Clinical and immunological efficacy of intradermal vaccine plus lamivudine with or without interleukin-2 in patients with chronic hepatitis B

HLA and cytokine gene polymorphisms are independently associated with responses to hepatitis B vaccination

Variable immune responses to hepatitis B virus (HBV) infection and recombinant HBV vaccines have been associated with polymorphisms in several genes within the human leukocyte antigen (HLA) complex. Analyses of polymerase chain reaction (PCR)-based genotyping data from 164 North American adolescents vaccinated with recombinant HBV products confirmed that HLA-DRB1*07 (relative odds [RO] = 5.18, P <.0001) and human immunodeficiency virus type 1 (HIV-1) infection (RO = 3.91, P <.001) were both associated with nonresponse to full-dose vaccination. Further associations were observed with single nucleotide polymorphisms (SNPs) at the IL2 and IL4 loci along with insertion/deletion variants at the IL12B locus (P =.003-.01). Host genetic associations were independent of one another as well as other HLA (A, B, C, and DQB1) and cytokine gene (IL4R, IL6, IL10, and TNF) variants. Statistical adjustments for nongenetic factors (gender, ethnicity, age, HIV-1 infection, and vaccination protocols) did not substantially alter the strengths of the genetic relationships. The overall distribution pattern of genetic variations was similar between the analyzed vaccinees and additional adolescents (n = 292) from the same cohort. In conclusion, DRB1*07 (or a closely linked allele) and immunoregulatory cytokine gene polymorphisms correlate with variable immune response to recombinant HBV vaccines.

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The lack of effect of therapeutic vaccination with a pre-S2/S HBV vaccine in the immune tolerant phase of chronic HBV infection

BACKGROUND/AIMS

Even if the results are controversial and preliminary, several reports suggest that the HBV vaccine might be effective in treating HBV infection. In this study, we aimed to evaluate the efficacy and safety of specific anti-HBV vaccination for the immune tolerance phase of chronic HBV infection in a randomized, controlled study.

PATIENTS AND METHODS

The 47 subjects included patients that were treatment-naive with hepatitis B e antigen positivity, active hepatitis B virus replication as measured by hepatitis B virus DNA levels, persistently normal alanine transaminase levels, and with minimal or absent disease activity by liver biopsy. Thirty patients were given three intramuscular injections of 20 micro g of a pre-S2/S vaccine (GenHevac-B) on days 0, 30, and 60, and the remaining 17 patients were included in the control group. The efficacy of vaccination was evaluated by testing for loss of serum HBV DNA or decrease in its level and for HBeAg seroconversion. A significant decrease in HBV DNA levels was accepted as a decrease of >50% of initial values. The complete response was defined as loss of HBV DNA in serum with HBeAg seroconversion. Postvaccination follow-up lasted 12 months after the first dose.

RESULTS

No significant effects were observed in the vaccination population in the reduction of HBV DNA to undetectable levels, or to <50% of prevaccination levels, in HBeAg/anti-HBe seroconversion, or in transaminase levels. There was an early clearance/decrease in HBV DNA levels in five vaccinated patients by 3 months, and none in controls (P = 0.143), and two of them had sustained responses later. At the end of follow-up, complete response is almost similar in study as well as control group (13% vs. 12%, P > 0.05). Disappearance of serum HBV DNA was more frequently observed in those patients who had pretreatment viremia of <100 pg/mL in both groups. The median levels of HBV DNA and alanine transaminase activity between baseline and 12 months did not differ significantly in both groups. All patients remained HBsAg positive and none developed anti-HBs. No serious adverse event was encountered in vaccinated patients, and the therapy was well tolerated. Follow-up lasted a median of 16 months (range 12-30 months) for the study group and 18 months (range 12-31months) for the control group.

CONCLUSIONS

Immunotherapy with specific anti-HBV vaccine in the immune tolerance phase of chronic HBV infection did not offer additional benefit. New immunotherapeutic strategies to control HBV infection by specific HBV vaccines in chronically infected subjects are needed.

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

Patients who undergo transplantation for hepatitis B virus (HBV)-related diseases are treated indefinitely with hepatitis B hyperimmunoglobulin (HBIG) to prevent endogenous HBV reinfection of the graft. Active immunization with standard hepatitis B vaccines in these patients has recently been reported with conflicting results. Two groups of 10 liver transplant recipients on continuous HBIG substitution who were hepatitis B surface antigen (HBsAg) positive and HBV DNA negative before transplantation were immunized in a phase I study with different concentrations of hepatitis B s antigen formulated with the new adjuvants 3-deacylated monophosphoryl lipid A (MPL) and Quillaja saponaria (QS21) (group I/vaccine A: 20 microg HBsAg, 50 microg MPL, 50 microg QS21; group II/vaccine B: 100 microg HBsAg, 100 microg MPL, 100 microg QS21). Participants remained on HBIG prophylaxis and were vaccinated at weeks 0, 2, 4, 16, and 18. They received 3 additional doses of vaccine B at bimonthly intervals if they did not reach an antibody titer against hepatitis B surface antigen (anti-HBs) greater than 500 IU/L. Sixteen (8 in each group) of 20 patients (80%) responded (group I: median, 7,293 IU/L; range, 721-45,811 IU/L anti-HBs; group II: median, 44,549 IU/L; range, 900-83,121 IU/L anti-HBs) and discontinued HBIG. They were followed up for a median of 13.5 months (range, 6-22 months). The vaccine was well tolerated. In conclusion, most patients immunized with the new vaccine can stop HBIG immunoprophylaxis for a substantial, yet to be determined period of time.

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

Patients who undergo transplantation for hepatitis B virus (HBV)-related diseases are treated indefinitely with hepatitis B hyperimmunoglobulin (HBIG) to prevent endogenous HBV reinfection of the graft. Active immunization with standard hepatitis B vaccines in these patients has recently been reported with conflicting results. Two groups of 10 liver transplant recipients on continuous HBIG substitution who were hepatitis B surface antigen (HBsAg) positive and HBV DNA negative before transplantation were immunized in a phase I study with different concentrations of hepatitis B s antigen formulated with the new adjuvants 3-deacylated monophosphoryl lipid A (MPL) and Quillaja saponaria (QS21) (group I/vaccine A: 20 microg HBsAg, 50 microg MPL, 50 microg QS21; group II/vaccine B: 100 microg HBsAg, 100 microg MPL, 100 microg QS21). Participants remained on HBIG prophylaxis and were vaccinated at weeks 0, 2, 4, 16, and 18. They received 3 additional doses of vaccine B at bimonthly intervals if they did not reach an antibody titer against hepatitis B surface antigen (anti-HBs) greater than 500 IU/L. Sixteen (8 in each group) of 20 patients (80%) responded (group I: median, 7,293 IU/L; range, 721-45,811 IU/L anti-HBs; group II: median, 44,549 IU/L; range, 900-83,121 IU/L anti-HBs) and discontinued HBIG. They were followed up for a median of 13.5 months (range, 6-22 months). The vaccine was well tolerated. In conclusion, most patients immunized with the new vaccine can stop HBIG immunoprophylaxis for a substantial, yet to be determined period of time.

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Reduced virus specific T helper cell induction by autologous dendritic cells in patients with chronic hepatitis B - restoration by exogenous interleukin-12

Insufficient stimulatory capacities of autologous dendritic cells (DC) may contribute in part to impaired T cell stimulation and therefore viral persistence in patients with chronic hepatitis B virus (HBV) infection. In order to characterize the antigen presenting functions of DC from chronic HBV carriers and controls antigen specific T cell responses were analysed. CD34+ peripheral blood progenitor cells were differentiated to immature DC in the presence of GM-CSF, IL-6/IL-6R fusion protein and stem cell factor. Proliferative CD4+ T cell responses and specific cytokine release were analysed in co-cultures of DC pulsed with HBV surface and core antigens or tetanus toxoid and autologous CD4+ T cells. Cultured under identical conditions DC from chronic HBV carriers, individuals with acute resolved hepatitis B and healthy controls expressed similar phenotypical markers but chronic HBV carriers showed less frequent and weaker HBV antigen specific proliferative T helper cell responses and secreted less interferon-gamma while responses to the tetanus toxoid control antigen was not affected. Preincubation with recombinant IL-12 enhanced the HBV specific immune reactivities in chronic HBV patients and controls. In conclusion, the weak antiviral immune responses observed in chronic hepatitis B may result in part from insufficient T cell stimulating capacities of DC. Immunostimulation by IL-12 restored the HBV antigen specific T cell responses and could have some therapeutical benefit to overcome viral persistence.