Immunization with an adjuvant hepatitis B vaccine after liver transplantation for hepatitis B-related disease

An Overview of the Current Hepatitis B Treatment Strategies after Liver Transplantation

Currently, liver transplantation (LT) is considered as the only option for the treatment of patients with various causes of liver failure, including patients with chronic hepatitis B virus (HBV) infections. Overall, patients with HBV who undergo LT are at increased risk of hepatitis B infection recurrence. Although the current knowledge regarding the pathophysiology of this infection has been dramatically increased over the past few decades, it is still considered a complex disease process with varying degrees of clinical characteristics and changing patterns over time. There are various treatment strategies for preventing HBV recurrence in the LT setting. Generally, these regimens include oral nucleoside/ nucleotide analogues (NAs), hepatitis B immune globulin (HBIG), and vaccines or the combination of these drugs. The treatment strategy of choice should be based on cost-effectiveness, along with other patients underlying conditions. In this case, studies indicate that potent NAs are more cost-effective than HBIG in most case scenarios. In this article, we aimed to review the general medications used in the prophylaxis of the recurrence of HBV infection after LT.

De novo HBV Hepatitis in a Child with Liver Transplantation

Background: Omental torsion (OT) presents as a rare, infrequent pathology with often non-specific symptoms. This condition occurs when the greater omentum is twisted around its axis, producing perfusion defects and vascular impairment of the organ. This case report describes an overweight 26-year-old Caucasian man presenting with acute abdomen in previous appendectomy, whose definitive surgical diagnosis was omental torsion. Omental torsion is a rare pathology regarding the causes of acute abdomen associated with a challenging diagnosis. Case report: We report about a female toddler with liver transplantation due to extrahepatic biliary atresia, who was detected to have positive HBsAg, 27 months after transplantation. Before liver transplantation, routine serologic assessments were negative for HBV infection, the child was vaccinated with three doses of HBV vaccine and developed seroprotective Abs titers. Organ donor was the father, who was negative for HBV infection had negative anti-HBc and had seroprotective titers of anti HBs. A PCR assay in our patient revealed the presence of serum HBV DNA with an increased viral load. The patient started antiviral treatment with Entecavir and had serological response within three months, showing elimination of serum HBV DNA and HBsAg values. Serological investigation of all family members and information from the transplantation unit did not reveal the infection source. Conclusion:de novo Hepatitis B in liver recipients is a rare phenomenon. In donor positive anti-HBc cases, it appears as reactivation of HBV infection. There are very few published cases in which recipients developed de novo HBV hepatitis, despite seronegative HBcAb donors. Caregivers should always be alert for de novo hepatitis B in liver transplanted children as loss of immunity could be an unexpected phenomenon, despite pre-transplant negative serology of the donor and recipient as so as despite seroprotective Abs titers after immunisation of the recipient.

Humoral and Cellular Vaccination Responses against SARS-CoV-2 in Hematopoietic Stem Cell Transplant Recipients

The cellular response to SARS-CoV-2 vaccination and infection in allogeneic hematopoietic stem cell transplant (HSCT) recipients is not yet clear. In the current study, HSCT recipients prior to and post vaccination were tested for SARS-CoV-2-specific humoral and cellular immunity. Antibodies against spike (S) 1 were assessed by Anti-SARS-CoV-2 IgG ELISA (Euroimmun). Cellular immunity was analyzed by an in house interferon-gamma ELISpot and T-SPOT.COVID (Oxford Immunotec), using altogether seven SARS-CoV-2-specific antigens. In 117 HSCT patients vaccinated twice, SARS-CoV-2 IgG antibodies were significantly higher than in HSCT controls pre vaccination (p < 0.0001). After the second vaccination, we observed a median antibody ratio of 4.7 and 68% positive results, whereas 35 healthy controls reached a median ratio of 9.0 and 100% positivity. ELISpot responses in patients were significantly (p < 0.001) reduced to ≤33% of the controls. After the second vaccination, female HSCT patients and female healthy controls showed significantly higher antibody responses than males (6.0 vs. 2.1 and 9.2 vs. 8.2, respectively; p < 0.05). Cellular immunity was diminished in patients irrespective of sex. In conclusion, especially male HSCT recipients showed impaired antibody responses after SARS-CoV-2 vaccination. Changing the vaccine schedule or composition could help increase vaccine responses.

Clinical and Histological Long-Term Follow-Up of De Novo HBV-Infection after Liver Transplantation

Background and Objectives: Development of hepatitis-B is considered a serious complication after liver transplantation. HBV de novo infection is a rather rare phenomenon, however it deserves attention in the era of donor organ shortage. The aim of the present analysis was to examine its course in liver transplant patients. Materials and Methods: Prevalence of de novo HBV-infections was extracted from our local transplant data base. Analysis focused on the moment of HBV-detection and on the long-term follow-up in terms of biochemical and histological changes over 30 years. Results: 46 patients were identified with the diagnosis of de novo hepatitis B. Median time from liver transplantation to diagnosis was 397 days (7-5505). 39 patients received antiviral therapy. No fibrosis progression could be detected, whereas the grade of inflammation significantly lessened from the moment of HBV detection to the end of histological follow-up over a median of 4344 days (range 123-9490). Patients with a poor virological control demonstrated a significantly poorer overall survival. Conclusions: De novo hepatitis B in liver transplant patients is a condition that can be controlled very well without significant fibrosis progression or graft loss if recognized on time within a regular transplant follow-up schedule.

A Global View to HBV Chronic Infection: Evolving Strategies for Diagnosis, Treatment and Prevention in Immunocompetent Individuals

Hepatitis B Virus (HBV) is a significant public health challenge. Around 250 million people live with chronic HBV infection. With a global approach to this issue, we focus on new perspective in diagnosis, management and prevention of HBV chronic infection. Precise diagnosis of HBV status is crucial to guide patient management. Although available drugs reduce the risk of liver disease progression, they are not able to definitely eradicate HBV, and new therapeutic options are urgently needed. Thus, prevention of HBV infection is still the most effective strategy to achieve the control of the disease. Key aspects of prevention programs include surveillance of viral hepatitis, screening programs and immunization strategies. In spite of the high success rate of licensed HBV vaccines, a need for improved vaccine persists, especially in order to provide coverage of current non-responders.

High prevalence of hepatitis B-antibody loss and a case report of de novo hepatitis B virus infection in a child after living-donor liver transplantation

AIM

To assess the seroprevalence of hepatitis B virus (HBV) immunity among previously vaccinated pediatric liver transplant recipients and present a case report of de novo hepatitis B infection after liver transplantation.

METHODS

This study focused on children with chronic liver diseases who received primary hepatitis B immunization and had a complete dataset of anti-HBs before and after liver transplantation between May 2001 and June 2017. Medical records were retrospectively reviewed for potential factors relating to HBV immunity loss.

RESULTS

In total, 50 children were recruited. The mean time from liver transplantation to anti-HBs testing was 2.53 ± 2.11 years. The mean anti-HBs levels before and after liver transplantation were 584.41 ± 415.45 and 58.56 ± 6.40 IU/L, respectively. The rate of non-immunity (anti-HBs < 10 IU/L) in the participants was 46% (n = 26) at one year, 57% (n = 7) at two years and 82% (n = 17) at > three years following liver transplantation. The potential factors relating to HBV immunity loss after liver transplantation were identified as anti-HBs (P = 0.002), serum albumin (P = 0.04), total bilirubin (P = 0.001) and direct bilirubin (P = 0.003) before liver transplantation. A five-year-old boy with biliary cirrhosis received 4 doses of HBV vaccine with an anti-HBs titer of > 1000 IU/L and underwent liver transplantation; his anti-HBc-negative father was the donor. After liver transplantation, the boy had stenosis of the hepatic artery up to the inferior vena cava anastomosis and underwent venoplasty three times. He also received subcutaneous injections of enoxaparin for 5 mo and 20 transfusions of blood components. Three years and ten months after the liver transplantation, transaminitis was detected with positive tests for HBsAg, HBeAg, and anti-HBc (2169.61, 1706 and 8.45, respectively; cutoff value: < 1.00) and an HBV viral load of 33212320 IU/mL.

CONCLUSION

The present study showed that loss of hepatitis B immunity after liver transplantation is unexpectedly common. In our case report, despite high levels of anti-HBs prior to transplantation, infection occurred at a time when, unfortunately, the child had lost immunity to hepatitis B after liver transplantation.

The detection of (total and ccc) HBV DNA in liver transplant recipients with hepatitis B vaccine against HBV reinfection

To investigate the levels of hepatitis B virus total DNA (HBV DNA) and covalently closed circular (ccc) DNA in liver transplant recipients who received hepatitis B vaccination, including responders and non-responders, following liver transplantation due to hepatitis B-related diseases and to investigate the efficacy of hepatitis B immune reconstitution against HBV reinfection. Twenty responders and 34 non-responders were enrolled in the present study. The levels of HBV total DNA and ccc DNA in peripheral blood mononuclear cells (PBMCs) and the liver and plasma were detected by real-time polymerase chain reaction (PCR). Fifty-three blood samples and 38 liver allograft tissues were acquired. For the responders, the mean serum titer for anti-HBs (antibodies against hepatitis B surface antigen) was 289 (46.64-1000) IU/ml. Also for the responders, HBV total DNA was detected in PBMCs for one recipient and in the liver for another recipient, but ccc DNA was not detected in either of those 2 recipients. For the non-responders, HBV total DNA was detected in PBMCS for 2 recipients, neither of whom had ccc DNA. Also for the non-responders, HBV total DNA was detected in the livers of 3 recipients, 2 of whom also had ccc DNA. All responders had discontinued hepatitis B immunoglobulin (HBIG), and 13 responders had discontinued antiviral agents. One responder experienced HBV recurrence during the follow-up period. For the majority of liver transplant recipients, no HBV total DNA or ccc DNA was detected in the blood or liver. The lack of HBV total DNA and ccc DNA both in PBMCs and the liver in liver transplant recipients who received hepatitis B vaccination to prevent HBV reinfection should be a prerequisite for the withdrawal of HBIG and/or antiviral agents.

Rational Basis for Optimizing Short and Long-term Hepatitis B Virus Prophylaxis Post Liver Transplantation: Role of Hepatitis B Immune Globulin

Antiviral therapy using newer nucleos(t)ide analogues with lower resistance rates, such as entecavir or tenofovir, suppress hepatitis B virus (HBV) replication, improve liver function in patients with compensated or decompensated cirrhosis, and delay or obviate the need for liver transplantation in some patients. After liver transplantation, the combination of long-term antiviral and low-dose hepatitis B Immune globulin (HBIG) can effectively prevent HBV recurrence in greater than 90% of transplant recipients. Some forms of HBV prophylaxis need to be continued indefinitely after transplantation but, in patients with a low-risk of HBV recurrence (i.e., HBV DNA levels undetectable before transplantation), it is possible to discontinue HBIG and maintain only long-term nucleos(t)ide analogue(s) therapy. A more cautious approach is necessary for those patients with high pretransplant HBV DNA levels, those with limited antiviral options if HBV recurrence occurs (i.e., HIV or hepatitis D virus coinfection, preexisting drug resistance), those with a high risk of hepatocellular carcinoma recurrence, and those at risk of noncompliance with antiviral therapy. In this group, HBIG-free prophylaxis cannot be recommended.

The combination of long-term antiviral and low-dose Hepatitis B Immune globulin (HBIG) can effectively prevent HBV recurrence in > 90% of liver transplant recipients. In patients with low HBV DNA levels, nucleos(t)ide analogue(s) treatment without HBIG is possible.

Prevention and Treatment of Recurrent Hepatitis B after Liver Transplantation

Chronic hepatitis B is a global health problem that leads to development of various complications, such as cirrhosis, liver cancer, and liver failure requiring liver transplantation. The recurrence of hepatitis B virus (HBV) post-liver transplantation is a major cause of allograft dysfunction, cirrhosis of the allograft, and graft failure. Patients with high viral load at the time of transplantation, hepatitis B e antigen (HBeAg) positivity, or those with a history of anti-viral drug resistance are considered as high-risk for recurrent HBV post-liver transplantation, while patients with low viral load, including HBeAg negative status, acute liver failure, and hepatitis D virus (HDV) co-infection are considered to be at low-risk for recurrent HBV post-liver transplantation. Antivirals for patients awaiting liver transplantation(LT) cause suppression of HBV replication and reduce the risk of recurrent HBV infection of the allograft and, therefore, all HBV patients with decompensated cirrhosis should be treated with potent antivirals with high genetic barrier to resistance (entecavir or tenofovir) prior to liver transplantation. Prevention of post-liver transplantation recurrence should be done using a combination of hepatitis B immunoglobulin (HBIG) and antivirals in patients at high risk of recurrence. Low dose HBIG, HBIG-free protocols, and monoprophylaxis with high potency antivirals can still be considered in patients at low risk of recurrence. Even, marginal grafts from anti-HBc positive donors can be safely used in hepatitis B surface antigen (HBsAg) negative, preferably in anti-hepatitis B core (HBc)/anti-hepatitis B surface (HBs) positive recipients. In this article, we aim to review the mechanisms and risk factors of HBV recurrence post-LT in addition to the various treatment strategies proposed for the prevention of recurrent HBV infection.

Prophylactic managements of hepatitis B viral infection in liver transplantation

Liver transplantation (LT) is a considerably effective treatment for patients with end-stage hepatitis B virus (HBV)-related liver disease. However, HBV infection often recurs after LT without prophylaxis. Since the 1990s, the treatment for preventing HBV reinfection after LT has greatly progressed with the introduction of hepatitis B immunoglobulin (HBIG) and nucleos(t)ide analogues (NAs), resulting in improved patient survival. The combination therapy consisting of high-dose HBIG and lamivudine is highly efficacious for preventing the recurrence of HBV infection after LT and became the standard prophylaxis for HBV recurrence. However, mainly due to the high cost of HBIG treatment, an alternative protocol for reducing the dose and duration of HBIG has been evaluated. Currently, combination therapy using low-dose HBIG and NAs is considered as the most efficacious and cost-effective prophylaxis for post-LT HBV reinfection. Recently, NA monotherapy and withdrawal of HBIG from combination therapy, along with the development of new, potent high genetic barrier NAs, have provided promising efficacy, especially for low-risk recipients. This review summarizes the prophylactic protocol and their efficacy including prophylaxis of de novo HBV infection from anti-HBc antibody-positive donors. In addition, challenging approaches such as discontinuation of all prophylaxis and active immunity through hepatitis B vaccination are discussed.

Management of hepatitis B virus infection after liver transplantation

Chronic hepatitis B virus (HBV) infection is responsible for up to 30% of cases of liver cirrhosis and up to 53% of cases of hepatocellular carcinoma. Liver transplantation (LT) is the best therapeutic option for patients with end-stage liver failure caused by HBV. The success of transplantation, though, depends on receiving prophylactic treatment against post-transplant viral reactivation. In the absence of prophylaxis, liver transplantation due to chronic hepatitis B (CHB) is associated with high rates of viral recurrence and poor survival. The introduction of treatment with hepatitis B immunoglobulins (HBIG) during the 1990s and later the incorporation of oral antiviral drugs have improved the prognosis of these patients. Thus, LT for CHB is now a universally accepted option, with an estimated 5 years survival of around 85% vs the 45% survival seen prior to the introduction of HBIG. The combination of lamivudine plus HBIG has for many years been the most widely used prophylactic regimen. However, with the appearance of new more potent oral antiviral agents associated with less resistance (e.g., entecavir and tenofovir) for the treatment of CHB, new prophylactic strategies are being designed, either in combination with HBIG or alone as a monotherapy. These advances have allowed for more personalized prophylaxis based on the individual risk profile of a given patient. In addition, the small pool of donors has required the use of anti-HBc-positive donors (with the resulting possibility of transmitting HBV from these organs), which has been made possible by suitable prophylactic regimens.

Management of chronic hepatitis B before and after liver transplantation

Liver transplantation remains the only curative option for eligible patients with complications of chronic hepatitis B (CHB) infection, including severe acute hepatitis flares, decompensated cirrhosis, and hepatocellular carcinoma. In general, all patients with CHB awaiting liver transplantation should be treated with oral nucleos(t)ide analogs (NAs) with high barriers to resistance to prevent potential flares of hepatitis and reduce disease progression. After liver transplantation, lifelong antiviral therapy is also required to prevent graft hepatitis, which may lead to subsequent graft loss. Although combination therapy using NA and hepatitis B immune globulin (HBIG) has been the regimen most widely adopted for over a decade, recent studies have demonstrated that newer NAs with low rates of resistance are effective in preventing graft hepatitis even without the use of HBIG, achieving excellent long term outcome. For patients without pre-existing resistant mutations, monotherapy with a single NA has been shown to be effective. For those with resistant strains, a combination of nucleoside analog and nucleotide analog should be used. To date, clinical trials using therapeutic vaccination have shown suboptimal response, as CHB patients likely have an immune deficit against HBV epitopes. Future strategies include targeting different sites of the hepatitis B replication cycle and restoring the host immunity response to facilitate complete viral eradication.

Reestablishment of active immunity against HBV graft reinfection after liver transplantation for HBV-related end stage liver disease

Background. The aim of this study was to establish a hepatitis B virus (HBV) vaccination protocol among orthotopic liver transplantation (OLT) recipients under the coverage of a low-dose hepatitis B immunoglobulin (HBIG) combined with an antiviral agent prophylaxis protocol. Method. Two hundred OLT recipients were included in this study. The vaccine was injected at months 0, 1, 2, and 6. Low-dose HBIG combined with antiviral agent prophylaxis protocol was continued before reestablishment of active immunity against HBV in order to maintain a steady anti-HBs titer. Results. Active immunity against HBV was reestablished in 50 patients, for an overall response rate of 25%. Of the 50 patients, 24 discontinued HBIG without any HBV graft reinfection during a follow-up period of 26.13 ± 7.05 months. 21 patients discontinued both HBIG and antiviral agents during a follow-up period of 39.86 ± 15.47 months, and 4 patients among them appeared to be HBsAg positive. There was no recipient death or graft loss because of HBV reinfection. Conclusions. Vaccination preventing HBV reinfection for OLT recipients is feasible. The strategy withdrawal of HBIG with induction of active immunity against hepatitis B is reasonable for long-term survivors of OLT; however, discontinuation nucleoside analogues should be cautious.

Prophylaxis against Recurrence in Liver Transplantation Patients with Hepatitis B Virus: What is New?

Hepatitis B virus (HBV) causes an endemic infection that affects nearly 2 billion patients worldwide. It is one of the leading causes of liver cirrhosis, hepatocellular carcinoma (HCC), and liver transplantation (LT). Recurrence of HBV infection after LT is due to specific HBV-host genome interactions. Although hepatitis B immunoglobulin treatment constituted the backbone of HBV recurrence, use of the nucleoside and nucleotide analogs (especially the ones with a higher genetic barrier to resistance), either alone or in combination, offer us new and powerful options in overcoming this serious issue.

Prevention of post liver transplant HBV recurrence

BACKGROUND

Twenty years ago, liver transplantation for hepatitis B had been a relative contraindication to universal HBV recurrence and poor outcomes. Over the ensuing two decades, there has been refinement of prevention strategies in order to minimize HBV recurrence in the allograft.

RESULTS

Currently, the most efficacious and cost-effective strategies include newer oral antiviral drugs in combination with low doses of hepatitis B immunoglobulin (HBIG). More recently, strategies have been successful in withdrawing HBIG and newer approaches of HBIG avoidance are currently under development.

CONCLUSION

Thus, 20 years afterward, HBV recurrence is <5% and outcomes following liver transplantation are excellent.

TLR-based immune adjuvants

This work describes the nature and strength of the immune response induced by various Toll-like receptor ligands and their ability to act as vaccine adjuvants. It reviews the various ligands capable of triggering individual TLRs, and then focuses on the efficacy and safety of those agents for which clinical results are available.

Different effect of HBV vaccine after liver transplantation between chronic HBV carriers and non-HBV patients who received HBcAb-positive grafts

BACKGROUND

Combination of nucleos(t)ide analogue and anti-HBs immunoglobulin (HBIg) is the standard protocol for prevention of HBV reactivation after liver transplantation, but because of the extremely high cost of HBIg, HBV vaccine is tried as a much cheaper and potentially safer substitute. Here we show the different effect of HBV vaccine between chronic HBV carrier and non-HBV patients who received grafts from HBc antibody-positive donors.

METHODS

Fifteen chronic HBV carriers and 6 non-HBV patients who received grafts from HBc antibody-positive donors were included in this study. These patients received double dose of pre-S-containing HBV vaccine every month from later than 12 months after liver transplantation. Successful vaccination was defined as HBsAb >100 IU/l without HBIg administration for 3 months.

RESULTS

None of the 15 chronic HBV carriers succeeded in maintaining high enough HBsAb titers. In contrast, 5 of 6 non-HBV patients with HBcAb-positive donors achieved HBsAb >100 IU/l without HBIg coadministration. Recipient HBV status (HBV carrier/non-HBV) was considered to have a stronger effect on vaccine success (p < 0.001) though recipient age (p = 0.006) was also selected as a significant factor.

CONCLUSIONS

Recipient HBV status seems to be the most important factor affecting success of HBV vaccine after liver transplantation. In non-HBV patients who received grafts from HBcAb-positive donors, HBV vaccination is an effective, cost-saving, and safe method for prevention of HBV reactivations. In contrast in chronic HBV patients, response rate was quite poor, so some modifications such as combination with adjuvant or modification of administration schedules should be considered.

Optimized subunit vaccine protects against experimental leishmaniasis

Development of a protective subunit vaccine against Leishmania spp. depends on antigens and adjuvants that induce appropriate immune responses. We evaluated a second generation polyprotein antigen (Leish-110f) in different adjuvant formulations for immunogenicity and protective efficacy against Leishmania spp. challenges. Vaccine-induced protection was associated with antibody and T cell responses to Leish-110f. CD4 T cells were the source of IFN-gamma, TNF, and IL-2 double- and triple-positive populations. This study establishes the immunogenicity and protective efficacy of the improved Leish-110f subunit vaccine antigen adjuvanted with natural (MPL-SE) or synthetic (EM005) Toll-like receptor 4 agonists.

Current prophylactic strategies against hepatitis B virus recurrence after liver transplantation

Prophylactic strategies against hepatitis B virus (HBV) recurrence after liver transplantation (LT) are essential for patients with HBV-related disease. Before LT, lamivudine (LAM) was proposed to be down-graded from first- to second-line therapy. In contrast, adefovir dipivoxil (ADV) has been approved not only as first-line therapy but also as rescue therapy for patients with LAM resistance. Furthermore, combination of ADV and LAM may result in lower risk of ADV resistance than ADV monotherapy. Other new drugs such as entecavir, telbivudine and tenofovir, are probably candidates for the treatment of hepatitis-B-surface-antigen-positive patients awaiting LT. After LT, low-dose intramuscular hepatitis B immunoglobulin (HBIG), in combination with LAM, has been regarded as the most cost-effective regimen for the prevention of post-transplant HBV recurrence in recipients without pretransplant LAM resistance and rapidly accepted in many transplant centers. With the introduction of new antiviral drugs, new hepatitis B vaccine and its new adjuvants, post-transplant HBIG-free therapeutic regimens with new oral antiviral drug combinations or active HBV vaccination combined with adjuvants will be promising, particularly in those patients with low risk of HBV recurrence.

Rational design of a multiepitope vaccine encoding T-lymphocyte epitopes for treatment of chronic hepatitis B virus infections

Protein sequences from multiple hepatitis B virus (HBV) isolates were analyzed for the presence of amino acid motifs characteristic of cytotoxic T-lymphocyte (CTL) and helper T-lymphocyte (HTL) epitopes with the goal of identifying conserved epitopes suitable for use in a therapeutic vaccine. Specifically, sequences bearing HLA-A1, -A2, -A3, -A24, -B7, and -DR supertype binding motifs were identified, synthesized as peptides, and tested for binding to soluble HLA. The immunogenicity of peptides that bound with moderate to high affinity subsequently was assessed using HLA transgenic mice (CTL) and HLA cross-reacting H-2(bxd) (BALB/c x C57BL/6J) mice (HTL). Through this process, 30 CTL and 16 HTL epitopes were selected as a set that would be the most useful for vaccine design, based on epitope conservation among HBV sequences and HLA-based predicted population coverage in diverse ethnic groups. A plasmid DNA-based vaccine encoding the epitopes as a single gene product, with each epitope separated by spacer residues to enhance appropriate epitope processing, was designed. Immunogenicity testing in mice demonstrated the induction of multiple CTL and HTL responses. Furthermore, as a complementary approach, mass spectrometry allowed the identification of correctly processed and major histocompatibility complex-presented epitopes from human cells transfected with the DNA plasmid. A heterologous prime-boost immunization with the plasmid DNA and a recombinant MVA gave further enhancement of the immune responses. Thus, a multiepitope therapeutic vaccine candidate capable of stimulating those cellular immune responses thought to be essential for controlling and clearing HBV infection was successfully designed and evaluated in vitro and in HLA transgenic mice.

Hepatitis B vaccination after living donor liver transplantation

BACKGROUND

The efficacy of hepatitis B vaccination after living donor liver transplantation (LDLT) in patients transplanted anti-HBc-positive grafts or in patients who underwent LDLT for fulminant hepatitis B remains unknown.

METHOD

A total of 11 recipients who underwent LDLT between October 1996 and October 2002 prospectively received hepatitis B vaccination three times within 6 months, starting a few weeks after the cessation of hepatitis B immunoglobulin (HBIG) prophylaxis. Serial quantification of the hepatitis B surface antibody (HBsAb) was performed.

RESULTS

At the last follow-up, six out of 11 patients (54.5%) had seroconversion and were free from HBIG thereafter. Four out of those six responders had a peak HBsAb level of more than 1000 IU/L, while the other two patients had peak HbsAb levels below 1000 IU/L. Five patients never responded to the treatment and were back to HBIG prophylaxis. The average age of the six responders was 25.5 years, which was significantly younger than that of non-responders (44.4 years, P<0.05). None had side effects or hepatitis B infection during the study period.

CONCLUSIONS

In conclusion, the use of this treatment modality could be used to reduce the cost of HBIG.

Prevention of hepatitis B virus recurrence after liver transplantation

Liver transplantation for hepatitis B virus (HBV)-related liver disease has changed from a contraindication to outcomes comparable with non-HBV-related liver transplantations during the last two decades. Mainly the implementation of immunoprophylaxis with hepatitis B immunoglobulin (HBIG) and the use of nucleoside analogs such as lamivudine and adefovir account for this dramatic change. The standard of care in most centers today consists of lamivudine treatment in replicating hepatitis B pre-orthotopic liver transplantation (OLT) and a combination regimen of lamivudine and HBIG post-OLT. With adefovir, a potent antiviral drug became available in recent years that allows for the treatment of patients with lamivudine-resistant tyrosine-methionine-aspartate-aspartate (YMDD)-mutant HBV. In the transplantation setting, first studies indicate that a triple prophylactic therapy consisting of lamivudine, adefovir, and HBIG will become the standard of care for YMDD-mutant-related hepatitis B. With new drugs emerging for the treatment of chronic HBV, there is optimism for new options also in the transplant setting.

Efficacy of a pre-S containing vaccine in patients receiving lamivudine prophylaxis after liver transplantation for chronic hepatitis B

Lamivudine monoprophylaxis against hepatitis B virus (HBV) reinfection after liver transplantation is associated with recurrence due to escape mutants and second generation recombinant HBV vaccine is not effective. We studied the efficacy of two courses each of three double-doses (20 microg) of third-generation recombinant pre-S containing vaccine (Sci-B-Vac) in 20 patients on lamivudine prophylaxis at a median of 637 days (range, 390-2666 days) after transplantation. At enrollment, all patients were seronegative for HBsAg, anti-HBs and HBVDNA (by qPCR). Lamivudine (100 mg/day) was continued throughout the study. Five patients (25%) responded to the first course and five additional patients responded after the second course (overall response rate 50%). The response rate was 88% in patients younger than 50 years old and 25% in older patients (p = 0.02). The median peak anti-HBs titer was 153 mIU/mL with six responders having a titer >100 mIU/mL and seven sustained >6 months. Among seven previous nonresponders to second generation recombinant vaccine, three (44%) responded. At the end of the study, all patients remained seronegative for HBsAg. In conclusion, Sci-B-Vac is effective in about 50% of patients receiving lamividine prophylaxis and may prevent recurrence due to escape mutants.

Hepatitis B virus immunization with an adjuvant containing vaccine after liver transplantation for hepatitis B-related disease: failure of humoral and cellular immune response

Long-term hepatitis B reinfection prophylaxis after liver transplantation with hepatitis B immunoglobulin (HBIG) and nucleoside analogues is expensive and inconvenient. Studies evaluating humoral immune responses to hepatitis B virus (HBV) vaccines showed conflicting results. Best results were achieved under continuous HBIG administration with an adjuvant-containing HBsAg vaccine. In the present study, 8 patients who had been HBsAg positive and HBV DNA negative prior to liver transplantation were immunized with HBsAg-vaccine containing the adjuvant 3-deacylated monophosphoryl-lipid-A. Vaccination was started after discontinuation of HBIG. Six vaccinations were administered at weeks 0, 2, 4, 12, 16 and 24. Humoral (anti-HBs titres) and cellular (enzyme-linked immunospot assay and fluorescence-activated cell sorting analysis) immune responses were studied. Only one of eight patients responded with a humoral immune response (maximum anti-HBs titre 561 U/l). In this patient, decrease of anti-HBs titre before vaccination was significantly slower than in the other seven patients and anti-HBs did not become negative before first vaccination. A T-cell response to HBsAg could not be detected in any of the patients. The responder was the only patient who showed a T-cell response to HBcAg. In conclusion, the adjuvant-containing vaccine did not induce a humoral or a detectable cellular immune response in most patients. Patient-related preconditions and concomitant HBIG administration should be further investigated as possible predictors for response.

Asian-Pacific consensus statement on the management of chronic hepatitis B: a 2005 update

BACKGROUND/AIMS

A large amount of new data on the treatment of chronic hepatitis B has become available such that the 2003 consensus statement requires revision and update.

METHODS

New data were presented, discussed and debated in an expert pre-meeting to draft a revision. The revised contents were finalized after discussion in a general meeting of APASL.

RESULTS

Conceptual background, including the efficacy and safety profile of currently available and emerging drugs, was reviewed. Nineteen recommendations were formed and unresolved issues and areas for further study were suggested.

CONCLUSION

The current therapy of chronic hepatitis B is modestly effective but not satisfactory. The development of new drugs and new strategies is required to further improve the outcomes of treatment.

Viral infection in the renal transplant recipient

Viruses are among the most common causes of opportunistic infection after transplantation and the most important. The risk for viral infection is a function of the specific virus encountered, the intensity of immune suppression used to prevent graft rejection, and other host factors governing susceptibility. Viral infection, both symptomatic and asymptomatic, causes the "direct effects" of invasive disease and "indirect effects," including immune suppression predisposing to other opportunistic infections and oncogenesis. Rapid and sensitive microbiologic assays for many of the common viruses after transplantation have replaced, for the most part, serologic testing and in vitro cultures for the diagnosis of infection. Furthermore, quantitative molecular tests allow the individualization of antiviral therapies for prevention and treatment of infection. This advance is most prominent in the management of cytomegalovirus, Epstein-Barr, hepatitis B, and hepatitis C viruses. Diagnostic advances have not been accompanied by the development of specific and nontoxic anti-viral agents or effective antiviral vaccines. Vaccines, where available, should be given to patients as early as possible and well in advance of transplantation to optimize the immune response. Studies of viral latency, reactivation, and the cellular effects of viral infection will provide clues for future strategies in prevention and treatment of viral infections.

Prevention of infection in adult travelers after solid organ transplantation

Increasing numbers of solid organ transplant recipients are traveling to the developing world. Many of these individuals either do not seek or do not receive optimal medical care prior to travel. This review considers risks of international travel to adult solid organ transplant recipients and the use of vaccines and prophylactic agents in this population.

Management of HBV Infection in Liver Transplantation Patients

In the absence of preventative therapy, reinfection of allografts with hepatitis B virus (HBV) after orthotopic liver transplantation (OLT) resulted in dismal allograft and patient survival. Major advances in the management of HBV-infected recipients of OLT during the past 15 years have steadily reduced the rate of reinfection, resulting in improved outcomes. Initially, long-term use of hepatitis B immune globulin (HBIG) as a source of anti-HBs antibodies was effective in preventing or delaying reinfection. Lamivudine monotherapy made it possible to suppress HBV replication prior to OLT, markedly decreasing the risk of reinfection. Although lamivudine monotherapy used before and after OLT could prevent reinfection, its effectiveness was limited by progressive development of lamivudine-resistant mutant infections. Combination therapy with HBIG and lamivudine after OLT reduced both HBV recurrence and the risk of lamivudine resistance even in patients with active HBV replication. Introduction of adefovir provided a safe, alternative oral antiviral able to treat effectively lamivudine-resistant mutants HBV. Available strategies to prevent reinfection have resulted in OLT outcomes for HBV-infected patients comparable to those for patients transplanted for non-HBV indications. In the future, combination therapies of HBIG and both nucleoside and/or nucleotide agents will undoubtedly be optimized. Development of new drugs to treat HBV will increase opportunities to combine agents to enhance safety, efficacy and prevent emergence of HBV escape mutants. New vaccines and adjuvants may make it possible to generate anti-HBs in immunosuppressed patients, eliminating the need for HBIG.