the use of PCR and it should not yet be regarded as a routine test. The main developments to be expected in the near future deal with automatisation, prevention of contamination, and quantification.

Persistence of hepatitis B and hepatitis C viral genomes in primary liver cancers from HBsAg-negative patients: a study of a low-endemic area

The role of HBV and HCV in the course of primary liver cancer in patients who are negative for HBsAg has been debated. Using a combination of serological and polymerase chain reaction assays, we investigated the association between HCV and HBV infections and primary liver cancer in 24 HBsAg-negative patients living in France. The presence of HCV RNA and HBV DNA sequences was tested for in serum and in tumorous and nontumorous liver samples. Twelve patients had anti-HCV, and 11 patients had anti-HBs and/or anti-HBc. HCV RNA sequences were found in the serum samples of all anti-HCV-positive patients and none of the patients who were negative. Patients with HCV viremia had HCV RNA genomic sequences and presumed replicative intermediates in both tumorous and nontumorous specimens. Sequence analysis of a hypervariable region in the E2/NS1 gene of HCV showed significant variations between the viral molecules isolated from the nontumorous, tumorous and serum samples. This eliminated the hypothesis of the contamination of the tumor by nontumorous cells and serum particles and assessed that liver tumor cells did contain HCV RNA genomes. Eleven of 22 patients tested had HBV DNA in the serum; 5 patients were anti-HBc positive and anti-HBs positive. Patients with HBV viremia had HBV DNA sequences in both tumorous and nontumorous liver specimens. Selective loss of part of the HBV genome in the tumorous tissue of two of these patients suggested HBV DNA persistence in clonally expanded malignant cells. Only 4 of the 22 patients were negative for both viruses. Our results show that HBsAg-negative hepatocellular cancer in France is associated with chronic HBV or HCV infection and, in some cases, both; these findings are consistent with an etiological role for HBV and HCV in HCC that develops in cirrhotic patients living in areas of low prevalence.

Assessment of former and newly developed HBV assays in a Third World setting

Newly available HBV serological assays have not been established routinely in most underdeveloped countries. Utilizing enzyme-immune assays to determine the presence of pre-S1 antigen and anti-pre-S2, and using two conventional hybridization techniques and the PCR assay to detect HBV-DNA, we studied 30 HBsAg chronic carriers and as a reference group 10 subjects whose only HBV routine marker was anti-HBc. Seventy-nine percent of the HBeAg positive carriers showed detectable HBV-DNA by a non-radioactive slot-blotting technique. The PCR assay was more sensitive than the slot-blotting technique, detecting HBV-DNA in anti-HBe positive patients with moderate or normal ALT activity. Pre-S1 antigen was mostly related to the presence of HBsAg and anti-pre-S2 was associated with active viremic state, increased ALT activity (ranges 51 to 640 IU/L), and with self-limited HBV infection. The presence of HBV-DNA in the group with anti-HBc only was detectable solely by the PCR assay. For an underdeveloped country the addition of a PCR assay or pre-S/anti-pre-S protein tests to the current assessment procedures of HBV chronic infection should be used only in selective cases. HBeAg/anti-HBe serological evaluation and HBV-DNA detection by a non-isotopic conventional hybridization technique still remain as useful tools to screen initially for the presence of viremia in chronic HBsAg carriers. The presence of HBV-DNA in individuals with anti-HBc only suggests that anti-HBc screening should be maintained and expanded to all the blood banks of less industrialized countries where the rate of HBV infection in apparently healthy people tends to be high.

Hepatitis B and C viral infections in patients with hepatocellular carcinoma

The prevalence of hepatitis B and C virus infections was studied in 70 patients diagnosed as having hepatocellular carcinoma. In addition to viral serological markers, serum hepatitis B virus DNA and hepatitis C virus RNA were determined with a nested polymerase chain reaction assay. Twelve patients (17%) were HBsAg positive, 26 (37%) had antibodies to HBs, HBc or both and 32 (46%) were negative for all hepatitis B virus serological markers. Prevalence of the antibody to hepatitis C virus was 63% (44 patients). Hepatitis B virus DNA was detected in 24 of the 66 tested patients (36%). Twelve of these hepatitis B virus DNA-positive patients were HBsAg negative (seven were positive for antibody to HBs, antibody to HBc or both and five were negative for all hepatitis B virus serological markers). Hepatitis C virus RNA was found in 42 of 68 patients (62%). A high correlation (95%) existed between hepatitis C virus RNA and hepatitis C virus antibodies. Nevertheless, two patients without antibody to hepatitis C virus had serum hepatitis C virus RNA sequences. Coinfection by the two viruses was detected in nine subjects (14%), but no clinical differences were found between these and the rest of the patients. We conclude that nearly 90% (62 of the 70 patients studied) of cases of hepatocellular carcinoma in our geographical area are related to hepatitis virus infections (detected by serological or molecular studies). Hepatitis C is more prevalent than hepatitis B virus in patients with hepatocellular carcinoma, and the infection is still active when the tumor is diagnosed.(ABSTRACT TRUNCATED AT 250 WORDS)

New assays for quantitative determination of viral markers in management of chronic hepatitis B virus infection

We performed a quantitative study of serum hepatitis B virus (HBV) markers, including new parameters such as pre-S1 antigen (Ag), pre-S2 Ag, and anti-HBx, in 88 chronic hepatitis B surface antigen (HBsAg) carriers. New IMx assays for HBsAg and immunoglobulin M (IgM) anti-HBc detection were also used. The population studied was composed of 65 chronic hepatitis cases (40 positive for hepatitis B antigen [HBeAg] and 25 positive for anti-HBe) and 23 anti-HBe-positive, asymptomatic HBsAg carriers. Serum HBsAg levels detected by IMx were higher in HBeAg-positive than in anti-HBe-positive HBsAg carriers (all patient subgroups included) and correlated with the serum HBV DNA level (P = 0.0001). Both pre-S1 and pre-S2 Ags were detected by enzyme immunoassays in almost all HBsAg carriers. Both pre-S1 and pre-S2 Ag titers correlated positively with the serum HBsAg concentration (P = 0.0001), but only the pre-S1 Ag titer correlated with the level of serum HBV DNA (P = 0.02). The detection of low levels of IgM anti-hepatitis B core (anti-HBc) antibodies by IMx was associated with the presence of liver disease (P = 0.05) but not with the level of viral replication. The prevalence of anti-HBx antibodies detected by the enzyme immunoassay was slightly, although not significantly, higher in patients with high levels of HBV DNA (greater than 100 pg/ml) than in patients without detectable HBV DNA (P = 0.16). In anti-HBe-positive chronic HBsAg carriers, the quantitative detection of serum HBV DNA, pre-S Ag titers, and IgM anti HBc allowed us to predict which patients suffered from chronic liver disease and/or supported viral replication (P < 0.05). In a follow-up study of eight patients undergoing antiviral therapy, the clearance of both pre-S1 Ag and HBV DNA was associated with a subsequent clearance of HBV. Therefore, the quantitative determination of HBV DNA, pre-S Ags, IgM anti-HBc may prove useful for the decision to use and the monitoring of antiviral therapy, especially in anti-HBe-positive HBsAg carriers.

A rapid and quantitative solution hybridization method for detection of HBV DNA in serum

A sensitive and convenient solution hybridization technique was adapted for the semiquantitative detection of hepatitis B virus DNA in serum. The assay utilizes 35S-isotope as label and biotin-avidin interaction for collection of the hybrids onto microtitre plate wells. Results are obtained as numerical values, which allow quantification. 10(6) molecules of HBV DNA/ml serum could be detected by a 3-h hybridization followed by a 2-h collection reaction. By analyzing 500 microliters of serum, 30 (88%) of 34 patient sera positive for HBeAg were also positive for HBV DNA and 17 HBsAg-positive sera, 16 of which were anti-HBe-positive, were DNA-negative. The amount of HBV DNA varied from 5 x 10(6) to 3 x 10(9) molecules/ml. The solution hybridization method which was developed allows fast and accurate quantification of HBV DNA in serum providing an estimate of the virus titre.

Clinical significance of the polymerase chain reaction (PCR) assay in chronic HBV carriers

PCR was evaluated as a clinical tool for use in accurate identification of the specific etiologic agent in chronic HBV carriers. The method was found to be valuable in diagnosis and for monitoring therapy, as well as for elucidation of genotypic variants of HBV in chronic HBV cases. By this means an HBV defective variant with alterations in the preS1/preS2 sequence was detected and is consequently described here.

Advantage of PCR for detecting low amounts of HBV DNA in patients' sera

Serum hepatitis B virus DNA (HBV DNA) is now the most important and reliable marker for monitoring viral replication. Quantitative detection of HBV DNA in serum is based on a commercial standardized solution hybridization assay (Genostics). In this work, we studied the sensitivity and specificity of this method, in comparison with the polymerase chain reaction (PCR) technique, for low-value HBV DNA serum samples. Fifty-four patients with or without HBV serological markers were divided into 4 groups according to their HBV DNA values. Genomic amplification was found to affect 2 conserved regions of the viral genome, the S and C regions. Samples with an HBV DNA concentration equal to or greater than 1.5 pg/ml were considered positive in the "Genostics" test. A total of 38% of patients considered negative in the quantitative assay (less than 1.5 pg/ml) were found to be positive for HBV DNA in serum after PCR. Only 26% of patients with an HBV DNA concentration of between 1.5 and 10 pg/ml in the Genostics test had PCR-detectable viral DNA in serum. Some 56% of patients with HBV DNA values between 10 and 20 pg/ml were found to be positive after amplification. All patients whose HBV DNA values were above 20 pg/ml had PCR-detectable viral DNA in serum. Our PCR results suggest that the positive limit level of the Genostics test has to be re-evaluated. Indeed, for low values of HBV DNA (under 20 pg/ml and especially under 10 pg/ml), it is not possible to conclude about the positivity from the quantitative assay, and results have to be estimated according to the clinical and serological status of the patients. Moreover, PCR can be falsely negative because of methodological problems. Nevertheless, this study confirms that PCR does enable detection of the viral genome in HBV-seronegative patients and in "old" and "cured" HBV-infection marker carriers.

Hepatitis B defective virus with rearrangements in the preS gene during chronic HBV infection

We have found a defective form of HBV2 in a HBsAg- and anti-HBe-positive patient with liver cancer. Viral deletions were identified in the preS coding region using PCR. The presence of deleted HBV forms was observed in serum, PBMC, and liver samples. After sequencing 12 clones were analyzed (subtype adr). In 9 out of 12 clones a 183-bp in-frame deletion was recorded in the preS1 region (2995 to 3177). Three out of 9 clones also yielded rearrangements of the preS2 N-terminal part. Four out of 9 showed numerous point mutations in the preS1 and preS2 sequence. In addition, 3 out of 12 clones, which did not show the 183-bp preS1 deletion were found to have small deletions and insertions in the same part of the preS1 gene. Immunological mapping using monoclonal anti-preS antibodies showed loss of preS epitopes located at the 3'-part of preS1 and the 5'-part of preS2. On the other hand, epitopes mapped to the 5'-part of preS1 and 3' of preS2 were conserved. PBMC were also tested and solely PCR showed the major form of defective HBV with preS1 183-bp deletion. However, viral deletions in the preS gene eliminated the preS2 promotor region and B- and T-cell recognition sites. In contrast to this, the preS1 binding site to hepatocytes was conserved. Therefore, such deletions would potentially lead to an impairment in viral clearance without affecting viral penetration in liver cells, possibly accounting for chronic HBV infection.

Hepatitis B defective virus with rearrangements in the preS gene during HBV chronic infection

We have found a defective form of hepatitis B in an anti-HBe positive chronic HBsAg carrier with liver cancer (HCC). Viral deletions were identified in the preS coding region using PCR and sequencing. The presence of deleted HBV forms was observed in serum, PBMC, and liver tissue. To conclude, rearrangements and deletions in the preS gene would potentially lead to an impairment in viral clearance without affecting viral penetration in liver cells, possibly accounting for chronic HBV infection.