Granulocyte macrophage colony-stimulating factor as an adjuvant for hepatitis B vaccination of healthy adults

Biodegradable scaffolds for enhancing vaccine delivery

Sustained release of vaccine components is a potential method to boost efficacy compared with traditional bolus injection. Here, we show that a biodegradable hyaluronic acid (HA)-scaffold, termed HA cryogel, mediates sustained antigen and adjuvant release in vivo leading to a durable immune response. Delivery from subcutaneously injected HA cryogels was assessed and a formulation which enhanced the immune response while minimizing the inflammation associated with the foreign body response was identified, termed CpG-OVA-HAC2. Dose escalation studies with CpG-OVA-HAC2 demonstrated that both the antibody and T cell responses were dose-dependent and influenced by the competency of neutrophils to perform oxidative burst. In immunodeficient post-hematopoietic stem cell transplanted mice, immunization with CpG-OVA-HAC2 elicited a strong antibody response, three orders of magnitude higher than dose-matched bolus injection. In a melanoma model, CpG-OVA-HAC2 induced dose-responsive prophylactic protection, slowing the tumor growth rate and enhancing overall survival. Upon rechallenge, none of the mice developed new tumors suggesting the development of robust immunological memory and long-lasting protection against repeat infections. CpG-OVA-HAC2 also enhanced survival in mice with established tumors. The results from this work support the potential for CpG-OVA-HAC2 to enhance vaccine delivery.

Hepatitis B virus vaccination in HIV-infected people: A review

HBV immunization is highly recommended in people infected with HIV. However, the classical schedule used in the general population has been shown to be insufficient in people living with HIV. This review summarizes the main studies dealing with HBV vaccination in people living with HIV, depending on their baseline status (in particular, never vaccinated, already vaccinated, or with an isolated anti-HBc serological profile). It shows that reinforced 40µg intramuscular HBV vaccination schedules are now frequently recommended, either initially in people never vaccinated, or in the lack of an anamnestic response in other situations. Adjuvants cannot be currently recommended. Anti-HBs titers have to be checked 1 to 2 months following the last vaccine dose, and annually thereafter a booster is necessary if antiHBs titers decrease below 10 mIU/mL. In patients with a CD4 cell count <200/µL, guidelines recommend starting the vaccination regimen as soon as possible after HAART has been started.

Immune Responses to Single-Dose Versus Double-Dose Hepatitis B Vaccines in Healthcare Workers not Responding to the Primary Vaccine Series: A Randomized Clinical Trial

BACKGROUND

Recommendations to immunize healthcare workers (HCWs) against hepatitis B are well known. However, a proportion of individuals do not respond to the primary standard three-dose HB vaccination schedule.

OBJECTIVES

The current study aimed to evaluate whether a double-dose HB booster vaccine could induce better protective anti-HB titers than a single-dose booster in non-protected HCWs.

MATERIALS AND METHODS

This was a randomized clinical trial. A total of 91 HCWs not responding to the primary vaccine series in 2014 were enrolled. The participants were randomized into two groups that received a double dose of the HB vaccine containing 40 µg of antigen or a single dose of the HB vaccine containing 20 µg of antigen in three doses (at zero, one and six months after vaccination). Blood samples were collected before vaccinations and 28 days after the third dose to assess the seroconversion rate, according to the anti-HB antibody titer threshold of > 10 mIU/mL.

RESULTS

The seroconversion rates were 93.2% and 87.2% after the first booster doses of the double-dose and single-dose HB vaccines, respectively (P = 0.64). In the double-dose HB vaccine group, the seroconversion rate was 97.8% compared with 89.6% in the single-dose group following the second vaccine dose (P = 0.83). All of the participants in both groups were seroprotected after the third HB vaccine dose.

CONCLUSIONS

Both the single- and double-dose HB vaccines were adequately immunogenic, and the double-dose HB vaccine was not significantly more immunogenic than the single-dose vaccine in terms of the seroconversion rates of HCWs who had not responded to the primary vaccine series.

Improving vaccines by incorporating immunological coadjuvants

While vaccination continues to be the most successful interventionist health policy to date, infectious disease remains a significant cause of death worldwide. A primary reason that vaccination is not able to generate effective immunity is a lack of appropriate adjuvants capable of initiating the desired immune response. Adjuvant combinations can potentially overcome this problem; however, the possible permutations to consider, which include the route and kinetics of vaccination, as well as combinations of adjuvants, are practically limitless. This review aims to summarize the current understanding of adjuvants and related immunological processes and how this knowledge can and has been applied to the strategic selection of adjuvant combinations as components of vaccines against human infectious disease.

Effect of GM-CSF in combination with hepatitis B vaccine on revacination of healthy adult non-responders

OBJECTIVE

To assess the immune effects and safety of using GM-CSF with the yeast-recombinant hepatitis B virus (HBV) vaccine for the re-vaccination of healthy adults who did not respond to a previous vaccination.

METHODS

Study participants included 1784 healthy adults and 100 individuals diagnosed as non-responders. These healthy non-responders were randomly assigned to one of the three treatment groups: Group A (34 individuals) was given 150 microg of granulocyte-macrophage colony stimulating factor (GM-CSF) the first day, then 20 microg of the vaccine; Group B (33 individuals) was given 40 microg of the vaccine only; and, group C (33 individuals) was injected with 20 microg of vaccine each time. All participants were injected three times, at time of study enrollment and one and six months later. Anti-HB surface antigen (HBs) antibody titers were tested before treatment and at one (T1), two (T2) and eight (T8) months post-first injection.

RESULTS

At T1, the rate of anti-HBs antibody(+) in groups A, B and C was 26.47%, 48.48% and 18.18%, respectively (p = .027). At T8, the seropositive rate of group A (64.71%) and group B (75.76%) was significantly higher than in group C (39.39%) (p = .011); the geometric mean of the antibody titer for groups A and B was higher than for group C (p = .0173). All three treatments were safe and well-tolerated.

CONCLUSIONS

Augmentation of the vaccine dose and co-administration of GM-CSF and the standard vaccine dose are effective for HBV vaccine non-responders. In fact, changing the vaccine dose had a better seropositive response than injecting the vaccine in combination with GM-CSF.

Broad immunogenicity of a multigene, multiclade HIV-1 DNA vaccine boosted with heterologous HIV-1 recombinant modified vaccinia virus Ankara

BACKGROUND

A human immunodeficiency virus (HIV) vaccine that limits disease and transmission is urgently needed. This clinical trial evaluated the safety and immunogenicity of an HIV vaccine that combines a plasmid-DNA priming vaccine and a modified vaccinia virus Ankara (MVA) boosting vaccine.

METHODS

Forty healthy volunteers were injected with DNA plasmids containing gp160 of HIV-1 subtypes A, B, and C; rev B; p17/p24 gag A and B, and RTmut B by use of a needle-free injection system. The vaccine was administered intradermally or intramuscularly, with or without recombinant granulocyte macrophage colony-stimulating factor, and boosted with a heterologous MVA containing env, gag, and pol of CRF01A_E. Immune responses were monitored with HIV-specific interferon (IFN)-gamma and interleukin (IL)-2 ELISpot and lymphoproliferative assays (LPAs).

RESULTS

Vaccine-related adverse events were mild and tolerable. After receipt of the DNA priming vaccine, 11 (30%) of 37 vaccinees had HIV-specific IFN-gamma responses. After receipt of the MVA boosting vaccine, ELISpot assays showed that 34 (92%) of 37 vaccinees had HIV-specific IFN-gamma responses, 32 (86%) to Gag and 24 (65%) to Env. IFN-gamma production was detected in both the CD8(+) T cell compartment (5 of 9 selected vaccinees) and the CD4(+) T cell compartment (9 of 9). ELISpot results showed that 25 (68%) of 37 vaccinees had a positive IL-2 response and 35 (92%) of 38 had a positive LPA response. Of 38 subjects, a total of 37 (97%) were responders. One milligram of HIV-1 DNA administered intradermally was as effective as 4 mg administered intramuscularly in priming for the MVA boosting vaccine.

CONCLUSION

This HIV-DNA priming-MVA boosting approach is safe and highly immunogenic.

TRIALS REGISTRATION

International Standard Randomised Controlled Trial number: ISRCTN32604572 .

Effect of levamisole supplementation on hepatitis B virus vaccination response in hemodialysis patients

AIM

As an immune-modulating agent, levamisole has been reported to stimulate depressed T-cell activity, enhance B lymphocyte function and restore delayed hypersensitivity reactions in immune-depressed patients. There are a number of recent studies claiming that levamisole can improve response rate to hepatitis B virus (HBV) vaccination in haemodialysis patients. The present study has examined this hypothesis amongst some Iranian patients, using double-blind randomized clinical trial.

METHODS

During a 12 month period, 70 patients on maintenance haemodialysis with negative anti-hepatitis B surface antibody (HBsAb) and HBV core antibody (HBcAb), from four different dialysis centres were enrolled into the study. The patients were randomized to two groups. The first group (levamisole group) received 40 microg doses of recombinant HBV vaccine i.m. at 0, 1 and 6 months, plus 100 mg levamisole p.o., after each haemodialysis session. The second group (placebo group) received the same vaccination protocol, except for the placebo instead of levamisole. The patients were followed on serum HBsAb level. Those with an HBsAb level of above 10 mIU/mL, 1 month after the third dose of vaccination, were considered as responders.

RESULTS

The levamisole group was comprised of 38 patients and the placebo group of 32 patients. Thirty-one patients (81.6%) of levamisole group and 26 patients (81.3%) of placebo group responded to vaccination. The difference between two groups was not significant.

CONCLUSION

This study indicated that in a haemodialysis population with high response to HBV vaccination, levamisole might have no significant effect in enhancing the response. Further studies with higher power can give more accurate results.

Evaluation of the effects of human leukocyte IFN-alpha on the immune response to the HBV vaccine in healthy unvaccinated individuals

HBV vaccine needs 3 injections over 6 months to induce immunity. Thus, the use of adjuvants capable of inducing earlier immune protection would be highly desirable. Most adjuvants may act by inducing cytokines, and among them, type I interferons (IFNs), deserve a special attention in view of the potent immunomostimulatory activity observed in mouse models and on dendritic cell functions. The aim of the present trial was to evaluate the effects of IFN-alpha administered as an adjuvant of HBV vaccine in healthy unvaccinated individuals. No significant enhancing effect on the antibody response was observed, in spite of an early and transient upregulation of costimulatory molecule expression on peripheral blood mononuclear cells, which may be suggestive of an IFN-mediated activation of antigen presenting cells. We conclude that, under the conditions used in this trial, natural IFN-alpha does not act as an adjuvant of the HBV vaccine in healthy unvaccinated individuals.

Review of hepatitis B surface antigen-1018 ISS adjuvant-containing vaccine safety and efficacy

Existing hepatitis B virus (HBV) vaccines produce seroprotective titers in > 90% of healthy adult recipients following 3 doses administered over 6 months. The durability of this response is variable. Vaccine efficacy is greatly diminished in immune compromised patients. Given the high worldwide prevalence and burden of disease produced by chronic HBV infection, vaccines capable of producing high rates of durable seroprotective HBV surface antibody titers are required. Immunostimulatory sequences (ISS) containing repeating sequences of cytosine phosphoguanosine (CpG) dinucleotide motifs have emerged as useful tools for modulating immune responses. Dynavax Technologies produced a synthetic oligodexynucleotide (ODN) containing these motifs, resulting in an unmethylated cytosine and phosphoguanosine ODN called 1018 ISS. Dynavax's hepatitis B virus vaccine HEPLISAV is comprised of 1018 ISS mixed with recombinant hepatitis B surface antigen. Clinical trials, to date, have shown that HEPLISAV produces rapid, high titer, sustained seroprotection in healthy adults and vaccine hyporesponsive populations. Although additional supporting data are required, this represents a promising strategy to facilitate worldwide HBV prevention efforts.

Granulocyte macrophage colony-stimulating factor as an adjuvant for hepatitis B vaccination: A meta-analysis

The efficacy of granulocyte macrophage colony-stimulating factor (GM-CSF) to enhance the immune response to hepatitis B virus vaccine has been object of several reports. We searched for randomized controlled clinical trials comparing GM-CSF given concomitantly to hepatitis B virus vaccine to vaccine given alone or with placebo. Data on rates of seroconversion (anti-HBs titers >10 IU/ml) from 13 studies (734 subjects) produced combined estimates that favored GM-CSF as compared to controls: rate ratio after a single immunization was 1.54 [95% confidence interval (CI), 1.04-2.27] and 1.20 (95% CI, 1.02-1.42) at the end of the vaccination cycle. Using a logistic approach a significant dose/response effect of GM-CSF was seen. Moreover, in renal failure patients who have responded to the vaccine, GM-CSF increased anti-HBs titers. Our findings suggest that GM-CSF induced a significant effect in terms of response rate and achievement of an earlier seroconversion to the vaccine in the overall populations examined, in renal failure patients and in healthy individuals.

Progress in drug development of immunostimulatory CpG oligodeoxynucleotide ligands for TLR9

Oligodeoxynucleotides (ODNs) with unmethylated deoxycytosine-deoxyguanosine (CpG) motifs are recognised by Toll-like receptor (TLR)9 expressed in specialised cell subsets of the human immune system, B cells and plasmacytoid dendritic cells. TLR9-mediated stimulation of the immune system leads to a plethora of directed effects linking innate to adaptive immune responses. This allows the use of TLR9 agonists as highly effective targeted immunomodulatory drugs with broad potential applications as vaccine adjuvants, stand-alone therapy or in combination with other therapies in cancer, infectious diseases or asthma and allergy. TLR9 agonists represent a new class of small (8-30 bases long), easily synthesised, non-antisense ODN pharmaceuticals.

CPG 7909, an immunostimulatory TLR9 agonist oligodeoxynucleotide, as adjuvant to Engerix-B HBV vaccine in healthy adults: a double-blind phase I/II study

Oligodeoxynucleotides containing immunostimulatory CpG motifs (CpG ODN) act as potent Th1-like immune enhancers with many antigens in animal models. We have extended these observations to the first clinical evaluation of the safety, tolerability and immunogenicity of CPG 7909 when added to a commercial HBV vaccine. In a randomized, double-blind phase I dose escalation study, healthy volunteers aged 18-35 years were vaccinated at 0, 4 and 24 weeks by intramuscular injection with Engerix-B (GlaxoSmithKline). The regular adult dose of 20 microg recombinant hepatitis B surface antigen (HBsAg) adsorbed to alum was administered mixed with saline (control) or with CPG 7909 at one of three doses (0.125, 0.5 or 1.0 mg). HBsAg-specific antibody responses (anti-HBs) appeared significantly sooner and were significantly higher at all timepoints up to and including 24 weeks in CPG 7909 recipients compared to control subjects (p< or = 0.001). Strikingly, most CpG 7909-vaccinated subjects developed protective levels of anti-HBs IgG within just two weeks of the priming vaccine dose. A trend towards higher rates of positive cytotoxic T cell lymphocyte responses was noted in the two higher dose groups of CPG 7909 compared to controls. The most frequently reported adverse events were injection site reactions, flu-like symptoms and headache. While these were more frequent in CPG 7909 groups than in the control group (p<0.0001), most were reported to be of mild to moderate intensity regardless of group. In summary, CPG 7909 as an adjuvant to Engerix-B was well-tolerated and enhanced vaccine immunogenicity. CPG 7909 may allow the development of a two-dose prophylactic HBV vaccine.

Efficacy of granulocyte-macrophage colony-stimulating factor (GM-CSF) as a vaccine adjuvant for hepatitis B virus in patients with HIV infection

Recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) is a cytokine with a potential vaccine adjuvant activity. It is also known that human immunodeficiency virus (HIV) infected patients often show poor immunologic responses to immunization. We examined whether the use of GM-CSF could augment the immunologic response to recombinant vaccine against the hepatitis B virus (HBV) in 80 HIV infected patients (18-35 years old). They received a double dose (40 microg) of recombinant HBV vaccine IM at 0, 1 and 6 months and were randomized to receive either concurrent 20 microg of GM-CSF (n=40) or placebo IM (n=40) with the first vaccine dose. A significant increase in the seroconversion rate was observed after the second vaccine dose in the GM-CSF group (62% GM-CSF versus 30% control group P<0.0074). The average anti-HBs titers measured on days 28, 60 and 210 were 40.3; 366.5 and 644.8 milli-international units per milliliter (mIU/ml), respectively, in the GM-CSF group, and 62.4; 166.4 and 375.0 mIU/ml, respectively, in the control group, with significant differences at 60 and 210 days (P<0.01). There were no significant differences between CD4/CD8 cells, viral load, risk factors, age, sex and the serological responses to the HBV vaccine. This study suggests that GM-CSF increases the immunogenicity of recombinant HBV vaccine in HIV infected individuals.

Vaccinations for adult solid-organ transplant recipients: current recommendations and protocols

Recipients of solid-organ transplantation are at risk of severe infections due to their life-long immunosuppression. Despite emerging evidence that vaccinations are safe and effective among immunosuppressed patients, most vaccines are still underutilized in these patients. The efficacy, safety, and protocols of several vaccines in this patient population are poorly understood. Timing of vaccination appears to be critical because response to vaccinations is decreased in patients with end-stage organ disease and in the first 6 months after transplantation. For these reasons, the primary immunizations should be given before transplantation, as early as possible during the course of disease. Vaccination strategy should include vaccination of household contacts and health care workers at transplant centers unless contraindicated. No conclusive data are available on the use of immunoadjuvants and screening for protective titers. Most vaccines appear to be safe in solid-organ transplantation recipients, but live vaccines should be avoided until further studies are available. The risk of rejection appears minimal. Recommended vaccines include pneumovax, hepatitis A and B, influenza, and tetanus-diphtheria. We outline specific protocols and recommendations in this particular patient population. Specific contraindications exist for other vaccines, such as yellow fever, oral polio vaccine, bacillus Calmette-Guerin, and vaccinia. We conclude that solid-organ recipients will benefit from consistent immunization practices. Further studies are recommended to improve established protocols in this patient population.

Cytokines as clinical adjuvants: how far are we?

In spite of the explosive growth in the discovery of cytokines and chemokines and in the understanding of their modes of action, clinical use of such agents as adjuvants has been primarily restricted to patients with cancer or chronic viral infections suffering from various levels of immune impairment and for whom the chemotherapeutic armamentarium, as well as other forms of immunotherapy, have been exhausted. This cautious approach has been justified by the difficulties inherent to the biological function and delivery of such pleiotropic agents, where doses needed to achieve the targeted immune enhancement often result in serious side effects, especially during systemic administration. In addition, optimization of dosages, administration schedules and biological effects in humans often do not correlate well with preclinical data derived from animal models. Nevertheless, novel preventive immunization strategies that target a precise type of immune response in immunocompetent individuals are expected to greatly benefit from the incorporation of cytokines and chemokines. This review provides an overview of current clinical administration of cytokines as well as a description of select Phase I testing of new agents designed to enhance immune defenses in vivo.

Granulocyte-macrophage-colony-stimulating factor added to a multipeptide vaccine for resected Stage II melanoma

BACKGROUND

Forty-eight patients with resected Stages IIA and IIB melanoma were immunized with two tumor antigen epitope peptides derived from gp100(209-217) (210M) (IMDQVPSFV) and tyrosinase(368-376) (370D) (YMDGTMSQV) emulsified with incomplete Freund's adjuvant (IFA). Patients were assigned randomly to receive either peptides/IFA alone or with 250 microm of granulocyte-macrophage-colony-stimulating factor (GM-CSF) subcutaneously daily for 5 days to evaluate the toxicities and immune responses in either arm. Time to recurrence and survival were secondary end points.

METHODS

Immunizations were administered every 2 weeks x 4, then every 4 weeks x 3, and once 8 weeks later. A leukapheresis to obtain peripheral blood mononuclear cells for immune analyses and skin testing with peptides and recall reagents was performed before and after eight vaccinations.

RESULTS

Local pain and granuloma formation, fever, and lethargy of Grade 1 or 2 were observed. Transient vaccine-related Grade III and no Grade IV toxicity was observed. Seventeen of the 40 patients for whom posttreatment skin tests were performed developed a positive skin test response to the gp100 peptide, but only 1 of the 40 patients developed a positive skin test response to tyrosinase. Immune responses were measured by release of interferon-gamma (IFN-gamma) in an enzyme-linked immunosorbent assay (ELISA) by effector cells in the presence of peptide-pulsed antigen-presenting cells, by cytokine release of IFN-gamma, GM-CSF, and tumor necrosis factor-alpha in a Luminex assay, or by an antigen-specific tetramer flow cytometry assay. Thirty-four of the 39 patients for whom the ELISA data were performed demonstrated an immune response after vaccination, as did 37 of 42 patients by tetramer assay. Enzyme-linked immunosorbent assay, Luminex, and tetramer responses in the GM-CSF/peptide/IFA group were higher than in the peptide/IFA group. Epitope spreading to the MART-1/MelanA 27-35 and 26-35 (27L) epitopes was detected by tetramer assay in 10 patients. Seven of 48 patients experienced disease recurrence with a median of 24 months of follow-up and 2 patients in this intermediate to high risk group have died.

CONCLUSION

These data suggest a significant number of patients with resected melanoma mount an antigen-specific immune response against a peptide vaccine. There is a trend for GM-CSF to modestly increase the immune response and support further development of GM-CSF as a vaccine adjuvant.

A randomized, placebo-controlled trial of subcutaneous administration of GM-CSF as a vaccine adjuvant: effect on cellular and humoral immune responses

Thirty healthy volunteers were randomly assigned to receive either a single subcutaneous injection of GM-CSF or placebo at the time of vaccination with tetanus and diptheria toxoid (Td), influenza and hepatitis A vaccines. Humoral response was measured by weekly serum samples assayed for antibodies to tetanus toxoid (TT), influenza and hepatitis A; while cellular response to TT was determined by measuring IL-2 expression in T-cells following in vitro exposure to TT antigen using a flow cytometric assay. It was hypothesized that (1). GM-CSF would augment immune response and (2). that the frequencies of TT responsive T-cells in the blood would predict humoral responses. The administration of subcutaneous GM-CSF as an adjuvant at the time of vaccination did not augment the antibody responses to influenza or hepatitis A in normal volunteers when compared to placebo. Subjects who received GM-CSF had statistically significant lower increases in anti-tetanus antibodies than placebo recipients. Immunization with TT resulted in an increase in the frequency of antigen responsive T-cells in the blood over time. The frequencies of TT responsive T-cells in baseline blood samples were correlated with baseline anti-tetanus antibody titers, but humoral and cellular responses were not correlated following vaccination. Recipients of GM-CSF did not develop significantly higher numbers of TT responsive T-cells after vaccination compared to recipients who received placebo.

The use of Flt3 ligand as an adjuvant for hepatitis B vaccination of healthy adults

A phase I/II clinical trial was carried out to determine the safety of Flt3 ligand used as a vaccine adjuvant when administered to healthy human volunteers on two different schedules. In the first phase of this study, Flt3 ligand was administered SQ at a dose of 20 microg/kg (to a maximum of 1500 microg) every day (N=10) or every other day (N=10) for 1 week. The Flt3 ligand injection series was followed 1 day later by the first of three vaccinations with the licensed hepatitis B vaccine. In the second phase of the trial, 30 volunteers received either Flt3 ligand or placebo on the alternate day schedule in a randomized, double-blind design. The Flt3 ligand injections were safe and very well-tolerated. The number of lineage negative, HLA-DR(hi), CD11c(+), CD123(-) dendritic cells (DCs) increased 23-fold, and the lineage negative, HLA-DR(hi), CD11c(-), CD(123 bright) pre-DCs increased 6-fold. There was an associated increase in monocytes and WBCs in the Flt3 ligand recipients. Despite the marked increase in peripheral circulating dendritic cells, no increase was observed in the hepatitis B antibody titers induced after vaccination.

Randomized trial of influenza vaccine with granulocyte-macrophage colony-stimulating factor or placebo in cancer patients

PURPOSE

To determine whether granulocyte-macrophage colony-stimulating factor (GM-CSF) would improve response to influenza vaccination in cancer patients.

PATIENTS AND METHODS

In a randomized, patient-blinded, placebo-controlled trial carried out in 1997 to 2000, 133 patients were stratified into five groups of treatment and disease. Single doses of standard split trivalent influenza vaccine and either placebo or 250 micro g of GM-CSF were administered at the same time. Hemagglutination inhibition assay titers were measured before and 4 weeks after vaccination.

RESULTS

Standard analyses, which define response as at least a four-fold increase in titers, detect no effect of GM-CSF for any of the three influenza subtypes in the trivalent vaccines (P >or=.12). Analysis that includes the magnitude of the change in titers and combines responses of the subtypes suggests that the placebo group had the greater response (P =.051), thus indicating that GM-CSF does not improve response. Ancillary analyses show that response declines both with increasing age and with higher initial titers. The fraction of patients with at least a four-fold increase in titers was 0.36 (95% confidence interval, 0.29 to 0.42)

CONCLUSION

A single 250- micro g dose of GM-CSF administered with the influenza vaccine does not improve response to vaccination. Response in cancer patients is low and declines as age and initial titer increase.

Levamisole treatment enhances protective antibody response to hepatitis B vaccination in hemodialysis patients

Hemodialysis shows a high risk for hepatitis B infection, and hepatitis B virus (HBV) vaccination has now become a routine procedure. Unfortunately, 40% to 50% of hemodialysis patients do not have adequate protective antibodies against the HBV vaccination which is thought to be due to depressed cell mediated immunity. Levamisole has been reported to stimulate depressed T-cell activity and enhance B lymphocyte function and restore delayed hypersensitivity reactions in immune-depressed patients. We studied the effects of levamisole, an immunomodulatory agent, on the protective antibody response of hemodialysis patients to the HBV vaccination. Our hemodialysis patients with negative anti-HBs antibody routinely received 40 microg doses of recombinant HBV vaccine intramuscularly at 0, 1, and 6 months, and we followed serum anti-HBs levels. Patients with a serum antibody level of >10 mIU/ml were considered as responders. Study groups were classified as follows. Group 1 was comprised of 96 chronic hemodialysis patients with negative anti-HBs and HBV core antibody (52 male, 44 female, mean age of 45 +/- 15 years and mean hemodialysis duration of 46 +/- 40 months) who received HBV vaccination; 55 patients (57%) were found to be responders. Group 2 was comprised of 19 randomly selected patients who had never received hepatitis B vaccine (13 male, 6 female, mean age of 42 +/- 14 years, mean duration of hemodialysis 31 +/- 27 months) and who were started on an HBV vaccination protocol with levamisole per os 80 mg after each hemodialysis session for 4 months and followed up on serum anti-HBs levels. Seventeen of the patients completed this levamisole treatment. Fourteen of the 17 patients had the levels of the protective serum antibody indicating a higher response rate when compared with patients who did not receive levamisole (82% versus 57%, respectively, p < 0.05). Group 3 was comprised of 19 patients randomly selected from persons who did not respond to previous vaccination programs (10 male, 9 female, mean age of 51 +/- 14 years, mean duration of hemodialysis 41 +/- 31 months). A second HBV vaccination program was started with the same levamisole protocol. In this group, 18 patients completed this treatment model. Fourteen of them responded to the vaccination model. In Group 4, a second HBV vaccination program was applied without levamisole to 20 randomly selected persons who did not respond to the previous routine vaccination program (12 male, 8 female, mean age of 53 +/- 17 years, mean duration of dialysis 51 +/- 38 months). Only 3 of them responded to a second vaccination program. Comparing Group 3 with Group 4, there was a higher responder rate to HBV vaccination (77% versus 15%, respectively, p < 0.0001). These results show that levamisole treatment increases the response rate to the first HBV vaccination and of the previously unresponsive cases by modulating possible cellular immune response.

AM3 (Inmunoferón) as an adjuvant to hepatitis B vaccination in hemodialysis patients

BACKGROUND

Patients with end-stage renal disease (ESRD) undergoing hemodialysis have severe alterations in cell-mediated immunity (CMI) that increases their risk of contracting chronic hepatitis B virus (HBV) infection and decreases their protective responses to HBV vaccine. In an effort to improve the humoral response to an accelerated HBV vaccine protocol in these patients, the ability of an immunomodulator, AM3, to improve seroconversion was investigated.

METHODS

A total of 269 patients were enrolled in a multicenter trial. All patients received a DNA recombinant vaccine (40 microg HBsAg/dose/day) on days 0, 10, 21, and 90. AM3 or placebo (3 g/day) was given orally for 30 consecutive days beginning 15 days prior to the first vaccine dose. Anti-HBsAg titers were measured on days 120 and 270 after the beginning of the trial.

RESULTS

After one month, 207 patients could be evaluated and 132 patients after six months. The placebo and AM3-treated groups had comparable seroconversion and protective response rates one month after the final vaccine dose. The AM3 treatment group, but not the placebo group, maintained these protective titers up to six months after the final vaccine dose. At this time, the percentage of high responders (anti-HBsAg>100 IU/L) and mean anti-HBsAg titers in the AM3 group was significantly higher than in the placebo group.

CONCLUSIONS

AM3 is a safe and easily tolerated oral agent that potentiates long-term serological immunity to hepatitis B in hemodialysis patients after vaccination.

Hepatitis B immunization of healthy elderly adults: relationship between naïve CD4+ T cells and primary immune response and evaluation of GM-CSF as an adjuvant

The efficacy of granulocyte-macrophage colony-stimulating factor (GM-CSF) to enhance the primary immune response to hepatitis B vaccine was studied in healthy elderly with young volunteers included as controls in this double-blind, placebo-controlled trial of GM-CSF as an immune adjuvant. Naïve T-helper cells (CD4+CD45RA+) were determined at baseline. Forty-five healthy elderly (average age, 74 years) and 37 healthy young controls (average age, 28 years) were randomized. Hepatitis B vaccine was administered at 0, 1, and 6 months. GM-CSF as a single injection of either 80 microg or 250 microg with the first and second doses of hepatitis B vaccine. In this trial GM-CSF did not enhance antibody responses. However, the antibody responses were dramatically different between these two groups: 35/35 young developed a protective titer versus 19/45 elderly (P < 0.0001). In addition, the mean logarithm of anti-hepatitis B antibody level in the 35 young who completed the study was 3.17 (log mIU/ml) but only 2.21 in the 19 elderly responders (P < 0.0001). Naïve T-helper cells differed significantly between the two groups: the mean percentage of CD4+CD45RA+ T cells was 47.9% versus 35.0% (P < 0.0001) in the young and elderly volunteers respectively. Naïve T cells also differed significantly between elderly who did or did not respond to HBV (39.9% vs. 31.7%, P = 0.039). Using linear regression, age, and percent naive, CD4 T cells were determined to significantly influence the anti-hepatitis B antibody response, but sex and dose of GM-CSF did not. For a two-parameter model: logarithm of antibody titer = (-0.038 x age in years) + (0.031 x % naïve CD4T cells) + 2.68; adjusted r2 = 0.605 and P < 0.0001. However, age had a larger effect than naive CD4 T cells, i.e., in comparing young and elderly groups the log antibody titer decreased by 1.73 due to the increase in age but only 0.40 due to the decrease in naive CD4 T cells. Thus, there was a large effect of age that could not be explained by the quantitative change in the naïve T-helper cells.