Frequent incidence of escape mutants after successful hepatitis B vaccine response and stopping of nucleos(t)ide analogues in liver transplant recipients

Exchanges in the 'a' determinant of the hepatitis B virus surface antigen revisited

The hepatitis B virus surface antigen's (HBsAg) 'a' determinant comprises a sequence of amino acid residues located in the major hydrophilic region of the S protein, whose exchanges are closely associated with compromising the antigenicity and immunogenicity of that antigen. The HBsAg is generally present in the bloodstream of individuals with acute or chronic hepatitis B virus (HBV) infection. It is classically known as the HBV infection marker, and is therefore the first marker to be investigated in the laboratory in the clinical hypothesis of infection by this agent. One of the factors that compromises the HBsAg detection in the bloodstream by the assays adopted in serological screening in both clinical contexts is the loss of S protein antigenicity. This can occur due to mutations that emerge in the HBV genome regions that encode the S protein, especially for its immunodominant region - the 'a' determinant. These mutations can induce exchanges of amino acid residues in the S protein's primary structure, altering its tertiary structure and the antigenic conformation, which may not be recognized by anti-HBs antibodies, compromising the infection diagnosis. In addition, these exchanges can render ineffective the anti-HBs antibodies action acquired by vaccination, compromise the effectiveness of the chronically HBV infected patient's treatment, and also the HBsAg immunogenicity, by promoting its retention within the cell. In this review, the residues exchange that alter the S protein's structure is revisited, as well as the mechanisms that lead to the HBsAg antigenicity loss, and the clinical, laboratory and epidemiological consequences of this phenomenon.

Antiviral prophylaxis against hepatitis B recurrence after liver transplantation: Current concepts

The advance in treatment against hepatitis B virus (HBV) infection with the development of nucleos(t)ide analogues (NAs) with high genetic barrier to resistance, including entecavir and tenofovir, has improved clinical outcomes of patients transplanted for HBV infection, by preventing HBV recurrence after liver transplantation (LT) effectively. Currently, after LT, the combination of hepatitis B immunoglobulin (HBIG) and a high-barrier NA is considered as the standard of care for prophylaxis against HBV recurrence. However, because of the high cost of intravenous high-dose HBIG, other routes of HBIG administration, such as intramuscular or subcutaneous, have come to the foreground. In addition, several transplant centres tend to use a NA as monoprophylaxis, following a short post-LT period of HBIG and NA combination. Lately, studies using HBIG-free prophylactic regimens with entecavir or tenofovir have shown promising outcomes in preventing HBV recurrence, mostly regarding patients with undetectable HBV DNA at the time of LT. Although vaccination against HBV has been an attractive prophylactic approach, its efficacy has been controversial. Moreover, further studies are needed regarding long-term outcomes of complete withdrawal anti-HBV prophylaxis. For patients transplanted for HBV/HDV co-infection, combined regimen should be administered for a longer period post-LT. Finally, the use of grafts from hepatitis B core antibody-positive donors is safe for HBV-negative recipients, with the administration of lifelong antiviral prophylaxis.

Prevention of HBV Recurrence after Liver Transplant: A Review

Globally, hepatitis B virus (HBV) infection is recognized as a major risk factor for the development of hepatocellular carcinoma, and HBV-induced liver failure is one of the leading indications for liver transplantation. Until about two decades ago, liver transplantation in patients with chronic HBV infection was a relative contraindication, due to high risk of viral replication with the use of immunosuppressants which could result in graft infection. In the 1990s, hepatitis B immunoglobulin (HBIg) use significantly reduced the risk of graft infection, improving outcomes of liver transplant in patients with chronic HBV infection. However, very high costs, especially with the need for long-term use, became a major concern. With the advent of nucleos(t)ide analogs (NAs), there was less need for high-dose, long-term HBIg use to prevent HBV recurrence. Lamivudine was initially used but resistance soon became a major issue. This was followed by more potent NAs, such as entecavir and tenofovir, emerging as the more preferred agents. Additionally, the use of these antiviral agents (HBIg and/or NAs) have made it possible to use the grafts from donors with positivity for hepatitis B core antibody, allowing for expansion of the donor pool. Nevertheless, there is no consensus on management protocols, which vary significantly amongst centers. In this review, we appraise studies on management strategies used and the role of active vaccination in the prevention of HBV recurrence in post-liver transplant patients.

Prophylaxis and treatment in liver transplantation. VII Consensus Document of the Spanish Society of Liver Transplantation

Whilst prophylaxis of hepatitis B is universally accepted after liver transplantation (LT), national recommendations for the prophylaxis and treatment of hepatitis B virus (HBV) infection after LT are lacking in Spain. The aim of the VII consensus meeting organised by the Spanish Society of Liver Transplantation (SETH) was to set recommendations on the prophylaxis and treatment of hepatitis B after LT. The scientific evidence and strength of recommendations was evaluated by using the "Grading of Recommendations Assessment, Development and Evaluation" (GRADE) system. This document describes the recommendations and their level of evidence for: the definition and risk factors for hepatitis B recurrence after LT, monitoring and prophylaxis of hepatitis B recurrence at different periods after LT, treatment of hepatitis B before and after LT, and the prophylaxis of HBV infection by the recipients of LT with hepatitis B core antigen positive donors.

Hepatitis B virus recurrence after living donor liver transplantation of anti-HBc-positive grafts: A 22-year experience at a single center

The use of hepatitis B core antibody (anti-HBc)-positive grafts is one strategy for expanding the donor pool for liver transplantation (LT). The aim of this study was to determine the risk factors associated with hepatitis B virus (HBV) recurrence after living donor LT (LDLT) of anti-HBc-positive grafts. From January 1996 to December 2018, a total of 609 LDLT procedures were performed at our center. A retrospective review was performed for 31 patients (23 males and 8 females; median age = 47 years) who underwent LDLT for HBV-unrelated liver disease from anti-HBc-positive donors. The factors associated with HBV recurrence were evaluated and compared between the HBV recurrence and non-recurrence groups. The median follow-up period after LT was 135 months (range, 6-273 months). Four of 31 patients (12.9%) developed post-LT HBV recurrence. All four cases were HBV-naïve patients (anti-HBc-negative and Hepatitis B surface antibody-negative). The median interval between LDLT and HBV recurrence was 42 months (range, 20-51). The overall actuarial rates of HBV recurrence at 1, 3, 5, 10, and 20 years were 0%, 7.2%, 15.7%, 15.7%, and 15.7%, respectively. Although there were no significant differences between the HBV recurrence and non-recurrence groups, HBV recurrence tended to occur in HBV-naïve recipients (P = 0.093). HBV-naïve status may contribute to HBV recurrence after LDLT for HBV-unrelated liver disease from anti-HBc-positive donors. Careful monitoring for serological HBV markers is needed, particularly in this group.

Long-term consequences of stopping HBIG and/or nucleotide analogues in liver transplant recipients administered hepatitis B vaccination to prevent HBV reinfection

BACKGROUND

The long-term administration of nucleotide analogues (NAs) and hepatitis B immune globulin (HBIG) comprises standard prophylaxis for patients with hepatitis B virus (HBV)-related liver diseases to prevent HBV reinfection after liver transplantation (LT). However, prolonging the prophylaxis strategy involves safety issues, such as the development of escape mutations and/or emerging resistant strains, and is also associated with high costs; further, it remains unclear how long prophylactic treatment should be continued.

METHOD

Liver transplantation recipients responding to hepatitis B vaccination due to HBV-related liver diseases were retrospectively analysed after stopping HBIG and/or NAs, administered to prevent HBV reinfection, after long-term follow-up. The safety and effectiveness of the strategy were then evaluated for these responders.

RESULT

Seventy-eight responders were enrolled. All responders discontinued HBIG, among which 36 stopped both HBIG and NAs. During follow-up, four recipients experienced HBV reinfection, which was associated with HBV escape mutations, after the withdrawal of both HBIG and NAs. No death or graft loss occurred in recipients during the follow-up period.

CONCLUSION

A careful withdrawal of HBIG and/or NAs is feasible and safe for responders to hepatitis B vaccination receiving transplants for HBV-related liver diseases.

Hepatitis B Vaccination in Patients Receiving Oral Antiviral Therapy Without Hepatitis B Immunoglobulin After Liver Transplant

Our study aimed to determine if a double-dose pre-S containing hepatitis B virus (HBV) vaccination (Sci-B-Vac) could elicit an adequate and sustainable immune response in HBV patients who developed spontaneous hepatitis B surface antibody (anti-HBs) response after liver transplant.

PATIENTS AND METHODS

All patients who received transplants for HBV-related disease for >1 year with normal graft function and hepatitis B surface antigen seronegativity were evaluated. They received a 40-μg HBV vaccine if they were responders in our previous vaccine trial, if anti-HBs was positive for >1 year after liver transplant (LT), or if a peak anti-HBs at any time point after LT was >100 mIU/mL. Primary endpoint was the development of anti-HBs ≥ 10 mIU/mL from previous negative value or a 1-log increase from baseline.

RESULTS

A total of 86 patients were recruited; 5 were responders from a previous trial; 45 patients had detectable anti-HBs >1 year after LT, and 36 patients had an anti-HBs >100 mIU/mL. All (5/5, 100%) previous responders responded to booster vaccination. For the remaining 81 patients, 10 of 81 (12.3%) responded.

CONCLUSION

All previous responders responded to booster vaccination, implying durability and memory of HBV immune response, which is an important prerequisite for definitive host immunity for HBV. In patients who had spontaneous anti-HBs production after LT, a single vaccination can induce response in 12.3% of patients.

Recurrent Hepatitis B and D Virus Infection in a Liver Transplant Recipient

Hepatitis B virus (HBV) and hepatitis delta virus (HDV) co-infections progress rapidly and lead to cirrhosis. In Japan, the prevalence of HBV and HDV co-infected patients is low. Therefore, there are few reports of patients with HBV and HDV co-infection having undergone liver transplantation. Herein, we report a rare case of recurrence of HBV and HDV in a 41-year-old man who underwent living donor liver transplantation 4 years prior.

Discontinuation of Hepatitis B Immunoglobulin by Long-term Hepatitis B Vaccine Inoculation in Preventing Hepatitis B Recurrence After Liver Transplantation

INTRODUCTION

For the patients undergoing liver transplantation for hepatitis B virus (HBV)-related diseases, hepatitis B immunoglobulin (HBIG) should be administered to prevent reinfection. Because HBIG is highly expensive and a blood product, an alternative strategy using HBV vaccination has been made in an attempt to discontinue use of HBIG. The aim of this study was to evaluate the impact of long-term HBV vaccination for discontinuation of HBIG, paying attention to the status of active immunization using T-cell proliferation assay.

PATIENTS AND METHODS

Among the 144 recipients who underwent liver transplantation in our hospital, 16 had HBV-related liver diseases; the 14 patients who had received vaccination were subjects in our study. To evaluate the status of active immunization, T-cell proliferation was examined by counting the number of T cells after adding HBV vaccine to the culture supernatant of T cells, and tumor necrosis factor α and interferon γ were measured in the culture supernatant.

RESULTS

The ratio of male/female was 13/1 (median age: 55 years; range: 37 years to 67 years). The median follow-up time was 102 months (range: approximately 14 months to 148 months). All 14 patients were free of HBV recurrence. HBIG-free status could be achieved in 9 patients (64.3%) during the treatment period for more than 50 months after beginning of HBV vaccination, of whom 5 (35.7%) became HBV vaccine-free. T-cell proliferation was confirmed by fact that the stimulation index ranged from 2.34 to 5.2 in the patients who were HBIG-free.

CONCLUSION

Long-term HBV vaccination after LT is a useful and effective treatment in preventing HBV recurrence, allowing the discontinuation of HBIG treatment.

Impacts of the G145R Mutation on the Structure and Immunogenic Activity of the Hepatitis B Surface Antigen: A Computational Analysis

BACKGROUND

Vaccine-escaped hepatitis B virus (HBV) mutations occur within the "a" determinant area, which is located in the major hydrophilic region (MHR) of the hepatitis B surface antigen (HBsAg) protein. It is now well established that the common G145R mutation is highly capable of escaping from HBsAg immune recognition. However, the impacts of this mutation on the structure and immunogenic activity of HBsAg have been poorly investigated.

OBJECTIVES

The present study analyzed the effects of the G145R mutation on the structure and immunogenic activity of the HBsAg.

MATERIALS AND METHODS

Three-dimensional (3D) structure of HBsAg for both the wild-type and G145R mutant were predicted and refined using several web tools. After quantitative evaluations, the effects of the G145R mutation on the secondary and 3D structures of the HBsAg were investigated. In parallel, the immunogenic activity of the wild-type and mutant HBsAg was also analyzed using a ClusPro docking server as well as the IEDB web tool. Further analyses were performed via molecular dynamics (MD) simulations using the GROMACS v5.0.2 simulation package.

RESULTS

The G145R mutation causes a considerable reduction in the immunogenic activity of the HBsAg through a conformational change in the HBsAg antigenic loops. This mutation inserts a new β-strand in the "a" determinant region of the HBsAg, leading to a reduced binding affinity to its monoclonal antibody, MAb12. The G145R mutation also increased the compactness and stability of the HBsAg by enhancing the rigidity of the "a" determinant.

CONCLUSIONS

These data will be beneficial for designing more advanced antibodies for the recognition of the HBsAg in diagnostics. In addition, the results of this study may assist in the design or development of more effective hepatitis B vaccines.

HBV genotypes and drug resistance mutations in antiretroviral treatment-naive and treatment-experienced HBV-HIV-coinfected patients

BACKGROUND

The presence of HBV resistance mutations upon initiation or during antiretroviral therapy (ART) in HIV-coinfected patients is an important determinant of treatment response. The main objective of the study was to determine the prevalence of HBV resistance mutations in antiretroviral treatment-naive and treatment-experienced HBV-HIV-coinfected Ghanaian patients with detectable HBV viraemia.

METHODS

HBV-HIV-coinfected patients who were ART-naive or had received at least 9 months of lamivudine (3TC)-containing ART were enrolled in a cross-sectional study. Demographic and clinical data were collected and HBV DNA quantified. Partial HBV sequences were amplified by PCR and sequenced bi-directionally to obtain a 2.1-2.2 kb fragment for phylogenetic analysis of HBV genotypes and evaluation of drug resistance mutations.

RESULTS

Of the 100 HBV-HIV-coinfected study patients, 75 were successfully PCR-amplified, and 63 were successfully sequenced. Of these 63 patients, 27 (42.9%) were ART-experienced and 58 (92.1%) had HBV genotype E. No resistance mutations were observed in the 36 ART-naive patients, while 21 (77.8%) of 27 treatment-experienced patients had resistance mutations. All patients with resistance mutations had no tenofovir in their regimens, and 80% of them had HIV RNA <40 copies/ml. The 3TC resistance mutations rtL180M and rtM204V were observed in 10 (47.6%) of the 21 patients, while 5 patients (23.8%) had rtV173L, rtL180M and rtM204V mutations.

CONCLUSIONS

A high proportion of HBV-HIV-coinfected patients with detectable viraemia on 3TC-containing ART had resistance mutations despite good ART adherence as determined by HIV RNA suppression. This study emphasizes the need for dual therapy as part of a fully suppressive ART in all HBV-HIV-coinfected patients in Ghana.

Long-term efficacy of hepatitis B vaccination as post-transplant prophylaxis in hepatitis B surface antigen (HBsAg) positive recipients and HBsAg negative recipients of anti-hepatitis B core positive grafts

AIM

Hepatitis B virus (HBV) reactivation after liver transplantation in HBV patients, or in HBV negative recipients of anti-hepatitis B core (HBc) positive grafts, has been prevented by prophylactic use of hepatitis B immunoglobulin (HBIG) and/or nucleoside/nucleotide analogs (NA). Vaccination against HBV is an alternative that may provide a chance to discontinue prophylaxis by producing anti-hepatitis B surface (HBs) antibodies.

METHODS

We retrospectively reviewed 40 HBV positive recipients (HBV+ group) and 27 HBV negative recipients of anti-HBc positive grafts (HBV-/anti-HBc+ graft group), who were administrated double-dose hepatitis B vaccination. Recipients were regarded as responders when anti-HBs greater than 100 IU/L was maintained for 6 months or more without HBIG. Response rates of vaccine and long-term outcomes were analyzed.

RESULTS

Eighteen of the 40 patients in the HBV+ group (45%) and 18 of the 27 patients in the HBV-/anti-HBc+ graft group (67%) responded to vaccination after a median of four and three times, respectively. Younger age was the only independent factor associated with vaccine response in the HBV-/anti-HBc+ graft group (P = 0.03), whereas no factor was found to be an independent predictor for vaccine response in the HBV+ group. Among the 18 responders in the HBV+ group, 17 remained without NA or HBIG 8.2 years after the start of vaccination. Ten of those required periodic booster vaccination. All 18 responders in the HBV-/anti-HBc+ graft group remained free from HBV prophylaxis 6.2 years after the start of vaccination.

CONCLUSION

Younger recipients have a greater chance to develop sufficient anti-HBs after double-dose HBV vaccination, leading to discontinue HBV prophylaxis.

Functional analysis of 'a' determinant mutations associated with occult HBV in HIV-positive South Africans

Occult hepatitis B is defined by the presence of hepatitis B virus (HBV) DNA in the absence of hepatitis B surface antigen (HBsAg). Occult HBV is associated with the development of hepatocellular carcinoma, reactivation during immune suppression, and virus transmission. Viral mutations contribute significantly to the occult HBV phenotype. Mutations in the 'a' determinant of HBsAg are of particular interest, as these mutations are associated with immune escape, vaccine escape and diagnostic failure. We examined the effects of selected occult HBV-associated mutations identified in a population of HIV-positive South Africans on HBsAg production in vitro. Mutations were inserted into two different chronic HBV backbones and transfected into a hepatocyte-derived cell line. HBsAg levels were quantified by enzyme-linked immunosorbent assay (ELISA), while the detectability of mutant HBsAg was determined using an HA-tagged HBsAg expression system. Of the seven mutations analysed, four (S132P, C138Y, N146D and C147Y) resulted in decreased HBsAg expression in one viral background but not in the second viral background. One mutation (N146D) led to a decrease in HBsAg detected as compared to HA-tag, indicating that this mutation compromises the ability of the ELISA to detect HBsAg. The contribution of occult-associated mutations to the HBsAg-negative phenotype of occult HBV cannot be determined adequately by testing the effect of the mutation in a single viral background, and rigorous analysis of these mutations is required.

One-year extended, monthly vaccination prophylaxis combined with hepatitis B immune globulin for hepatitis B after liver transplantation

AIM

The feasibility of vaccination in liver transplant recipients is highly controversial, and the present study aimed to investigate the efficacy of a 1-year extended, monthly vaccine prophylaxis protocol of a second-generation recombinant vaccine for transplant recipients.

METHODS

The recombinant hepatitis B vaccine (10 µg) was administrated s.c. every month for 12 months as the vaccination protocol to 39 liver transplant recipients in stable condition, including those with hepatitis B-related chronic liver disease (n = 30), those with acute hepatitis B liver failure (hepatitis B surface antibody [HBsAb], n = 4), and those with hepatitis B core antibody positive grafts (n = 5). A fixed dose of hepatitis B immune globulin (HBIG) was administrated during the study based on the monoprophylaxis approach, and the increase in the hepatitis B surface antibody titer was measured to evaluate the efficacy of the vaccination.

RESULTS

The vaccination protocol was initiated a mean of 54 months (range, 13-124) after liver transplantation, and all patients tolerated the vaccination well without adverse effects. The overall hepatitis B virus (HBV) recurrence rate was 5% (2/39) based on hepatitis B surface antigen positivity, and 2% (1/39) based on HBV DNA detectability. Six (15%) patients showed a good response to vaccination with an increase in the HBsAb titer greater than 100 IU/L at the end of vaccination, but only three (8%) maintained an adequate HBsAb level to spare HBIG during the 2-year observation period.

CONCLUSION

While a few patients demonstrated an adequate response to vaccination, the clinical indication for the HBV vaccination for liver transplant recipients is currently minimal.

Change of strategies and future perspectives against hepatitis B virus recurrence after liver transplantation

A few decades ago, liver transplantation in patients with chronic hepatitis B virus (HBV) infection was considered a relative contraindication because of the high rate of graft infections and poor prognosis. Since then, remarkable progress was introduced by using nucleos(t)ide analogues and/or hepatitis B immunoglobulin (HBIg) and liver transplantation for HBV-related disease is now becoming one of the good indication. However, high cost burden is the main problem for this combination prophylaxis for a long time use, and this issue should be emerged to be resolved. In this review, we show the progress of post anti-HBV strategies showing the history from introduction of HBIg and nucleos(t)ide analogues to recent new strategies with hepatitis B vaccine or saving or stopping protocols of HBIg, and clarify and discuss how to do for further improvement of prevention strategies with better quality.

Characterization of Acute and Chronic Hepatitis B Virus Genotypes in Canada

Objective

The prevalence and distribution of hepatitis B virus (HBV) genotypes in Canada is not known. Genotypic analysis may contribute to a better understanding of HBV strain distribution and transmission risk.

Methods

HBV surface antigen (HBsAg) positive samples of acute (n = 152) and chronic (n = 1533) HBV submitted for strain analysis or reference genotype testing between 2006 and 2012 were analyzed. The HBsAg coding region was amplified to determine the HBV genotype by INNO-LiPA assay or sequence analysis. Single and multivariate analyses were used to describe genotypes’ associations with known demographic and behavioral risk factors for 126 linked cases of acute HBV.

Results

Nine genotypes were detected (A to I), including mixed infections. Genotype C (HBV/C) dominated within chronic infections while HBV/D and A prevailed among acute HBV cases. History of incarceration and residing with a chronic HBV carrier or injection drug user were the most frequently reported risks for acute HBV infection. Over time, HBV/A increased among both acute and chronic infections, and HBV/C and HBV/D decreased among chronic infections.

Conclusion

Chronic and acute HBV genotypes in Canada differ in the relative distribution and their associations with known risk factors, suggesting different routes of transmission and clinical progression of infection.

Molecular Mechanisms to Control Post-Transplantation Hepatitis B Recurrence

Hepatitis B often progresses to decompensated liver cirrhosis requiring orthotopic liver transplantation (OLT). Although newer nucleos(t)ide analogues result in >90% viral and hepatitis activity control, severely decompensated patients still need OLT because of drug-resistant virus, acute exacerbation, or hepatocellular carcinoma. Acute hepatitis B is also an indication for OLT, because it can progress to fatal acute liver failure. After OLT, the hepatitis B recurrence rate is >80% without prevention, while >90% of transplant recipients are clinically controlled with combined hepatitis B immunoglobulin (HBIG) and nucleos(t)ide analogue treatment. However, long-term HBIG administration is associated with several unresolved issues, including limited availability and extremely high cost; therefore, several treatment protocols with low-dose HBIG, combined with nucleos(t)ide analogues, have been investigated. Another approach is to induce self-producing anti-hepatitis B virus (HBV) antibodies using an HBV envelope (HBs) antigen vaccine. Patients who are not HBV carriers, such as those with acutely infected liver failure, are good candidates for vaccination. For chronic HBV carrier liver cirrhosis patients, a successful vaccine response can only be achieved in selected patients, such as those treated with experimentally reduced immunosuppression protocols. The present protocol for post-OLT HBV control and the future prospects of newer treatment strategies are reviewed.

A Human Monoclonal Antibody against Hepatitis B Surface Antigen with Potent Neutralizing Activity

We describe the production and characterization of human monoclonal antibodies (mAb) specific for the major hepatitis B virus (HBV) S protein. The mAbs, two IgG1κ and one IgG1λ, were secreted by B-cell clones obtained from peripheral blood mononuclear cells (PBMC) of one person convalescent from acute hepatitis B and one vaccinated individual. The former recognized a denaturation-insensitive epitope within the p24 protein whereas the latter recognized a denaturation-sensitive, conformational epitope located within the HBsAg common "a" determinant. This mAb, denominated ADRI-2F3, displayed a very high protective titer of over 43,000 IU/mg mAb and showed an extremely potent neutralizing activity in the in vitro model of HBV infection using primary hepatocytes from Tupaia belangeri as target. Recombinant variable heavy and light domain sequences derived from mAb ADRI-2F3 were cloned into eukaryotic expression vectors and showed identical fine specificity and 1 log10 higher titer than the original IgG1λ. It is envisaged that such mAb will be able to efficiently prevent HBV reinfection after liver transplantation for end-stage chronic HBV infection or infection after needle-stick exposure, providing an unlimited source of valuable protective anti-HBs antibody.

Reactivation of resolved infection with the hepatitis B virus immune escape mutant G145R during dasatinib treatment for chronic myeloid leukemia

Reactivation of hepatitis B virus (HBV) following immunosuppressive therapy or hematopoietic stem cell transplantation is a potentially fatal complication that may occur even in patients with prior resolution of HBV infection. Dasatinib is a small-molecule inhibitor of the tyrosine kinases SRC and ABL that has been approved for the treatment of chronic myeloid leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia. Here, we report the first case of reactivation of resolved infection with the HBV immune escape mutant G145R in a CML patient receiving dasatinib. Although dasatinib is not recognized as an immunosuppressant, our observations suggest that dasatinib may enhance HBV replication and induce its reactivation in immunocompetent patients, that HBV escape mutants may contribute to the pathogenesis of HBV reactivation, and that close monitoring of HBV status is advisable in patients with current or resolved HBV infection.