Hepatitis B virus reactivation in patients receiving chemotherapy for malignancies: role of precore stop-codon and basic core promoter mutations

Hepatitis B virus (HBV) strains carrying the precore stop-codon mutation (A1896) have been considered among the predisposing factors for reactivation during chemotherapy for malignancies. The role of the T1762/A1764 basic core promoter (BCP) mutations has not been fully evaluated. We aimed to record any changes in HBV serological markers after reactivation, detect the presence of A1896 and BCP mutations and evaluate the type of cytotoxic drugs involved. We retrospectively screened eight patients presenting with HBV reactivation following chemotherapy for malignancies. The chemotherapy regimens used included corticosteroids (CSs), fludarabine and cyclophosphamide/adriamycine. The INNO-LiPA HBV PreCore kit was used for the detection of the A1896 and BCP mutations. Six patients who were hepatitis B surface antigen (HBsAg)-(+)/hepatitis B e antigen (HBeAg)-(-) before chemotherapy, had disease reactivation following a mean of four cycles of chemotherapy. Four survived and two died of hepatic failure. At the time of reactivation, all six patients carried the A1896 and five of them the BCP mutations. The remaining two patients were HBsAg-(-)/anti-HBs-(+)/anti-hepatitis B core (HBc)-(+)/HBeAg-(-) before chemotherapy. One of them reverted to HBeAg-(+) status but remained HBsAg-(-), while the other became HBsAg-(+)/HBeAg-(+), following three and eight cycles of fludarabine treatment, respectively. The former carried the A1896 and the latter the wild-type virus. Both died from causes associated with their haematological disease. All but one of our patients with HBV reactivation during chemotherapy carried the precore stop-codon and BCP mutations. Whether this occurs more frequently in such patients than those carrying the wild-type virus needs further investigation. Fludarabine should be added to the list of drugs inducing HBV reactivation. HBV reactivation following fludarabine treatment occurred in HBsAg-(-) patients who had been anti-HBs-(+).     

High hepatitis B virus (HBV) DNA viral load is an important risk factor for HBV reactivation in breast cancer patients undergoing cytotoxic chemotherapy

Summary.  Hepatitis B virus (HBV) reactivation during cytotoxic chemotherapy for cancer may complicate treatment and cause liver damage. The complication has been reported to occur in 10% to over 50% of HBV carriers, but the factors that determine which patients will develop reactivation remain unclear. The objective of the study is to test the hypothesis that the prechemotherapy HBV DNA level is a risk factor for the development of HBV reactivation. We studied 41 women undergoing cytotoxic chemotherapy for breast cancer, 17 of whom developed reactivation and 24 who did not. We developed a novel, ultra-sensitive, real-time polymerase chain reaction assay for the measurement of HBV DNA. The sera of 37 patients (16 who developed reactivation and 21 who did not) were available for measurement of HBV DNA using this technique. The results showed that patients in the reactivation group had a significantly higher median HBV DNA load (1.03 × 10⁶ copies/mL; range <2.9 × 10³ to 8.723 × 10⁷) than did the nonreactivation group (<2.9 × 10³ copies/ml; range <2.9 × 10³ to 6.331 × 10⁷) ( P  < 0.001). The optimal cut-off between the two groups was found to be at serum HBV DNA level of 3 × 10⁵, which gave a sensitivity of 81.0% and a specificity of 85.0%. In conclusion, for breast cancer patients receiving standard cytotoxic chemotherapy, a high HBV viral load prior to the administration of cytotoxic chemotherapy is a significant predictive factor for the development of HBV reactivation. Such information may be useful in determining which patients would benefit most from prophylactic antiviral therapy during cytotoxic chemotherapy.     

Role of hepatitis B virus base core and precore/core promoter mutations on hepatocellular carcinoma in untreated older genotype C Chinese patients

The aim of the study was to investigate the prevalence of mutations of basal core promoter (BCP) and precore (PreC) region of hepatitis B virus (HBV) and their association with hepatocellular carcinoma. A total of 341 untreated older HBV patients were divided into three groups: chronic hepatitis B (CHB, 185), cirrhotic hepatocellular carcinoma (LC-HCC, 113) and non-cirrhotic hepatocellular carcinoma (non-LC-HCC, 43). HBV BCP and PreC mutations and genotypes were determined by direct sequencing. Using univariate analysis, age (≥ 45 years), single mutations including A1896 and A1899 and multiple mutations T1762/A1764 + A1896, T1762/A1764 + A1899 and T1762/A1764 + A1896 + A1899 were more frequently detected in LC-HCC and non-LC-HCC patients than in CHB patients. BCP T1762/A1764 mutations were highly detected in LC-HCC patients than in CHB patients. Multivariate logistic regression analysis (adjusted for age and gender) revealed that among HBeAg-positive patients, BCP T1762/A1764 mutations (OR, 5.975; P = 0.05), PreC A1899 mutation (OR, 4.180; P = 0.013) and multiple mutations T1762/A1764 + A1899 (OR, 6.408; P = 0.006) were independently associated with the development of LC-HCC; PreC A1899 mutation (OR, 7.347; P = 0.034) was also independently associated with the development of non-LC-HCC. On the other hand, among HBeAg-negative patients, PreC A1896 mutation (OR, 5.176; P = 0.002) and multiple mutations T1762/A1764 + A1896 (OR, 4.149; P = 0.007) were independently associated with the development of non-LC-HCC. These results indicated that older age (≥ 45 years) was associated with LC-HCC and non-LC-HCC development. BCP T1762/A1764 mutations and PreC A1899 mutation were associated with the LC-HCC development in HBeAg-positive patients. PreC A1896 mutation was associated with the non-LC-HCC development in HBeAg-negative patients.     

Performance of sequence analysis, INNO-LiPA line probe assays and AFFIGENE assays in the detection of hepatitis B virus polymerase and precore/core promoter mutations

In this study, we compare results obtained by sequences analysis and commercial kits in the detection of hepatitis B virus (HBV) polymerase and precore (PC) and core promoter mutations. A total of 23 serum samples from lamivudine treated patients were tested for polymerase mutations by direct sequencing, INNO-LiPA HBV DR and AFFIGENE HBV DE/3TC. Full concordance among the three assays was observed in 63% of the total analysed codons. Concordant results were obtained between sequencing and LiPA in 80%, between sequencing and AFFIGENE in 73% and between LiPA and AFFIGENE in 74% of all tested codons. All discrepancies were observed in mixed population samples in which AFFIGENE and LiPA detected additional viral variants not revealed by sequence. In two patients, with serial samples, LiPA detected earlier than sequence and AFFIGENE an emerging mutate strain. PC and core promoter viral variants were detected in 28 serum samples collected from 14 HBV inactive carriers and from 14 hepatitis B patients with chronic liver disease. Direct sequencing, INNO-LiPA HBV PreCore and AFFIGENE HBV MUTANT VL 19 showed fully coincident results in 88% of tested positions. These findings showed that all assays evaluated were sensitive and accurate tools to analyse HBV genomic variability. Sequence analysis is essential to study new emerging mutations as LiPA and AFFIGENE assays are more easily useful in clinical laboratories to detect the appearance of well-characterized HBV variants.     

Evolution of hepatitis B virus precore/basal core promoter gene in HBeAg‐positive chronic hepatitis B patients receiving lamivudine therapy

Aim: Lamivudine is effective in hepatitis B e antigen (HBeAg)‐positive chronic hepatitis B, but the relapse rate after cessation of treatment is high. The evolution of viral genome may contribute to the viral replication under antiviral pressure of lamivudine. We therefore determined the evolution of hepatitis B virus (HBV) precore/basal core promoter and polymerase genes in HBeAg‐positive chronic hepatitis B patient during lamivudine therapy. Method: Thirteen patients with HBeAg‐positive chronic hepatitis who had received short‐term lamivudine therapy (mean, 30 weeks) during 1999–2001 were enrolled. The precore/basal core promoter region and polymerase gene were amplified and directly sequenced before, during and post lamivudine treatment. Result: HBeAg loss or seroconversion occurred in 11, but eight relapsed after stopping therapy and five had reversion of HBeAg. Before treatment, basal core promoter mutation was found in 1. In the first 3 months of therapy, a rapid decline of serum HBV DNA level accompanied with basal core promoter mutation appeared in 11 of 13 patients (vs. before therapy; P=0.003). However, this mutant was replaced by wild‐type virus in four of eight patients who relapsed after treatment. There was no significant change of precore sequences before and during therapy. Conclusions: Lamivudine therapy may result in the rapid development of basal core promoter mutation of HBV, but this mutation may revert to wild type gradually after cessation of therapy.     

乙型重型肝炎患者血清HBV前C/BCP变异检测及临床意义

目的探索乙型重型肝炎患者HBV前C/BCP区变异与临床病情关系。方法用荧光定量PCR法检测血清HBVDNA载量;PCR扩增前C/BCP区基因后进行序列测定。结果30例乙型重型肝炎患者中BCP变异有18例,HB-VDNA平均水平为2.71×107copies/mL,未发生BCP变异者有12例,HBVDNA平均水平为5.35×106copies/mL,两者间有显著差异。测序结果显示HBV前C区nt1896G→A终止变异和BCP变异(nt1762A→T和1764G→A)在乙型重型肝炎患者中发生率分别为43.3%(13/30)和60%(18/30),在慢性乙型肝炎患者则分别为40%(12/30)和30%(9/30),两组BCP变异(nt1762A→T和1764G→A)相比有显著差异(P=0.02)。结论BCP变异可影响病毒复制,BCP变异可能与肝病的严重程度存在着相关性。     

High risk of hepatitis B‐virus reactivation after hematopoietic cell transplantation in hepatitis B core antibody‐positive patients

We investigated the serological changes in hepatitis B virus (HBV)‐related markers in 55 and 26 hepatitis B surface antigen (HBsAg)‐negative patients undergoing allogeneic and autologous stem cell transplantation, respectively, over the past 4 yr. Five of the 17 allogeneic and one of the five autologous patients with pretransplant anti‐hepatitis B core antigen antibodies (anti‐HBc) were HBsAg‐positive after transplantation, whereas none of the patients negative for anti‐HBc were HBsAg‐positive in both groups. All patients who became HBsAg‐positive received steroid‐containing immunosuppressive therapy for chronic graft versus host disease (GVHD) or myeloma. Four of the six patients developed flare of HBV hepatitis, and two patients did not. One patient developed fulminant hepatitis treated with lamivudine and plasma exchange. Other five patients received entecavir from the detection of HBsAg. Although HBV‐DNA levels became below the limit of detection in all patients, HBsAg positivity remained in three patients after 6 months of treatment. We concluded that anti‐HBc positivity is a risk factor for reactivation of HBV after both autologous and allogeneic transplantation, and HBV‐related markers should be monitored regularly in these patients. We also stress the efficacy of pre‐emptive use of antiviral agents in controlling HBV replication and limiting hepatic injury due to reactivation of HBV in these patients.     

Low frequency of mutations in the X gene, core promoter and precore region of hepatitis B virus infected Vietnamese

Numerous mutations in the hepatitis B virus (HBV) genome have been described, but in most cases their role in the pathogenesis of HBV infection is still unclear. Therefore, we analysed specific mutations in HBV-infected Vietnamese patients and assessed their potential relationship with their clinical outcome. A total of 153 HBV-infected Vietnamese patients with well-characterised clinical profiles were enrolled. None of the study participants had a history of alcohol or drug use and none received any antiviral or immunosuppressive therapy before or during the course of this study. The HBx- and core promoter regions were analysed by sequencing. The majority of isolates corresponded to genotype A. The presence of hepatitis B e antigen (HBeAg) was associated with significantly higher viral loads in the chronic HBV-infection group (P = 0.026). Double mutations in the core promoter (1762/1764) were more frequent in those with cancer than in noncancer patients (P < 0.01). Mutations at nucleotide (nt) 1766/1773 were found at low prevalence but with no obvious association to clinical presentation. Cytosine at nt 1858 was predominant but the stop codon mutation in the precore region was not detected. In the study, 4/48 hepatocellular carcinoma (HCC) patients revealed truncated HBx, whilst the serine to alanine mutation (codon 31) of HBx was more prevalent in cancer patients than in asymptomatic HBV carriers (P < 0.01). Thus, the low frequency of mutations indicates the relation of the absence of antiviral pressure in this population. The exclusively found prevalence of certain mutations detected in those with HBV-related carcinoma nevertheless indicates a degree of association with disease progression.     

Basal core promoter T1762/A1764 and precore A1896 gene mutations in hepatitis B surface antigen-positive hepatocellular carcinoma: a comparison with chronic carriers.

BACKGROUND: Chronic hepatitis B virus (HBV) infection is associated with hepatocellular carcinoma (HCC), and specific viral factors have been identified that may increase the risk for HCC development. However, the differences in these viral factors in chronic carriers who seldom develop HCC compared with HCC patients have not been adequately evaluated. METHODS: From 1989 to 2005, 101 hepatitis B surface antigen-positive patients presented to our clinic with HCC. Baseline basal core promoter (BCP) T1762/A1764 mutants, precore (PC) A1896 mutants, HBV genotypes and HBV DNA in HCC patients were compared with 67 chronic carriers who had been followed for a mean of 112.1+/-77.7 standard deviation months. RESULTS: At baseline, HCC patients had lower levels of serum albumin, but higher values of alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, bilirubin and alpha-foetoprotein than those of chronic carriers (P<0.001 for all comparisons). The presence of genotype C, higher frequencies of PC A1896 mutants, BCP T1762/A1764 mutants and higher circulating levels of HBV DNA were more frequently detected in HCC patients than that in chronic carriers (P<0.001 for all observations). Logistic regression analysis revealed that BCP T1762/A1764 mutants [odds ratio (OR) 11.14, 95% confidence interval (CI) 3.05-40.72; P<0.001] and PC A1896 mutants (OR 3.75, 95% CI 1.14-12.34; P<0.05) were significantly associated with HCC development. CONCLUSION: Our results indicate that the presence of BCP and PC mutations significantly increases the risk for HCC in chronic hepatitis B patients. These mutations were less often detected in chronic carriers who seldom develop HCC.     

Prevention of hepatitis B virus reactivation in patients receiving immunosuppressive therapy or chemotherapy

With the increasing use of potent immunosuppressive therapy, reactivation of hepatitis B virus (HBV) in endemic regions is becoming a clinical problem requiring special attention. A recent annual nationwide survey clarified that HBV reactivation related to immunosuppressive therapy has been increasing in patients with malignant lymphoma, other hematological malignancies, oncological or rheumatological disease. In the survey, rituximab plus steroid‐containing chemotherapy was identified as a risk factor for HBV reactivation in hepatitis B surface antigen (HBsAg) negative patients with malignant lymphoma. In this setting, HBV reactivation resulted in fatal fulminant hepatitis regardless of the treatment of nucleoside analog. The Intractable Hepatobiliary Disease Study Group and the Study Group for the Standardization of Treatment of Viral Hepatitis Including Cirrhosis jointly developed guidelines for preventing HBV reactivation. The essential features of the guideline are as follows. All patients should be screened for HBsAg by a sensitive method before the start of immunosuppressive therapy. Second, hepatitis B core antigen (HBcAb) and hepatitis B surface antibody (HBsAb) testing should be performed in HBsAg negative patients, especially those receiving intensive immunosuppressive therapy. Prophylaxis with nucleoside analogs is essential for preventing HBV reactivation in HBsAg positive patients. In contrast, HBsAg negative with HBcAb and/or HBsAb positive patients should be monitored monthly for an increase in serum HBV DNA during and 12 months after completion of chemotherapy. Nucleoside analogs should be administrated immediately when HBV DNA becomes positive during this period. This strategy facilitates commencement of nucleoside analogs at an early stage of HBV reactivation and results in prevention of severe hepatitis.     

Retrospective evaluation of the risk of hepatitis B virus reactivation after transplantation

Abstract: Numerous case reports describe patients with previously documented immunity developing active hepatitis B virus (HBV) infection after transplantation. However, the risk of reactivation of HBV under long‐term immunosuppression in hepatitis B core antibody (HBcAb)‐positive, hepatitis B surface antigen (HBsAg)‐negative transplant recipients has not been clearly described. Herein, we present a long‐term follow‐up for 49 HBcAb‐positive, HBsAg‐negative recipients (27 liver, 18 kidney, 4 pancreas) transplanted between June 1996 and April 2001. Among these, 37 recipients (76%) were HBsAb positive at transplantation. Immunosuppression consisted of various antibody induction regimens in 20 (41%) of the recipients with either tacrolimus (33 [67%])‐ or cyclosporine (16 [33%])‐based maintenance immunosuppression. The incidence and duration of HBV prophylaxis was not significant. No patient received hepatitis B immunoglobulin (HBIG) before or after transplantation. Additionally, only two patients received lamivudine, which was started post transplant without clinical indication. The mean length of follow‐up was 3.1±1.4 years. At the last follow‐up, overall patient and graft survival were 98% and 96%, respectively. Patient survival was 96% in liver, 100% in kidney, and 100% in pancreas transplant recipients. The graft survival for each organ type was 93% in liver, 100% in kidney, and 75% in pancreas transplant recipients at the end of follow‐up. There was no incidence of HBV reactivation defined as recurrence of HBsAg and/or HBV DNA positivity. These data suggest that the risk of reactivation of HBV in HBcAb‐positive, HBsAg‐negative transplant recipients under immunosuppression is negligible, regardless of immunosuppressive regimen, lamivudine prophylaxis, or HBsAb status. These patients should have access to transplantation as they enjoy excellent patient and graft survival rates.     

234例慢性乙型肝炎患者HBV前C/BCP区突变分析

目的调查慢性乙型肝炎患者血清HBV前C/基本核心启动子（BCP）区的突变情况,分析各种突变对HBeAg表达的影响。方法抽提患者血清DNA,采用改进的巢式PCR技术,扩增HBV前C/BCP区基因,对PCR产物进行DNA测序。用NTI软件比对结果,根据文献报道,选取1753、1762、1764、1862、1896和1899共6个位点进行突变分析,并重点分析不同突变对患者血清HBeAg阳性率和病情的影响。结果在234例中6个位点均无突变者为74例（31.6%）,其血清HBeAg阳性率为74.3%（55/74）。在234例中6个位点检出至少1种突变的病例为160例（68.4%）,突变形式包括4种单一位点突变和21种组合形式的突变;检出G1896A突变73例（31.2%）,其中36例检出有共存未突变序列,37例仅检出突变序列,后者血清HBeAg的阳性率为18.9%（7/37）。检出G1896A以外其他形式突变的有87例,HBeAg阳性率为63.2%（55/87）;其中以A1762T＋G1764A最为常见,HBeAg阳性率为69.4%（34/49）。在1753、1862位点上检出4种特殊碱基突变,前C区有基因片段插入或缺失的有2例。结论多数慢性乙型肝炎患者在HBV前C/BCP区可检出突变,突变形式多样,其中G1896A突变样本血清HBeAg阳性率显著下降,而其他突变对其影响较小。应用DNA序列测定法分析HBV前C/BCP区基因突变,获得的信息全面,对临床评估病情进展和实施抗病毒治疗有参考价值。     

Hepatitis B virus: prevalence of precore/core promoter mutants in different clinical categories of Indian patients

Summary. To determine the association of precore (Pre-C)/basal core promoter (BCP) mutants with clinical outcome of hepatitis B in Western India, 192 hepatitis B virus (HBV) infected individuals were investigated. HBV-DNA PCR positivity among asymptomatic hepatitis B surface antigen (HBsAg) positive carriers (61/100) was lower ( P  < 0.0001) than chronic hepatitis B (CHB), acute ( P  = 0.0001), and fulminant hepatitis B patients ( P  = 0.047). Pre-C status was based on restriction fragment length polymorphism (RFLP, n  = 153) and sequencing ( n  = 118). Prevalence of Pre-C mutants was higher among carriers (23/61) than CHB (10/62, P  = 0.0071) or acute (3/22; P  = 0.037) patients. Children from carrier and CHB categories showed significantly higher circulation of Pre-C-wild than mutant HBV. Clinical manifestations were independent of BCP mutations (1762/64-T/A). Hepatitis B e antigen (HBeAg) negative CHB patients [62.5% (15/24)] were circulating wild HBV. Higher HBV-DNA levels were associated with chronic hepatitis and HBeAg positivity, whilst Pre-C mutant positives had lower levels. BCP mutations did not affect HBV-DNA levels. Multivariate regression analysis identified HBeAg (OR = 4.3) and Pre-C mutants (OR = 3.1) to be associated with chronic hepatitis and carriers respectively. In a separate sub-set analysis ( n  = 59), HBV-DNA level was identified as the only variable. In conclusion, chronic or fulminant hepatitis B was not associated with Pre-C or BCP mutants and switching over to Pre-C mutant was beneficial for the infected individual in maintaining disease free status for extended periods.     

重型乙型肝炎病毒C基因启动子变异

目的了解我国重型肝炎Ｃ基因调节序列变异特点。方法克隆及聚合酶链反应（ＰＣＲ）产物直接测序方法对,检测７例重型乙型肝炎患者乙型肝炎病毒（ＨＢＶ）Ｃ基因调节序列变异。结果４例存在Ｔ１７６２Ａ１７６４变异;但在Ｔ１７６２Ａ１７６４以外位点也存有诸多变异,其中１例在ｎｔ１７７６－１７７７之间有１１ｂｐ的插入变异。结论重型肝炎ＨＢＶＣ基因启动子区存在较多的变异位点,推测这些变异对Ｃ启动子的调节活性影响可能是综合性的。     

Nucleotide sequence analysis of precore and proximal core regions in patients with chronic hepatitis B treated with interferon

The aim of the study was to estimate the prevalence of HBeAg defective mutants among patients with chronic hepatitis B (CHB) in the United States and to study the effect of interferon- (IFN-) on determining the occurrence of mutations in the HBV precore and proximal core regions. Twenty CHB patients who were treated with IFN- were studied. Initially, all were HBV DNA positive by dot-blot hybridization; 17/20 were HBeAg positive, and 3/20 were anti-HBe positive. The precore (87 nt) and proximal core (81 nt) regions were sequenced after PCR amplification by the dideoxy chain termination method. In pretreatment sera, 15/20 patients harbored wild-type HBV only, while in 5/20 at least one nucleotide substitution was found. Mutations that prevent HBeAg synthesis were found in three patients, all of whom had G-to-A substitution at nt 1896 and two of them were anti-HBe positive. Follow-up sera were available in 18 patients. With respect to pretreatment specimen, 15/18 patients had no changes in the sequenced regions after therapy. Sequence changes were observed in the remaining three patients: In one an HBeAg defective strain was replaced by a wild-type strain; in the second a wild-type strain was replaced by an HBeAg defective strain; and in the third two mutations changing the deduced amino acid sequence of the core protein developed in the wild-type strain. In conclusion, most of our patients (85%) were initially infected by HBV strains having no mutations that prevented HBeAg synthesis. IFN- therapy infrequently resulted in the appearance of mutations in the precore and proximal core regions.This study was supported by grant CR20 (to J.R.) from the Mayo Clinic and Foundation, and in part by Public Health Service grants AI32403, AR41497, and AI30548 from the National Institutes of Health (to D.H.P.).     

Sequential analysis of hepatitis B virus core promoter and precore regions in cancer survivor patients with chronic hepatitis B before,during and after interferon treatment

We analysed the hepatitis B virus (HBV) core-promoter (CP) and precore (PC) regions before, during and after interferon treatment in young Caucasian cancer survivors who had acquired HBV infection during chemotherapy for malignancies. Fourteen patients with chronic hepatitis B [hepatitis B e antigen (HBeAg) /HBV-DNA positive] received α-2a interferon (IFN), 5  M U/m² t.i.w. for 12 months. HBV CP and PC region sequences were analysed following polymerase chain reaction (PCR) amplification. Sera from responders were studied at: T₀ (before starting IFN), T₁ [at alanine aminotransferase (ALT) peak preceding HBeAg seroconversion], T₂ (at ALT normalization), T₃ (at end of IFN) and T₄ (at one year after IFN) and in nonresponders at time points T₀, T₃ and T₄. Amplified HBV-DNA was cloned and sequenced automatically. Six of 14 patients (43%) responded to IFN treatment. Five of the six (83%) responders displayed the double CP mutation A1762T/G1764A always in association with a T1753C change. None of the nonresponders showed these mutations at any time point. The G1896A change creating the PC stop codon mutation was never detected in any of the patients. In our cancer survivors, IFN-induced HBeAg/anti-HBe seroconversion appeared to correlate with CP mutations and was not influenced by previous chemotherapy. These mutations in addition to low HBV DNA levels and elevated ALT can be considered favourable factors of response to IFN-induced anti-HBe seroconversion.     

Delayed hepatitis B virus reactivation after cessation of preemptive lamivudine in lymphoma patients treated with rituximab plus CHOP

Preemptive lamivudine in lymphoma patients undergoing intensive chemotherapy can effectively prevent chemotherapy-related HBV reactivation. Nevertheless, the safety profile after withdrawal of lamivudine and the impact of rituximab-containing chemotherapy on HBV reactivation has not been defined. To illustrate the necessity of prolonged surveillance after cessation of preemptive lamivudine in lymphoma patients treated with rituximab and chemotherapy, four patients with B-cell NHL carrying HBV received rituximab plus CHOP. Preemptive lamivudine therapy was administered 1 week before chemotherapy until 4 weeks after completion of chemotherapy. Serial serum alanine aminotransferase (ALT), total bilirubin, and HBV-DNA levels were prospectively monitored in three patients. The fourth patient was closely monitored for ALT. The HBV DNA was checked after development of clinical overt hepatitis. The peripheral blood CD20⁺ B-lymphocyte counts were analyzed periodically in two patients. All of the three patients studied prospectively had virological relapses with surgence of HBV DNA 6–8 months after completion of rituximab-plus-CHOP (R+CHOP) therapy. Two of the three patients had biochemical relapses and one of them developed severe hepatitis. Sequencing for HBV polymerase gene in these patients failed to show evident emergence of lamivudine-resistant mutations. The fourth patient developed a hepatitis flare-up 6 months after completion of chemotherapy. The CD20⁺ lymphocytes were totally depleted when HBV DNA started to increase. Delayed HBV reactivation can occur in lymphoma patients receiving R+CHOP after withdrawal of preemptive lamivudine. More protracted lamivudine therapy may be an alternative to close monitoring following chemotherapy, and further studies are needed to define optimal duration of lamivudine therapy.