Hepatitis B virus reactivation following allogeneic hematopoietic stem cell transplantation

Outcomes of Cessation of Nucleos(t)ide Analog Administration on Hepatitis B Virus Reactivation after Allogeneic Hematopoietic Stem Cell Transplantation: A Nationwide Retrospective Study

Monitoring of hepatitis B virus (HBV)-DNA and HBV-DNA-guided preemptive therapy using nucleos(t)ide analogs (NAs) are recommended to prevent the development of hepatitis due to HBV reactivation after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in recipients with resolved HBV infection. However, little is known about the appropriate duration of NA treatment and the effect of NA cessation on the recurrence of HBV reactivation. This study aimed to clarify the consequences of NA cessation in allo-HSCT recipients with resolved HBV infection who experienced HBV reactivation following transplantation. We retrospectively reviewed the clinical records of recipients with resolved HBV infection (hepatitis B surface antigen [HBsAg]-negative, anti-HBc-positive) before allo-HSCT who had been diagnosed with HBV reactivation (HBsAg-positive and/or HBV-DNA detectable) after allo-HSCT between January 2010 and December 2020. A total of 72 patients from 16 institutions were registered (median age, 60 years; age range, 27 to 73 years; 42 males and 30 females). The day of initial HBV reactivation ranged from day 10 to day 3034 after allo-HSCT (median, 513 days). Anti-HBs were lost in >80% of the patients at the time of HBV reactivation. All 72 patients received preemptive NAs, and no fatal HBV reactivation-related hepatitis was observed. HBV-DNA without hepatitis was continuously detected in 5 patients during the follow-up period. Administration of NAs was discontinued in 24 of 72 patients (33%) by physician decision. Second HBV reactivation occurred in 11 of the 24 patients (46%) in whom administration of NAs was discontinued. The duration of NA treatment did not differ significantly between patients with or without second HBV reactivation. The frequency of further HBV reactivation tended to be lower in patients with an anti-HBs titer of >10 mIU/mL at the time of NA cessation. Multiple reactivations of HBV after NA cessation was common in patients with HBV reactivation who underwent allo-HSCT despite the long duration of NAs. Careful monitoring of HBV-DNA is important even after the discontinuation of NAs in the case with HBV reactivation after allo-HSCT, because multiple reactivations could occur. Active immunization by HB vaccine might be effective for suppressing further HBV reactivation after cessation of NAs.

Epstein-Barr virus reactivation correlates with worse outcomes for patients exposed to hepatitis B virus after haploidentical hematopoietic stem cell transplantation

Hepatitis B virus (HBV)has a high, chronic infection rate in Asian populations, but only few studies have analyzed the effect of Epstein-Barr virus (EBV) or Cytomegalovirus (CMV) reactivation in patients exposed to HBV after haploidentical hematopoietic stem cell transplantation (haplo-HSCT). This study aimed to assess the clinical outcomes of these patients. We conducted a retrospective research including 61 patients exposed to HBV after undergoing haplo-HSCT. The patients were classified into two groups: the CMV reactivation group and no CMV reactivation group. The results were compared between the two groups using the K-W test for continuous variables, Pearson's chi-square test for categorical variables, Kaplan-Meier curves to estimate overall survival (OS) and leukemia-free survival (LFS), and a Cox proportional hazards model to analyze multivariable influences. The 3-year cumulative HBV reactivation rate was 8.2%. The median duration of HBV reactivation was 16 months (16-22 months) after haplo-HSCT. The CMV reactivation group had a higher cumulative incidence of HBV reactivation than the group without CMV reactivation. The EBV reactivation was substantially higher in the CMV reactivation group compared to that in the no CMV reactivation group (37.0% vs.5.9% respectively; P = 0.002). Furthermore, EBV reactivation was a risk factor for 1-year LFS and 1-year OS. Based on our data, EBV reactivation was related to worse outcomes in patients exposed to HBV after haplo-HSCT, whereas CMV reactivation was not.

Hepatitis B Virus Reactivation in Kidney Transplant Recipients Treated With Belatacept

Introduction

Hepatitis B virus (HBV) reactivation in kidney transplant recipients has been reported in 3% to 9% of anti-HBc antibody (HBcAb)-positive HBs antigen (HBsAg)-negative patients. It has not been studied in patients receiving belatacept, a selective costimulation blocker.

Methods

We performed a retrospective study of all transplant recipients receiving belatacept in 2 kidney transplantation centers in France. Among HBcAb-positive patients, we analyzed HBV reactivation rate, outcomes, and risk factors.

Results

A total of 135 patients treated with belatacept were included: 32 were HBcAb-positive and 2 were HBsAg-positive. Seven patients reactivated HBV (21.9% of HBcAb-positive patients), including 5 HBsAg-negative patients (16.7% of HBcAb-positive HBsAg-negative patients). Reactivation occurred 54.8 (± 70.9) months after transplantation. One patient presented with severe hepatitis and 1 patient developed cirrhosis. There was no significant difference in survival between patients that reactivated HBV and patients that did not: 5-year patient survival of 100% (28.6; 100) and 83.4% (67.6; 100), respectively (P = 0.363); and 5-year graft survival of 100% (28.6; 100) and 79.8% (61.7; 100), respectively (P = 0.335). No factor, including HBsAb positivity and antiviral prophylaxis, was statistically associated with the risk of HBV reactivation.

Conclusion

HBV reactivation rate was high in patients treated with belatacept when compared with previous transplantation studies. HBV reactivation did not impact survival. Further studies are needed to confirm these results. A systematic antiviral prophylaxis for these patients should be considered and evaluated.

Lamivudine 24-month-long prophylaxis is a safe and efficient choice for the prevention of hepatitis B virus reactivation in HBsAg-negative/HBcAb-positive patients with advanced DLBCL undergoing upfront R-CHOP-21

Introduction

Occult hepatitis B infection (OBI) is a condition where replication-competent hepatitis B virus-DNA (HBV-DNA) is present in the liver, with or without HBV-DNA in the blood [<200 international units (IU)/ml or absent] in HB surface antigen (HBsAg)-negative/HB core antibody (HBcAb)-positive individuals. In patients with advanced stage diffuse large B-cell lymphoma (DLBCL) undergoing 6 cycles of R-CHOP-21+2 additional R, OBI reactivation is a frequent and severe complication. There is no consensus among recent guidelines on whether a pre-emptive approach or primary antiviral prophylaxis is the best solution in this setting of patients. In addition, questions still unresolved are the type of prophylactic drug against HBV and adequate prophylaxis duration.

Methods

In this case-cohort study, we compared a prospective series of 31 HBsAg-/HBcAb+ patients with newly diagnosed high-risk DLBCL receiving lamivudine (LAM) prophylaxis 1 week before R-CHOP-21+2R until 18 months after (24-month LAM series) versus 96 HBsAg-/HBcAb+ patients (from January 2005 to December 2011) undergoing a pre-emptive approach (pre-emptive cohort) and versus 60 HBsAg-/HBcAb+ patients, from January 2012 to December 2017, receiving LAM prophylaxis [1 week before immunochemotherapy (ICHT) start until 6 months after] (12-month LAM cohort). Efficacy analysis focused primarily on ICHT disruption and secondarily on OBI reactivation and/or acute hepatitis.

Results

In the 24-month LAM series and in the 12-month LAM cohort, there were no episodes of ICHT disruption versus 7% in the pre-emptive cohort (P = 0.05). OBI reactivation did not occur in any of the 31 patients in the 24-month LAM series versus 7 out of 60 patients (10%) in the 12-month LAM cohort or 12 out of 96 (12%) patients in the pre-emptive cohort (P = 0.04, by χ ² test). No patients in the 24-month LAM series developed acute hepatitis compared with three in the 12-month LAM cohort and six in the pre-emptive cohort.

Discussion

This is the first study collecting data regarding a consistent and homogeneous large sample of 187 HBsAg-/HBcAb+ patients undergoing standard R-CHOP-21 for aggressive lymphoma. In our study, 24-month-long prophylaxis with LAM appears to be the most effective approach with a null risk of OBI reactivation, hepatitis flare-up, and ICHT disruption.

Occult Hepatitis B Virus Infection: An Update

Occult hepatitis B virus (HBV) infection (OBI) refers to a condition in which replication-competent viral DNA is present in the liver (with detectable or undetectable HBV DNA in the serum) of individuals testing negative for the HBV surface antigen (HBsAg). In this peculiar phase of HBV infection, the covalently closed circular DNA (cccDNA) is in a low state of replication. Many advances have been made in clarifying the mechanisms involved in such a suppression of viral activity, which seems to be mainly related to the host's immune control and epigenetic factors. OBI is diffused worldwide, but its prevalence is highly variable among patient populations. This depends on different geographic areas, risk factors for parenteral infections, and assays used for HBsAg and HBV DNA detection. OBI has an impact in several clinical contexts: (a) it can be transmitted, causing a classic form of hepatitis B, through blood transfusion or liver transplantation; (b) it may reactivate in the case of immunosuppression, leading to the possible development of even fulminant hepatitis; (c) it may accelerate the progression of chronic liver disease due to different causes toward cirrhosis; (d) it maintains the pro-oncogenic properties of the "overt" infection, favoring the development of hepatocellular carcinoma.

Occult hepatitis B virus infection in hepatitis C virus negative chronic liver diseases

Data concerning the prevalence of hepatitis B virus (HBV) occult infection (OBI) varies greatly in the different studies according to the sensitivity and specificity of the diagnostic approaches and the HBV prevalence in the different populations examined. The clinical implications of OBI are still debated. While the impact of OBI in HBV transmission as well as in HBV reactivation under immunosuppression are well established, the role of OBI in liver disease and hepatocellular carcinoma (HCC) development are still not definitively elucidated. It has been hypothesized that OBI might contribute to worsening the liver disease course when other causes of liver damage co-exist. Furthermore, much evidence suggests a role of OBI in the hepato-carcinogenesis processes through both indirect and direct oncogenic mechanisms that might favour HCC development. Data on the OBI clinical implications mainly come from studies performed in patients with hepatitis C virus (HCV) infection. However, HCV prevalence has dramatically fallen in the past years also because of the advent of specific and highly effective direct acting antivirals, with a consequent abrupt change of the worldwide scenario of chronic liver disease. Information about OBI prevalence and possible clinical impact in non-HCV-related liver disease are fragmentary, and the objective of this review is to critically summarize the available data in this field.

Global prevalence of occult hepatitis B: A systematic review and meta-analysis

The study aimed to investigate the prevalence and risk factors associated with occult hepatitis B virus (HBV) infection (OBI) in the global population. We searched PubMed, Embase, CINAHL, Cochrane and Web of Science from database inception through 27 Dec, 2018. Studies reporting HBV-DNA serological data in previously undiagnosed hepatitis B patients were included. The data were further categorized according to the presence of risk factors. After an initial screening of 2,325 records, we finally included 98 articles about the prevalence of OBI from 34 countries and regions. The OBI prevalence was 0.82% (95% CI:0.69-0.96) in the general population, 16.26% (95% CI:10.97-22.34) in HIV patients, 13.99% (95% CI:8.33-20.79) in patients with other liver diseases, 4.25% (95% CI:1.64-7.87) in haemodialysis patients and 5.14% (95% CI:2.26-9.01) patients with other risk factors. In conclusion, OBI prevalence varies significantly across different populations and nations, which deserve attention from the public health authorities. Our results generate further epidemiological data to identify the population with OBI, which has important clinical implications in finding these high-risk populations to design preventive and management strategies.

Hepatitis B virus vaccination after allogeneic hematopoietic cell transplantation prevents post-transplant HBV reactivation

BACKGROUND

Hepatitis B virus (HBV) reactivation in allogeneic hematopoietic-cell transplant (HCT) recipients with evidence of pre-transplantation resolved HBV infection is an important cause of morbidity, usually occurring a year or later after HCT.

OBJECTIVES

We retrospectively studied a cohort of allogeneic HCT recipients with resolved HBV infection, some of whom were vaccinated for HBV following transplantation, to understand if post-HCT HBV vaccination influenced the risk of HBV reactivation.

STUDY DESIGN

The study included all patients with resolved HBV who underwent allogeneic HCT at our institution between 1/1/2000 and 12/31/2015, where HBV vaccination starting at 1 year after HCT became standard in 2012 and antiviral prophylaxis is not utilized. Resolved HBV infection was defined as positive HBV-core IgG (HBcAb), negative HBV-surface antigen (HBsAg) and undetectable HBV DNA before HCT. HBV reactivation was defined as development of detectable HBsAg and HBV DNA after HCT. Follow up for outcomes concluded 1/1/2018.

RESULTS

Among 136 patients with resolved HBV before HCT, 19 developed reactivation during follow up (cumulative incidence 14%). Median time to HBV reactivation was 21 months (range, 2-47 months). The cumulative probability of HBV reactivation among HCT recipients who survived for a year or more after transplant without early HBV reactivation and were HBV-vaccinated versus those who were unvaccinated was 2.9% vs. 10.0 % at two years and 6.6% vs. 26.5% at 4 years post-HCT (P = 0.03, Gray's test). In a time-dependent Cox model, the adjusted hazard ratio (aHR) of HBV reactivation in patients with pre-transplant HBsAb levels greater than 10 IU/L was 0.34 (95% confidence interval [CI], 0.13-0.90). The aHR of HBV reactivation in patients who were vaccinated with 2 or more doses of recombinant HBV vaccine after HCT was 0.18 (95% CI, 0.04-0.80) compared to those who received 1 or no post-HCT vaccine doses.

CONCLUSIONS

HBV reactivation is a late complication of allogeneic HCT in at-risk recipients, particularly in those with low pre-HCT HBsAb. HBV vaccination starting 1 year after HCT may be protective.

Hepatitis B Virus Reactivation Associated With Therapeutic Interventions

Hepatitis B virus (HBV) reactivation associated with various therapeutic interventions is an important cause of morbidity and mortality in patients with current or resolved HBV infection. Because no curative treatment for HBV infection is yet available, there are many individuals at risk for HBV reactivation in the general population. Populations at risk for HBV reactivation include patients who are currently infected with HBV or who have been exposed to HBV in the past. HBV reactivation and its potential consequences is a concern when these populations are exposed to anti-cancer chemotherapy, immunosuppressive or immunomodulatory therapies for the management of various malignancies, rheumatologic diseases, inflammatory bowel disease, or solid-organ or hematologic stem cell transplantation. Accordingly, it has become important to understand the basics of HBV reactivation and the mechanisms by which certain therapies are more susceptible to HBV reactivation. This review aims to raise the awareness of HBV reactivation and to understand the mechanisms and the risks of HBV reactivation in various clinical settings.

May Previous Hepatitis B Virus Infection Be Involved in Etiology and Pathogenesis of Autoimmune Liver Diseases?

INTRODUCTION

Viral infections, especially with hepatotropic viruses, may trigger autoimmune liver diseases (AILDs) and deteriorate their course. However, association of previous hepatitis B virus (HBV) infection (presence of anti-HBc with or without anti-HBs or HBV DNA in serum) with AILDs is poorly studied so far. The aim of the study was to assess the prevalence of previous hepatitis B virus infection markers and its clinical significance in patients with autoimmune liver diseases.

METHODS

The study was based on the data obtained from 234 consecutive HBsAg-negative patients with AILDs [81 with autoimmune hepatitis (AIH), 122 with primary biliary cholangitis (PBC) and 31 with primary sclerosing cholangitis (PSC)] and 131 subjects of the control group without liver diseases. Blood samples of the enrolled patients were tested for anti-HBc and HBV DNA. Samples of liver tissue were examined by standard morphologic protocol and, in anti-HBc positive subjects, for HBV DNA. We assessed estimated risks of AILDs according to anti-HBc positivity and association of anti-HBc positivity with stage of liver fibrosis.

RESULTS

Anti-HBc was detected in 14.5% participants in the control group vs 26.1% (p = 0.016) in patients with AILDs (including 27.1% subjects with PBC (p = 0.021 vs control group), in 29% of PSC and 23.5% in AIH. HBV DNA was detected in three patients with PBC and in one with AIH. Positive anti-HBc test result was associated with higher risk of AILDs-odds ratio (OR) = 2.078 [95% confidence interval (CI) 1.179-3.665], especially in PBC: OR (95% CI) 2.186 (1.165-4.101). Odds of advanced stage of liver fibrosis (F3-F4 by METAVIR) in anti-HBc-positive subjects with PBC were also higher compared to those who had no previous HBV infection: OR (95% CI) 2.614 (1.153-5.926).

CONCLUSIONS

Significant proportions of patients with AILDs are anti-HBc positive, and some of them have OBI. Among patients with AILDs, anti-HBc-positivity is most widespread in the PBC group and in subjects with advanced stage of liver fibrosis. Our data may support the idea of an important role of previous HBV infection in the etiology and pathogenesis of AILDs (namely PBC).

Detection of the hepatitis B surface antigen in patients with occult hepatitis B using an assay with enhanced sensitivity

Patients with occult hepatitis B infection (OBI) have undetectable hepatitis B surface antigen (HBsAg) by conventional assays but detectable hepatitis B virus (HBV) DNA in blood/liver. We evaluated the key performance characteristics of a sensitive HBsAg assay (ARCHITECT HBsAg Next Qualitative Assay, referred as NEXT) with respect to HBsAg detection. Assay precision, sample carryover and seroconversion sensitivity of NEXT were evaluated. HBsAg was measured by NEXT in 1,138 individuals, including 1,038 patients who attended liver clinics in a tertiary hospital (200 HBV DNA-positive blood donors whose HBsAg was undetectable by conventional assays, and 38 patients receiving immunosuppressive therapy, 800 chronic hepatitis B patients with HBsAg seroclearance) and 100 HBsAg-negative subjects recruited from a community project. The within-run and within-laboratory coefficients of variation were <6% for the positive sample pools. In 9 seroconversion panels tested, NEXT allowed an earlier HBsAg detection than conventional assays. NEXT detected HBsAg in 10/200 (5%) HBsAg-negative blood donors, 1/20 (5%) and 0/18 HBsAg-negative patients with and without HBV reactivation respectively, and 59/800 (7.3%) patients with HBsAg seroclearance. HBsAg was detectable by NEXT in 27.8%, 8.2%, 6.9%, 3.8% and 1.9% samples at <3, 3-5, >5-8, >8-11, and >11 years after HBsAg seroclearance, respectively. Seven out of 100 HBsAg-negative community identified subjects was tested positive by NEXT. Comparing with conventional HBsAg assays, NEXT demonstrated a higher sensitivity and conferred an increment of 5-7% detection rate in patients with OBI, thereby helping in identifying HBV carriers and prevention of OBI-associated HBV transmission and reactivation.

Hepatitis B virus reactivation: overview and management

Hepatitis B virus (HBV) can hide in the liver in the form of covalently closed circular DNA. When the body’s immunity changes, HBV reactivation (HBV-R) can occur. The risk of HBV-R is determined by the complex interaction among virological factors, medication factors and host factors. However, many patients do not know that they are infected with HBV, and doctors often do not invest enough time to systematically evaluate the patient’s HBV-R risk factors before immunosuppressive treatment. Therefore, HBV clinical screening should be vigorously promoted to achieve early detection and early prevention for patients with high risk of HBV-R. The mechanism, clinical features, risk factors, HBV-R under different disease etiologies, prevention and treatment of HBV-R were summarized to improve the in-depth understanding and awareness.

Hepatitis B Virus Infection in Patients Receiving Allogeneic Hematopoietic Stem Cell Transplantation

Considering a steady increase in the number of allogeneic hematopoietic stem cell transplantations (allo-HSCT) worldwide and the significant proportion of the world’s population that has been exposed to hepatitis B virus (HBV) infection, HBV reactivation following allo-HSCT remains an important issue for post-transplant morbidity and mortality. Antiviral prophylaxis can reduce HBV replication, severity of HBV-related hepatitis, and mortality; therefore, identification of patients at risk is crucial. It is recommended that all recipients and donors should be screened for active or prior HBV infection, including HBsAg, antiHBc, and antiHBs. Adoptive immunity transfer from the donor seems to have protective effects against HBV reactivation. Antiviral prophylaxis should be initiated in all HBsAg-positive patients. HBsAg-negative, antiHBc-positive patients remain at risk; therefore, antiviral prophylaxis should be considered if baseline serum HBV DNA is detectable. In HBsAg-negative, antiHBc-positive patients without detectable HBV DNA, close monitoring of viral load with an on-demand therapy is necessary. Entecavir or tenofovir rather than lamivudine are more appropriate for the emergence of lamivudine resistance. The treatment duration remains unclear, with 6- to 12-month therapy after cessation of immunosuppressive therapy commonly recommended. Here we review the updated evidence and recent recommendations regarding HBV reactivation in patients undergoing allo-HSCT for individualized therapy.

Hepatitis B Core-Related Antigen and New Therapies for Hepatitis B

The hepatitis B core-related antigen (HBcrAg) is an unprecedented novel HBV biomarker that plays an essential role in reflecting covalently closed circular DNA (cccDNA) in chronic hepatitis B (CHB) because its levels correlate with intrahepatic cccDNA and serum HBV DNA. In this review, we describe the clinical application of serum HBcrAg in CHB patients, with a particular focus on new therapies targeting intrahepatic HBV replication. (1) HBcrAg can be detected in clinical cases where serum HBV DNA is undetectable during anti-HBV therapy. (2) A highly sensitive HBcrAg assay (iTACT-HBcrAg) may be useful for monitoring HBV reactivation, as an alternative to HBV DNA. (3) Decreased HBcrAg levels have been significantly associated with promising outcomes in CHB patients, reducing the risk of progression or recurrence of hepatocellular carcinoma. Additionally, we focus on and discuss several drugs in development that target HBV replication, and monitoring HBcrAg may be useful for determining the therapeutic efficacies of such novel drugs. In conclusion, HBcrAg, especially when measured by the recently developed iTACT-HBcrAg assay, may be the most appropriate surrogate marker, over other HBV biomarkers, to predict disease progression and treatment response in CHB patients.

Novel strategies for the early diagnosis of hepatitis B virus reactivation

Hepatitis B virus (HBV) reactivation under systemic chemotherapy or immunosuppressive therapy is a serious complication among HBV-resolved patients. Some medications, such as more than 2 weeks of corticosteroid therapy, can influence HBV reactivation; therefore, screening tests that measure hepatitis B surface antigen (HBsAg), hepatitis B core antibody, and hepatitis B surface antibody before therapy are required. Additionally, because HBV reactivation has been reported in patients positive for HBsAg treated with immune checkpoint inhibitors (ICIs), the prophylactic administration of nucleos(t)ide analogues prior to administering ICIs is recommended for HBsAg-positive patients. Under these circumstances, highly sensitive novel biomarkers are expected to be used for the early diagnosis of HBV reactivation. A fully automated high-sensitivity HBsAg assay (detection limit: 5 mIU/ml) by Lumipulse HBsAg-HQ, with 10-fold higher sensitivity than that of conventional assays, is currently used. Furthermore, ultra-sensitive HBsAg assays using a semi-automated immune complex transfer chemiluminescence enzyme immunoassay (ICT-CLEIA; detection limit: 0.5 mIU/ml) have been developed. Recently, a fully automated, novel high-sensitivity hepatitis B core-related antigen assay (iTACT-HBcrAg; cut-off value: 2.1 Log U/mL) has been developed and reported. The utility of ICT-CLEIA and iTACT-HBcrAg for the diagnosis of HBV reactivation appears comparable to the use of HBV DNA. In this review, we provide the latest information related to medications that influence HBV reactivation and recently developed novel biomarkers that predict and monitor HBV reactivation.

Prevention of hepatitis B reactivation in patients requiring chemotherapy and immunosuppressive therapy

Hepatitis B virus (HBV) reactivation can lead to severe acute hepatic failure and death in patients with HBV infection. HBV reactivation (HBVr) most commonly develops in patients undergoing cancer chemotherapy, especially B cell-depleting agent therapy such as rituximab and ofatumumab for hematological or solid organ malignancies and that receiving hematopoietic stem cell transplantation without antiviral prophylaxis. In addition, the potential consequences of HBVr is particularly a concern when patients are exposed to either immunosuppressive or biologic therapies for the management of rheumatologic diseases, inflammatory bowel disease and dermatologic diseases. Thus, screening with HBV serological markers and prophylactic or pre-emptive antiviral treatment with nucleos(t)ide analogues should be considered in these patients to diminish the risk of HBVr. This review discusses the clinical manifestation, prognosis and management of HBVr, risk stratifications of cancer chemotherapy and immunosuppressive therapy and international guideline recommendations for the prevention of HBVr in patients with HBV infection and resolved hepatitis B.

The Roles of γδ T Cells in Hematopoietic Stem Cell Transplantation

The αβ T-cell-depleted hematopoietic stem cell transplantation (HSCT) leads to lower relapse and better outcome, and may correlate strongly with expansion of donor-derived γδ T cells. γδ T cells play an important role in immune reconstitution and can exert a graft-versus-leukemia effect after HSCT. This review showed the recent literature on immune functions of γδ T cells after HSCT. The discrepancies between studies of γδ T cells in graft-versus-host disease may cause by its heterogeneous and various distinct subsets. And reconstitution of γδ T cells may play a potential immunoregulatory role in the infections after HSCT.

Hepatitis B Seropositive Status in Recipients or Donors Is Not Related to Worse Outcomes after Haploidentical Hematopoietic Stem Cell Transplantation

Hepatitis B virus (HBV) has a high rate of chronic infection in Asian populations, and only limited studies have been performed to analyze the impact of HBV-seropositive haploidentical hematopoietic stem cell transplantation (haplo-HSCT) recipients and donors. The present study aimed to evaluate the effect on clinical outcomes in those patients. We conducted a retrospective study enrolling 237 consecutive patients undergoing first haplo-HSCT. The patients were classified into 3 groups: recipient HBV-positive group (R+D-; n = 62), donor HBV-positive group (D+; n = 83), and HBV-negative group (R-D-; n = 92). Corresponding prophylactic antiviral treatment was given in the R+D- and D+ groups. The results were compared among the 3 groups using the Kruskal-Wallis test for continuous variables, Pearson's chi-square test for categorical variables, the competing-risk method to evaluate cumulative incidence, Kaplan-Meier curves to estimate overall survival (OS) and disease-free survival (DFS), and a Cox proportional hazard model to analyze multivariable influences. The 3-year cumulative HBV reactivation rate was 4.2%. The median time to HBV reactivation was 845 days (range, 545 to 1439 days) after haplo-HSCT. The R+D- group tended to have a higher cumulative incidence of HBV reactivation compared with the D+ group (11.8% versus 3.1%; P = .080). Significant differences in the causes of hepatic damage were observed among the 3 groups (P = .017), and all patients with acute hepatitis B after haplo-HSCT were from the R+D- group. Multivariate analysis showed that pretransplantation HBV status was associated with cytomegalovirus reactivation (R+D- versus R-D-: hazard ratio, 1.514; 95% confidence interval, 1.060 to 2.163; P = .023). The 3-year OS and DFS, 3-year cumulative incidence of nonrelapse mortality (NRM), rates of relapse and graft-versus-host disease (GVHD), and causes of death were comparable among the 3 groups. Pretransplantation HBV serostatus had no significant effect on OS, DFS, NRM, relapse, or GVHD in the multivariate analysis. Based on our data, seropositivity for hepatitis B surface antigen (HbsAg) or core antibody (HBcAb) in donors or recipients before transplantation did not negatively affect the overall outcome after haplo-HSCT under the premise of proper antiviral prophylaxis along with regular post-transplantation surveillance, and HBV seropositivity should not be considered a contraindication to haplo-HSCT.

Management of Hepatitis B Virus Reactivation in Malignant Lymphoma Prior to Immunosuppressive Treatment

Hepatitis B reactivation is a common complication in lymphoma patients under immunosuppressive treatment with potentially serious and life-threating consequences. In this review, we discuss the basis of chronic Hepatitis B virus (HBV) infection, the definition and risk factors for HBV reactivation. We overview the management of HBV reactivation based on virological status and immunosuppressive regimen risk stratification. We also highlight and update information about the HBV reactivation in lymphoma patients under novel agent treatment, including newer monoclonal antibodies, small molecule inhibitors, and even chimeric antigen receptor T-cell immunotherapy.

Management of Hepatitis B Virus in Allogeneic Hematopoietic Stem Cell Transplantation

The high morbidity of HBV reactivation following allogeneic hematopoietic stem cell transplantation (allo-HSCT) is partially due to the intense immunologic potency of complex therapeutic regimens, the use of antithymocyte globulin and calcineurin inhibitors to prevent graft versus-host disease (GVHD), prolonged immune reconstitution, and hematological malignancies infected with hepatitis B virus (HBV). Immunosuppression results in the reactivation of HBV replication from covalently closed circular DNA (cccDNA) residing in hepatocytes. However, the role of viral mutations during HBV reactivation needs to be validated. All individuals scheduled to receive allo-HSCT or wish to donate stem cells should be screened for hepatitis B surface antigen (HBsAg), antibodies to hepatitis B core (anti-HBc), and HBV-DNA. HBsAg-positive recipients of allo-HSCT have a high risk of HBV reactivation; thus, they should receive prophylactic antiviral therapy. The high barrier to resistance nucleos(t)-ide analogs (NAs) seems to be superior to the low barrier agents. Resolved-HBV recipients have a lower risk of HBV reactivation than HBsAg-positive recipients. Although prophylactic antiviral therapy remains controversial, regular monitoring of alanine transaminase (ALT) and HBV-DNA combined with preemptive antiviral treatment may be an optimized strategy. However, optimal antiviral therapy duration and time intervals for monitoring remain to be established. Accepting stem cells from HBsAg-positive donors is associated with a risk of developing HBV-related hepatitis. The overall intervention strategy, including donors and recipients, may decrease the risk of HBV-related hepatitis following HSCT from HBsAg positive stem cells. In this review, we summarize the issues of HBV in allo-HSCT, including HBV reactivation mechanism, HBsAg-positive recipients, HBV-resolved infection recipients, and donor-related factors, and discuss their significance.

Prevalence of occult HBV infection in Western countries

Due to a lack of standardized tests, it is difficult to obtain prevalence data and define the real impact of occult HBV infection (OBI) in Western countries. The present review article addresses the prevalence of OBI, defined as presence of hepatitis B virus (HBV) DNA in liver tissue or plasma in HBsAg-negative subjects, in Western countries. This varies in different studies according to the different methodologies used (based on serology vs virology), to the sample analyzed for the diagnosis (liver tissue vs plasma), to the different populations studied, to the different geographical variations in the HBV spread, to the host characteristics (age, gender, risk factors for acquiring HBV infection) and to the presence of other parenteral infections (hepatitis C virus and/or human immunodeficiency virus [HIV] infections). Considering the different liver diseases analyzed, that is in patients with cryptogenic cirrhosis or advanced liver fibrosis, the prevalence of OBI ranges 4% to 38%. Considering the different populations studied, in the case of parenteral blood exposure it is about 45%, in patients with chronic hepatitis C it is estimated at about 52%, in HIV-infected patients it ranges from 0% to 45%, in blood donors from 0% to 22.7% and in hemodialysis patients it ranges from 0% to 54%. In conclusion, OBI is a virological entity to be considered when performing the patient's evaluation for immunosuppressive diseases, liver pathologies, or for blood transfusions. Knowing the prevalence and clinical impact of OBI will allow better patient management.

Reducing infectious complications after allogeneic stem cell transplant

INTRODUCTION

Infections remain a significant problem, in patients undergoing an allogeneic hematopoietic stem-cell transplant (HSCT) and efforts have been made over the years, to reduce the incidence, morbidity and mortality of infectious complications.

AREAS COVERED

This manuscript is focused on the epidemiology, risk factors and prevention of infections after allogeneic HSCT. A systematic literature review was performed using the PubMed database, between November 2019 and January 2020, with the following MeSH terms: stem-cell transplantation, infection, fungal, bacterial, viral, prophylaxis, vaccines, prevention. The authors reviewed all the publications, and following a common revision, a summary report was made and results were divided in three sections: bacterial, fungal and viral infections.

EXPERT OPINION

Different infections occur in the early, intermediate and late post-transplant period, due to distinct risk factors. Improved diagnostic techniques, pre-emtive therapy and better prophylaxis of immunologic complications, have reduced the morbidity and mortality of infections. The role of the gut microbiota is under careful scrutiny and may further help us to identify high-risk patients.

Reconsidering the management of patients with cancer with viral hepatitis in the era of immunotherapy

In the evolving immune-oncology landscape, numerous patients with cancer are constantly treated with immune checkpoint inhibitors (ICPIs) but among them, only sporadic cases with pre-existing hepatitis B virus (HBV) and hepatitis C virus (HCV) are recorded. Despite the global dissemination of HBV and HCV infections, viral hepatitis-infected patients with cancer were traditionally excluded from ICPIs containing trials and current evidence is particularly limited in case reports, retrospective cohort studies and in few clinical trials on advanced hepatocellular carcinoma. Thus, many concerns still remain about the overall oncological management of this special subpopulation, including questions about the efficacy, toxicity and reactivation risks induced by ICPIs. Here, we examine the natural course of both HBV and HCV in cancer environment, review the latest antiviral guidelines for patients undergoing systematic cancer therapies, estimating treatment-related immunosuppression and relocate immunotherapy in this therapeutic panel. Among the ICPIs-treated cases with prior viral hepatitis, we focus further on those experienced HBV or HCV reactivation and discuss their host, tumor and serological risk factors, their antiviral and immunological management as well as their hepatitis and tumor outcome. Based on a low level of evidence, immunotherapy in these specific cancer cases seems to be associated with no inferior efficacy and with a relevantly low reactivation rate. However, hepatitis reactivation and subsequent irreversible complications appeared to have poor response to deferred antiviral treatment. While, the prophylactic use of modern antiviral drugs could eliminate or diminish up front the viral load in most cases, leading to cure or long-term hepatitis control. Taking together the clinical significance of preventive therapy, the low but existing reactivation risk and the potential immune-related hepatotoxicity, a comprehensive baseline assessment of liver status, including viral hepatitis screening, before the onset of immunotherapy should be suggested as a reasonable and maybe cost-effective strategy but the decision to administer ICPIs and the necessity of prophylaxis should always be weighed at a multidisciplinary level and be individualized in each case, up to be established by future clinical trials.

Hepatitis B virus persistence and reactivation

Hepatitis B virus (HBV) infection causes chronic hepatitis and has long term complications. Individuals ever infected with HBV are at risk of viral reactivation under certain circumstances. This review summarizes studies on HBV persistence and reactivation with a focus on the definitions and mechanisms. Emphasis is placed on the interplay between HBV replication and host immunity as this interplay determines the patterns of persistence following viral acquisition. Chronic infections exhibit as overt persistence when a defective immune response fails to control the viral replication. The HBV genome persists despite an immune response in the form of covalently closed circular DNA (cccDNA) and integrated DNA, rendering an occult state of viral persistence in individuals whose infection appears to have been resolved. We have described HBV reactivation that occurs because of changes in the virus or the immune system. This review aims to raise the awareness of HBV reactivation and to understand how HBV persists, and discusses the risks of HBV reactivation in a variety of clinical settings.

Hepatitis B reactivation in hematopoietic stem cell transplanted patients: 20 years of experience of a single center from a middle endemic country

Hematopoietic stem cell transplantation (HSCT) is a risk factor for viral hepatitis reactivations because it affects lymphocyte number and functions. Latent hepatitis B virus (HBV) may stay in dormant form in hepatocytes and may be reactivated in prolonged immunosuppression. This study analyzes the incidence of reactivation of HBV infections in HSCT patients in a middle endemic country like Turkey. Five hundred and sixty-one HSCT patients from 1994 to 2015 were retrospectively evaluated. Sixty-six patients had a serologic feature of HBV infection. Fifteen patients were hepatitis B surface antigen (HBsAg)-positive patients (3 allogeneic and 12 autologous) while 51 of them were anti-hepatitis B core IgG (anti-HBc IgG)-positive patients (22 allogeneic and 29 autologous). Although under lamivudine prophylaxis, reactivation was seen in three of 12 (25%) chronic HBV (HBsAg positive) patients who received autologous HSCT and in two of the three HBsAg-positive patients who received allogeneic HSCT. Rate of reactivation in the whole HBsAg-positive group was 33%. Reactivation occurred on median 270th day (range: 60-730). Reverse seroconversion incidence was 10% on 133th day for HBsAg negative, but anti-HBc IgG-positive patients, which increased to 17% on 360th and to 23% on 1500th day. Cumulative incidence increased to 41% on 2280th day for isolated anti-HBc IgG-positive patients. Hepatitis B surface antibodies (anti-HBs) were found to be protective as reactivation did not exceed 11% on 5050th day when anti-HBs was positive. When anti-HBc IgG-positive cases were analyzed according to their transplantation types, allogeneic HSCT was found to have higher cumulative incidence (45% on 3258th day) for HBV reactivation than autologous HSCT (7% on 5050th day). Besides, HBV reactivation in anti-HBc IgG-positive patients who received allogeneic transplantation was related to mortality. Findings of this study suggest that HBV prophylaxis extending over 1 year should be prescribed for HBsAg-positive patients independent of the transplantation type. Prophylaxis should also be given to anti-HBc IgG-positive patients if an allogeneic HSCT is to be performed.

A prospective trial of vaccine to prevent hepatitis B virus reactivation after hematopoietic stem cell transplantation

Hepatitis B virus (HBV) reactivation reportedly occurs frequently after hematopoietic stem cell transplantation (HSCT) in resolved HBV-infected patients. Here, 50 patients with resolved HBV infections and scheduled to undergo HSCT were enrolled; all subjects were vaccinated with three doses of hepatitis B vaccine 12 months after HSCT and the incidence of HBV reactivation was monitored. The patients' characteristics were: median age, 61 (34-72) years; male/female, 27/19; allogeneic/autologous, 40/6; bone marrow/peripheral blood stem cells/cord blood, 26/16/4. Of the 46 patients who underwent HSCT, 19 were excluded and did not make it to vaccination due to relapse of underlying disease, HBV reactivation within 12 months of HSCT, or transfer of patients. The remaining 27 were vaccinated 12 months after HSCT and monitored for 2 years. Six showed HBV reactivation, with a 2-year cumulative reactivation incidence of 22.2%; the same incidence was 27.3% only in allogeneic HSCT patients. Factors associated with HBV reactivation included the discontinuation of immunosuppressants (P = 0.0379) and baseline titers of antibody against hepatitis B surface antigen (P = 0.004). HBV reactivation with vaccination following HSCT could occur despite maintenance of serum anti-HBs at more than protective levels.

Prevention and management of viral hepatitis in inflammatory bowel disease: a clinical practice guideline by the Korean Association for the Study of Intestinal Diseases

The treatment of inflammatory bowel disease (IBD) has been revolutionized for the last 10 years by the increasing use of immunomodulators and biologics. With immunosuppression of this kind, opportunistic infection is an important safety concern for patients with IBD. In particular, viral hepatitis is determined by the interaction between the virus and the host's immunity, and the risk of reactivation increases if immunity is compromised by immunosuppression therapy. Parts of Asia, including Korea, still show intermediate endemicity for the hepatitis A virus and hepatitis B virus compared with the United States and Western Europe. Thus, members of IBD research group of the Korean Association for the Study of Intestinal Diseases have produced a guideline on the prevention and management of viral hepatitis in IBD.

HBV Reactivation in Patients Undergoing Hematopoietic Stem Cell Transplantation: A Narrative Review

HBV reactivation (HBVr) can occur due to the ability of HBV to remain latent in the liver as covalently closed circular DNA and by the capacity of HBV to alter the immune system of the infected individuals. HBVr can occur in patients undergoing hematopoietic stem cell transplantation (HSCT) with a clinical spectrum that ranges from asymptomatic infection to fulminant hepatic failure. The risk of HBVr is determined by a complex interplay between host immunity, virus factors, and immunosuppression related to HSCT. All individuals who undergo HSCT should be screened for HBV. HSCT patients positive for HBsAg and also those HBcAb-positive/HBsAg-negative are at high risk of HBV reactivation (HBVr) due to profound and prolonged immunosuppression. Antiviral prophylaxis prevents HBVr, decreases HBVr-related morbidity and mortality in patients with chronic or previous HBV. The optimal duration of antiviral prophylaxis remains to be elucidated. The vaccination of HBV-naïve recipients and their donors against HBV prior to HSCT has an important role in the prevention of acquired HBV infection. This narrative review provides a comprehensive update on the current concepts, risk factors, molecular mechanisms, prevention, and management of HBVr in HSCT.

New Markers in Monitoring the Reactivation of Hepatitis B Virus Infection in Immunocompromised Hosts

Hepatitis B virus (HBV) persistence is at the basis of HBV reactivation as a consequence of chemotherapy and immunosuppressive treatments. The identification of early viral replication indicators and markers of effective HBV immunological control would be useful in monitoring patients who are at risk of potential viral reactivation during the course of immunosuppressive treatment. Currently, international guidelines have shared some criteria to identify patients with a low, medium or high risk of HBV reactivation; however, permanently placing a patient in a definitive category is not always easy. More often, patients move from one category to another during the course of their immunosuppressive treatment; therefore, in many cases, there are no precise indicators or tools for monitoring possible reactivation and establishing the duration and suspension of antiviral prophylaxis. Historically, the sequence of HBV antigens and antibodies and HBV DNA levels has been used to evaluate the different stages of the acute and chronic phases of an HBV infection. In the last few years, new biomarkers, such as anti-HBs and anti-HBc titres, HBV core-related antigen (HBcrAg), ultra-sensitive HBsAg evaluation and HBV RNA, have been used in patients with an HBV infection to evaluate their diagnostic and prognostic potential. The aim of this review is to evaluate the published results on the use of new infection markers in the diagnosis and monitoring of HBV reactivation over the course of immunosuppressive treatments. Moreover, the importance of viral genotypic studies was emphasized, given the diagnostic and therapeutic implications of the mutational profiles of HBsAg during the HBV reactivation phase.

Update of the statements on biology and clinical impact of occult hepatitis B virus infection

In October 2018 a large number of international experts with complementary expertise came together in Taormina to participate in a workshop on occult hepatitis B virus infection (OBI). The objectives of the workshop were to review the existing knowledge on OBI, to identify issues that require further investigation, to highlight both existing controversies and newly emerging perspectives, and ultimately to update the statements previously agreed in 2008. This paper represents the output from the workshop.

Screening and Prophylaxis to Prevent Hepatitis B Reactivation: Transplant Recipients

Organ transplantation is a lifesaving procedure for many patients. To prevent rejection or graft-versus-host disease, recipients require long-term immunosuppression. In patients who have ever been exposed to hepatitis B, it is possible for reactivation to occur; this includes patients who are anti-hepatitis B core antibody-positive only or both anti-hepatitis B core antibody-positive and hepatitis B surface antibody-positive. The susceptibility to this varies with the nature of the transplant. Hepatitis B can be transmitted from donor to recipient. It is important to assess the hepatitis B status and formulate a strategy to prevent transmission and prevent reactivation.

Reactivation of hepatitis B virus infection in patients with hemo-lymphoproliferative diseases, and its prevention

Reactivation of hepatitis B virus (HBV) replication is characterized by increased HBV-DNA serum values of about 1 log or by HBV DNA turning positive if previously undetectable in serum, possibly associated with liver damage and seldom life-threatening. Due to HBV reactivation, hepatitis B surface antigen (HBsAg)-negative/anti-HBc-positive subjects may revert to HBsAg-positive. In patients with hemo-lymphoproliferative disease, the frequency of HBV reactivation depends on the type of lymphoproliferative disorder, the individual's HBV serological status and the potency and duration of immunosuppression. In particular, it occurs in 10%-50% of the HBsAg-positive and in 2%-25% of the HBsAg- negative/anti-HBc-positive, the highest incidences being registered in patients receiving rituximab-based therapy. HBV reactivation can be prevented by accurate screening of patients at risk and by a pharmacological prophylaxis with anti-HBV nucleo(t)sides starting 2-3 wk before the beginning of immunosuppressive treatment and covering the entire period of administration of immunosuppressive drugs and a long subsequent period, the duration of which depends substantially on the degree of immunodepression achieved. Patients with significant HBV replication before immunosuppressive therapy should receive anti-HBV nucleo(t)sides as a long-term (may be life-long) treatment. This review article is mainly directed to doctors engaged every day in the treatment of patients with onco-lymphoproliferative diseases, so that they can broaden their knowledge on HBV infection and on its reactivation induced by the drugs with high immunosuppressive potential that they use in the care of their patients.

[Hepatobiliary complications following allogeneic hematopoietic cell transplantation: Recommendations of the Francophone Society of Bone Marrow transplantation and cellular Therapy (SFGM-TC)]

Hepatobiliary complications are frequent in the context of allogeneic hematopoietic cell transplantation (allo-HCT) and contribute largely to the morbidity and mortality after transplantation. Within the framework of the ninth workshops of practice harmonization of the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC) held in Lille in September 2018, diagnostic approaches and treatments of hepatobiliary dysfunctions prior to and following transplantation were reviewed according to the analysis of published studies.

Adoptive donor immunity protects against resolved hepatitis B virus reactivation after allogeneic haematopoietic stem cell transplantation in the world's largest retrospective cohort study

Reactivation of hepatitis B virus (HBV) by reverse seroconversion (HBV-RS) after allogeneic haematopoietic stem cell transplantation (allo-HSCT) can occur in patients with resolved HBV infection (rHBV, defined as negative HBV surface antigen [HBsAg] and positive HBV core antibody), and may cause fatal hepatitis. To explore the risk factors, we retrospectively identified 817 consecutive patients who underwent allo-HSCT from 2005 to 2016 in this largest single centre cohort from National Taiwan Univerisity Hospital. Transplants using donors or recipients positive for HBsAg or HBV DNA were excluded, leaving 445 rHBV patients for analysis. The 3- and 5-year cumulative incidence of HBV-RS after allo-HSCT was 8·7% and 10·5%, respectively, at a median 16 months after allo-HSCT. All had concurrent HBV reactivation. HBV flares developed in 19% of HBV-RS cases, but none experienced hepatic failure. Neither did it impact non-relapse mortality or overall survival. Multivariate analysis revealed that patients with donor lacking hepatitis B surface antibody and extensive chronic graft-versus-host disease (cGVHD) have the highest risk for HBV-RS, with 5-year incidence of 24·2%. In conclusion, adoptive immunity transfer from the donor seems to have protective effects against HBV-RS, which may alter future donor selection algorithms, and combined with extensive cGVHD provides a good target for risk-adaptive HBV prophylaxis.

Reactivation of hepatitis B virus infection in patients with hematologic disorders

Hepatitis B reactivation is the reappearance or rise of hepatitis B virus (HBV) DNA in patients with past or chronic HBV infection, usually occurring in the context of immunosuppression. HBV reactivation has been most commonly reported in patients with hematologic disorders, with potentially serious and life-threatening consequences. In this review, we discuss the basis and presentation of HBV reactivation, and risk factors in terms of the host, the virus and the immunosuppression regimen, including newer agents used to manage hematologic malignancies. We overview the management of HBV reactivation, highlighting an up-dated recommendation on the use of newer nucleoside and nucleotide analogs, such as tenofovir and entecavir, for antiviral prophylaxis.

[Prophylaxis of infections post-allogeneic transplantation: Guidelines from the Francophone Society of Bone Marrow Transplantation and Cellular Therapy (SFGM-TC)]

Allogeneic hematopoietic stem cell transplantation is a curative treatment for many hematological diseases. However, this procedure causes the patient to be susceptible to infection. Prophylactic treatments are administered in clinical practice even thought the level of evidence of their effectiveness is not always high. In addition, changes in the transplantation procedures - use of reduced intensity conditioning, development of alternative graft sources - must lead to a rethinking of attitudes towards prophylaxis. Our working group based its recommendations on a review of referential articles and publications on the subject found in the literature. These recommendations concern the prophylaxis of infections caused by HSV1, HSV2, varicella zoster, and hepatitis B, as well as anti-bacterial and digestive decontamination prophylaxis, prevention of pneumocystis, toxoplasmosis, tuberculosis, as well as prophylaxis of fungal infections. Other infectious agents usually involved in infections post-allotransplant have been the subject of another set of recommendations from the French Society of Bone Marrow Transplantation and Cellular Therapy.

Reactivation of Hepatitis B Virus Infection With Reverse Seroconversion Following Umbilical Cord Allogeneic Hematopoietic Cell Transplantation in a Hepatitis-B-Immune Patient: A Case Report

Hepatitis B virus (HBV) reactivation in patients with prior exposure to HBV and protective levels of hepatitis B surface antibody (HBsAb) is a rare phenomenon and is termed reverse seroconversion. We describe a case of reactivation of HBV infection following reverse seroconversion in a patient who underwent umbilical cord allogeneic hematopoietic cell transplantation (UHCT). The patient developed acute hepatitis with positive hepatitis B surface antigen (HBsAg) and HBV DNA in the context of prior strongly positive HBsAb. The patient was treated with oral tenofovir and liver function tests returned to normal 3 months later. Long-term monitoring for HBV reactivation should be considered in patients with prior exposure to HBV undergoing UHCT regardless of HBsAb status.

Infections in Allogeneic Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has become a widely used modality of therapy for a variety of malignant and nonmalignant diseases. Despite advances in pharmacotherapy and transplantation techniques, infection remains one of the most severe and frequently encountered complications of allo-HSCT.

This chapter will address the risk factors for development of infection following allo-HSCT, including those related to the host, the conditioning regimen, and the graft, as well as the timing of opportunistic infections after allo-HSCT. The most common bacterial, viral, fungal, and parasitic infections, as well as issues surrounding their diagnostics and treatment, will be discussed. Finally, this chapter will address vaccination and other preventative strategies to be utilized when caring for patients undergoing allo-HSCT.

Severe hepatitis B reactivation during direct-acting antiviral treatment in "the absence" of hepatitis B surface antigen

Hepatitis C virus (HCV) treatment with direct-acting antivirals (DAA) can be associated with reactivation of hepatitis B (HBV). We report a case of a kidney transplant recipient who had a fatal severe HBV reactivation during treatment for chronic hepatitis C with DAA. Diagnosis of HBV reactivation was delayed due to undetectable surface antigen (HBsAg) by standard assays. The latter was explained by the presence of HBsAg escape mutants. The case illustrates the relevance of HBV-DNA testing in transplant recipients with previous exposure to HBV, even in the absence of HBsAg, and particularly when liver test abnormalities are present.

Efficacy of lamivudine prophylaxis in preventing hepatitis B virus reactivation in patients with resolved infection undergoing allogeneic SCT and receiving rituximab

PURPOSE

Hepatitis B virus (HBV) reactivation during immunosuppressive therapy is common in patients with hematological malignancies, even in case of resolved infection. Prophylaxis of HBV reactivation is universally recommended in stem cell transplant (SCT) recipients and patients treated with anti-CD20 agents (i.e., rituximab). Despite its well-established favorable safety profile, lamivudine (LAM) use in prophylaxis has been debated because of the possible emergence of resistant viral strains. The aim of this study was to investigate the efficacy of LAM in preventing HBV reactivation in allogeneic SCT recipients with a resolved HBV infection.

METHODS

Patients who received first allogeneic SCT in years 2009-2016 were evaluated. Sixty-three patients with resolved infection received LAM prophylaxis and were included in the study. Baseline and post-SCT characteristics were recorded, including rituximab exposure, length of LAM prophylaxis, and time from transplant to the last clinical and virological follow-up.

RESULTS

Overall, 39 patients (62%) were male, 39 (62%) had acute myeloid leukemia, 38 (60%) received transplant from haploidentical donor, 29 (53%) received myeloablative conditioning, and 15 (24%) received rituximab post-transplant. Median clinical follow-up was 24 months after SCT (range 0.3-97); median virological follow-up 16 months (range 0.3-78), and median length of LAM prophylaxis of 14.5 months (range 0.3-78). No patient experienced HBV reactivation while on LAM prophylaxis. One patient experienced reactivation 8 months after discontinuing prophylaxis.

CONCLUSIONS

In this high-risk population, LAM prophylaxis was effective in preventing HBV reactivation in patients with resolved infection. It should be considered a reasonable first-line prophylactic agent to be administered in this setting.

Hepatitis B virus reactivation in patients treated with immunosuppressive drugs: a practical guide for clinicians

Hepatitis B virus reactivation (HBVr) is emerging as an important clinical entity, with the advent of highly potent immunosuppression licensed for use as the treatment of a widening range of clinical indications. HBVr can lead to severe acute liver failure and death. Risk can be minimised through appropriate screening, monitoring and antiviral prophylaxis. Screening for serological markers at the -earliest opportunity is recommended. Risk stratification should then be performed on the basis of characteristics of the -underlying disease, markers of viral activity and the potency of proposed immunosuppression. In this review, we summarise the most recent recommendations from the relevant international societies. We also provide suggestions on how a robust multidisciplinary service can be delivered to prevent HBVr in UK clinical practice through optimisation of resources and introduction of checkpoints to prevent the inappropriate administration of immunosuppression to those at significant risk of HBVr.

Hepatitis B virus reactivation in HBsAg-negative, anti-HBc-positive patients receiving immunosuppressive therapy: a systematic review

Background:

The optimal management of HBsAg-negative, anti-HBc-positive patients who receive immunosuppression remains unclarified. We systematically reviewed the available data on potential predictors of the risk of hepatitis B virus (HBV) reactivation in such patients.

Methods:

A literature search identified 55 studies with 3640 HBsAg-negative, anti-HBc-positive patients who received immunosuppressive regimens.

Results:

HBV reactivation was reported in 236 (6.5%) patients. The pooled HBV reactivation rates did not differ between patients with detectable or undetectable HBV DNA in studies with hematological diseases or regimens containing rituximab, but it was higher in patients with detectable than in those with undetectable HBV DNA who were taking rituximab-free regimens (14% vs. 2.6%; risk ratio [RR] 12.67, 95% CI: 95%CI 2.39-67.04, P=0.003) or had non-hematological diseases, although the latter was not confirmed by sensitivity analysis (RR 8.80, 95%CI 0.71-109.00, P=0.09). The pooled HBV reactivation rates were lower in patients with positive than in those with negative anti-HBs in studies with hematological (7.1% vs. 21.8%; RR 0.29, 95%CI 0.19-0.46, P<0.001) or non-hematological (2.5% vs. 10.7%; RR 0.28, 95%CI 0.11-0.76, P=0.012) diseases, and rituximab-containing (6.6% vs. 19.8%; RR 0.32, 95%CI 0.15-0.69, P=0.003) or rituximab-free (3.3% vs. 9.2%; RR 0.36, 95%CI 0.14-0.96, P=0.042) regimens.

Conclusions:

The risk of HBV reactivation is high; therefore, anti-HBV prophylaxis should be recommended in HBsAg-negative, anti-HBc-positive patients with hematological diseases and/or rituximab-containing regimens, regardless of HBV DNA and anti-HBs status. In contrast, patients with non-hematological diseases or rituximab-free regimens have a low risk of HBV reactivation and may not require anti-HBV prophylaxis if they have undetectable HBV DNA and positive anti-HBs.

Isolated anti-HBc: The Relevance of Hepatitis B Core Antibody-A Review of New Issues

Hepatitis B core antibody (anti-HBc) is considered the most sensitive serological marker for history of hepatitis B virus (HBV) infection. In a subset of anti-HBc carriers, anti-HBc is present in the absence of hepatitis B surface antigen and hepatitis B surface antibody-a serological pattern known as "isolated anti-HBc" (IAHBc). IAHBc has been of clinical interest over the past several years, with growing data to suggest its role as a serological marker for occult HBV infection (OBI). This article reviews the clinical significance and association of IAHBc with hepatitis C virus (HCV) co-infection, risk of HBV reactivation during direct-acting antiviral therapy for HCV as well as immune suppression, and development of hepatocellular carcinoma (HCC). Hepatitis B core-related antigen is also highlighted as an emerging laboratory assay that may identify OBI and predict HCC development in non-cirrhotic patients receiving nucleoside/nucleotide analog therapy.

HBV reactivation in allogeneic stem cell transplant recipients: Risk factors, outcome, and role of hepatitis B virus mutations

Hepatitis B virus (HBV) reactivation (HBVr) in recipients of allogeneic hematopoetic stem cells (aHSCs) appears heterogeneously with respect to its frequency, manifestation, and outcome. The aim of this study was to present data from a large German cohort of recipients of aHSC transplantation (aHSCT), focusing on the incidence of HBVr in antibody to hepatitis B core antigen (anti-HBc)-positive aHSCT recipients, its clinical outcome, and the role of mutations in HBV. Between 2005 and 2015, 1,871 patients received aHSCT at University Hospital Essen. A follow-up of at least 6 months after transplant was available in 55 patients who were anti-HBc-positive; clinical and virologic data were analyzed. The HBV genome was sequenced with next generation technology from serum samples of 8 patients with HBVr. Thirteen out of 55 (23.6%) patients developed HBVr at a median of 26 months after aHSCT. After initiation of antiviral treatment, complete HBV DNA suppression was achieved in 7/10 (70%) patients 1 to 40 months after HBVr. Nine of 13 patients had increased alanine aminotransferase; 3 patients had compromised coagulation and model for end-stage liver disease scores of 18-27, and 1 of these patients died due to liver failure 5 weeks after HBVr. As a risk factor for HBVr, we identified anti-HBc signal to cut-off ration (S/CO) ≥7.5 before transplantation. Complete HBV DNA suppression was achieved in 7/10 patients; therapy-relevant mutations were found in 1 patient. In 4/8 patients, immune escape mutations were detected either as majority or minority variants. Conclusion: HBVr is common in anti-HBc-positive aHRCT recipients and can lead to severe hepatitis with compromised coagulation. The level of anti-HBc S/CO before transplantation is a risk factor for HBVr. Complete virologic response under adequate antiviral treatment could not be achieved in all patients. (Hepatology Communications 2017;1:1014-1023).