Transfer of humoral and cellular hepatitis B immunity by allogeneic hematopoietic cell transplantation

Cellular Immune Response after Vaccination with an Adjuvanted, Recombinant Zoster Vaccine in Allogeneic Hematopoietic Stem Cell Transplant Recipients

Hematopoietic stem cell transplant (HSCT) recipients have a high risk of developing primary varicella-zoster virus (VZV) infection and reactivation. VZV vaccination may prevent infection and reactivation. In the current study, recipients of allogeneic HSCT (34 females, 45 males) were vaccinated with adjuvanted, recombinant zoster vaccine Shingrix™, which contains the VZV glycoprotein E. Cellular immunity against various VZV antigens was analyzed by interferon-gamma ELISpot. Peripheral blood mononuclear cells (PBMC) of recipients with versus without prior shingles (n = 36 and n = 43, respectively) showed approximately twofold higher VZV-specific responses prior to and post vaccination. After the first and second vaccination, ELISpot responses towards the glycoprotein E were significantly higher in males versus females (median of spots increment 18 versus 1 and 17 versus 4, respectively, p ≤ 0.02 each). Multivariate analysis showed that shingles and sex both impacts significantly on VZV immunity. Whereas vaccination-induced changes could hardly be detected after stimulation with a whole VZV antigen, there was a significant increase in responses towards glycoprotein E after vaccination (p < 0.005). These data indicate that vaccination with Shingrix™ augmented cellular, VZV-specific immunity in HSCT recipients. Shingles and male sex could both be identified as factors leading to increased immunity.

Development of a Vaccine against Human Cytomegalovirus: Advances, Barriers, and Implications for the Clinical Practice

Human cytomegalovirus (hCMV) is one of the most common causes of congenital infection in the post-rubella era, representing a major public health concern. Although most cases are asymptomatic in the neonatal period, congenital CMV (cCMV) disease can result in permanent impairment of cognitive development and represents the leading cause of non-genetic sensorineural hearing loss. Moreover, even if hCMV mostly causes asymptomatic or pauci-symptomatic infections in immunocompetent hosts, it may lead to severe and life-threatening disease in immunocompromised patients. Since immunity reduces the severity of disease, in the last years, the development of an effective and safe hCMV vaccine has been of great interest to pharmacologic researchers. Both hCMV live vaccines-e.g., live-attenuated, chimeric, viral-based-and non-living ones-subunit, RNA-based, virus-like particles, plasmid-based DNA-have been investigated. Encouraging data are emerging from clinical trials, but a hCMV vaccine has not been licensed yet. Major difficulties in the development of a satisfactory vaccine include hCMV's capacity to evade the immune response, unclear immune correlates for protection, low number of available animal models, and insufficient general awareness. Moreover, there is a need to determine which may be the best target populations for vaccine administration. The aim of the present paper is to examine the status of hCMV vaccines undergoing clinical trials and understand barriers limiting their development.

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.

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.

Vaccinating donors for hematopoietic cell transplantation: A systematic review and future perspectives

Allogeneic hematopoietic cell transplantation (Allo-HCT) recipients are at an increased risk of infectious complications, which is a major cause of morbidity and mortality post-transplant. Vaccination of donors is one of the strategies that has been studied to improve immune reconstitution post-transplant, however the efficacy and safety of this strategy is not well reviewed in the literature. In this systematic review we sought to evaluate the current strategies of donor vaccination along with their immunogenicity, effectiveness and safety. Utilizing strict selection criteria with defined MeSH terminology, an electronic search was conducted from the following databases: Medline, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews and Scopus. Abstracts of various professional society meetings were also screened and hand searching of various reviews and guideline articles was carried out. The full text of 52 articles were reviewed, from which 5 articles satisfied the inclusion/exclusion criteria for effectiveness and immunogenicity trials and 1 article was included for safety data. Jadad score was used to assess the quality of included studies. The results of the included studies were inconsistent, and the studies were generally of suboptimal methodological quality. Most of the included studies (n = 3) investigated the use of more than one vaccine, however not all commonly used vaccines in HCT were investigated. None of the studies reported any long-term benefits for HCT recipients of vaccinated donors. Only one study reported safety data of using vaccination in donors. Given the suboptimal quality of the studies, and questionable effectiveness, donor vaccination cannot be recommended for all. Prospective high-quality vaccine trials in HCT donors are needed.

Management of chronic viral hepatitis in the hematological patient

INTRODUCTION

Infection with HBV and HCV represents a growing challenge in the management of patients with hematological malignancies. Recently, hepatitis E (HEV) was recognized as an endemic infection in developed countries and as an emerging health problem in immunocompromised patients. Areas covered: We reviewed the current knowledge on the impact of chronic viral hepatitis in the hematological setting. Epidemiological features, screening strategies and indications for treatment and monitoring have been explored and commented. Expert commentary: Knowing patient's complete HBV serostatus is mandatory in order to choose between treatment, prophylaxis or a pre-emptive approach. Recent guidelines favor treatment with high barrier molecules in all patients with chronic HBV infection and long lasting prophylaxis with those with inactive or resolved one. With regard to HCV, the new direct-acting antiviral agents have been safely administered in the hematological setting. Their use as first-line single treatment in indolent lymphomas, and combined with chemotherapy in aggressive ones, should be considered. Due to the existing risk of chronic HEV infection in the immunocompromised, screening with serum HEV-RNA should be performed in case of signs and symptoms indicative of hepatitis. In the event of HEV infection, reduction of immunosuppression and, if not feasible or unsuccessful, ribavirin treatment should be prescribed.

Lymphocyte function following radioiodine therapy in patients with thyroid carcinoma

Aim: Since the nuclear disaster in Fukushima has raised great concern about the danger of radioactivity, we here addressed the question if the therapeutic use of iodine 131, the most frequently applied radionuclide, was harmful to immune function in patients. It was our aim to define for the first time in a clinical setting how radioiodine therapy alters anti-microbial immune responses. Patients, methods: In 21 patients with thyroid carcinoma anti-microbial lymphocyte responses were assessed by lymphocyte transformation test and ELISpot – measuring lymphocyte proliferation and on a single cell level production of pro- and anti-inflammatory cytokines (interferon-γ and interleukin- 10) – prior to therapy, at day 1 and day 7 post therapy. Results: Proliferative lymphocyte responses and interferon-γ production after in vitro stimulation with microbial antigens were significantly (p < 0.05) increased at day 1 vs. pre therapy, and returned to pre therapy levels at day 7. On the contrary, at day 1 interleukin-10 production was significantly (p < 0.05) reduced. Thus, we observed a short-term increase in pro-inflammatory immune responses. However, T lymphocyte responses were in the range of healthy controls at all three time points. Conclusion: Thyroid carcinoma patients receiving radioiodine therapy do not display any sign of immunosuppression.

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.

Management of viral hepatitis in patients with haematological malignancy and in patients undergoing haemopoietic stem cell transplantation: recommendations of the 5th European Conference on Infections in Leukaemia (ECIL-5)

Viral hepatitis affects millions of people worldwide, and host immunity is the key determinant of patient outcome. Viral hepatitis can be life threatening in patients with haematological malignancy, including haemopoietic stem cell transplant recipients, because of the virus itself, or through a need to decrease the dose of chemotherapy. A past or currently infected haemopoietic stem cell donor could also transmit viral hepatitis. The burden of viral hepatitis in patients with haematological malignancies and the weak evidence on which previous guidelines are based has prompted the European Conference on Infection in Leukaemia (ECIL-5) to convene a group of experts in the fields of viral hepatitis and of haematological malignancy to specifically address previously unconsidered issues and grade the available quality of evidence according to the Infectious Diseases Society of America grading system. The group recommends that all patients should be screened for hepatotropic viruses before haematological treatment and that patients or haemopoietic stem cell donors with markers of past or current viral hepatitis should be assessed by an expert. Screening, vaccination, and treatment rules are reported in this Review.

Donor- and recipient-derived immunity in ABO incompatible living-related liver transplantation

This report describes how donor- and recipient-derived immunity was influenced by immunosuppressive treatment of ABO incompatibility (rituximab and immunoadsorption/plasmaphereses) in the long-term. We present an 8-year course of Hepatitis B virus (HBV) immunity, isohemagglutinins and B cell numbers. Whereas cellular HBV immunity was transferred from the HBV vaccinated donor (blood group A1) to the HBV naïve recipient (blood group 0), humoral HBV specific immune transfer was lacking. Starting at month 17 after transplantation, the recipient was vaccinated six times against HBV. Anti-HBs did not appear until the sixth vaccination at month 44. Immunoadsorption prior to transplantation reduced anti-A1 IgG titers from 256 to 2. Titers after transplantation remained low (⩽64). B cell numbers were below standard values up to month 26, then normalized and exceeded normal values from year 7 to 8 post transplantation. In conclusion, donor-derived B cell immunity was lost but recipient-derived immunity persisted after ABO incompatible transplantation.

Ex vivo assessment of cellular immune function - applications in patient care and clinical studies

Cellular ex vivo assays have a broad range of applications in patient care and clinical studies, especially when they are standardized and highly sensitive. As compared to analyses by molecular genetics such as the single nucleotide polymorphism (SNP) testing, they are usually more global. These assays partly mimic the in vivo situation, relying on a complex interaction of various immune cells. For example, they can be used to determine modulation of alloresponses by treatment or underlying disease, diagnose and quantify primary and secondary cellular immunodeficiency, follow-up vaccination responses, measure adoptive transfer of virus-specific immunity via hematopoietic stem cell or liver transplantation, assess allergy, antimicrobial immunity and also rare effector/memory cells directed against tumor antigens. This review will first shortly describe various cellular in vitro methods and then present applications, summarizing some own studies performed within the last 18 years.

Evaluation and management of hepatitis B virus infection in hematopoietic stem cell transplantation: before and after transplantation

HBV infection remains a major global health problem and continues to be a common cause of liver-related morbidity and mortality in both immunocompetent and immunosuppressed individuals. Reactivation of HBV is a serious complication of chemotherapy/immunosuppressive therapy in patients with HBV infection. In this article, we aim to describe the diagnosis, prevention and management of HBV infection in allogeneic hematopoietic stem cell transplant candidates, from the pre- to post-transplant period. The data currently available suggest that all individuals with hemato-/onco-logical malignancies who undergo chemotherapy/immunosuppressive therapy should be screened for hepatotropic viruses such as HBV and HCV. HBV surface antigen-positive individuals who receive chemotherapy/immunosuppressive therapy are at considerable risk of HBV reactivation. Antiviral prophylaxis prevents HBV reactivation, decreases reactivation-related morbidity and mortality, and prevents interruptions in chemotherapy/immunosuppressive therapy in such individuals. The optimal duration of antiviral prophylaxis remains to be elucidated. The vaccination of HBV-naive recipients and their donors against HBV infection prior to transplantation plays an important role in preventing acquired HBV infection. The presence of hepatitis B surface antigen positivity is not an absolute contraindication for allogeneic hematopoietic stem cell transplantation.

Clinical evaluation of safety and immunogenicity of PADRE-cytomegalovirus (CMV) and tetanus-CMV fusion peptide vaccines with or without PF03512676 adjuvant

BACKGROUND

It has been reported that cytomegalovirus (CMV) pp65-specific T cells can protect hematopoietic cell transplant (HCT) recipients from CMV complications. Two candidate CMV peptide vaccines composed of the HLA A*0201 pp65(495-503) cytotoxic CD8(+) T-cell epitope fused to 2 different universal T-helper epitopes (either the synthetic Pan DR epitope [PADRE] or a natural Tetanus sequence) were clinically evaluated for safety and ability to elicit pp65 T cells in HLA A*0201 healthy volunteers.

METHODS

Escalating doses (0.5, 2.5, 10 mg) of PADRE or Tetanus pp65(495-503) vaccines with (30 adults) or without (28 adults) PF03512676 adjuvant were administered by subcutaneous injection every 3 weeks for a total of 4 injections.

RESULTS

No serious adverse events were reported, although vaccines used in combination with PF03512676 had enhanced reactogenicity. Ex vivo responses were detected by flow cytometry exclusively in volunteers who received the vaccine coadministered with PF03512676. In addition, using a sensitive in vitro stimulation system, vaccine-elicited pp65(495-503) T cells were expanded in 30% of volunteers injected solely with the CMV peptides and in all tested subjects receiving the vaccines coinjected with PF03512676.

CONCLUSIONS

Acceptable safety profiles and vaccine-driven expansion of pp65(495-503) T cells in healthy adults support further evaluation of CMV peptide vaccines combined with PF03512676 in the HCT setting.

CLINICAL TRIALS REGISTRATION

NCT00722839.

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.

Changes of hepatitis B virus serologic status after allogeneic hematopoietic stem cell transplantation and impact of donor immunity on hepatitis B virus

Reverse seroconversion (RS) of Hepatitis B virus (HBV) has been reported after allogeneic transplantation with an incidence of 14% to 86%. However, most prior studies on HBV RS were performed in HBV nonendemic areas. In this study, the frequency of HBV RS at a single center in Korea, endemic for HBV, was evaluated. Also, the influence of the donor's immunity for HBV on posttransplantation HBV serologic changes in recipients was also investigated. A total of 288 patients underwent allogeneic transplantation between February 1996 and June 2008. We retrospectively reviewed the medical records of 288 patients and their paired donors. Among the 268 HBsAg(-) patients, 205 were assessed for posttransplantation HBsAg, and 114 (55.6%) of 205 had HBcAb before transplantation. With a median follow-up of 77.9 months, 3 of 114 patients experienced HBV RS (2.6%). With regard to donor immunity, significantly more patients with anti-HBs(-) donors experienced anti-HBs loss (P = .006), and the donor anti-HBs showed significant protective effects against the anti-HBs loss with an HR of 0.4. HBV RS after allogeneic transplantation may not be as common in HBV endemic areas. Also, donor anti-HBs showed a significant favorable effect on maintaining HBV immunity in recipients.

Viral suppression correlates with dendritic cell restoration in chronic hepatitis B patients with autologous cytokine-induced killer cell transfusion

BACKGROUND

Myeloid and plasmacytoid dendritic cells (mDCs, pDCs) are functionally impaired in patients with chronic hepatitis B (CHB). Adoptive immunotherapy can suppress hepatitis B virus (HBV) replication in CHB patients, but whether it can restore the functionality of mDCs and pDCs remains unknown.

METHODS

Autologous cytokine-induced killer (CIK) cells obtained from 14 CHB patients were transfused back to patients, case by case, to observe the effect of CIK-cell treatment on the frequency and functionality of mDCs and pDCs in CHB patients during a 24-week follow-up investigation.

RESULTS

Seven virological responders exhibited a sustained decrease in HBV load after CIK-cell transfusion; another seven non-virological responders showed only sustained high levels of HBV load during the 24-week period following CIK-cell transfusion. The rate of hepatitis B e antigen loss or seroconversion was also higher in virological responders than in non-virological responders. Importantly, we found that the frequency and cytokine-producing capacity of mDCs and pDCs increased significantly in virological responders, but not in non-virological responders. In addition, these patients exhibited a close correlation between restoration DC subsets and a decrease in HBV DNA load, rather than a change in the alanine aminotransferase level.

CONCLUSION

Cytokine-induced killer-cell treatment reduced HBV DNA load in some CHB patients; the efficiency at least partially correlates with the restoration of frequency and functionality of mDCs and pDCs.

Allografted Recipients Immunized Against Hepatitis B Virus are at High Risk of Gradual Surface Antibody (HbsAb) Disappearance Post Transplant, Regardless of Adoptive Immunity Transfer

Immunized against hepatitis B virus (HBV) recipients are at risk of developing HBV postallogeneic stem cell transplantation because of the potential loss of their HBV immunity. The aim of the study was to evaluate: (1) the HbsAb eradication incidence posttransplant and potential risk factors, (2) the impact of donor's immunity on HbsAb loss, (3) the incidence of hepatitis B in patients with HbsAb disappearance. We studied, retrospectively, in 26 vaccinated and 56 naturally immunized recipients, the posttransplant HbsAb titers for a median period of 36 (6-132) months. The probability of HbsAb loss and HBV-related hepatitis was determined in all recipients. The impact of donor's immunity origin in the HBsAb disappearance was evaluated in the subgroup of, actively or naturally, immunized recipients/donors pairs. The 5-year probability of HbsAb disappearance was 90% for all patients with 18% probability of developing hepatitis at 12 years, for those who lost HbsAb. Marrow graft, antithymocyte globulin administration, age<30 years and chronic graft-versus-host disease were significant risk factors for HbsAb loss. In the subgroup of immunized recipients/donors, the donor's active immunization significantly affected this loss. Allotransplanted patients are at high risk of losing protection against HBV. The adoptive transfer of active HBV immunity does not seem to offer sustained protection posttransplant.

Cellular and humoral immune response to a third generation hepatitis B vaccine

Liver transplantation is often the ultimate option of therapy for chronically hepatitis B virus (HBV) infected patients. Adoptive transfer of HBV immunity with the liver after vaccination of living liver donors (LLD) could be a new approach to prevent reinfection in the recipients. The time to achieve HBV immunity in LLD is usually short (1-2 months). Therefore, we established a short time immunization protocol (four injections in 2 weeks intervals) using Hepimmune, a recombinant vaccine that contains the L, M and S proteins of HBV. We examined cellular and humoral immune responses after immunization with Hepimmune and compared its immunogenicity to that of a standard HBV vaccine containing only the S protein (HBVAXPRO). Cellular immunity was measured by interferon (IFN)-gamma ELISpot and proliferation assay. HBV-specific T cells were detectable in the Hepimmune group after the second and in the standard group after the third vaccination. IFN-gamma production of T cells was significantly higher (P < 0.001) after the third vaccination with Hepimmune. Proliferative responses were also significantly (P < 0.01) higher in the Hepimmune group after the second to fourth vaccination. The humoral immune response could already be detected after the first immunization in nine of 15 Hepimmune vaccinated test persons while it was only observed in one of 15 probands of the later group. Titres differed significantly (P < 0.01) following all four vaccinations. Thus, Hepimmune appears to be a good candidate for short time immunization protocols.

Screening, prevention and treatment of viral hepatitis B reactivation in patients with haematological malignancies

The prevalence of hepatitis B virus (HBV) infection in patients with haematological malignancies is increased compared with the general population worldwide. HBV reactivation is common following chemotherapy and is associated with a high mortality despite prompt anti-viral treatment. HBV reactivation may necessitate interruption of chemotherapy with adverse prognostic consequences for the haematological disease. Chemotherapy-induced immune suppression may lead to increased HBV replication. Immune reconstitution within the weeks and months following recovery from chemotherapy may be associated with a flare of hepatitis B manifested by hepatocellular injury. Risk factors associated with HBV reactivation include detectable hepatitis B surface antigen (HBsAg), HBV DNA, Hepatitis B e (HBeAg) antigen, antibodies to hepatitis B core antigen (anti-HBc), treatment with corticosteroids, young age and male gender. Lamivudine is effective during HBV reactivation due to immune suppression. Clinical trials have demonstrated that pre-emptive antiviral treatment with lamivudine is superior to deferred treatment. Current recommendations emphasise screening for HBV infection in all haematology patients, particularly prior to chemotherapy. Patients who are HBsAg positive or HBV DNA positive should receive pre-emptive treatment with lamivudine before chemotherapy. The duration of lamivudine treatment may be prolonged commensurate with the degree of immunosuppression. HBV naïve patients should be immunised against hepatitis B, as should haematopoietic stem cell donors. In summary, overt and occult HBV pose a serious, but preventable, threat. Pre-treatment screening of patients at risk should be practiced diligently by all clinicians that treat patients with malignancies.

Identification of hepatitis B virus-specific lymphocytes in human liver grafts from HBV-immune donors

Both animal and human studies have demonstrated the adoptive transfer of immunity against hepatitis B virus (HBV) through liver transplantation that may be attributed to the presence of HBV-specific immunocompetent cells of donor origin in liver grafts. In this study, we characterized the resident lymphocytes in 41 human liver grafts by immunohistochemical staining and flow cytometry and directly identified the intragraft HBV-specific lymphocytes in relation to the donor's and subsequent recipient's immunity using enzyme-linked immunospot assay. A significant number of HBV-specific T and B cells were detectable in 59.4% (19/32) and 28.1% (9/32), respectively, of liver grafts from HBV-immune donors. The presence of various HBV-specific lymphocytes was closely associated with each other and with a higher serum titer of antibody against hepatitis B surface antigen (anti-HBs) in donors (P < 0.05). After liver transplantation, 17 of 35 (48.6%) patients with chronic HBV infection showed a spontaneous anti-HBs production, which was significantly associated with a higher number of donor-derived T lymphocytes specific for hepatitis B surface antigen (P = 0.043). In conclusion, the presence of considerable numbers of donor-derived HBV-specific immunocompetent cells in grafts may account for the adoptive transfer of HBV immunity through liver transplantation.

Progressive Disappearance of Anti-Hepatitis B Surface Antigen Antibody and Reverse Seroconversion after Allogeneic Hematopoietic Stem Cell Transplantation in Patients with Previous Hepatitis B Virus Infection

Reactivation of resolved hepatitis B virus (HBV) infection, which is known as reverse seroconversion (RS), has been reported as a rare complication of allogeneic hematopoietic stem cell transplantation. We retrospectively studied HBV serologic markers in 14 recipients with pretransplant anti-hepatitis B surface antigen antibody (anti-HBs). Progressive decreases in anti-HBs titer were observed in all cases. In 12 cases, anti-HBs titer had decreased to under the protective value. RS occurred in seven cases after disappearance of anti-HBs. Although reseroconversion occurred in five cases, two cases remained in an HBV-carrier status after resolution of hepatitis. In the other five cases, RS did not occur even after disappearance of anti-HBs. The actual risks of anti-HBs disappearance and RS were estimated to be 75.0% and 39.8% at 2 years and 100.0% and 70.0% at 5 years, respectively. In conclusion, RS is a late-onset complication with high frequency that can be predicted by careful monitoring of progressive decrease in anti-HBs titer.

Adoptive transfer of immunity: a new strategy to interfere with severe hepatitis virus reinfection after woodchuck liver transplantation

BACKGROUND

The effective transfer of humoral immunity to hepatitis B virus was first demonstrated after clinical and experimental bone marrow transplantation. This strategy is now evaluated in the woodchuck transplantation model, in which protection from reinfection can be tested.

METHODS

Animals negative for woodchuck hepatitis virus (WHV) (n = 3) were vaccinated using plasmids expressing woodchuck hepatitis virus surface (WHs), woodchuck hepatitis virus core (WHc), and woodchuck interferon-gamma in combination with a protein vaccine (WHs antigen [Ag]) three times before liver donation. Control animals (n= 4) received the liver from non-immunized donors. Chronic WHV carriers served as recipients. The viral load in serum and liver tissue was monitored pretransplant and posttransplant for up to 11 weeks by dot blot, Northern blot, Southern blot, and immunohistochemistry for WHc and WhsAg.

RESULTS

Donor vaccination was effective, as indicated by the development of anti-WHc and anti-WHs antibodies. Transplanting the livers of these donors resulted in a reduction of viral load in two of three animals. No viral DNA was detected in repeated serum samples by dot-blot hybridization technique. However, polymerase chain reaction for viral DNA extracted from serum was always positive. WHV replication intermediates and WHV RNA were absent in repeated liver biopsies. Only few hepatocytes stained weakly positive for WHc protein and frequency, and the intensity of WHsAg positive hepatocytes was low. The third animal developed severe reinfection within 3 weeks, similar to the woodchucks in the control group.

CONCLUSIONS

Liver transplantation from immunized donors to chronic carriers seems to be a promising strategy to reduce and delay severe reinfection, which may be applicable in clinical liver transplantation.

Critical overview and outlook: pathogenesis, prevention, and treatment of hepatitis and hepatocarcinoma caused by hepatitis B virus

Viral hepatitis B is an enigmatic disease in which the host's own immune response to persistent viral infection may bring about host destruction through antiviral inflammatory responses which might otherwise present as a benign or inapparent disease. The simple solution to the hepatitis B problem is by immunoprophylaxis using the vaccine licensed in 1981, which prevents both infection and the late sequelae of liver cirrhosis and hepatocarcinoma. Immunotherapeutic vaccines against persistent hepatitis B infection have not been successful and new explorations are being directed to therapies which include antisense, ribozymes, gene silencing by RNA interference (RNAi) and aptamer approaches. Limited benefits from nucleoside therapy and limitations in opportunity for liver transplantation have left a large void of curative treatments. Findings with respect to e antigen tolerance provide a basis for exploration to determine whether passively administered e antigen might suppress cell-mediated immunity, creating a commensal state in which virus persists but without pathologic damage to the host. Therapy of hepatocarcinoma by conventional chemotherapy, radiation, or surgical resection and ablation gives little hope for restoration of health unless the tumor is detected very early. The large engagement of the world medical science community to develop therapeutic vaccines against cancer is now in major clinical trials to determine the hope and credibility for the immunization approach. Vaccines based on tumor peptides which are linked to heat shock proteins and directed to host dendritic cells give reason for excitement and may be the "best show in town". A new era of tumor therapy will need to be based on new discoveries in immune function which are required to pursue immunotherapy on a more rational basis. The many facets of current hepatitis B virology, pathogenesis, immunoprophylaxis, immunotherapeusis, chemotherapy, and tumor pathogenesis and therapy are discussed here, in depth, but in keeping with needed brevity.

Correction of a mouse model of sickle cell disease: lentiviral/antisickling beta-globin gene transduction of unmobilized, purified hematopoietic stem cells

Although sickle cell anemia was the first hereditary disease to be understood at the molecular level, there is still no adequate long-term treatment. Allogeneic bone marrow transplantation is the only available cure, but this procedure is limited to a minority of patients with an available, histocompatible donor. Autologous transplantation of bone marrow stem cells that are transduced with a stably expressed, antisickling globin gene would benefit a majority of patients with sickle cell disease. Therefore, the development of a gene therapy protocol that corrects the disease in an animal model and is directly translatable to human patients is critical. A method is described in which unmobilized, highly purified bone marrow stem cells are transduced with a minimum amount of self-inactivating (SIN) lentiviral vector containing a potent antisickling beta-globin gene. These cells, which were transduced in the absence of cytokine stimulation, fully reconstitute irradiated recipients and correct the hemolytic anemia and organ pathology that characterize the disease in humans. The mean increase of hemoglobin concentration was 46 g/L (4.6 g/dL) and the average lentiviral copy number was 2.2; therefore, a 21-g/L /vector copy increase (2.1-g/dL) was achieved. This transduction protocol may be directly translatable to patients with sickle cell disease who cannot tolerate current bone marrow mobilization procedures and may not safely be exposed to large viral loads.