Low-dose intramuscular revaccination against hepatitis B

KLRG1 impairs CD4+ T cell responses via p16ink4a and p27kip1 pathways: role in hepatitis B vaccine failure in individuals with hepatitis C virus infection

Coinfection of hepatitis B virus (HBV) with hepatitis C virus (HCV) is quite common, leading to an increase in morbidity and mortality. As such, HBV vaccination is recommended in HCV-infected individuals. However, HBV vaccine responses in HCV-infected individuals are often blunted compared with uninfected populations. The mechanism for this failure of vaccine response in HCV-infected subjects remains unclear. In this study, we investigated the expression and function of an inhibitory receptor, killer cell lectin-like receptor subfamily G member 1 (KLRG1), in the regulation of CD4(+) T cells and HBV vaccine responses during HCV infection. We demonstrated that KLRG1 was overexpressed on CD4(+) T cells from HCV-infected, HBV vaccine nonresponders compared with HBV vaccine responders. The capacity of CD4(+) T cells to proliferate and secrete IL-2 cytokine was inversely associated with the level of KLRG1 expression. Importantly, blocking KLRG1 signaling resulted in a significant improvement in CD4(+) T cell proliferation and IL-2 production in HCV-infected, HBV vaccine nonresponders in response to TCR stimulation. Moreover, blockade of KLRG1 increased the phosphorylation of Akt (Ser(473)) and decreased the expression of cell cycle inhibitors p16(ink4a) and p27(kip1), which subsequently enhanced the expression of cyclin-dependent kinase 2 and cyclin E. These results suggest that the KLRG1 pathway impairs CD4(+) T cell responses to neoantigen and induces a state of immune senescence in individuals with HCV infection, raising the possibility that blocking this negative-signaling pathway might improve HBV vaccine responses in the setting of chronic viral infection.

Immune exhaustion and immune senescence: two distinct pathways for HBV vaccine failure during HCV and/or HIV infection

Given the shared risk factors for transmission, co-infection of hepatitis B virus (HBV) with hepatitis C virus (HCV) and/or human immunodeficiency virus (HIV) is quite common, and may lead to increases in morbidity and mortality. As such, HBV vaccine is recommended as the primary means to prevent HBV super-infection in HCV- and/or HIV-infected individuals. However, vaccine response (sero-conversion with a hepatitis B surface antibody titer >10 IU/L) in this setting is often blunted, with poor response rates to standard HBV vaccinations in virally infected individuals when compared with the healthy subjects. This phenomenon also occurs to other vaccines in adults, such as pneumococcal and influenza vaccines, in other immunocompromised hosts who are really at risk for opportunistic infections, such as individuals with hemodialysis, transplant, and malignancy. In this review, we summarize the underlying mechanisms involving vaccine failure in these conditions, focusing on immune exhaustion and immune senescence--two distinct signaling pathways regulating cell function and fate. We raise the possibility that blocking these negative signaling pathways might improve success rates of immunizations in the setting of chronic viral infection.

Improved cell mediated immune responses after successful re-vaccination of non-responders to the hepatitis B virus surface antigen (HBsAg) vaccine using the combined hepatitis A and B vaccine

We successfully re-vaccinated hepatitis B virus (HBV) vaccine non-responders using a double dose of the combined hepatitis A virus (HAV) and HBV vaccine. The hope was to improve priming of hepatitis B surface antigen (HBsAg)-specific cell mediated immune response (CMI) by an increased antigen dose and a theoretical adjuvant-effect from the local presence of a HAV-specific CMI. A few non-responders had a detectable HBsAg-specific CMI before re-vaccination. An in vitro detectable HBsAg-specific CMI was primed equally effective in non-responders (58%) as in first time vaccine recipients (68%). After the third dose a weak, albeit significant, association was observed between the magnitude of HBsAg-specific proliferation and anti-HBs levels. This regimen improves the priming of HBsAg-specific CMIs and antibodies.

Persistence of hepatitis B vaccine immunity in hemodialysis patients

Although the efficacy of hepatitis B vaccines in patients undergoing chronic hemodialysis (HD) treatment has been documented, the persistence of immunity in this population remains largely unknown. In this study we evaluated the persistence of hepatitis B vaccine immunity in HD patients. We followed 37 hepatitis B vaccinated HD patients (following a four-dose vaccination schedule of 40 mug injections intramuscularly in the deltoid muscle at 0, 1, 2, and 6 months) for up to one year to evaluate the persistence of immunity (as indicated by serum levels of hepatitis B surface antibody (anti-HBs) equal to or higher than 10 IU/L). One year after vaccination, 18.9% of patients had lost their anti-HBs (transient responders), while 81.1% still had detectable antibodies in the serum (persistent responders). From 81.1% of persistent responders 11.5% and 88.5% were weak and high responders, respectively. There was no significant difference between persistent and transient responders regarding age, sex, or nutritional factors. We did not find any factors that related to maintaining protective levels of anti-HBs in HD patients. It seems that an antibody titer above 100 IU/L following vaccination is necessary in order to maintain that level of antibody one year later.

Levamizole enhances immune responsiveness to intra-dermal and intra-muscular hepatitis B vaccination in chronic hemodialysis patients

Background

Hemodialysis patient are at high risk for hepatitis B virus (HBV) infection.

Although preventive vaccination is done routinely, the response to vaccination is low in this patient population. The aim of this study was to evaluate the effect of Levamizol, an enhancer of the immune responsiveness, on different routs of vaccination, i.e., intradermal (ID) versus intramuscular (IM), in stable chronic hemodialysis patients.

Materials and methods

Forty four chronic heamodialyses patient were divided into four equal groups. The first group was received 40 μg HB vaccine intramuscularly. The second group was received 20 μg HB vaccine intradermally. The third and the fourth group received 20 μg vaccine IM or ID, respectively, in three doses plus oral Levamisole (100 mg for 12 day). After one and six months from the last dose of vaccine, HBs antibody titers were measured.

Results

The response rate to vaccine (HBs Antibody>10 μg/L) in the routine IM HB vaccination was low (60%). It increased to 70% with ID route. Levamisole significantly raised the response rate to 90% (P < 0.01). Also in the Levamisole groups protective HB antibody titers were maintained until the end of six months.

We conclude that HD patients must be vaccinated by ID route and addition of Levamisole. Levamisole also increases antibody maintenance.

Recombinant hepatitis B vaccine (Engerix-B): a review of its immunogenicity and protective efficacy against hepatitis B

Engerix-B (Hep-B[Eng]) is a noninfectious recombinant DNA vaccine containing hepatitis B surface antigen (HBsAg). It is produced from genetically engineered yeast (Saccharomyces cerevisiae). Intramuscular Hep-B(Eng) [0-, 1-, 6-month schedule] has excellent immunogenicity in healthy neonates and infants, children, adolescents and adults, with seroprotection rates of 85-100% seen approximate, equals 1 month after the final dose of vaccine; seroprotection was defined as an antibody against HBsAg (anti-HBs) titre of > or =10 IU/L. The use of alternative Hep-B(Eng) immunisation schedules (e.g. a 0-, 1-, 2-, 12-month schedule in neonates and infants, 0-, 12-, 24-month or two-dose schedules in children and adolescents, and accelerated schedules in adults) have also been associated with high rates of seroprotection. Seroprotection rates were generally similar with Hep-B(Eng) and the recombinant vaccine Recombivax HB (Hep-B[Rax]) or plasma-derived vaccines (PDVs) approximate, equals 1 month after the final dose (although anti-HBs geometric mean titres were significantly higher with Hep-B[Eng] than with Hep-B[Rax]). One month after the final dose, adults had significantly higher seroprotection rates with the recombinant triple-antigen vaccine Bio-Hep-B (Hep-B[Bio]) than with Hep-B(Eng), although seroprotection rates in healthy infants were similar with Hep-B(Eng) and Hep-B(Bio). Hep-B(Eng) had excellent immunogenicity in several groups considered at high risk of acquiring hepatitis B (e.g. neonates born to hepatitis B carrier mothers and healthcare workers). The immunogenicity of Hep-B(Eng) was reduced in patients with conditions associated with impaired immune function (e.g. patients undergoing haemodialysis or being treated for malignancy), although it had good immunogenicity in patients with diabetes mellitus.Hep-B(Eng) had excellent protective efficacy against HBsAg carriage in healthy infants and children, and in neonates born to hepatitis B carrier mothers (protective efficacy of 95-99%). Hep-B(Eng) also demonstrated good protective efficacy in a number of other high-risk groups. Hep-B(Eng) is generally well tolerated with a tolerability profile similar to that of Hep-B(Rax), Hep-B(Bio) and PDVs. In conclusion, Hep-B(Eng) is a well established, highly immunogenic hepatitis B vaccine with good tolerability and excellent protective efficacy; it offers flexibility through a variety of immunisation schedules. In addition, it appears that Hep-B(Eng) confers immunity for at least 10 years. Hep-B(Eng) has an important role in mass vaccination campaigns against hepatitis B, as well as in groups considered at high risk of acquiring hepatitis B.

Intramuscular versus intradermal administration of anti-hepatitis B vaccine in non-cirrhotic hepatitis C patients

Intradermal vaccination has been proposed as an alternative for the administration of anti-hepatitis B vaccine. Patients (n=66) with chronic viral hepatitis C without cirrhosis were randomised into two groups (intramuscular, n=38; and intradermal, n=28) for prospective immunisation with 20 microg recombinant vaccine, using an ultra-rapid schedule (doses at 0, 15 and 30 days). Sero-conversion (antibody level >/=10 mU/ml) in the intramuscular group was reached by 20, 40 and 72% of patients at days 15, 30 and 60 compared to 4, 8 and 36% for the intradermal group (P=0.010 at day 60). Additionally, levels rose more rapidly in the intramuscular group (P=0.004). Our results do not support the use of intradermal route of immunisation against HBV in HCV patients.