Hepatitis B virus DNA in patients with chronic liver disease and negative tests for hepatitis B surface antigen

We assessed the presence of hepatitis B virus (HBV) DNA in liver or serum samples from 134 patients with hepatitis B surface antigen (HBsAg)-negative chronic liver disease, including 20 with hepatocellular carcinoma. HBV DNA sequences were detected in 52 of the 88 liver samples (59 per cent), including 17 of the 20 samples from patients with hepatocellular carcinoma. Presumably "replicative forms" of HBV DNA were detected in only 5 of the 88 liver samples, 3 of which were from patients with no serologic marker for HBV. In most of the liver samples the DNA patterns were consistent with the presence of HBV or a closely related virus. Of the 105 serum samples tested, HBV DNA sequences were identified in 10 (9.5 per cent), 6 of which had no HBV serologic marker. Moreover, HBsAg-associated determinants were detected in 5 of 17 patients who were positive for HBV DNA and in none of 14 patients who were negative. This study demonstrates the high frequency of HBsAg-negative HBV DNA-positive viral infection of the liver and suggests that multiplication of HBV may occur in the absence of any conventional serologic marker for HBV.     

Occult hepatitis B virus infection in patients with chronic hepatitis C liver disease.

BACKGROUND: Hepatitis B virus (HBV) infections in patients who lack detectable hepatitis B surface antigen (HBsAg) are called occult infections. Although such infections have been identified in patients with chronic hepatitis C liver disease, their prevalence and clinical significance are not known. METHODS: With the polymerase chain reaction, we searched for HBV DNA in liver and serum samples from 200 HBsAg-negative patients with hepatitis C virus (HCV)-related liver disease (147 with chronic hepatitis, 48 with cirrhosis, and 5 with minimal histologic changes). One hundred of the patients had detectable antibodies to the HBV core antigen (anti-HBc); 100 were negative for all HBV markers. Eighty-three were treated with interferon alfa. We also studied 50 patients with liver disease who were negative both for HBsAg and for HCV markers. In six patients found to have occult HBV infection, we evaluated possible genomic rearrangements through cloning or direct sequencing procedures. RESULTS: Sixty-six of the 200 patients with chronic hepatitis C liver disease (33 percent) had HBV sequences, as did 7 of the 50 patients with liver disease unrelated to hepatitis C (14 percent, P=0.01). Among the 66 patients, 46 were anti-HBc-positive and 20 were negative for all HBV markers (P<0.001). Twenty-two of these 66 patients (33 percent) had cirrhosis, as compared with 26 of the 134 patients with hepatitis C infection but no HBV sequences (19 percent, P=0.04). HBV sequences were detected in 26 of the 55 patients in whom interferon therapy was ineffective and 7 of the 28 patients in whom interferon therapy was effective (P=0.06). None of the sequenced HBV genomes had changes known to interfere with viral activity and gene expression. CONCLUSIONS: Occult hepatitis B infection occurs frequently in patients with chronic hepatitis C liver disease and may have clinical significance.     

Hepatitis B virus concentrations in serum determined by sensitive quantitative assays in patients with established chronic hepatitis delta virus infection.

To clarify the correlation between hepatitis B virus (HBV) DNA levels and serum alanine aminotransferase (ALT) levels in patients with established chronic hepatitis delta virus (HDV) infection, sensitive HBV quantitative assays were used for the study. Thirty-four consecutive patients with chronic liver disease who were positive for both hepatitis B surface antigen (HBsAg) and antibody to HDV (anti-HDV), including 19 patients with chronic hepatitis, 8 patients with liver cirrhosis and 7 patients with hepatocellular carcinoma. All were negative for hepatitis Be antigen (HBeAg) and positive for antibody to HBeAg. HBV DNA was detected in 25 (73.5%) of the 34 patients using real-time detection PCR, and the HBV DNA levels of these patients were significantly lower compared with HBeAg status and ALT level-matched patients with chronic liver disease positive for HBsAg but negative for anti-HDV. There was no correlation between serum HBV DNA and ALT levels among the 34 patients with chronic liver disease positive for anti-HDV. Whereas serum ALT levels in anti-HDV-positive HBsAg carriers with HDV RNA were significantly higher than those without HDV RNA. Liver damage in patients with established chronic HDV infection may be caused mainly by ongoing HDV infection not by HBV replication.     

Serum hepatitis B virus DNA in hepatitis B virus seropositive and seronegative patients with normal liver function

The presence of hepatitis type B virus (HBV) DNA in serum specimens from 926 apparently healthy people with normal liver functions was determined by polymerase chain reaction; 41.2% of people with positive results for HBV surface antigen (HBsAg) (94 of 228) and 95.2% of people with positive results for HBV e antigen (HBeAg) (60 of 63) were found to have positive results for serum HBV DNA. On the other hand, serum HBV DNA was found in 11.0% (77 of 698) of HBsAg-negative people and in 13% (69 of 530) of those who had positive results for serum antibodies directed against HBsAg. The results seem to suggest that HBV DNA can be found in a significant portion of apparently healthy people with normal liver function who are either seronegative for HBsAg or seropositive for antibodies directed against HBsAg.     

Different levels of hepatitis B virus replication among hepatitis Be antigen-positive chronic carriers

Detection of hepatitis B virus DNA polymerase (HBV DNA-pol) activity and of HBV DNA sequences in serum allowed to distinguish the different degrees of HBV replication in chronic HBsAg carriers. The amount of HBV DNA in the serum of 48 HBsAg and HBeAg positive patients in relation with the presence or absence of HBV DNA-pol was determined by dot-blot hybridization. The HBeAg positive cases with HBV DNA-pol activity had significantly higher HBV DNA levels than those which were DNA-pol negative (p less than 0.001). However, no significant differences with respect to liver function tests (transaminase, albumin, gammaglobulin) or to the histological diagnosis were found between both groups. Quantitative detection of serum HBV DNA in HBsAg chronic carriers may be helpful for learning the natural history of HBV infection and monitoring the antiviral therapy.     

Hepatitis B virus DNA in leukocytes of patients with hepatitis B virus-associated liver diseases

In order to determine the relationship between hepatitis B virus (HBV) infection of human white blood cells and different forms of HBV-associated liver diseases, we tested for HBV DNA in the sera and leukocytes of 11 healthy individuals without any serological markers of HBV infection and 91 patients with HBV infection and other gastrointestinal and urinary diseases by dot and Southern blot hybridization. HBV DNA was found in leukocytes of chronic HBV carriers, in acute and chronic hepatitis, and in patients with liver cirrhosis and hepatocellular carcinoma. Between 27 and 50% of individuals in different categories of patients examined were positive for leukocyte HBV DNA. HBV DNA was also detected in the sera of some of these patients but was absent in others. Serum HBV DNA-positive rates seemed to be highest in hepatitis B e antigen-positive asymptomatic carriers (8/10, 80%), and tended to drop to lower levels as the disease progressed to liver cirrhosis (0/8) while leukocyte HBV DNA-positive rates were highest in patients with cirrhosis (4/8, 50%). The results also show that in individuals who were serologically negative for hepatitis B surface antigen (HBsAg) and positive for antibodies to HBsAg and/or HBcAg, HBV DNA was absent in most of the sera (27/28, 96%) but it was present in leukocytes of some of these patients (7/28, 25%). In control experiments with 11 healthy individual, HBV DNA was not detected in either sera or leukocytes. In all the cases with leukocyte HBV DNA, the HBV DNA molecules were present in free forms with discrete sizes. The exceptions were a case of liver cirrhosis and a case of chronic hepatitis with possible HBV sequence integration into high molecular weight cellular DNA. Since HBV does infect human leukocytes, it may perhaps interfere with the immunological functions of the white blood cells, and thus play an important role in the pathogenesis of HBV-induced liver disease.     

Screening for hepatitis B virus in healthy blood donors by molecular DNA hybridization analysis.

A DNA molecular hybridization technique employing a purified adw subtype hepatitis B virus (HBV) cloned DNA of 3.2 kilobase pairs as a probe was used to screen for the presence of HBV DNA in blood samples collected from 486 apparently healthy blood donors. Eighteen of 104 (17.3%) hepatitis B surface antigen (HBsAg) carriers and 7 of 382 (1.8%) HBsAg-negative individuals had circulating HBV DNA in their sera. Among the seven individuals who were positive for HBV DNA but negative for HBsAg, three had antibodies against both HBsAg (anti-HBsAg) and hepatitis B core antigen, one had only anti-HBsAg, one had both anti-hepatitis B core antigen and anti-hepatitis B e antigen and two were negative for all the above HBV markers. The results suggest that the absence of HBsAg in otherwise apparently healthy individuals may not be enough to ensure lack of circulating HBV.     

Detection of serum hepatitis B virus DNA using the polymerase chain reaction assay

We compared the sensitivity of the polymerase chain reaction (PCR) assay to that of slot blot hybridization for detecting hepatitis B virus (HBV) DNA in the serum of a chimpanzee infected with HBV and 52 patients. Also, we utilized a rapid PCR procedure for the detection: Viral DNA was released from virions by incubating serum with NaOH. After a primary PCR amplification, the sample was reamplified using a second set of primer pairs (PCR/PCR). In the chimpanzee, HBV DNA was detected 3 weeks earlier than the appearance of hepatitis surface antigen (HBsAg) and persisted for two weeks with antibody to HBsAg. Of the 14 chronic hepatitis B patients positive for both HBsAg and HBV e antigen (eAg), 9 were positive for HBV DNA by slot blot hybridization and all 14 by PCR. Also, of 9 patients positive for HBsAg and antibody to eAg, 2 were positive for HBV DNA by slot blot hybridization and 8 by PCR. Three of the 11 patients who had lost HBsAg during follow up examination of chronic hepatitis B were positive for HBV DNA by PCR, whereas none of them was positive by slot blot hybridization. Six patients who had recovered from acute hepatitis B more than one year ago and 12 cases who had had vaccination of HBV were negative for HBV DNA by PCR. This technique should yield valuable information on the biology of HBV.     

Integration of hepatitis B virus DNA into the genome of liver cells in chronic liver disease and hepatocellular carcinoma. Studies in percutaneous liver biopsies and post-mortem tissue specimens

We used recombinant-DNA technology and gel electrophoresis to find hepatitis B virus DNA (HBV-DNA) in liver and tumor tissue from patients with hepatocellular carcinoma and chronic liver disease, and to study the integration of HBV-DNA into the genome of these tissues' cells. In 12 patients with hepatocellular carcinoma who had hepatitis B surface antigen (HBsAg) in their serum, integrated HBV-DNA was identified in the tumors; it was also found in tumors from three of eight patients who were seronegative for HBsAg but positive for antibody to HBsAg. In some cases, integrated HBV-DNA was also present in nontumorous liver tissue that had the same hybridization pattern or one different from that of the tumor. In five carriers of HBsAg who had evidence of the carrier state and chronic liver disease for less than two years, HBV-DNA was present but not integrated in liver tissue. In the two patients who had carried HBsAg for more than eight years, HBV-DNA was integrated into the host genome. These data suggest that integration of HBV-DNA into hepatocytes occurs during the course of persistent HBV infection and precedes development of gross neoplasm.     

Hepatitis B virus DNA in liver, serum, and peripheral blood mononuclear cells after the clearance of serum hepatitis B virus surface antigen

The integration of hepatitis B virus (HBV) DNA in the liver of chronic HBV carriers has been documented extensively. However, the status of the viral genome during acute infection has not been assessed conclusively. While HBV DNA sequences are detected often in serum, liver, and peripheral blood mononuclear cells (PBMCs) after the clearance of serum the hepatitis B virus surface antigen (HBsAg), the precise status of the viral genome, and in particular the possible persistence of integrated genomes in PBMCs, has not been established. A highly sensitive PCR-derived assay (Alu-PCR) was employed to re-examine liver and PBMC specimens obtained from patients with acute (n = 19) and chronic (n = 22) hepatitis in whom serum HBsAg was present (n = 12) (HBV-related chronic active hepatitis) or absent with anti-HCV (n = 10) (HCV-related chronic active hepatitis). Viral integration was demonstrated in 3 out of 19 liver specimens from patients with acute hepatitis and 12 out of 12 specimens from patients with chronic hepatitis. Viral integration was also observed in 4 out of 7 PBMC samples from HBV-related chronic active hepatitis patients and 2 out of 10 liver and PBMC samples from HCV-related chronic active hepatitis patients. In one liver specimen from an acute hepatitis patient, HBV DNA was found integrated in the intronic sequence of the tumour necrosis factor (TNF)-induced protein gene; viral integration into cellular sequences was also found in the PBMCs of four HBV-related chronic active hepatitis and two HCV-related chronic active hepatitis. The results demonstrate the early integration of HBV genome during acute viral infections and the persistence of the viral genome in an integrated form in PBMCs.     

供受者感染乙肝病毒对造血干细胞移植后肝炎复发及愈后的影响

目的分析移植前供、受者感染乙肝病毒对造血干细胞移植后肝炎复发及愈后的影响。方法对上海第一人民医院2006年1～11月移植前供、受者感染乙肝病毒的23例恶性血液病患者,进行移植前后肝功能、乙肝免疫标记物、HBVDNA等检测,并结合临床综合分析。血清丙氨酸氨基转移酶（ALT）、γ谷氨酰转肽酶（GGT）采用速率法,血清总胆红素（TBIL）采用终点比色法检测;乙肝病毒血清标志物采用酶免疫测定（EIA）;HBVDNA测定采用聚合酶链反应（PCR）试剂盒。结果①9例HBV感染的自体移植患者移植后3例发生乙型肝炎,其中2例为移植前HBsAg阳性,乙肝发作时3例HBVDNA及肝功能指标均明显增高;②14例HBV感染的供、受者移植后5例患者发生乙型肝炎,HBVDNA及肝功能指标均明显增高;③移植前HBsAg或HBVDNA阳性移植后发生乙肝相关性肝损的几率显著高于阴性组（X^2分别为8.44、9.07,均大于X0.005^2,P〈0.005）;④移植前HBsAg或HBVDNA阳性对移植预后均无影响（X^2分别为2.58、0.24,均小于X0.05^2,P〉0.05）;⑤1例患者异体移植后41d,乙肝合并戊肝,发生急性黄疸性肝炎,第46天重症GVHD死亡。结论移植前HBsAg和HBVDNA阳性均是HBV感染和再激活的高危因素,移植要密切监测免疫标志物和HBVDNA。移植前HBsAg和HBVDNA阳性不影响患者的生存,要注意非常见肝炎的多重感染。     

Nosocomial transmission in simultaneous outbreaks of hepatitis C and B virus infections in a hemodialysis center

Reported here are details of a simultaneous outbreak of hepatitis B virus (HBV) and hepatitis C virus (HCV) infections that occurred in a hemodialysis centre in northern Italy, with three patients seroconverting for HBsAg and four patients seroconverting for HCV antibodies. Phylogenetic analysis of the E2 region of the isolates from HCV-seroconverted patients showed the sequences were grouped in the same distinct branch as in a chronically HCV-infected patient, suggesting that the chronically infected patient was the index case. For the patients with HBV infection, phylogenetic analysis showed strong clustering among the sequences of the three patients who seroconverted to HBsAg and no relatedness between them and the sequences of patients chronically infected with HBV. For one of the patients who seroconverted to HBsAg, the last test with negative results for HBV markers had been performed 18 months prior to HBsAg seroconversion. This patient may have been previously infected with HBV and is presumed to be the source of the outbreak. This report emphasizes the importance of using universal precaution measures and HBV vaccination to prevent the transmission of viral hepatitis among chronic hemodialysis patients.     

High prevalence of hepatitis B,C and delta virus infections among blood donors in Mongolia

Summary. Serum samples obtained from 289 first-time and 114 repeat donors at the Blood Center of Mongolia (MBC) were tested for serological and molecular markers of hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis delta virus (HDV) infections. Among the 403 blood donors, 33 (8.2%), 21 (5.2%), and 27 (6.7%) tested positive for hepatitis B surface antigen (HBsAg) and/or HBV DNA, HCV RNA, and HDV RNA, respectively. Collectively, 55 donors were viremic for one or more of these viruses, and included 54 first-time donors (18.7%) and 1 repeat donor (0.9%) (P < 0.0001). One discrepant case with HBsAg detectable only at MBC was negative for HBsAg, HBV DNA and anti-HBc in this study. Four donors who were HCV-viremic in this study were negative for anti-HCV by the MBC method. Further efforts to increase the sensitivity and specificity of the currently-used tests are urgently required in Mongolia. Three donors who were positive for anti-HBc and anti-HDV but negative for HBsAg, had both HBV DNA and HDV RNA. This suggests that introduction of a new anti-HDV serological test is useful for not only HDV screening but also HBV screening of anti-HBc-positive, HBsAg negative donors, considering a possibility of viral interference by coexisting HDV.     

Frequent detection of hepatitis B virus DNA in hepatocellular carcinoma of patients with sustained virologic response for hepatitis C virus

Hepatocellular carcinoma (HCC) develops several years after the eradication of hepatitis C virus (HCV) by interferon therapy. Risk factors for the development of HCC are only partly understood. To elucidate the role of occult hepatitis B virus (HBV) infection in hepatocarcinogenesis in patients with sustained virologic response, the prevalences of HBV‐related makers were examined. Study group comprised 16 patients with sustained virologic response (group A) and 50 with HCV (group B). Anti‐HBc and anti‐HBs in serum were examined by enzyme‐linked immunoassay. HBV DNA in liver was examined by nested polymerase chain reaction, using primers specific for genes encoding for HBx, HBsAg, HBcAg, and HBV cccDNA. Sequence of the amplified HBV DNA for ‘a’ determinant of HBsAg was determined in HCC. Anti‐HBc was positive in 10 of 16 in group A and 25 of 50 in group B. HBV DNA in liver was detected in 12 of 16 in group A and 21 of 50 in group B (P = 0.044). In group A, HBV DNA in liver was detected frequently in patients without cirrhosis and in those with a longer period from the time of HCV eradication to the development of HCC. Mutation in ‘a’ determinant of HBsAg was found in three HCC of group A. Occult HBV infection may be one of the most important risk factors in hepatocarcinogenesis of Japanese patients with sustained virologic response. J. Med. Virol. 81:1009–1014, 2009. © 2009 Wiley‐Liss, Inc.     

Clinical significance of a highly sensitive enzyme immunoassay of hepatitis B surface antigen using a novel electron spin resonance technique.

We developed a highly sensitive enzyme immunoassay (EIA), the p-AP/HHTIO method, that detects serum hepatitis B surface antigen (HBsAg) by measuring stabilized nitroxide radicals using a novel electron spin resonance technique [Matsuo et al. (1998) Free Radic Biol Med 25:929-935]. To demonstrate the clinical significance of this method and to reveal occult hepatitis B virus (HBV) infection in patients, we used the method to analyze serum samples of 30 patients with acute or fulminant hepatitis who were negative for HBsAg by standard EIA, and those of seven chronic HBV carriers who became negative for HBsAg during a follow-up period by standard EIA. We also examined serum HBV DNA by amplification of the HBV S gene, using the polymerase chain reaction (PCR) technique. The p-AP/HHTIO method showed that 9 of 20 (45%) patients with acute hepatitis and 2 of 10 (20%) with fulminant hepatitis were positive for HBsAg; PCR detected HBV DNA in these HBsAg-positive patients. Antibody against hepatitis B core antigen was detected in one patient with fulminant hepatitis. The p-AP/HHTIO method demonstrated prolonged seropositivity of HBsAg even after standard EIA showed a loss of HBsAg in all seven HBV carriers. Our p-AP/HHTIO method is useful for screening and diagnosing HBV infection in patients with liver diseases who are negative for conventional HBV-related serological markers.     

The histopathology of the liver in older patients with hepatitis B virus surface antigenaemia

Summary The histopathology of the liver and the detectability of intrahepatic hepatitis B virus (HBV) markers were studied in 34 autopsy cases in elderly patients (mean age 73.9 years, range 60–91 years) who had had a history of positive HBV surface antigenaemia prior to death. Seven of 14 persistent HBV carrier cases (group A) in which long-lasting HBV surface antigen (HBsAg) carriage in the sera had been confirmed by sequential assays, and 5 out of 15 HBV-infected people (group C, single assay) showed significant primary liver damages including chronic hepatitis, toxic hepatitis, liver cirrhosis and hepatocellular carcinoma. In 5 cases (group B), one of which was type B liver cirrhosis, HBsAg became negative and HBsAb appeared during the follow-up period (up to 33 months). Among confirmed HBV carriers, HBsAg and HBV core antigen were most frequently found in the liver of cirrhotic cases with and without hepatocellular carcinoma (5 of 6), whereas these were rarely detected in those with nonspecific changes or slight hepatitic activity (1 of 7). All 5 cases in group B were negative for histological HBV-related antigens and the findings in group C were variously interpreted. Post-mortem cases of the aged HBV carriers who survived their mean life expectancy represent an important population in which to study the natural history of HBV carriers.     

Correlation between HBV DNA detection by polymerase chain reaction and Pre-S1 antigenemia in symptomatic and asymptomatic hepatitis B virus infections

The presence of hepatitis B virus (HBV) genome in sera from 73 symptomatic and asymptomatic HBsAg carriers was studied by the polymerase chain reaction (PCR) with primers specific for the S and C regions. Pre-S proteins of the HBV envelope were detected in serum by a specific monoclonal antibody in a double immunoradiometric assay. Out of twenty-five symptomatic patients with chronic active hepatitis (14 with HBeAg and 11 with anti-HBe), all were positive for HBV DNA by PCR, while 14/14 HBeAg and 2/11 (18%) of the anti-HBe patients were positive by dot blot hybridization. All but one anti-HBe patient (96%) carried Pre-S1 proteins. Among the asymptomatic HBsAg carriers, HBV DNA was detected by PCR in 14/14 (100%) HBeAg positive patients and in 25/34 (73%) anti-HBe positive patients. Pre-S1 proteins were found, respectively, in 14/14 (100%) and 11/22 (50%) of the same cases tested in parallel. The 20 healthy blood donors devoid of HBV markers and with normal transaminases tested were found negative for HBV DNA using PCR. Out of 12 patients who recovered from acute hepatitis B, all were found negative by PCR analysis after a mean follow up of 1 year after seroconversion to anti-HBs. When serial samples from 2 patients (one with acute hepatitis B, the other with chronic hepatitis B) were tested for the presence of HBV DNA and of Pre-S1 proteins, both markers showed parallel development.(ABSTRACT TRUNCATED AT 250 WORDS)     

Different forms of hepatitis B virus DNA and expression of HBV antigens in peripheral blood mononuclear cells in chronic hepatitis B

The presence of both hepatitis B virus (HBV) DNA and HBV antigens (HBsAg, HBeAg) was assessed in peripheral blood mononuclear cells (PBMC) from 32 patients chronically infected with HBV. Three different molecular forms of HBV DNA were observed: free monomers (5), high-molecular-weight free concatemers (11), and integrated HBV DNA (9). The HBV DNA patterns in the PBMC were different from those found in liver and did not correlate with any specific profile of serum HBV markers. When the same PBMC were assayed for HBsAg, 22 of the 25 HBV DNA positive samples, but only three of the seven HBV DNA negative samples, were positive. By contrast, none of the PBMC samples from five healthy HBV vaccine recipients gave any positive signal in the HBV DNA or HBsAg assays. In some patients, T and B cells, monocytes, and polymorphonuclear (PMN) cells were assayed separately, showing that the DNA pattern was similar for these different leucocytes subsets and ruling out the possibility that these patterns might reflect PMN cell contamination. Thus, in chronic HBV infection, 87.5% (28/32) of patients were found to contain at least one HBV marker in their PBMC, and a strong correlation was found between the presence of HBV DNA and viral antigens, suggesting a specific expression of HBV encoded proteins.     

Elimination of hepatitis delta virus infection after loss of hepatitis B surface antigen in patients with chronic delta hepatitis

The aim of this study was to evaluate whether patients with chronic hepatitis delta virus (HDV) infection treated with alpha interferon and subsequent loss of hepatitis B surface antigen (HBsAg) eliminate HDV. HDV RNA was detected in 26 of 28 patients with chronic delta hepatitis using the polymerase chain reaction. Seventeen patients in whom HDV RNA was detected were treated with alpha interferon; in 65%, HDV RNA remained detectable during treatment or reappeared after stopping therapy whereas in three patients HDV RNA remained absent (17.5%). HDV RNA became and remained undetectable in serum and liver of two of these three patients who lost HBsAg from serum and in one patient who was intermittently HBsAg negative during therapy. After loss of HBsAg, hepatitis B virus (HBV) DNA was still detectable in the liver, but not HBV RNA, indicating absent or very low HBV replication. Three patients were lost to follow up (17.5%). Two nontreated patients with chronic HDV infection also lost HBsAg during follow up; HDV RNA also became undetectable in their serum. Thus, HDV replication does not persist after the loss of HBsAg. Clearance of HBsAg may be a useful guide to when therapy can be stopped. © 1994 Wiley-Liss, Inc.