Successful clearance of hepatitis B virus after allogeneic stem cell transplantation: beneficial combination of adoptive immunity transfer and lamivudine

Infectious diseases in allogeneic haematopoietic stem cell transplantation: prevention and prophylaxis strategy guidelines 2016

Infectious complications after allogeneic haematopoietic stem cell transplantation (allo-HCT) remain a clinical challenge. This is a guideline provided by the AGIHO (Infectious Diseases Working Group) of the DGHO (German Society for Hematology and Medical Oncology). A core group of experts prepared a preliminary guideline, which was discussed, reviewed, and approved by the entire working group. The guideline provides clinical recommendations for the preventive management including prophylactic treatment of viral, bacterial, parasitic, and fungal diseases. The guideline focuses on antimicrobial agents but includes recommendations on the use of vaccinations. This is the updated version of the AGHIO guideline in the field of allogeneic haematopoietic stem cell transplantation utilizing methods according to evidence-based medicine criteria.

Hepatitis B Virus Replication in CD34+ Hematopoietic Stem Cells From Umbilical Cord Blood

BACKGROUND Hepatitis B virus (HBV) is a hepatotropic virus that can infect extrahepatic tissue. Whether hematopoietic stem cells (HSCs) can be infected by HBV and serve as a potential virus reservoir is still unknown. In this study, the susceptibility of CD34+ HSCs to HBV was investigated. MATERIAL AND METHODS Cord blood-derived CD34+ HSCs were exposed to HBV in vitro, and immunocytochemistry, transmission electron microscopy, and RT-PCR were used to identify viral-related proteins and specific viral genomic sequences. Then, CD34+ HSCs were challenged by different titers of HBV, and intracellular and supernatant HBV DNA, and hepatitis B surface antigen (HBsAg) levels, were examined. In addition, CD34+ peripheral blood stem cells (PBSCs) from chronic HBV carriers were isolated and cultured, and HBV DNA levels were measured. RESULTS HBV-infected CD34+ cells showed positive signals for HBsAg by DAB staining and TRITC staining, and HBV particles were identified. RT-PCR results showed that the 403 bp PCR products corresponding to the amplified hepatitis B S gene fragment were observed in CD34+ HSCs infected by HBV. In addition, supernatant and intracellular HBV DNA increased with the proliferation of CD34+ HSCs. Similar results were obtained from intracellular HBsAg quantification tests. In addition, HBV DNA levels both in cells and in supernatants of CD34+ PBSCs increased proportionally, and the increments of HBV DNA in the supernatants paralleled those found in cells. CONCLUSIONS HBV can replicate in CD34+ HSCs in cord blood or peripheral blood of chronic HBV carriers.

Sustained seroconversion of chronic hepatitis B infection after stem cell transplantation

  We present an 18-yr-old adolescent with acute lymphocytic leukemia, who underwent peripheral blood SCT with serologically and histologically documented chronic hepatitis B infection. Prior and during the transplant process, lamivudine was administered orally and he underwent SCT with a twofold decrease in viral load at the time of transplant from his HLA full matched, HBV natural immune (anti-HBs and anti-HBc positive) donor. Successful engraftment was achieved and three months after SCT, HBV seroconversion was documented accompanied with an ALT flare. Chronic graft-versus-host disease coincided after the transplantation, and he has been on immunosuppressive treatment for 25 months with sustained HBV seroconversion. We assume that adoptive immunity transfer combined with antiviral treatment might also constitute sustained seroconversion in chronic HBV, besides the reported risk of reactivation.

Development of immunity against hepatitis B virus after donor lymphocyte infusion in a peripheral blood stem cell transplantation recipient with chronic hepatitis B

Hepatitis B virus (HBV) infection is one of the main concerns in blood and marrow transplantation (BMT) patients for possible breakthrough hepatitis. Active recipient immunization against HBV was found to be ineffective and many studies had showed that the adoptive transfer of immunity against hepatitis B virus would be possible by BMT with unknown duration and mechanism. A 46-year-old female patient with chronic hepatitis B had persistent detectable HBV DNA and positive serum hepatitis B e antigen (HBeAg), even while on long-term lamivudine and adefovir therapy. She received allogeneic matched unrelated donor peripheral blood stem cell transplantation (allo-MUD-PBSCT) for her refractory acute myeloid leukemia (AML). The HBV DNA became undetectable and she developed HBeAg seroconversion after PBSCT. Her hepatitis B surface antigen (HBsAg) remained positive, which disappeared later, along with the development of antibody to HBsAg after one shot of donor lymphocyte infusion (DLI) as a boost against her AML. In summary, BMT from an immunized donor would probably bring adoptive immunity against HBV. This adoptive immunity might be further enhanced by the subsequent DLI.

[Change in the serologic markers of hepatitis B after allogenic hematopoietic stem-cell transplantation]

BACKGROUND/AIMS

This study examined the effects of hepatitis B virus (HBV) infection state and immunologic capability in both the recipients and donors of allogenic hematopoietic stem-cell transplantation (allo-HSCT) on changes in HBV serologic markers in recipients.

METHODS

A total of 537 patients underwent allo-HSCT for the treatment of leukemia, malignant lymphoma, and solid tumor. HBV serologic markers were examined in both recipients and donors prior to and following the transplantation. The mean follow-up period was 36.6 months (range 3-80 months).

RESULTS

Of the 537 patients who underwent allo-HSCT, 45 recipients were positive for HBsAg prior to transplantation. Of these 45 patients, 21 were transplanted from anti-HBs-positive donors and the remaining 24 were transplanted from anti-HBs-negative donors. In the former cases, seroconversion was noted in 4 of the 21 patients (19%). In the latter cases, however, no seroconversion was noted following the transplantation. Thirty patients who were negative for both HBsAg and anti-HBs were transplanted from anti-HBs-positive donors, and 15 out of 30 patients (50%) acquired anti-HBs. Four hundred and seven patients who were positive for anti-HBs were transplanted from anti-HBs-positive or HbsAg-negative donors; 8 of these proved HBsAg-positive following the transplantation. There were no changes in HBV serological markers following transplantation in 41 patients who were transplanted from HbsAg-positive donors.

CONCLUSIONS

Due to the adoptive immunity that was transferred from anti-HBs-positive donors, a seroconversion of HBsAg could occur in some HBsAg-positive recipients. HBsAg-positive donors had a lesser effect on the HBV serologic markers of recipients. However, a reactivation of HBV can occur following hematopoietic stem-cell transplantation in the cases of recipients or donors with a history of HBV, infection by an accompanying immune suppression. Therefore, prevention should be instigated.

Protection from infection with severe acute respiratory syndrome coronavirus in a Chinese hamster model by equine neutralizing F(ab')2

To warrant potential clinical testing, the equine anti-severe acute respiratory syndrome coronavirus (SARS-CoV) F(ab')(2) requires evaluation in as many animal models as possible. In this study, we established a new animal model, the Chinese hamster, susceptible to SARS-CoV infection. SARS-CoV could propagate effectively and sustain high levels for 1 wk in animal lungs. All animals were protected from SARS-CoV infection in preventive settings. Further, when used therapeutically this antibody led to an approximately 4-log(10) decrease in viral burden in infected animal lungs. The pathological changes in lungs correlated closely with the dose of antibody administered. The excellent preventive and therapeutic roles of equine anti-SARS-CoV F(ab')(2) in several animal models, including the novel Chinese hamster model described in this study, have provided exciting data concerning its potential clinical study.

Evaluation of the safety, immunogenicity and pharmacokinetics of equine anti-SARS-CoV F(ab')(2) in macaque

To warrant potential clinical testing, the equine anti-SARS-CoV F(ab')(2) requires evaluation in as many animal models as possible and a safety test in a primate model. In this study, we evaluated the pharmacokinetics, tolerance and immunity of this kind of antibody in macaques and rats. Results showed that the F(ab')(2) fragments had a normal metabolism in injected animals. The general physiological indexes did not differ between animals injected with anti-SARS-CoV F(ab')(2) or saline. However, a mild inflammatory response in local injection site and a moderate immune response against this antibody in the successively injected animals were observed, which however recovered 3 weeks after the last injection. The antibody titring from 1:100 to 400 against the equine anti-SARS-CoV F(ab')(2) in the inoculated hosts could be detected at week 2 during the successive injections of the equine F(ab')(2). The considerable safety of this antibody used in primates and the fact that the immune system of the host can be motivated by post-injection of the F(ab')(2) indicate that this type of anti-SARS-CoV antibody can be used for prevention and treatment of SASR, especially at the early stage of this virus infection. In addition, it can also provide the precious time for the combined use of other anti-SARS-CoV agents such as antiviral drug and vaccine.

Risk assessment in haematopoietic stem cell transplantation: The liver as a risk factor

Patients with liver dysfunction have an increased risk of developing early and late complications after haematopoietic stem-cell transplantation (HSCT). That's why it is mandatory to evaluate liver status before transplantation in all cases. This evaluation should allow us to decide whether HSCT can be performed or whether we should adopt measures focused on preventing these complications. The evaluation of the liver in an HSCT candidate requires the collection of information by history-taking, physical examination, liver-function tests and, occasionally, imaging tests and liver biopsy. Additionally, as infection by hepatitis B or C viruses represents the most relevant cause of hepatic dysfunction after HSCT, the serological status of the patient should be carefully evaluated. This chapter tries to analyse and systematise the most important aspects in the patient's evaluation. Finally, as some liver dysfunctions in the stem-cell donor can have a negative impact for the donor during the harvest and/or for the recipient during HSCT, the methodology to evaluate the donors will also be analysed.

Inhibition of infection caused by severe acute respiratory syndrome-associated coronavirus by equine neutralizing antibody in aged mice

The high susceptibility of elderly to severe acute respiratory syndrome-associated coronavirus (SARS-CoV) indicates how crucial it is to protect the elderly by various strategies. Aged BALB/c mice displayed a high susceptibility to SARS-CoV and have been a valuable platform for evaluation of strategies against SARS-CoV infection. In this study, we confirmed the validity of this model using various methods, and verified that equine anti-SARS-CoV F(ab')₂ can prevent aged animals from SARS-CoV infection. In a therapeutic setting, treatment with anti-SARS-CoV F(ab')₂ decreased viral load more than several thousand folds in the lungs. Thus, this antibody should be a potential candidate for treatment of elderly patients suffering from SARS.

Antiviral prophylaxis in patients with haematological malignancies and solid tumours: Guidelines of the Infectious Diseases Working Party (AGIHO) of the German Society for Hematology and Oncology (DGHO)

Morbidity and mortality in patients with malignancies are increased by viral infections. These mostly are reactivations of asymptomatic latent infections. They primarily concern clinical entities associated with the reactivation of herpes viruses, such as varicella zoster virus (VZV) and cytomegalovirus (CMV). Respiratory tract infections caused by influenza, parainfluenza or respiratory syncytial virus (RSV) are less common. Since reactivation of latent infections has major clinical impact, antiviral prophylaxis is an attractive approach for patients expecting immunosuppression. The main risk factor for clinically relevant reactivation is profound disruption of cellular immune response. Duration and severity of chemotherapy induced neutropenia are of lesser importance. The risk of viral complications rises significantly in the presence of sustained suppression of T-cell function, e.g. in recipients of allogeneic stem cell transplants or of alemtuzumab (Campath-1H) antibody therapy. The objective of this guideline is to review the basis of prophylactic strategies and to provide recommendations for clinicians treating patients with haematological malignancies and solid tumors.

Passive immunotherapy for influenza A H5N1 virus infection with equine hyperimmune globulin F(ab')2 in mice

Background

Avian influenza virus H5N1 has demonstrated considerable pandemic potential. Currently, no effective vaccines for H5N1 infection are available, so passive immunotherapy may be an alternative strategy. To investigate the possible therapeutic effect of antibody against highly pathogenic H5N1 virus on a mammal host, we prepared specific equine anti-H5N1 IgGs from horses vaccinated with inactivated H5N1 virus, and then obtained the F(ab')₂ fragments by pepsin digestion of IgGs.

Methods

The horses were vaccinated with inactivated H5N1 vaccine to prepare anti-H5N1 IgGs. The F(ab')₂ fragments were purified from anti-H5N1 hyperimmune sera by a protocol for 'enhanced pepsin digestion'. The protective effect of the F(ab')₂ fragments against H5N1 virus infection was determined in cultured MDCK cells by cytopathic effect (CPE) assay and in a BALB/c mouse model by survival rate assay.

Results

By the protocol for 'enhanced pepsin digestion', total 16 g F(ab')₂ fragments were finally obtained from one liter equine antisera with the purity of over 90%. The H5N1-specific F(ab')₂ fragments had a HI titer of 1:1024, and the neutralization titre of F(ab')₂ reached 1: 2048. The in vivo assay showed that 100 μg of the F(ab')₂ fragments could protect BALB/c mice infected with a lethal dose of influenza H5N1 virus.

Conclusion

The availability of highly purified H5N1-specific F(ab')₂ fragments may be promising for treatment of influenza H5N1 infection. Our work has provided experimental support for the application of the therapeutic equine immunoglobulin in future large primate or human trials.

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Fatal fulminant hepatitis B after withdrawal of prophylactic lamivudine in hematopoietic stem cell transplantation patients

Hepatitis B virus (HBV) reactivation can give rise to acute hepatitis and even fatal fulminant hepatitis in patients receiving immunosuppressive or cytostatic treatment. Recently, the prophylactic use of lamivudine for HBV reactivation in HBV surface antigen-positive chronic-disease patients undergoing hematopoietic stem cell transplantation (HSCT) has been reported. However, the appropriate duration for this prophylactic therapy is unclear. Here, we report 2 cases of fatal fulminant hepatitis B reactivation in HSCT patients after lamivudine withdrawal. One patient with non-Hodgkin's lymphoma completed 6 courses of CHOP chemotherapy (cyclophosphamide, doxorubicin, vincristine [Oncovin], and prednisone) and autologous peripheral blood SCT (PBSCT). Lamivudine was discontinued 3 months after transplantation. The second patient had acute myeloid leukemia. He received induction chemotherapy and postremission allogeneic PBSCT as late intensified consolidation therapy. Lamivudine treatment was discontinued 10 months after transplantation. In both patients, HBV reactivation 2 to 3 months following lamivudine cessation led to fatal fulminant hepatitis. We suggest that the duration of prophylactic use of lamivudine in chronic HBV carriers receiving HSCT be prolonged until the patient's immune system has been reconstituted.

Protection of Mammalian Cells from Severe Acute Respiratory Syndrome Coronavirus Infection by Equine Neutralizing Antibody

The aetiological agent for severe acute respiratory syndrome (SARS) has been determined to be a new type of coronavirus (SARS-CoV) that infects a wide range of mammalian hosts. Up to now, there have been no specific drugs to protect against SARS-CoV infection, thus developing effective strategies against this newly emerged viral infection warrants urgent efforts. Adoptive immune therapy with pathogen-specific heterologous immunoglobulin has been successfully used to control the dissemination of many viral infections. To investigate whether a neutralizing antibody against SARS-CoV raised in an artiodactylous host can have a protective role on primate cells, we prepared serum IgGs and their pepsin-digested F(ab’)2 fragments from horses inoculated with purified SARS-CoV (BJ-01 strain). The protective effect of the F(ab’)2 fragments against SARS-CoV infection was determined in cultured Vero E6 cells by cytopathic effect (CPE), MTT and plaque-forming assays and in a Balb/c mouse model by CPE and quantitative RT-PCR. The results showed the neutralization titres of F(ab’)2 from three horses all reached at least 1:1600, and 50 μg of the F(ab’)2 fragments could completely neutralize 1x104 TCID50 SARS-CoV in vivo. Additionally, we observed that F(ab’)2 against BJ-01 strain could also protect cells from infection by the variant GZ-01 strain in vitro and in vivo. Our work has provided experimental support for testing the protective equine immunoglobulin in future large primate or human trials.

Horse antilymphocytic globulin in hepatitis B exacerbation after bone marrow transplantation adoptive immunity transfer

We describe the case of a HBsAg+, HBeAg+ carrier, treated with lamivudine, who experienced exacerbation of hepatitis after BMT from an anti-HBs+, anti-HBc+, anti-HBe+ donor. The serological profile of the donor and the timing of exacerbation suggested that the adoptive immunity transfer played a major pathogenetic role. Antilymphocyte globulin administration resulted in resolution of hepatitis and seroconversion to anti-HBs+. Therapy aimed at blocking the effector arm of liver damage could represent a novel approach to avoid the risk of progression to fulminant hepatitis without hampering the chances of recovery from hepatitis B.