Is nonresponsiveness to hepatitis B vaccine due to latent hepatitis B virus infection?

Vaccination in the elderly: an immunological perspective

Successful vaccination of the elderly against important infectious pathogens that cause high morbidity and mortality represents a growing public health priority. Building on the theme of aging and immunosenescence, we review mechanisms of human immunosenescence and the immune response to currently licensed vaccines. We discuss the difficulties in identifying the risk factors that, in addition to aging, cause immunosenescence and address the relative paucity of vaccine studies in the elderly. We conclude that vaccine responses are blunted in the elderly compared with that of healthy young adults. However, it is also clear that our understanding of the mechanisms underlying immunosenescence is limited and much remains to be learned to improve the effectiveness of next generation vaccines.

Immunogenicity of recombinant hepatitis B vaccine in treatment-naive and treatment-experienced chronic hepatitis C patients: the effect of pegylated interferon plus ribavirin treatment

AIM

To retrospectively evaluate the vaccination-induced anti-HBs seroconversion rates in treatment-naive and treatment-experienced chronic hepatitis C (CHC) patients. Also to prospectively evaluate the seroconversion rates in CHC patients during pegylated interferon (PEG) plus ribavirin (RIB) treatment.

METHODS

Seventy treatment-naive CHC patients (group A), 22 sustained virological responders-SVR following interferon (IFN) plus RIB treatment CHC patients (group B) and 121 healthy subjects (group C) had been participated in the same HBV vaccination schedule (20 microg, 0-1-6 mo). Seroconversion was considered if anti-HBs levels were above 10 mIU/mL within 3 mo following the third dose of the vaccine. Moreover, we prospectively selected 30 non-cirrhotic CHC patients and evaluated them for the efficacy of the same vaccine schedule randomizing them in two groups: Group-1, 15 CHC patients received the first dose of the vaccine in parallel with the initiation of PEG plus RIB treatment and Group-2, 15 patients received the same vaccination schedule without concomitant treatment. Determination of anti-HBs was performed at mo 1, 2, and 7. Statistical analysis of data was based on ANOVA student's t-test and chi-square analysis (P < 0.05).

RESULTS

Fifty-eight of 70 group A patients (82.85%), 20/22 group B (90.9%) and 112/121 healthy subjects (92.56%) had been seroconverted. The seroconversion rates were significantly higher in the control group than in treatment-naive CHC patients (P = 0.04). The corresponding rates were comparable between group A and group B CHC patients (P = 0.38). The vast majority of non-responders (10/14, 71.43%) had been infected by genotype-1 of HCV. The seroconversion rates were comparable between group 1 and 2 CHC patients at mo 1 (20% versus 26.7%, P = 0.67), mo 2 (46.7% vs 60%, P = 0.46) and mo 7 (86.7% versus 93.3%, P = 0.54) of follow-up.

CONCLUSION

The immunogenicity of HBV vaccine seems to be lower in CHC patients compared to healthy subjects. SVR following IFN plus RIB treatment does not affect the antibody response to HBV vaccine. Infection by genotype-1 seems to negatively influence the seroconversion rates. Vaccination against HBV during PEG plus RIB combination treatment is not beneficial in terms of anti-HBs seroconversion rates.

The antibody response to hepatitis B virus vaccination is negatively influenced by the hepatitis C virus viral load in patients with chronic hepatitis C: a case-control study

The purpose of this work was to evaluate in a case-control study the immunogenicity of a recombinant hepatitis B virus (HBV) vaccine in patients with chronic hepatitis C. Seventy-seven patients with histologically proven chronic hepatitis C without cirrhosis were included in a prospective trial and matched for sex and age to 231 healthy adult subjects. Recombinant HBV vaccine was administered at a dose of 20 microg at months 0, 1 and 2. The definition of 'responder to vaccination' was anti-HBs titre > 10 mIU/ml after the three injections. Forty-nine (63.6%) chronic hepatitis C patients were responders to vaccination, compared with 217 (93.9%) controls (P < 0.0001). After the three injections, anti-HBs titres were 156 +/- 260 and 615 +/- 435 mIU/ml (P < 0.0001), respectively. Chronic hepatitis C patients who were non-responders to vaccination had significantly higher viral load than responders to vaccination. Moreover, a negative correlation was observed between viral load and anti-HBs concentration (r = -0.36, P = 0.003). No significant side effects were observed. There was no effect of vaccination on alanine aminotransferase (ALT) levels and hepatitis C virus (HCV) viral load during or after vaccination. In multivariate analysis, the main predictive factors of response to HBV vaccine were absence of anti-HCV antibodies (OR = 7.65, P < 0.0001), weight < 75 kg (OR = 1.99, P < 0.035), and age < 50 years (OR = 1.58, P < 0.082). Our results suggest that viral load seems to negatively influence the response to HBV vaccine.

High seroprotection rate induced by low doses of a recombinant hepatitis B vaccine in healthy Iranian neonates

Low-dose vaccination has been proposed as a cost-saving strategy to implement mass vaccination of neonates with hepatitis B (HB) vaccine, world-wide, particularly in developing countries. The effectiveness of low vaccine doses, however, needs to be evaluated and verified in newborns from different ethnic backgrounds. In this study, a recombinant HB vaccine (Heberbiovac) was administered in three different doses, including the standard 10 microg together with 5 and 2.5 microg to three groups of healthy Iranian neonates. Each group, consisting of 230-260 subjects, received triple doses of vaccine given i.m. at 0, 1.5 and 9 month intervals. Serum samples were collected 2-4 weeks after completion of vaccination, and anti-HBs antibody was quantitated by a sandwich ELISA. Seroprotection (anti-HBs>10 IU/L) was detected in 92, 97.4 and 96.1% of 2.5, 5 and 10 microg vaccine dose recipients, with geometric mean titer (GMT) of 4502, 5824 and 6104 IU/L, respectively. No significant differences were observed in seroprotection rate and GMT between the 10 and 5 microg dose recipients. Both parameters, however, were significantly lower in neonates vaccinated with a 2.5 microg vaccine dose (P<0.05 and P<0.001, respectively). These findings indicate induction of a strong protective immune response in healthy Iranian neonates by a low dose (5 microg) of the recombinant HB vaccine.

Decreased immunogenicity of recombinant hepatitis B vaccine in chronic hepatitis C

The immunogenicity of hepatitis B vaccine is unknown for patients with chronic hepatitis C, although hepatitis B vaccination is highly recommended in these patients. We therefore studied in a prospective open trial of 59 patients with chronic hepatitis C (mean age 42 years, hepatitis C for >10 years, Child-Pugh score < or = 5) and 58 healthy hospital staff persons the rate of nonresponse (anti-HBs <10 mIU/mL at 9 months) to recombinant hepatitis B vaccine (Gen H-B-Vax(R),10 microg intradeltoidal at month 0, 1, and 6). Nonresponse was observed in 18/59 (31%) patients with chronic hepatitis C and 5/58 (9%) healthy staff persons (P <.005) (vs. 7% in historical controls; P <.005), low response (anti-HBs 10-99 mIU/mL) in 19% of patients with chronic hepatitis C and 17% of staff persons. High-dose booster vaccination led to seroconversion in 12/15 (80%) of primary nonresponders. Primary nonresponse to HB vaccine was related neither to presence of early-stage liver cirrhosis nor magnitude of serum hepatitis C virus (HCV) RNA concentration, nor explained by the presence of human leukocyte antigen (HLA) types (B8 DR3, B44, DR7, DQ2) predisposing to low antibody response to hepatitis B surface antigen. The rate of primary nonresponse to the standard regimen of recombinant hepatitis B vaccine is surprisingly high in patients with longstanding chronic hepatitis C. Therefore, the antibody to HBV surface antigen (anti-HBs) titer response should be determined in these patients. Depending on the response titer, higher booster doses may be required to achieve and maintain seroprotection in these patients.

Response to hepatitis B vaccine: multiple HLA genes are involved

The mechanism underlying the impaired immune response to hepatitis B vaccines in up to 10% of healthy subjects is not known. An increased incidence of poor responsiveness in subjects with HLA-DR3+ or -DR7+ haplotypes has been documented, suggesting that HLA-DR-linked genes may regulate the human response to hepatitis B surface antigen. However, not all HLA-DR3+ and/or -DR7+ individuals are poor responders, and subjects with identical HLA-DR haplotypes sometimes display totally divergent antibody responses to vaccination. HLA class II DNA typing was performed in well and poorly responding hepatitis B vaccine recipients and we analyzed the role of the single HLA-DR, -DP, and -DQ molecules and of their associated (interaction) haplotypes in the response to hepatitis B vaccination. Statistical analysis revealed that HLA-DRB1*010*, -DR5, -DPB1*040*, -DQB1*0301, and -DQB1*0501 were more abundant in good responders, whereas HLA-DRB1*07, -DPB1*1101, and -DQB1*020* were associated with poor response, with DQB1*020* showing the strongest association with poor responsiveness. We further investigated whether there were interactions between the HLA factors contributing to poor responsiveness. We show here that HLA-DPB1*02 was negatively associated with responsiveness when it occurred in association with haplotype DRB1*0701/DRB4*0101-DQB1*020*, and DRB4*0101 was negatively associated with responsiveness when it occurred in association with haplotype DRB1*0301/DRB3*0101-DQB1*020*. Our results indicate that the immune response to hepatitis B vaccine is largely determined by HLA-DR, -DP, and -DQ genes and that interaction between HLA molecules that are not in linkage disequilibrium contributes to poor responsiveness.

Nonresponse to hepatitis B vaccines and the kinetics of anti-HBs production

No empirical data are available for the anti-HBs title required for protection against infection with the hepatitis B virus (HBV), but nonresponders to hepatitis B vaccines remain susceptible to infection. There may be an unexplained qualitative difference between hyporesponders and true nonresponders, but there is a clear association with HLA haplotypes. There is no evidence for silent infection with HBV in nonresponders.