Hepatitis B virus DNA in peripheral blood leukocytes. A comparison between hepatocellular carcinoma and other hepatitis B virus-related chronic liver diseases

Association between host TNF-α, TGF-β1, p53 polymorphisms, HBV X gene mutation, HBV viral load and the progression of HBV-associated chronic liver disease in Indonesian patients

In developing countries, including Indonesia, there is a high mortality rate associated with the progression of hepatitis B virus (HBV)-associated chronic liver disease (CLD). The pathogenesis of HBV infection is influenced by viral and host factors. To determine potential associations between these factors, host single nucleotide polymorphisms (SNPs) on TNF-α, TGF-β1 and p53, HBV X gene mutation and HBV viral load were investigated in patients with HBV-associated CLD in Surabaya, Indonesia. Sera were collected from 87 CLD patients with HBV infection. TNF-α, TGF-β1 and p53 SNPs were genotyped by PCR restriction fragment length polymorphism. The HBV X gene was sequenced and compared with reference strains to determine mutations and the viral load was measured using reverse transcription-quantitative PCR. In Indonesian patients, no association between TNF-α, TGF-β1 and p53 SNPs and CLD or X gene mutation were identified. A total of 23% (20/87) of samples had HBV X gene mutations, including ten substitution types, one deletion and one insertion. Multinomial regression analysis revealed that the K130M/V131I mutations were correlated with CLD progression (OR, 7.629; 95% CI, 1.578-36.884). Significant differences in viral load were found in HBV-infected patients who had X gene mutations, such as R87W/G, I127L/T/N/S and K130M/V131I mutations (P<0.05). The presence of K130M and V131I mutations may be predictive for the progression of HBV-associated CLD in Indonesia.

Hepatitis B virus infection is associated with younger median age at diagnosis and death in cancers

Several non-hepatocellular cancers were linked with hepatitis B virus (HBV) infection. This study was aimed to quantify the potential associations between HBV infection and multiple non-hepatocellular cancers. Continuous cases, including 5,715 non-cancer and 40,963 cancer cases diagnosed from 2008 to 2014 in Sun Yat-sen University Cancer Center were analyzed. HBV DNA and hepatitis B core antigen (HBcAg) were examed in gastric cancer tissues by polymerase chain reaction and immunohistochemical staining. After adjusting for age, sex, year of diagnosis, smoking, drinking and family history of cancer, significant associations were found between serum HBsAg and frequently reported HBV-related non-hepatocellular cancers, including non-Hodgkin's lymphoma, cholangiocarcinoma and pancreatic cancer [adjusted odds ratio (AOR) and 95% confidence interval (CI): 1.89 (1.65-2.16)], as well as total other non-hepatocellular cancers [AOR and 95% CI: 1.12 (1.03-1.22)]. The median ages at diagnosis, all-cause death and cancer-specific death of serum HBsAg positive cancer patients were all significantly younger than those with serum HBsAg negative. HBV DNA was detected in 12.4% (34/275) gastric cancer tissues and HBcAg was most commonly detected in lymphocytes. This was the first report that HBV infection had a modest but significant nonspecific association with total non-hepatocellular cancers. Median age at diagnosis and death was significantly younger in serum HBsAg positive cancer patients. The underlying mechanism needs further investigation.

Risk and prophylaxis strategy of hepatitis B virus reactivation in patients with lymphoma undergoing chemotherapy with or without rituximab

Hepatitis B virus (HBV) reactivation is a serious but preventable complication for patients with lymphoma receiving systemic therapy. Without antiviral prophylaxis, the HBV reactivation rate is estimated to be > 50% in patients who are positive for hepatitis B surface antigen (HBsAg), and fatal hepatic failure is not uncommon. Current guidelines suggest that routine antiviral prophylaxis should be administered to all HBsAg-positive patients until 6-12 months after completion of chemotherapy. For those who are negative for HBsAg and positive for hepatitis B core antibody, HBV reactivation is uncommon when a conventional dose of chemotherapy is administered. However, with rituximab-containing immunochemotherapy, the HBV reactivation rate is 18% and the clinical course can vary from asymptomatic viremia to fulminant hepatic failure that can be potentially fatal. In this review, we discuss the risk, clinical course and prophylactic strategy of HBV reactivation in patients with lymphoma treated with chemotherapy with or without rituximab.

Hepatitis B-related serological events in hematopoietic stem cell transplant patients and efficacy of lamivudine prophylaxis against reactivation

Reactivation of remote hepatitis B infection (RHBI) is an important cause of morbidity in hematopoietic cell transplant (HCT) patients. We analyzed the prevalence of RHBI in 205 patients who underwent HCT in our centre, serological events related to hepatitis B virus (HBV) reactivation and role of lamivudine prophylaxis in HCT patients with RHBI. The prevalence of RHBI was 14% (28/205 patients). Of these 28 patients, 15 received lamivudine prophylaxis (14 anti-HBcIgG positive and 1 only anti-HBs positive) while 13 did not receive lamivudine prophylaxis (12 anti-HBs positive and 1 anti-HBcIgG positive). None in prophylaxis group developed HBV reactivation while 12 of 13 in no-prophylaxis group reactivated (P < 0.001). The rate of HBV reactivation was 10% (21/205 patients), which included 9 patients with no evidence of RHBI pre-transplant. We conclude that lamivudine prophylaxis protects against HBV reactivation in HCT patients with evidence of RHBI. Lamivudine prophylaxis should be used not only in patients with anti-HBcIgG positivity but also in those with isolated anti-HBs positivity pre-transplant given the high rate of HBV reactivation in these patients. HBV serology cannot identify all cases with RHBI and therefore does not preclude HBV reactivation post-transplant. Copyright © 2015 John Wiley & Sons, Ltd.

Entecavir as a first-line treatment for hepatitis B virus reactivation following polychemotherapy for chronic lymphocytic leukemia and invasive ductal carcinoma: a report of two cases and review of the literature

OBJECTIVE

Hepatitis B reactivation has been reported in chronic carriers of hepatitis B [hepatitis B surface antigen (HBsAg)] or in patients with prior hepatitis B virus (HBV) infection who are HBsAg-negative and have antibodies against hepatitis B core antigen (anti-HBc) with or without antibodies to HBsAg (anti-HBs). Lamivudine has been the first and commonly used nucleoside analog to inhibit HBV replication; however, prolonged therapy has been associated with an increased risk for drug-resistant mutations and mortality rates. Entecavir, a deoxyguanosine analog, offers several advantages over lamivudine for the treatment of HBV reactivation following chemotherapy while exhibiting more potent antiviral activity and a lower resistance rate.

METHODS

Herein, we report rapid and sustained suppression of polychemotherapy-related HBV reactivation by entecavir administered as a prompt antiviral therapy in the cases of two patients with chronic lymphocytic leukemia and invasive ductal carcinoma. A review of the literature is discussed.

RESULTS

Entecavir produced a rapid and sustained suppression of polychemotherapy-related HBV reactivation as a prompt antiviral therapy in the cases of two patients with chronic lymphocytic leukemia and invasive ductal carcinoma.

CONCLUSION

Allowing a rapid and sustained control of HBV replication, entecavir seems to be a promising drug for first-line prompt treatment of HBV reactivation in patients undergoing chemotherapy for hematological as well as solid organ malignancies, with safe long-term use enabling maintenance of resolved hepatitis.

A drug safety evaluation of rituximab and risk of hepatitis B

INTRODUCTION

Rituximab is a widely prescribed anti-CD20 mAb for the treatment of CD20(+) B-cell non-Hodgkin Lymphoma and many other immune mediated conditions. There is a well-described association between rituximab containing chemo-immunotherapy treatment and reactivation of the hepatitis B virus (HBV). This review summarizes the current literature surrounding rituximab-associated HBV reactivation.

AREAS COVERED

Herein, we review the literature detailing the risk of HBV reactivation in inactive carriers and those with resolved hepatitis. The clinical presentation and management of HBV reactivation are also discussed along with a summary of clinical trials evaluating antiviral prophylaxis. Finally, clinical recommendations are detailed. Data from clinical trials, observational studies, reviews, and meta-analyses available in the Medline database were included in this narrative review.

EXPERT OPINION

Screening should be performed in all patients prior to the administration of any type of anti-CD20 mAb therapy. Among those with positive screening serology, testing for hepatitis B e antigen or viral load by polymerase chain reaction is appropriate. In those patients with detectable HBV DNA, the decision regarding the use of antiviral prophylaxis or observation should be individualized.

Hepatitis B virus reactivation associated with anti-neoplastic therapy

Reactivation of hepatitis B virus (HBV) infection is a known complication during and after anti-cancer therapy. This condition can affect two patient populations: it is most commonly seen in patients who are seropositive for hepatitis B surface antigen (HBsAg), but it is also being increasingly reported among patients who are HBsAg-negative but who have prior infection, as evident by seropositive status for antibody to hepatitis B core antigen (anti-HBc), irrespective of their anti-HBs (antibody to HBsAg) status. The clinical course can vary from asymptomatic hepatitis to fulminant hepatic failure that can be potentially fatal. With the increasing use of biological agents in addition to potent cytotoxic chemotherapy in the armamentarium of anti-cancer treatments, reactivation of hepatitis B has become a common clinical situation that is faced by both oncologists and hepatologists especially in HBV endemic areas. In this review, we discuss the clinical course of reactivation in the two HBV-infected sub-populations, and the role of anti-virals in the prevention and management of HBV reactivation in association with cytotoxic chemotherapy and biological therapies.

Treatment induced seroconversion to HBsAb following HBV reactivation in the immunosuppressed haematology and oncology patient: a clinical survey of 5 cases in Catania, Italy

BACKGROUND

In onco-haematological patients inactive or occult HBV infection may be reactivated as a result of disease-related immuno-suppression and/or chemotherapy with rituximab.

OBJECTIVES

This study reports the clinical features of five patients affected by onco-haematological disorders who experienced hepatitis B reactivation.

STUDY DESIGN

From 2005 to 2010, five onco-haematological patients with hepatitis B reactivation were admitted to the department of Infectious Diseases, Ferrarotto Hospital, Catania, Italy.

RESULTS

At the time of onco-haematological disease diagnosis, 3 patients were HBcAb positive; 1 HBsAb and HBcAb positive; and 1 HBsAg positive, HBV DNA negative. None of the patients received hepatitis B prophylaxis. Reactivation was observed following chemotherapy. One patient was treated with lamivudine, 2 with tenofovir and 2 with telbivudine. Following treatment all patients achieved undetectable HBV DNA and normalization of transaminases. Three patients, those treated with lamivudine and tenofovir, cleared HBsAg and developed protective titres of HBsAb. The remaining patients, who were treated with telbivudine, were HBV DNA negative and HBsAg positive one at 27 months and the other at 5 months of therapy. Treatment thus continued in these patients.

CONCLUSION

HBV reactivation can be a severe complication in onco-haematological patients undergoing chemotherapy with rituximab. In our experience all nucleos(t)ide analogues were safe and effective. Three patients seroconverted to HBsAb. This may be as a result of the antivirals enhancing the immune response to HBV. A similar role may also be played by immune recovery following the withdrawal of immune-suppressive treatment. This report confirms the importance of anti-viral prophylaxis in patients with a high risk of HBV reactivation.

Re-appearance of hepatitis B virus following therapy with rituximab for lymphoma is not rare in Japanese patients with past hepatitis B virus infection

BACKGROUND AND AIM

De novo hepatitis B virus (HBV)-related hepatitis is a well-known fatal complication following chemo-immunosuppressive therapy in patients with past HBV infection (HB surface antigen and serum HBV DNA negative, but HB core antibody and/or HB surface antibody positive). This research was conducted to evaluate the incidence of and clinical features associated with re-appearance of serum HBV DNA following chemo-immunosuppressive therapy in Japanese patients with past HBV infection.

METHODS

This is a retrospective review. Forty-five patients with past HBV infection who had received chemo-immunosuppressive therapy for haematological disease were followed up for >6 months, to determine whether the serum test for HBV changed from negative to positive (i.e. re-appearance of serum HBV DNA following chemo-immunosuppressive therapy).

RESULTS

Re-appearance of serum HBV DNA was confirmed in five (20.8%) of the 24 patients who had received treatment regimens containing rituximab, but in none of the 21 patients who had not received treatment regimens containing rituximab (P=0.035). The HBV genotype could be determined in four of the five aforementioned patients, and in all four, HBV genotype C, which is the most prevalent genotype in Japan, was identified.

CONCLUSION

This research showed that re-appearance of serum HBV DNA is not rare in Japanese patients treated with chemotherapy regimens containing rituximab, and no other factors related to such re-appearance of serum HBV DNA could be identified. Well-designed clinical studies, including immunological and genetic analyses of the host and of the HBV, are required for further elucidation.

Management of viral hepatitis in hematologic malignancies

Viral hepatitis is the third major cause of liver dysfunction in allogeneic transplant recipients and has become a significant concern in patients with hematological malignancies receiving chemotherapy. Thus, identification of patients at risk for viral hepatitis is very important when evaluating and treating hematological malignancies. Serologic screening for all patients should include anti-HCV, hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (anti-HBs), and hepatitis B core antibody (anti-HBc) testing. Current therapies for hepatitis B (HBV) virus infection are aimed at viral suppression, while treatment for hepatitis C (HCV) virus can eradicate infection in many treated patients. To prevent HBV viral reactivation, prophylaxis with nucleoside analogues should be initiated for all HBsAg-positive patients. HCV infection appears to have little impact on short-term survival after bone marrow transplantation (BMT), but eventually can impact long-term survival due to progression of liver disease. In this review we will highlight the mechanisms of virus reactivation, clinical manifestations, and management strategies to minimize acute and chronic morbidity in this population.

Increased hepatocarcinogenic potential of hepatitis B virus genotype A in Bantu-speaking sub-saharan Africans

Genotypes A, D, and E of the hepatitis B virus (HBV) circulate in southern Africa, with genotype A predominating. Their hepatocarcinogenic potential in Bantu-speaking sub-saharan Africans is, however, unknown. Using a case/control format, we investigated the hepatocarcinogenic potential of these genotypes and subgenotype A1 of genotype A, which accounts for the great majority of genotype A isolates. HBV isolates from 111 unselected Bantu-speaking sub-saharan Africans with hepatocellular carcinoma (HCC) and 111 matched asymptomatic chronic carriers, serving as controls, were genotyped using the method of [Lindh et al. (1997): J Infect Dis 175:1285-1293]. Subgenotypes of genotype A were determined using an in-house restriction fragment length polymorphism assay. Genotype A was present in 96 (86.5%) of patients with HCC and 76 (68.5%) of the carriers, giving a 4.5-fold (95% confidence limits: 1.86, 10.90) increased risk of HCC in carriers infected with genotype A compared with those infected with non-A genotypes. HCC patients infected with genotype A were significantly younger than those infected with non-A genotypes (P = 0.02). The distributions between these two groups according to sex, geographic background, and tribe were not significantly different. Subgenotype A1 was present in all of the 77 cancer patients and 69 of 70 carriers analyzed, yielding a relative risk of 4.21 (95% confidence limits: 1.73,10.23) of HCC in those infected with subgenotype A1 compared with those infected with non-A genotypes. Genotype A has a greater hepatocarcinogenic potential than non-A genotypes in Bantu-speaking sub-saharan Africans and this is entirely attributable to subgenotype A1.

Interruption of HBV intrauterine transmission: A clinical study

AIM: To investigate the effect of hepatitis B virus (HBV) specific immunoglobin (HBIG) and lamivudine on HBV intrauterine transmission in HBsAg positive pregnant women.

METHODS: Each subject in the HBIG group (56 cases) was given 200 IU HBIG intramuscularly (im.) every 4 wk from 28-week (wk) of gestation, while each subject in the lamivudine group (43 cases) received 100 mg lamivudine orally (po.) every day from 28-wk of gestation until the 30^th day after labor. Subjects in the control group (52 cases) received no specific treatment. Blood specimens were tested for HBsAg, HBeAg, and HBV-DNA in all maternities at 28-wk of gestation, before delivery, and in their newborns 24 h before the administration of immune prophylaxis.

RESULTS: Reductions of HBV DNA in both treatments were significant (P < 0.05). The rate of neonatal intrauterine HBV infection was significantly lower in HBIG group (16.1%) and lamivudine group (16.3%) compared with control group (32.7%) (P < 0.05), but there was no significant difference between HBIG group and lamivudine group (P > 0.05). No side effects were found in all the pregnant women or their newborns.

CONCLUSION: The risk of HBV intrauterine infection can be effectively reduced by administration of HBIG or Lamivudine in the 3^rd trimester of HBsAg positive pregnant women.

Presence of hepatitis B surface antigen mutant G145R DNA in the peripheral blood leukocytes of the family members of an asymptomatic carrier and evidence of its horizontal transmission

An asymptomatic carrier and all six of his family members were detected positive for HBV DNA in their peripheral blood leukocytes (PBL), by polymerase chain reaction. Direct sequencing of the amplified DNA revealed that the HBV DNA from the carrier and his wife was of subtype ayw. Interestingly, the amplified HBV DNA from the five other members of the family was found to be not only of subtype adw but also contained G to A mutation at nucleotide position 587. This indicates the presence of established vaccine escape mutant of the virus (G145R) and suggests two different sources of infection within the family. Southern blot hybridization of EcoR1 digested DNA from PBL indicated presence of HBV DNA, integrated into cellular DNA and also in the form of free viral DNA. The study not only establishes the persistence of surface mutant G145R HBV DNA, within the PBL of HBsAg negative individuals from the non-vaccinated random population, but also suggests possible horizontal transmission of the mutant among the family members although none of the family members has received immunoprophylaxis against HBV or had clinically apparent disease or any other known risk factors of HBV infection. As all of them were seronegative for HBsAg/antiHBc, the presence of G145R mutant in the PBL signaled possibility of spread of the vaccine escape mutant virus by blood transfusion, unsafe injection practices or through sexual root.

Hepatitis B virus nucleic acids circulating in the blood: distinct patterns in HBs carriers with hepatocellular carcinoma

Circulating nucleic acids in serum and plasma are common in a variety of disease conditions. Here, we focus (i) on our approach for the detection of various hepatitis B virus (HBV)-related nucleic acids in liver tissue and in serum, (ii) on the progression of the chronic HBV infection, (iii) on the relation of HBV-specific nucleic acids circulating in the blood of patients with hepatocellular carcinoma, and in general (iv) on the diagnostic potential of circulating HBV nucleic acids.

Hepatitis B virus precore mutants in serum and liver of Southern African Blacks with hepatocellular carcinoma

BACKGROUND/AIM

The aim of this study was to sequence the precore region of HBV isolated from serum and tumorous and non-tumorous liver tissue from patients with hepatocellular carcinoma to identify mutations that might play a role in malignant transformation.

METHODS

HBV DNA was extracted from 62 sera, 14 tumorous and 12 non-tumorous liver tissue samples of patients with hepatocellular carcinoma, amplified by the polymerase chain reaction and sequenced directly.

RESULTS

Thirty-nine patients were HBeAg-negative and 23 HBeAg-positive. Missense mutations were present predominantly in HBeAg-negative sera. The most common missense mutation, a guanine to thymine transversion, occurred at nucleotide 1862 in the bulge of the encapsidation signal; it was more prevalent in HBeAg-negative (10/39) than in HBeAg-positive patients (1/23) (p = 0.03). Mutations known to prevent HBeAg synthesis were detected in seven sera; five with an 1896 stop-codon mutation, one with an 1817 nonsense mutation, and one with a frameshift mutation caused by an insertion between 1838 and 1839. Missense mutations and deletions were present more often in tumorous tissue derived from HBsAg-negative patients. In the tumours missense mutations occurred at position 1862 and 1899, and the deletions affected direct repeat 1 and/or the encapsidation signal and included the x gene stop-codon.

CONCLUSIONS

The 1862 mutation, and other missense mutations and deletions detected in the precore gene, may disrupt HBV DNA replication and/or signal peptide cleavage leading to HBeAg-negativity. Disruption of viral replication may promote integration of unencapsidated replicative intermediates and hence contribute to hepatocarcinogenesis.

Detection of hepatitis B virus DNA and RNA in kidneys of HBV related glomerulonephritis

Glomerular deposition of hepatitis B virus (HBV) antigens are observed in chronic HBsAg carriers with different glomerulonephritides yet the etiologic role of HBV remains uncertain. We examined the paraffin section of kidney biopsies from 40 chronic HBsAg carriers with membranous nephropathy (MGN), mesangiocapillary glomerulonephritis (MCGN) or IgA nephropathy (IgAN) for HBV DNA and HBV RNA using in situ hybridization (ISH). Glomerular HBV antigens were present in all biopsies by immunofluorescence. HBsAg or HBcAg mRNA was also studied in RNA extracted from frozen renal tissue using a two-step polymerase chain reaction (PCR) following reverse transcription (RT). HBcAg DNA was not easily detected with ISH alone, but was readily found in 31 biopsies (78%) following PCR. HBV DNA was detected mainly in the cytoplasm of proximal tubular epithelia but not in glomerular cells. HBsAg and/or HBcAg mRNA were detected by RT-PCR in extracted RNA from 13 biopsies (33%). The PCR findings were further confirmed by (a) Southern blot hybridization using a cloned HBV probe and (b) absence of PCR product following treating RNA with RNase or omitting the RT. It is plausible that HBV DNA in renal tubules represents endocytosis of HBV DNA in the urinary filtrate and the HBV RNA extracted from kidney biopsies could derive from infiltrating cells bearing HBV RNA. Hence, ISH with specific HBV core gene RNA probe was performed subsequently. HBcAg RNA, localized in the nuclei and cytoplasm of glomerular and tubular cells, was detected in 56%, 20%, and 36% of renal biopsies in chronic HBsAg carriers with MGN, MCGN, and IgAN, respectively. Our findings indicate the presence of viral transcription in glomerular cells and renal tubular epithelia, supporting an etiological role of HBV in some chronic HBsAg carriers who develop coexisting glomerulonephritides.

Additive effect modification of hepatitis B surface antigen and e antigen on the development of hepatocellular carcinoma

To assess the role of hepatitis B e antigen (HBeAg) and its interaction with hepatitis B surface antigen (HBsAg) on the development of hepatocellular carcinoma (HCC), this case-control study included 361 age- and sex-matched pairs of patients with histologically proven HCC and healthy control subjects. HBsAg, HBeAg and antibody to HBeAg (anti-HBe) were detected by radioimmunoassay. Antibodies to hepatitis C virus (anti-HCV) were detected by second-generation enzyme immunoassay. The prevalences of HBeAg (20.2%), HBsAg (80.3%) and anti-HCV (29.5%) in cases were higher than in controls (1.9%, 20.7%, and 2.7% respectively; each P < 0.0001). Using patients negative for HBsAg, HBeAg and anti-HBe as a referent group, univariate analysis indicated that HBsAg alone or HBsAg and HBeAg were risk factors for HCC (P for trend < 0.0001). Calculation of incremental odds ratio indicated that there was additive interaction between HBsAg and HBeAg. Multivariate analysis indicated that HCC development was strongly associated with the presence of HBeAg (odds ratio, 8.1; 95% confidence interval, 2.4-27.1), HBsAg (odds ratio, 68.4; 95% confidence interval, 20.5-227.8) and anti-HCV (odds ratio, 59.3; 95% confidence interval, 13.6-258.4). In conclusion, HBsAg, HBeAg and anti-HCV are independent risk factors for HCC. There is additive and independent effect modification between HBsAg and HBeAg on the development of HCC.

Hepatitis B virus nucleic acids associated with human peripheral blood mononuclear cells do not originate from replicating virus

There have been numerous reports suggesting that human peripheral blood mononuclear cells (PBMCs) can be productively infected with human hepatitis B virus (HBV). We therefore examined whether the PBMCs can be used to establish an in vitro infection system for HBV. Freshly purified PBMCs were incubated with HBV with or without mitogen stimulation. Successful infection was tested using a newly developed PCR method that can differentiate between the relaxed circular (RC) DNA of the virus inoculum and the covalently closed circular (CCC) DNA which is formed only after successful virus entry. This method enables virus uptake to be proven even if the infection is abortive because there is no gene expression because of the lack of liver specific gene expression factors. All attempts to detect CCC DNA after incubation of PBMCs with HBV failed. On the contrary, CCC DNA could easily be detected in infected liver or after in vitro infection of primary human hepatocytes. Because this result appeared to be contradictory to the published data, we analyzed PMBCs isolated from infected patients. We could confirm that HBV DNA and RNA are associated with these cells. However, even after restimulation with mitogens, we could only detect RC DNA. Moreover, we could also demonstrate that viral RNA is present in free virus. Apparently, a certain amount of defective particles do not reverse transcribe the packaged pregenomic RNA. In summary we found no evidence that PMBCs can be infected with HBV and conclude that all previous observations can be explained by adsorbed virus.

Persistence of extrahepatic hepatitis B virus DNA in the absence of detectable hepatic replication in patients with baboon liver transplants

The presence of hepatitis B virus (HBV) DNA in extrahepatic tissues has been well documented. Whether HBV DNA can persist in extrahepatic tissues for long periods of time in the absence of replication in the liver has not been determined previously. Recently, two patients with end-stage liver disease secondary to chronic active HBV were treated with baboon liver xenotransplants as these animals are felt to be resistant to HBV infection. Multiple tissues from these two patients were examined for HBV DNA using polymerase chain reaction (PCR). HBV DNA was not detectable in four of five samples of the liver xenografts. A positive signal was observed in a single assay for one sample, but this sample was not positive in subsequent assays. HBV DNA was detected in peripheral blood lymphocytes, spleen, kidney, bone marrow, pancreas, lymph node, heart and small intestine. The level of HBV DNA in these tissues was too low for the detection of HBV DNA replicative intermediates by Southern hybridization; thus, it could not be determined whether the HBV DNA in these tissues represented actively replicating HBV in extrahepatic sites, integrated HBV sequences, HBV in infiltrating lymphocytes, or deposition of HBV immune complexes originating from the plasma. However, it is clear from this study that HBV DNA persisted in multiple tissues for 70 days after replication in the liver had ceased or at least was below the level of detection by PCR.