Contribution of human leukocyte antigens to the antibody response to hepatitis B vaccination

Association of HLA-DRB1 alleles with status of antibodies to hepatitis B surface and e antigen

Antigen presentation by HLA class II molecules to CD4+ T cells is an essential step for generating antibodies to hepatitis B antigens. In this study, we investigated the association between the HLA-DRB1 gene and the status of antibodies to hepatitis B surface and e antigens. Our results revealed a significant association between the status of anti-HBsAg and HLA-DRB1*04:03 (OR = 4.11, 95% CI = 1.50-10.84, p = 0.005, Padj. = 0.05) as well as HLA-DRB1*15:01 (OR = 1.74, 95% CI = 1.20-2.50, p = 0.002, Padj. = 0.045). MHC II binding predictions and in silico docking demonstrated strong binding affinity of HBsAg peptides to these two HLA-DRB1 molecules. Conversely, the status of anti-HBeAg was inversely associated with HLA-DRB1*14:54 (OR = 0.34, 95% CI = 0.18-0.64, p = 0.001, Padj. = 0.011), and in silico analysis revealed weak binding affinity of HBeAg peptides to HLA-DRB1*14:54. In conclusion, these findings support the involvement of HLA-DRB1 in humoral immunity against HBV infection.

Hepatitis B vaccine delivered by microneedle patch: Immunogenicity in mice and rhesus macaques

Vaccination against hepatitis B using a dissolving microneedle patch (dMNP) could increase access to the birth dose by reducing expertise needed for vaccine administration, refrigerated storage, and safe disposal of biohazardous sharps waste. In this study, we developed a dMNP to administer hepatitis B surface antigen (HBsAg) adjuvant-free monovalent vaccine (AFV) at doses of 5 µg, 10 µg, and 20 µg, and compared its immunogenicity to vaccination with 10 µg of standard monovalent HBsAg delivered by intramuscular (IM) injection either in an AFV format or as aluminum-adjuvanted vaccine (AAV). Vaccination was performed on a three dose schedule of 0, 3, and 9 weeks in mice and 0, 4, and 24 weeks in rhesus macaques. Vaccination by dMNP induced protective levels of anti-HBs antibody responses (≥10 mIU/ml) in mice and rhesus macaques at all three HBsAg doses studied. HBsAg delivered by dMNP induced higher anti-HBsAg antibody (anti-HBs) responses than the 10 µg IM AFV, but lower responses than 10 µg IM AAV, in mice and rhesus macaques. HBsAg-specific CD4+ and CD8+ T cell responses were detected in all vaccine groups. Furthermore, we analyzed differential gene expression profiles related to each vaccine delivery group and found that tissue stress, T cell receptor signaling, and NFκB signaling pathways were activated in all groups. These results suggest that HBsAg delivered by dMNP, IM AFV, and IM AAV have similar signaling pathways to induce innate and adaptive immune responses. We further demonstrated that dMNP was stable at room temperature (20 °C-25 °C) for 6 months, maintaining 67 ± 6 % HBsAg potency. This study provides evidence that delivery of 10 µg (birth dose) AFV by dMNP induced protective levels of antibody responses in mice and rhesus macaques. The dMNPs developed in this study could be used to improve hepatitis B birth dose vaccination coverage levels in resource limited regions to achieve and maintain hepatitis B elimination.

Vaccinomics: A scoping review

BACKGROUND

This scoping review summarizes a key aspect of vaccinomics by collating known associations between heterogeneity in human genetics and vaccine immunogenicity and safety.

METHODS

We searched PubMed for articles in English using terms covering vaccines routinely recommended to the general US population, their effects, and genetics/genomics. Included studies were controlled and demonstrated statistically significant associations with vaccine immunogenicity or safety. Studies of Pandemrix®, an influenza vaccine previously used in Europe, were also included, due to its widely publicized genetically mediated association with narcolepsy.

FINDINGS

Of the 2,300 articles manually screened, 214 were included for data extraction. Six included articles examined genetic influences on vaccine safety; the rest examined vaccine immunogenicity. Hepatitis B vaccine immunogenicity was reported in 92 articles and associated with 277 genetic determinants across 117 genes. Thirty-three articles identified 291 genetic determinants across 118 genes associated with measles vaccine immunogenicity, 22 articles identified 311 genetic determinants across 110 genes associated with rubella vaccine immunogenicity, and 25 articles identified 48 genetic determinants across 34 genes associated with influenza vaccine immunogenicity. Other vaccines had fewer than 10 studies each identifying genetic determinants of their immunogenicity. Genetic associations were reported with 4 adverse events following influenza vaccination (narcolepsy, GBS, GCA/PMR, high temperature) and 2 adverse events following measles vaccination (fever, febrile seizure).

CONCLUSION

This scoping review identified numerous genetic associations with vaccine immunogenicity and several genetic associations with vaccine safety. Most associations were only reported in one study. This illustrates both the potential of and need for investment in vaccinomics. Current research in this field is focused on systems and genetic-based studies designed to identify risk signatures for serious vaccine reactions or diminished vaccine immunogenicity. Such research could bolster our ability to develop safer and more effective vaccines.

Hepatitis B Immunization Status in Children with Chronic Kidney Disease: Experience at a Single Center, Egypt

Background: Children with chronic kidney disease (CKD), particularly those who require hemodialysis (HD), are at high risk of hepatitis B virus (HBV) infection. The HBV vaccine non-/hypo-response rate among HD children remains high, and it is critical to investigate the influencing factors and their linkages. The aim of this study was to identify the pattern of HB vaccination response in HD children and to analyze the interference of various clinical and biomedical factors with the immunological response to HB vaccination. Methods: This cross-sectional study included 74 children on maintenance hemodialysis, aged between 3 and 18 years. These children were subjected to complete clinical examination and laboratory investigations. Results: Out of a total of 74 children with HD, 25 (33.8%) were positive for the HCV antibody. Regarding the immunological response to hepatitis B vaccine, 70% were non-/hypo-responders (≤100 IU/mL) and only 30% mounted a high-level response (more than 100 IU/mL). There was a significant relation between non-/hypo-response and sex, dialysis duration, and HCV infection. Being on dialysis for more than 5 years and being HCV Ab-positive were independent variables for non-/hypo-response to HB vaccine. Conclusions: Children with CKD on regular HD have poor seroconversion rates in response to the HBV vaccine, which were influenced by dialysis duration and HCV infection.

Hepatitis B Vaccine Non-Responders Show Higher Frequencies of CD24highCD38high Regulatory B Cells and Lower Levels of IL-10 Expression Compared to Responders

Background

The cellular mechanisms involved in the lack of protective antibody response after hepatitis B vaccination are still rather unclear. Regulatory B cells (Breg) known as modulators of B-and T-cell responses may contribute to poor vaccine responsiveness. The current study aimed to investigate the role of regulatory B cells (Breg) in hepatitis B vaccine non-responsiveness after immunization with second- or third-generation hepatitis B vaccines.

Method

We performed comparative phenotypic and frequency analysis of Breg subsets (CD24⁺CD27⁺ and CD24^highCD38^high Breg) in second-generation hepatitis B vaccine non-responders (2^nd HBvac NR, n = 11) and responders (2^nd HBvac R, n = 8) before (d0), on day 7 (d7), and 28 (d28) after booster vaccination. Cryopreserved peripheral blood mononuclear cells were stimulated ex vivo with a combination of CpG, PMA, and Ionomycin (CpG+P/I) and analyzed for numbers and IL-10 expression levels of Breg by flow cytometry-based analyses.

Results

Flow cytometry-based analyses revealed elevated frequencies of CD24⁺CD27⁺ Breg at all time points and significantly higher frequencies of CD24^highCD38^high Breg on d0 (p = 0.004) and 28 (p = 0.012) in 2^nd HBvac NR compared to 2^nd HBvac R. In parallel, we observed significantly lower levels of CpG+P/I-induced IL-10 expression levels of CD24⁺CD27⁺ and CD24^highCD38^high Breg (d0: p < 0.0001; d7: p = 0.0004; d28: p = 0.0003 and d0: p = 0.016; d7: p = 0.016, respectively) in 2^nd HBvac NR compared to 2^nd HBvac R before and after booster immunization. Frequencies of CD24⁺CD27⁺ and CD24^highCD38^high Breg significantly decreased after third-generation hepatitis B booster vaccination (d7: p = 0.014; d28: p = 0.032 and d7: p = 0.045, respectively), whereas IL-10 expression levels of both Breg subsets remained stable.

Conclusion

Here we report significantly higher frequencies of CD24^highCD38^high Breg in parallel with significantly lower IL-10 expression levels of CD24⁺CD27⁺ and CD24^highCD38^high Breg in 2^nd HBvac NR compared to 2^nd HBvac R. Anti-HBs seroconversion accompanied by a decrease of Breg numbers after booster immunization with a third-generation hepatitis B vaccine could indicate a positive effect of third-generation hepatitis B vaccines on Breg-mediated immunomodulation in hepatitis B vaccine non-responders.

Association of HLA-DPA1, HLA-DPB1, and HLA-DQB1 Alleles With the Long-Term and Booster Immune Responses of Young Adults Vaccinated Against the Hepatitis B Virus as Neonates

The neonatal hepatitis B vaccination (HBVac) was implemented 35 years ago in Taiwan, but many vaccinees exhibit inadequate long-term vaccine-induced seroprotective hepatitis B surface antibody (anti-HBs) levels. We investigated the association of the human leukocyte antigen (HLA) alleles (DPA1, DPB1, DQA1, and DQB1) with the long-term immunological response to the neonatal HBVac and adolescent booster HBVac in a Taiwanese cohort. We divided 281 Han students (median age 22, age range 17–29 years) into the following groups: (1) Group A (n = 61): anti-HBs titer ≥ 10 mIU/mL at the beginning of the study; (2) Group B (n = 75): anti-HBs level > 1000 mIU/mL after the first booster; (3) Group C (n = 37): anti-HBs level < 10 mIU/mL after the first booster; and (4) Group D (n = 5): anti-HBs level < 10 mIU/mL after three boosters. DQA1, DQB1, DPA1, and DPB1 typing of the participants was performed using sequence-specific oligonucleotides. Associations of HLA alleles and haplotypes with effects on neonatal HBVac and booster HBVac were examined through logistic regression analysis and Fisher’s exact test. A false discovery rate-based measure of significance, the q-value, was used for multiple comparisons, and an association was considered significant if the corresponding q-value was < 0.1. DPA1 alleles were associated with the long-term immunological response to the neonatal HBVac. The estimated odds ratio (OR) of the lack of HBV protective immunity when carrying an additional DPA1*01 and DPA1*02 was 0.36 [95% confidence interval (CI) = 0.17–0.76, p = 0.0076] and 2.39 (95% CI = 1.17–4.87, p = 0.016), respectively. DPB1 and DQB1 alleles were associated with a response to the adolescent booster vaccination. The estimated ORs of being nonresponsive to the first booster when carrying an additional DPB1*05 and DQB1*02 were 2.11 (95% CI = 1.13–3.93, p = 0.019) and 3.73 (95% CI = 1.43–9.71, p = 0.0070), respectively. All DPB1*03 carriers responded to the first booster (p of Fisher’s exact test = 0.0045). In our study, we discovered that HLA-DPA1 was primarily associated with the long-term response of primary infantile HBVac, and HLA-DPB1 and HLA-DQB1 exhibited associations with the HBV booster vaccination.

Host genetics and infectious disease: new tools, insights and translational opportunities

Understanding how human genetics influence infectious disease susceptibility offers the opportunity for new insights into pathogenesis, potential drug targets, risk stratification, response to therapy and vaccination. As new infectious diseases continue to emerge, together with growing levels of antimicrobial resistance and an increasing awareness of substantial differences between populations in genetic associations, the need for such work is expanding. In this Review, we illustrate how our understanding of the host–pathogen relationship is advancing through holistic approaches, describing current strategies to investigate the role of host genetic variation in established and emerging infections, including COVID-19, the need for wider application to diverse global populations mirroring the burden of disease, the impact of pathogen and vector genetic diversity and a broad array of immune and inflammation phenotypes that can be mapped as traits in health and disease. Insights from study of inborn errors of immunity and multi-omics profiling together with developments in analytical methods are further advancing our knowledge of this important area.

Infectious diseases are an ever-present global threat. In this Review, Kwok, Mentzer and Knight discuss our latest understanding of how human genetics influence susceptibility to disease. Furthermore, they discuss emerging progress in the interplay between host and pathogen genetics, molecular responses to infection and vaccination, and opportunities to bring these aspects together for rapid responses to emerging diseases such as COVID-19.

Response to hepatitis B virus vaccination in individuals with chronic hepatitis C virus infection

BACKGROUND

Previous reports show conflicting results regarding hepatitis B virus (HBV) vaccine efficacy in Hepatitis C virus (HCV)-infected individuals.

AIMS

To evaluate HBV-vaccine response and identify possible factors that may contribute to lower vaccine efficacy in patients infected with HCV.

METHODS

We retrospectively evaluated all patients with chronic HCV infection at Hennepin County Medical Center, in Minneapolis, Minnesota, between 2002 and 2018. We addressed laboratory, liver-related, virus-related as well as vaccine-related variables, and their association to HBV vaccine response. Differences were tested using either a Chi-squared test or a T test to compare means between the two populations. Multivariate regression was modeled as a logistic regression.

RESULTS

1506 patients were evaluated, of which 525 received appropriate HBV vaccination and were assessed for response. Among those, 79% were vaccine responders and 21% were non-responders. On multivariate analysis, cirrhosis was associated with lower response to the vaccine (OR 0.6, CI 0.44-0.94). We found no significant differences for vaccine response in relation to smoking (87% vs 86%), IV drug abuse (74% vs 72%), Diabetes Mellitus (26% vs 22%) being on hemodialysis (2% vs.5%), or virus related variables.

CONCLUSION

HCV infection seems to impair HBV vaccine response, with cirrhosis being the only identifiable risk factor for hypo-responsiveness among studied clinical and virus-related variables.

Ethnicity and response to primary three-dose hepatitis B vaccination in employees in the Netherlands, 1983 through 2017

BACKGROUND AND AIMS

Hepatitis B virus (HBV) vaccination is recommended to all employees who have an occupational risk in the Netherlands. This study assessed the determinants of the immune response to primary standard three-dose HBV vaccination (0, 1, 6 months), with the main focus on ethnicity.

METHODS

Out of 76 239 individuals who received HBV vaccination between April 1983 and December 2017, 11 567 persons with a known country of birth and complete vaccination schedule were included in this study. Weighted multiple logistic regression with Firth's bias adjustment was used to assess the determinants of nonresponse (anti-HBs < 10 mIU/mL) and low response (anti-HBs 10-99 mIU/mL).

RESULTS

Baseline characteristics of the study population (n = 11 567) were as follows: mean age 27.5 years (95% confidence interval [CI], 27.23-27.72), 99.4% born in the Netherlands and 93.5% of Western European origin. Of all identified subjects, 180 (1.6%) were HBV vaccine nonresponders and 549 (4.8%) were low responders. When compared with individuals aged <40 years, the rate of nonresponse (4.3% vs 0.8%; P < .001) and low response (11.9% vs 2.9%; P < .001) was higher in those aged 40 years or older. The height of anti-HBs levels were lower in those subjects aged >40 years in comparison with those younger than 40 years, P < .001. All nonresponders were born in the Netherlands. Although no significant association was found between nonresponse and individuals of Western European origin (adjusted odds ratio [aOR] = 1.20; 95% CI, 0.66-2.44; P = .163), low response to HBV vaccination was significantly associated with Western European origin (aOR = 2.21; 95% CI, 1.41-3.86; P = .001). Significant determinants for nonresponse were older age at vaccination (aOR = 1.06; 95% CI, 1.06-1.07; P < .001) and male gender (aOR = 2.51; 95% CI, 1.97-3.22; P < .001).

CONCLUSIONS

The nonresponse rate was low in our study population. Our findings suggest that the vaccines being used for the primary vaccination are probably less immunogenic for older individuals, males, and persons of Western European origin.

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.

Efficacy of antepartum administration of hepatitis B immunoglobulin in preventing mother-to-child transmission of hepatitis B virus

The aim of this study was to investigate the efficacy of antepartum administration of three doses of hepatitis B immunoglobulin (HBIG) in interrupting mother-to-child transmission (MTCT) of hepatitis B virus (HBV). In this trial, a total of 728 HBeAg-positive pregnant women with chronic HBV infection who had an HBV DNA level higher than 6log₁₀  copies/mL were enrolled. They were divided into three groups based on individual preference. Subjects in group A and group B received 200 IU (unit) HBIG and 400 IU (unit) HBIG intramuscularly once a month at the third, second and first month before delivery, respectively. Subjects in the control group (C) received no special treatment. All the infants received passive-active immunoprophylaxis. The HBsAg-positive rate of all infants at 7-12 months of age was 5.1% (37/728). Specifically, the HBsAg-positive rate of infants was comparable in all three groups (5.3% vs 5.1% vs 5%, P = 0.988). No significant difference was found in anti-HBs levels between the infants aged 7-12 months in the three groups (P = 0.469). HBV DNA levels of the umbilical cord blood in the HBV-infected group were higher than those in the uninfected group (5.2 vs 3.4log₁₀  copies/mL, P < 0.001), and these with family history of HBV infection were also higher (45.9% vs 28.5%, P = 0.034). To conclude, administration of passive-active immunoprophylaxis to infants contributed to effective prevention of the MTCT of HBV; extra antepartum administration of HBIG during pregnancy could not decrease the rate of MTCT or increase the anti-HBs levels of infants born to HBsAg-positive mothers with HBV DNA higher than 6log₁₀  copies/mL.

Next-generation sequencing analysis of the human T-cell and B-cell receptor repertoire diversity before and after hepatitis B vaccination

The hepatitis B (HB) vaccine effectively prevents the incidence of hepatitis B virus (HBV) infection. However, vaccine failure occurs in 5-10% of the recipients. The precise mechanisms leading to responsiveness to the HB vaccine are poorly understood. High-throughput sequencing (HTS) may help clarify the immune response to the HB vaccine, so we applied this method to investigate whether the HB vaccine induced a specific change in the T-cell receptor (TCR) and B-cell receptor (BCR) repertoires. We conducted HTS of the TCR β chain and BCR IgG heavy (H) chain complementary determining region 3 (CDR3) repertoires in five volunteers before and after the second and third immunizations with the HB vaccine. The HB surface antibody (HBsAb) levels were >10 mIU/ml after the third vaccination in all five participants. The TCR β chain CDR3 repertoire diversity significantly increased, while the BCR IgG H chain CDR3 repertoire diversity significantly decreased after the second vaccination. Although there was no marked inter-individual variation in terms of the numbers of unique reads, it is possible that the TCR β chain and BCR IgG H chain CDR3 repertoires may have changed within the same numbers of unique reads. Our data failed to identify the specific dominant clones that responded to the HB vaccine. In summary, the TCR β chain CDR3 repertoire diversity significantly increased, while the BCR IgG H chain CDR3 repertoire diversity significantly decreased, after the second HB vaccination. These diversity changes might be associated with a better response to the HB vaccine.

Factors That Influence the Immune Response to Vaccination

There is substantial variation between individuals in the immune response to vaccination. In this review, we provide an overview of the plethora of studies that have investigated factors that influence humoral and cellular vaccine responses in humans. These include intrinsic host factors (such as age, sex, genetics, and comorbidities), perinatal factors (such as gestational age, birth weight, feeding method, and maternal factors), and extrinsic factors (such as preexisting immunity, microbiota, infections, and antibiotics). Further, environmental factors (such as geographic location, season, family size, and toxins), behavioral factors (such as smoking, alcohol consumption, exercise, and sleep), and nutritional factors (such as body mass index, micronutrients, and enteropathy) also influence how individuals respond to vaccines. Moreover, vaccine factors (such as vaccine type, product, adjuvant, and dose) and administration factors (schedule, site, route, time of vaccination, and coadministered vaccines and other drugs) are also important. An understanding of all these factors and their impacts in the design of vaccine studies and decisions on vaccination schedules offers ways to improve vaccine immunogenicity and efficacy.

HLA-B*07, HLA-DRB1*07, HLA-DRB1*12, and HLA-C*03:02 Strongly Associate With BMI: Data From 1.3 Million Healthy Chinese Adults

Strong associations between HLA alleles and infectious and autoimmune diseases are well established. Although obesity is also associated with these diseases, the relationship between HLA and obesity has not been systematically investigated in a large cohort. In the current study, we analyzed the association of HLA alleles with BMI using data from 1.3 million healthy adult donors from the Chinese Marrow Donor Program (CMDP). We found 23 HLA alleles, including 12 low-resolution and 11 high-resolution alleles, were significantly associated with BMI after correction for multiple testing. Alleles associated with high BMI were enriched in haplotypes that were common in both Chinese and European populations, whereas the alleles associated with low BMI were enriched in haplotypes common only in Asians. Alleles B*07, DRB1*07, DRB1*12, and C*03:02 provided the strongest associations with BMI (P = 6.89 × 10^-10, 1.32 × 10^-9, 1.52 × 10^-9, and 4.45 × 10^-8, respectively), where B*07 and DRB1*07 also had evidence for sex-specific effects (P_{heterogeneity} = 0.0067 and 0.00058, respectively). These results, which identify associations between alleles of HLA-B, DRB1, and C with BMI in Chinese young adults, implicate a novel biological connection between HLA alleles and obesity.

Searching for the human genetic factors standing in the way of universally effective vaccines

Vaccines have revolutionized modern public health. The effectiveness of some vaccines is limited by the variation in response observed between individuals and across populations. There is compelling evidence that a significant proportion of this variability can be attributed to human genetic variation, especially for those vaccines administered in early life. Identifying and understanding the determinants of this variation could have a far-reaching influence upon future methods of vaccine design and deployment. In this review, we summarize the genetic studies that have been undertaken attempting to identify the genetic determinants of response heterogeneity for the vaccines against hepatitis B, measles and rubella. We offer a critical appraisal of these studies and make a series of suggestions about how modern genetic techniques, including genome-wide association studies, could be used to characterize the genetic architecture of vaccine response heterogeneity. We conclude by suggesting how the findings from such studies could be translated to improve vaccine effectiveness and target vaccination in a more cost-effective manner.

Ex vivo assessment of cellular immune function - applications in patient care and clinical studies

Cellular ex vivo assays have a broad range of applications in patient care and clinical studies, especially when they are standardized and highly sensitive. As compared to analyses by molecular genetics such as the single nucleotide polymorphism (SNP) testing, they are usually more global. These assays partly mimic the in vivo situation, relying on a complex interaction of various immune cells. For example, they can be used to determine modulation of alloresponses by treatment or underlying disease, diagnose and quantify primary and secondary cellular immunodeficiency, follow-up vaccination responses, measure adoptive transfer of virus-specific immunity via hematopoietic stem cell or liver transplantation, assess allergy, antimicrobial immunity and also rare effector/memory cells directed against tumor antigens. This review will first shortly describe various cellular in vitro methods and then present applications, summarizing some own studies performed within the last 18 years.

Association of human leukocyte antigen DQB1 and DRB1 alleles with chronic hepatitis B

AIM: To investigate the effect of human leukocyte antigen (HLA) DRB1 and DQB1 alleles on the inactive and advanced stages of chronic hepatitis B.

METHODS: Patient records at a single institution’s hepatology clinic were reviewed. Demographic data, laboratory results, endoscopy results, virological parameters, biopsy scores and treatment statuses were recorded. In total, 355 patients were eligible for the study, of whom 226 (63.7%) were male. Overall, 82 (23.1%) were hepatitis B early antigen (HBeAg) positive, 87 (24.5%) had cirrhosis, and 66 (18.6%) had inactive disease. The presence of DQB1 and DRB1 alleles was determined by polymerase chain reaction with sequence-specific primers. The distribution of the genotyped alleles among patients with cirrhosis and patients with chronic active hepatitis was analyzed.

RESULTS: The most frequent HLA DQB1 allele was DQB1*03:01 (48.2%), and the most frequent HLA DRB1 allele was DRB1*13/14 (51.8%). DQB1*05:01 was more frequent in patients with active disease than in inactive patients (27% vs 9.1%; P = 0.002, P_c = 0.026). DRB1*07 was rare in patients with cirrhosis compared with non-cirrhotics (3.4% vs 16%; P = 0.002, P_c = 0.022). Older age (P < 0.001) and male gender (P = 0.008) were the other factors that affected the presence of cirrhosis. In a multivariate logistic regression analysis, DRB1*07 remained a significant negative predictor of cirrhosis (P = 0.015). A bioinformatics analysis revealed that a polymorphic amino acid sequence in DRB1*07 may alter interaction with the T-cell recognition site.

CONCLUSION: This study demonstrates that HLA alleles may influence cirrhosis development and disease activity in Turkish chronic hepatitis B patients.

Genetic variants within the MHC region are associated with immune responsiveness to childhood vaccinations

The influence of genetic variability within the major histocompatibility complex (MHC) region on variations in immune responses to childhood vaccination was investigated. The study group consisted of 135 healthy infants who had been immunized with hepatitis B (HBV), 7-valent pneumococcal conjugate (PCV7), and diphtheria, tetanus, acellular pertussis (DTaP) vaccines according to standard childhood immunization schedules. Genotype analysis was performed on genomic DNA using Illumina Goldengate MHC panels (Mapping and Exon Centric). At the 1 year post vaccination check-up total, isotypic, and antigen-specific serum antibody levels were measured using multiplex immunoassays. A number of single nucleotide polymorphisms (SNPs) within MHC Class I and II genes were found to be associated with variations in the vaccine specific antibody responses and serum levels of immunoglobulins (IgG, IgM) and IgG isotypes (IgG1, IgG4) (all at p<0.001). Linkage disequilibrium patterns and functional annotations showed that significant SNPs were strongly correlated with other functional regulatory SNPs. These SNPs were found to regulate the expression of a group of genes involved in antigen processing and presentation including HLA-A, HLA-C, HLA-G, HLA-H, HLA-DRA, HLA-DRB1, HLA-DRB5, HLA-DQA1, HLA-DQB1, HLA-DOB, and TAP-2. The results suggest that genetic variations within particular MHC genes can influence immune response to common childhood vaccinations, which in turn may influence vaccine efficacy.

The effect of HLA-DQB1 alleles on virologic breakthroughs during chronic hepatitis B treatment with genetically low barrier drugs

BACKGROUND

Chronic hepatitis B treatment with oral antiviral drugs is a long course. During this course, antiviral resistance is a serious issue, particularly, if genetically low barrier drugs are in use. Host immunity is accepted to have an effect on antiviral resistance development. The earliest clinical sign of drug resistance is virologic breakthrough. In this study, we aimed to investigate the relation between HLA-DQB1 alleles and virologic breakthrough events.

SUBJECTS AND METHODS

The patient records at single institution hepatology clinic were reviewed. Local institution ethics committee approval was taken. The patients' demographic data, virologic parameters, treatment statues were noted. Patients who had received lamivudine or adefovir were recruited and grouped into two according to virologic breakthrough occurrence. Patients who were not compliant to the given treatment were excluded. Blood samples were taken for DNA extraction. HLA-DQB1 alleles were determined at high level by sequence-specific primers-polymerase chain reaction. The distribution of DQB1 alleles among groups was analyzed.

RESULTS

One hundred ninety-eight patients were eligible for the study. Ninety-six of them had virologic breakthrough where 102 did not have. DQB1 0503 allele was more frequent in patients without breakthrough (28.4% vs. 12.4%, P=0.006). In univariate analysis, HBeAg seropositivity (P<0.001), absence of cirrhosis (P=0.007), younger age (P=0.002) and higher pretreatment logDNA (P<0.001) were related to breakthrough events. However, in multivariate analysis only logDNA (P<0.001) and DQB1*0503 (P=0.02) allele revealed statistically significant relation with breakthrough events.

CONCLUSION

Host immunity may have an effect on outcome during treatment with oral antiviral drugs. A patient with better immunologic profile may suppress the viral replication better and this may cause less resistance occurrence during treatment with genetically low barrier drugs.

The effect of HLA on immunological response to hepatitis B vaccine in healthy people: a meta-analysis

BACKGROUND AND AIM

Evidence is accumulating that several markers in the human leukocyte antigen (HLA) region have been associated with decreased or increased antibody response to hepatitis B vaccine in different individuals. This meta-analysis is to assess the associations of HLA class II DRB1 and DQB1 alleles with immunologic response to hepatitis B vaccine in healthy people.

METHODS

A systematic review of cohort studies in healthy people was performed. We searched databases for relevant studies that were published in English or Chinese up to February 17, 2012. Odds ratios (ORs) with corresponding 95% confidence intervals (CIs) of HLA alleles response to hepatitis B vaccine were pooled by using of a fixed-effects or random-effects model depending on absence or presence of significant heterogeneity. All statistical tests were two-sided.

RESULTS

Fifteen studies were included in this meta-analysis after scanning 774 potentially relevant articles. A total of 2308 subjects (including 1215 responders, 873 nonresponders and 220 control populations) were included. For DRB1 alleles, pooled ORs showed that three HLA variants, DRB1*01, DRB1*1301 and DRB1*15 were associated with a significant increase antibody response to hepatitis B vaccine, their pooled ORs were 2.73, 5.94 and 2.29 respectively. While DRB1 *03 (DRB1*0301), DRB1*04, DRB1*07 and DRB1*1302 were opposite, their pooled ORs were 0.55(0.42), 0.57, 0.24 and 0.25 respectively. And for DQB1 alleles, pooled ORs showed that DQB1*05 (DQB1*0501), DQB1*06, DQB1*0602 were associated with a significant increase antibody response to hepatitis B vaccine. Their merger ORs were 1.85, 2.35, 2.34 and 3.32 respectively. While DQB1*02 (pooled OR=0.27) was adverse. Sensitivity and specificity analysis of HLA alleles showed that DRB1*1301and DQB1*0602 had high specificity (94.2% and 90.1%) but low sensitivity (25.1% and 26.3%), respectively.

CONCLUSION

It was suggested that specific HLA class II alleles (DRB1 and DQB1) were associated with antibody response to HepB.

Immunologic hypo- or non-responder in natural dengue virus infection

Serologically defined primary dengue virus infection and/or subsequent homologous serotype infection is known to be associated with less severe disease as compared with secondary subsequent heterologous serotype infection. In geographical locales of high dengue endemicity, almost all individuals in the population are infected at some point in time and should therefore are at high risk of secondary infection. Interestingly, dengue viremia in healthy blood donors whose sera apparently lack detectable levels of specific antibody to dengue viral antigens has been reported. The incidence rate of potential immunologic hypo- or non-responders following natural primary dengue virus infection in dengue endemic regions, who do become immune responders only after repeated exposure, has not been described. These are the patients who may be diagnosed as primary infection in the subsequent infection, but actually are secondary infection. This concept has important implications with regards to the hypothesis of immunological enhancement of dengue pathogenesis, which has largely been advanced based on empirical observations and/or from in vitro experimental assays. The fact that dengue naïve travelers can suffer from severe dengue upon primary exposure while visiting dengue endemic countries underscores one of the major problems in explaining the role of immune enhancement in the pathogenesis of severe dengue virus infection. This evidence suggests that the mechanism(s) leading to severe dengue may not be associated with pre-existing enhancing antibody. Consequently, we propose a new paradigm for dengue virus infection classification. These include a) patients with naïve primary infection, b) those that are serologically defined primary in dengue endemic zones and c) those who are serologically defined secondary dengue virus infection. We submit that clarity with regards to such definitions may help facilitate the delineation of the potential mechanisms of severe dengue virus infection.

The role of human leukocyte antigen tissue groups in hepatitis B virus vaccination in Turkey

BACKGROUND/PURPOSE

Between 5% and 10% of the vaccinated population responds less well to standard vaccination schedules irrespective of hepatitis B virus (HBV) vaccination. This manuscript aims at describing possible correlation of different major histocompatibility complex (MHC) Class-I and MHC Class-II haplotype to anti-HBV humoral responsiveness following HBV vaccination.

MATERIALS AND METHODS

The study was conducted on 944 vaccinated hospital staff members and concentrated on the 38 nonresponders as defined by enzyme-linked immunosorbent assay (ELISA) results. In order to define significance of the different haplotypes from the nonresponders, their frequency was compared to the frequency of the same haplotype in 18 randomly selected responders. Human leukocyte antigen (HLA)-A and HLA-B antigens were typed among total mononuclear cells using a standard two-stage microlymphocytotoxicity test. The typing method of HLA Class-II is based on a technique that involves amplification of the second exon of different HLA Class-II genes by PCR.

RESULTS

Positive correlations were found between four HLA-DR (HLA-DRB1*04X, DRB1*0401X, DRB1*11/13, and DRB1*0401X0201) haplotypes and nonresponders but there was a negative correlation with one Class-I (HLA-B13).

CONCLUSION

This study suggested that certain HLA types are associated with nonresponsiveness to vaccination. The different HLA of ethnic groups should also be kept in mind when evaluating the response to hepatitis vaccination. The different HLA gene frequencies of ethnic groups should be examined in further large-scale population-based studies.

Association of polymorphisms of cytokine and TLR-2 genes with long-term immunity to hepatitis B in children vaccinated early in life

Hepatitis B vaccine is effective in preventing hepatitis B virus (HBV) infection. However, 5-10% of vaccinees fail to produce sufficient antibody against hepatitis B surface antigen (anti-HBs). In this study, we investigated the association of genetic polymorphisms with long-term response to hepatitis B vaccine in 301 children who received the vaccine 5-7 years ago. Of them, 86 (28.6%) had anti-HBs <10 mIU/ml (group A) and 215 (71.4%) had anti-HBs ≥10 mIU/ml (group B). While the frequencies of T allele and TT genotype in single nucleotide polymorphisms (SNP) rs2243250 and rs2070874 of interleukin (IL)-4 in group A were higher than those in group B (all P<0.05 and q<0.2), the frequency of C allele in SNP rs2243250, rs2070874 and rs2227284 of IL-4 in group B was higher than that in group A (all P<0.05 and q<0.2). None of 11 other SNP in IL-2, IL-10, IL-1β, IL-13, IL-12B, tumor necrosis factor-α, and toll-like receptor-2 genes was found to associate with anti-HBs response. SNP rs2070874 was associated with humoral response to hepatitis B vaccine after analyzed by multivariable logistic regression analysis (P=0.015). The haplotype TT defined by SNP rs2243250 and rs2070874 in IL-4 was associated with the poor humoral response (adjusted P=0.037). Our findings demonstrate that IL-4 gene polymorphisms may affect the long-term immune response to hepatitis B vaccine.

CD3Z genetic polymorphism in immune response to hepatitis B vaccination in two independent Chinese populations

Vaccination against hepatitis B virus is an effective and routine practice that can prevent infection. However, vaccine-induced immunity to hepatitis B varies among individuals. CD4⁺ T helper cells, which play an important role in both cellular and humoral immunity, are involved in the immune response elicited by vaccination. Polymorphisms in the genes involved in stimulating the activation and proliferation of CD4⁺ T helper cells may influence the immune response to hepatitis B vaccination. In the first stage of the present study, a total of 111 single nucleotide polymorphisms (SNPs) in 17 genes were analyzed, using the iPLEX MassARRAY system, among 214 high responders and 107 low responders to hepatitis B vaccination. Three SNPs (rs12133337 and rs10918706 in CD3Z, rs10912564 in OX40L) were associated significantly with the immune response to hepatitis B vaccination (P = 0.008, 0.041, and 0.019, respectively). The three SNPs were analyzed further with the TaqMan-MGB or TaqMan-BHQ probe-based real-time polymerase chain reaction in another independent population, which included 1090 high responders and 636 low responders. The minor allele ‘C’ of rs12133337 continued to show an association with a lower response to hepatitis B vaccination (P = 0.033, odds radio = 1.28, 95% confidence interval = 1.01–1.61). Furthermore, in the stratified analysis for both the first and second populations, the association of the minor allele ‘C’ of rs12133337 with a lower response to hepatitis B vaccination was more prominent after individuals who were overweight or obese (body mass index ≥25 kg/m²) were excluded (1^st stage: P = 0.003, 2^nd stage: P = 0.002, P-combined = 9.47e-5). These findings suggest that the rs12133337 polymorphism in the CD3Z gene might affect the immune response to hepatitis B vaccination, and that a lower BMI might increase the contribution of the polymorphism to immunity to hepatitis B vaccination.

Association between polymorphisms of the cytokine and cytokine receptor genes and immune response to hepatitis B vaccination in a Chinese Han population

The immune response to hepatitis B vaccination varies among individuals. It has been reported that polymorphisms in cytokine and cytokine receptor genes are associated with these individual differences. The aim of the current study was to investigate the association between polymorphisms of the Th1/Th2 cytokine and cytokine receptor genes and the response to hepatitis B vaccination in a Chinese Han population. A total of 10 single nucleotide polymorphisms distributed in 6 genes (TNFRSF1A, IL12A, IL12B, IFNG, IL4, and IL10) were genotyped in 214 high-responders [hepatitis B surface antibody (anti-HBs) ≥1,000 mIU/ml] and 107 low-responders (anti-HBs: 10-99 mIU/ml). The minor CTCTAA allele of rs17860508 in the IL12B gene was associated with a low response to hepatitis B vaccination (P = 0.039, odds ratio = 1.41, 95% confidence interval = 1.00-1.99). In addition, a significant gene-gene interaction was found: the frequency of the combined genotypes IL12A rs2243115 TT and IL12B rs17860508 CTCTAA/CTCTAA was significantly higher in the low-response group than in the high-response group (P = 0.008, odds ratio = 2.19, 95% confidence interval = 1.23-3.93). These findings suggest that polymorphisms in the IL12A and IL12B genes might play an important role jointly in determining the response to hepatitis B vaccination.

Association of HLA and TNF polymorphisms with the outcome of HBV infection in the South Indian population

The role of host genetic factors in the pathogenesis and outcome of hepatitis B virus (HBV) infection is not well known. We assessed the association of HLA and TNF (rs361525, rs1800629, rs1799724, rs1800630 and rs1799964) polymorphisms with HBV outcome in the South Indian population. Association of HLA polymorphism was analyzed in 90 individuals from each group, that is, spontaneous recovery (SR) and chronic-HBV (C-HBV) infection. The role of TNF polymorphisms was evaluated in 150 subjects with SR and 137 patients with C-HBV infection. After adjusting for age and sex, HLA-DRB1*07:01 was strongly associated with chronicity (corrected P-value (pc) <0.005, odds ratio (OR) 3.76, 95% confidence interval (CI) 1.84-7.68). The rs1800630 genotype was associated with HBV outcome in codominant (pc<0.01, OR=1.99, 95% CI 1.30-3.05) and dominant (pc<0.01, OR=2.28, 95% CI 1.35-3.84) analyzing models after adjusting for age and sex. Similarly, the rs1799964 genotype was associated with HBV outcome in codominant (pc=0.01, OR=1.57, 95% CI 1.09-2.27) and dominant (pc<0.01, OR=2.21, 95% CI 1.27-3.83) analyzing models. Haplotype analysis (rs1799964/rs1800630/rs1799724/rs1800629/rs361525) revealed that the CACGG haplotype was strongly associated with C-HBV infection (P=0.0004). Our study suggests that inheritance of HLA and TNF polymorphisms might explain the outcome of HBV infection in the South Indian population.

Role of HLA allele polymorphism in chronic hepatitis B virus infection and HBV vaccine sensitivity in patients from eastern Turkey

Human leukocyte antigen (HLA) alleles have been associated with the clinical outcomes of hepatitis B virus (HBV) infection, which range from spontaneous recovery to hepatocellular carcinoma. In this study involving subjects from eastern Turkey, the frequencies of HLA-B35, HLA-CW4, HLA-DQ2, and HLA-DQ8 were markedly higher in the chronic HBV group than those in the spontaneously recovered group; the frequencies of HLA-A11 and HLA-A24 in the nonresponsive HBV vaccine group were markedly higher than those in the responsive HBV vaccine group; and the frequency of HLA-CW6 in the nonresponsive HBV vaccine group was significantly lower than in the responsive group. A complete understanding of HLA types associated with the progression to chronic HBV infection and their effects within the cell at the molecular level will be an important contribution in the development of new HBV vaccines and new treatment strategies for chronic HBV infection.

New genetic associations detected in a host response study to hepatitis B vaccine

The immune response to hepatitis B vaccination differs greatly among individuals, with 5-10% of healthy people failing to produce protective levels of antibodies. Several factors have been implicated in determining this response, chiefly individual genetic variation and age. Aiming to identify genes involved in the response to hepatitis B vaccination, a two-stage investigation of 6091 single-nucleotide polymorphisms (SNPs) in 914 immune genes was performed in an Indonesian cohort of 981 individuals showing normal levels of anti-HBs versus 665 individuals displaying undetectable levels of anti-HBs 18 months after initial dose of the vaccine. Of 275 SNPs identified in the first stage (476 normal/372 nonresponders) with P<0.05, significant associations were replicated for 25 polymorphisms in 15 genes (503 normal/295 nonresponders). We validated previous findings (HLA-DRA, rs5000563, P-value combined=5.57 x 10(-10); OR (95%CI)=0.61 (0.52-0.71)). In addition, we detected a new association outside of the human leukocyte antigen loci region that passed correction for multiple testing. This SNP is in the 3' downstream region of FOXP1, a transcription factor involved in B-cell development (P-value combined=9.2 x 10(-6); OR (95%CI)=1.38 (1.2-1.6)).These findings might help to understand the biological reasons behind vaccine failure and other aspects of variation in the immune responses of healthy individuals.

Hepatitis B virus vaccine response in hemodialysis: baseline patient characteristics

BACKGROUND

Hepatitis B virus (HBV) vaccination is recommended for all individuals with renal failure. Nevertheless, the response rate for this vaccine in hemodialysis (HD) patients is low, ranging from 50% to 80%. The goal of this study was to determine patient characteristics at the initiation of HD that influence HBV vaccine response.

METHODS

Patients new to HD in an urban population in the United States were retrospectively examined. Analyzed patients were HBV antibody and antigen negative and hepatitis C virus antibody negative at the start of HD, who received HBV recombinant vaccine. Nonresponse was defined as failure to seroconvert (>10 UI/L) after six deltoid intramuscular injections of vaccine. Response was defined as a lasting seroconversion (at least two consecutive positive titers) with </=6 injections. Demographic, laboratory, and kinetic modeling data were examined.

RESULTS

A total of 33 nonresponders and 64 responders were identified. Univariate analysis demonstrated that nonresponders were older (59 vs. 51 years), had a higher prevalence of diabetes mellitus (DM) (70 vs. 39%), had lower serum albumin levels (3.2 vs. 3.3 g/dL), and had higher dry weights (84 vs. 71 kg) than responders at HD start. In addition, nonresponders had lower normalized protein catabolic rates (0.74 vs. 0.85 g/kg/day) and lower (single-pool) spKt/V(urea)values (0.95 vs. 1.19). Nonresponders had lower serum creatinine levels than responders, despite the greater dry weights. In a multiple logistic analysis model, the presence of DM, age >/= 55 years, body weight >/=80 kg, and normalized protein catabolic rate </=0.75 g/kg/day were associated with HBV vaccination nonresponse. At the end of the vaccination period, nonresponders versus responders continued to have lower serum albumin (3.5 vs. 3.8 g/dL) and creatinine levels (7.8 vs. 10.0 mg/dL) and spKt/V(urea)(1.27 vs. 1.39).

CONCLUSION

Hepatitis B vaccine nonresponders on HD are older, are more likely to have DM, are more malnourished, and have lower spKt/V(urea) than responders. Nonresponders may also have a different body composition with a lower ratio of lean to total body mass.

Clear and independent associations of several HLA-DRB1 alleles with differential antibody responses to hepatitis B vaccination in youth

To confirm and refine associations of human leukocyte antigen (HLA) genotypes with variable antibody (Ab) responses to hepatitis B vaccination, we have analyzed 255 HIV-1 seropositive (HIV(+)) youth and 80 HIV-1 seronegatives (HIV(-)) enrolled into prospective studies. In univariate analyses that focused on HLA-DRB1, -DQA1, and -DQB1 alleles and haplotypes, the DRB1*03 allele group and DRB1*0701 were negatively associated with the responder phenotype (serum Ab concentration > or = 10 mIU/mL) (P = 0.026 and 0.043, respectively). Collectively, DRB1*03 and DRB1*0701 were found in 42 (53.8%) out of 78 non-responders (serum Ab <10 mIU/mL), 65 (40.6%) out of 160 medium responders (serum Ab 10-1,000 mIU/mL), and 27 (27.8%) out of 97 high responders (serum Ab >1,000 mIU/mL) (P < 0.001 for trend). Meanwhile, DRB1*08 was positively associated with the responder phenotype (P = 0.010), mostly due to DRB1*0804 (P = 0.008). These immunogenetic relationships were all independent of non-genetic factors, including HIV-1 infection status and immunodeficiency. Alternative analyses confined to HIV(+) youth or Hispanic youth led to similar findings. In contrast, analyses of more than 80 non-coding, single nucleotide polymorphisms within and beyond the three HLA class II genes revealed no clear associations. Overall, several HLA-DRB1 alleles were major predictors of differential Ab responses to hepatitis B vaccination in youth, suggesting that T-helper cell-dependent pathways mediated through HLA class II antigen presentation are critical to effective immune response to recombinant vaccines.

HLA and infectious diseases

Following their discovery in the early 1970s, classical human leukocyte antigen (HLA) loci have been the prototypical candidates for genetic susceptibility to infectious disease. Indeed, the original hypothesis for the extreme variability observed at HLA loci (H-2 in mice) was the major selective pressure from infectious diseases. Now that both the human genome and the molecular basis of innate and acquired immunity are understood in greater detail, do the classical HLA loci still stand out as major genes that determine susceptibility to infectious disease? This review looks afresh at the evidence supporting a role for classical HLA loci in susceptibility to infectious disease, examines the limitations of data reported to date, and discusses current advances in methodology and technology that will potentially lead to greater understanding of their role in infectious diseases in the future.

Efficacy and long-term immunogenicity of hepatitis B vaccine in haemodialysis patients

BACKGROUND

Hepatitis B vaccine is effective in protection against hepatitis B virus (HBV) infection in haemodialysis (HD) patients, but the antibody response is variable in this population and the persistence of immunity in them remains largely unknown. In this study we aimed to evaluate the efficacy and long-term immunogenicity of hepatitis B vaccine in HD patients.

METHODS

In this study, we initially offered HBV vaccination as double dose, four vaccine series schedule (40 microg injections intramuscularly in the deltoid muscle at 0, 1, 2 and 6 months) to 54 HD patients who were negative for hepatitis B core antibody and did not receive any dose of HBV vaccine previously. Serum levels of hepatitis B surface antibody (anti-HBs) tested 1-2 months after completion of vaccination. Then we follow the patients up to 1 year after primary vaccination to evaluate the persistence of immunity (as indicated by serum levels of anti-HBs higher than or equal to 10 IU/l).

RESULTS

After primary vaccination, 87% of patients developed anti-HBs levels above 10 IU/l. 27.8% and 59.2% of them were weak responders and high responders respectively. 13% of patients were non-responders. After 1-year follow-up, 18.18% of responders had lost their anti-HBs (transient responders). All of them were initially in weak responders group and had lower anti-HBs levels.

CONCLUSION

We found an average percentage of seroconversion after primary HBV vaccination in HD patients. Our study also supported this fact that an antibody titre above 100 IU/l following primary vaccination is necessary to maintain that level of antibody 1 year later.

Gluten intake interferes with the humoral immune response to recombinant hepatitis B vaccine in patients with celiac disease

OBJECTIVE

Patients with celiac disease, who often carry human leukocyte antigen-DR3;DQ2, are prone to inadequate response to hepatitis B immunization. We evaluated vaccine response in relation to disease activity and whether previous treatment with a gluten-free diet influences the achievement of protective antibody titers.

PATIENTS AND METHODS

We studied 128 children and adolescents with celiac disease and 113 age-matched control subjects. Twenty-two patients with celiac disease were prospectively immunized after diagnosis during dietary treatment (group 1). A total of 106 (group 2) and the control subjects received vaccination by mass immunization in schools at 14 years of age regardless of diet status and when celiac disease was still undiagnosed in 27 of these children. Diet compliance and celiac disease activity were monitored by measurement of antibodies against transglutaminase and endomysium. Vaccine response was determined by measuring antihepatitis B antibodies from serum.

RESULTS

The seroconversion after hepatitis B vaccination was 95.5% in group 1. All of these patients carried human leukocyte antigen DQ2. The response rate in group 2 was 50.9% and correlated with gluten intake (untreated patients: 25.9%, non-strict diet: 44.4%, strict diet: 61.4%). Treated and compliant patients did not significantly differ from control subjects (75.2%). Thirty-seven antihepatitis B-negative patients with celiac disease received a booster during a controlled gluten-free diet, and 36 (97.3%) seroconverted, irrespective of the presence of human leukocyte antigen DQ2.

CONCLUSIONS

Nonresponse to recombinant hepatitis B surface antigen may be a sign of undiagnosed celiac disease. However, there is a good vaccine response in adequately treated patients. Human leukocyte antigen DQ alleles do not seem to have a primary role. Revaccination is recommended during a controlled gluten-free diet.

HLA and response to booster hepatitis B vaccination in anti-HBs-seronegative adolescents who had received primary infantile vaccination

To explore contemporarily genetic and non-genetic determinants of long-term immunological memory to hepatitis B (HB) vaccination, we conducted a case-control study nested in an adolescent cohort of booster recipients who had received primary infantile HB vaccination but with residual anti-HBs titers <10 mIU/mL at 15-18 years of age. High-resolution phenotypes of human leukocyte antigen (HLA)-A, -B, and -DRB1 loci were determined by sequence-specific oligonucleotide probe hybridization. After controlling for pre-booster anti-HBs levels, the absences of HLA-A*02 and -DRB1*08, simply expressed as A*02(-) and -DRB1*08(-), and the presence of B*15 were significantly associated with elevated risks of non-response (post-booster anti-HBs titers<10 mIU/mL) to booster vaccination. The adjusted odds ratios (ORs) were 3.85 (CI, 1.82-8.33), 4.55 (CI, 1.23-16.67), 3.59 (CI, 1.40-9.17), respectively. There was multiplicative synergism between A*02 and B*15 on the risk of non-response to booster vaccination. The multivariate-adjusted ORs for A*02(-)/B*15, A*02(-)/B*15(-), A*02/B*15, and A*02/B*15(-) haplotypes were 20.39 (p=0.0003), 3.29 (p=0.007), 1.32 (p>0.05), and 1.0, respectively. Recent cigarette smoking and/or betel-quid chewing was associated with a 12-fold risk of non-response to booster vaccination. Further comparisons between responders and adolescents who had undetectable post-booster anti-HBs titers (<0.1 mIU/mL) demonstrated similar results. Our results indicated that response to booster HB vaccination as well as long-term immunological responses to HB vaccination are closely related with host genetic factors, and probably modified by recent substance use.

Host genetic factors and vaccine-induced immunity to hepatitis B virus infection

Background

Vaccination against hepatitis B virus infection (HBV) is safe and effective; however, vaccine-induced antibody level wanes over time. Peak vaccine-induced anti-HBs level is directly related to antibody decay, as well as risk of infection and persistent carriage despite vaccination. We investigated the role of host genetic factors in long-term immunity against HBV infection based on peak anti-HBs level and seroconversion to anti-HBc.

Methods

We analyzed 715 SNP across 133 candidate genes in 662 infant vaccinees from The Gambia, assessing peak vaccine-induced anti-HBs level and core antibody (anti-HBc) status, whilst adjusting for covariates. A replication study comprised 43 SNPs in a further 393 individuals.

Results

In our initial screen we found variation in IFNG, MAPK8, and IL10RA to affect peak anti-HBs level (GMTratio of <0.6 or >1.5 and P≤0.001) and lesser associations in other genes. Odds of core-conversion was associated with variation in CD163. A coding change in ITGAL (R719V) with likely functional relevance showed evidence of association with increased peak anti-HBs level in both screens (1st screen: s595_22 GMTratio 1.71, P = 0.013; 2nd screen: s595_22 GMTratio 2.15, P = 0.011).

Conclusion

This is to our knowledge the largest study to date assessing genetic determinants of HBV vaccine-induced immunity. We report on associations with anti-HBs level, which is directly related to durability of antibody level and predictive of vaccine efficacy long-term. A coding change in ITGAL, which plays a central role in immune cell interaction, was shown to exert beneficial effects on induction of peak antibody level in response to HBV vaccination. Variation in this gene does not appear to have been studied in relation to immune responses to viral or vaccine challenges previously. Our findings suggest that genetic variation in loci other than the HLA region affect immunity induced by HBV vaccination.

Genetic variation in the response to vaccination

Vaccines are the most powerful means to prevent and diminish the burden of infectious disease. However, there are limitations to their use: vaccines are not yet available for all infectious diseases (including human immunodeficiency virus and respiratory syncytial virus), they sometimes lack efficacy, the response to vaccination is limited by maternal antibodies in very young infants, and the response to vaccination is variable or may even be absent in some individuals. This review focuses on genetic factors that determine the variable response to vaccination. The highly polymorphic human leukocyte antigen system, which is involved in antigen presentation, has been researched most in this aspect, and clearly affects the response to vaccination. Other, but less polymorphic pathways involved are the Toll-like receptor pathway, which is involved in antigen recognition and stimulation of the immune system, and the cytokine immunoregulatory network. The heritability, or the proportion of total variance that is due to additive genetic factors, appears to be particularly large for vaccine-induced antibody responses in young infants compared with cell-mediated responses and antibody responses in older, immunologically more mature individuals. Both antibody and cell-mediated responses are not only affected by loci within, but also strongly by loci outside the human leukocyte antigen system. Because most genes that are important in influencing immune responses to vaccination are still unknown, clearly more work is required. A better understanding of the factors that determine an effective response to vaccination may lead to the identification of specific genes and pathways as targets for the development of novel more uniformly effective vaccines.

A comparative review of HLA associations with hepatitis B and C viral infections across global populations

Hepatitis B (HBV) and hepatitis C (HCV) viral infection or co-infection leads to risk of development of chronic infection, cirrhosis and hepatocellular carcinoma (HCC). Immigration and globalization have added to the challenges of public health concerns regarding chronic HBV and HCV infections worldwide. The aim of this study is to review existing global literature across ethnic populations on HBV and HCV related human leukocyte antigen (HLA) associations in relation to susceptibility, viral persistence and treatment. Extensive literature search was conducted to explore the HLA associations in HBV and HCV infections reported across global populations over the past decade to understand the knowledge status, weaknesses and strengths of this information in different ethnic populations. HLA DR13 is consistently associated with HBV clearance globally. HLADRB1*11/*12 alleles and DQB1*0301 are associated with HBV persistence but with HCV clearance worldwide. Consistent association of DRB1*03 and *07 is observed with HCV susceptibility and non-responsiveness to HBV vaccination across the population. HLA DR13 is protective for vertical HBV and HCV transmission in Chinese and Italian neonates, but different alleles are associated with their susceptibility in these populations. HLA class I molecule interactions with Killer cell immunoglobulin like receptors (KIR) of natural killer (NK) cells modulate HCV infection outcome via regulating immune regulatory cells and molecules. HLA associations with HBV vaccination, interferon therapy in HBV and HCV, and with extra hepatic manifestations of viral hepatitis are also discussed. Systematic studies in compliance with global regulatory standards are required to identify the HLA specific viral epitope, stage specific T cell populations interacting with different HLA alleles during disease progression and viral clearance of chronic HBV or HCV infections among different ethnic populations. These studies would facilitate stage specific therapeutic strategies for clearance of HBV and HCV infections or co-infections across global populations and aid in identification of HBV-HCV combined vaccine. HLA associations of chronic HBV or HCV development with confounding host factors including alcohol, drug abuse, insulin resistance, age and gender are lacking and warrant detailed investigation across global populations.

Analysis of HLA-DQB1 gene polymorphisms in asymptomatic HBV carriers and chronic hepatitis B patients in the Chinese Han population

Host genetic factors and environment factors including hepatitis B virus (HBV) genotype are widely viewed as common basis of the different outcomes of HBV infection. Human leucocyte antigen (HLA) plays an important role in immunological reaction to HBV infection. The study aimed to explore whether the HLA-DQB1 allele polymorphisms are associated with the outcomes of HBV infection in the Chinese Han population. One hundred and thirty-four asymptomatic HBV carriers and 139 chronic hepatitis B patients were recruited in this case-control study in Beijing, China. Sequence-specific primers-polymerase chain reaction was used to detect 13 alleles of HLA-DQB1 gene. The frequency distributions of alleles in two groups were analysed using sas 9.1.2 software. After adjustment of confounders the frequencies of HLA-DQB1*0503 allele and *0303 allele in chronic hepatitis B group were statistically significant lower than those in asymptomatic HBV carrier group (P = 0.04; P = 0.05), and the frequency of exposure to alcohol consumption in patients with chronic hepatitis B was clearly higher than that in asymptomatic HBV carrier group (P = 0.004). HLA-DQB1*0503 allele and *0303 allele are independently resistant genetic factors to chronic hepatitis B, and alcohol consumption is the risk factor of chronic hepatitis B.

Human leukocyte antigen polymorphisms: variable humoral immune responses to viral vaccines

Antibody formation in response to antigen stimulation remains the basis for measuring an individual's response and protection for most viral vaccines. A significant proportion of the variation in individual humoral immune response to vaccination appears to be genetic. The collection of genes found on chromosome 6 forming the human leukocyte antigen system provides one of the greatest sources of genetic variation in individuals with respect to their immunological responses. Recent research has demonstrated significant associations between vaccine response and human leukocyte antigen alleles. These associations not only explain why vaccine-induced humoral immune responses vary among individuals and between populations, but these variations may also hold the key to the development of future generations of vaccines.

Partial delipidation improves the T-cell antigenicity of hepatitis B virus surface antigen

Hepatitis B virus surface antigen (HBsAg) is a complex macromolecular particle composed of glycoproteins and lipids. The latter, representing 25% of the particle mass, are of host origin and determine the solubility, stability, and, indirectly, B-cell immunogenicity of HBsAg. HBsAg is a T-cell-dependent immunogen that does not elicit a detectable humoral immune response in 5% of HBsAg vaccine recipients and in most subjects suffering from chronic hepatitis B. We investigated the influence of the lipid content on the antigenicity of the particle. Lipids were partially removed from HBsAg by treatment with beta-D-octyl glucoside and density centrifugation. Sham treatment consisted of density centrifugation of HBsAg only. We compared the in vitro proliferative responses of established T-cell lines and nonfractionated peripheral blood mononuclear cells (PBMC) from HBsAg vaccinees and chronic HBV patients when stimulated with partially delipidated HBsAg, untreated HBsAg, or sham-treated HBsAg. In all experiments, delipidated HBsAg turned out to be 10 to 100 times more antigenic than its untreated or sham-treated counterpart. Remarkably, PBMC from vaccine nonresponders or chronic HBV patients displayed a proliferative response towards delipidated HBsAg, whereas native HBsAg never induced a response. A series of control experiments demonstrated that this enhancement of T-cell antigenicity was HBsAg specific and directly linked to lipid extraction. Nonspecific adjuvant effects of any kind could be ruled out. In vivo evaluation in mice demonstrated that delipidated particles lose most of their B-cell antigenicity. However, when native and delipidated particles were mixed, these mixtures induced equal or slightly superior anti-HBs responses to those induced by the same quantity of native HBsAg alone. In conclusion, our data show that partial delipidation of HBsAg strikingly increases the T-cell antigenicity of this unique viral antigen.

Human CD4+ T cells induced by synthetic peptide malaria vaccine are comparable to cells elicited by attenuated Plasmodium falciparum sporozoites

Peptide vaccines containing minimal epitopes of protective Ags provide the advantages of low cost, safety, and stability while focusing host responses on relevant targets of protective immunity. However, the limited complexity of malaria peptide vaccines raises questions regarding their equivalence to immune responses elicited by the irradiated sporozoite vaccine, the "gold standard" for protective immunity. A panel of CD4+ T cell clones was derived from volunteers immunized with a peptide vaccine containing minimal T and B cell epitopes of the Plasmodium falciparum circumsporozoite protein to compare these with previously defined CD4+ T cell clones from volunteers immunized with irradiated P. falciparum sporozoites. As found following sporozoite immunization, the majority of clones from the peptide-immunized volunteers recognized the T* epitope, a predicted universal T cell epitope, in the context of multiple HLA DR and DQ molecules. Peptide-induced T cell clones were of the Th0 subset, secreting high levels of IFN-gamma as well as variable levels of Th2-type cytokines (IL-4, IL-6). The T* epitope overlaps a polymorphic region of the circumsporozoite protein and strain cross-reactivity of the peptide-induced clones correlated with recognition of core epitopes overlapping the conserved regions of the T* epitope. Importantly, as found following sporozoite immunization, long-lived CD4+ memory cells specific for the T* epitope were detectable 10 mo after peptide immunization. These studies demonstrate that malaria peptides containing minimal epitopes can elicit human CD4+ T cells with fine specificity and potential effector function comparable to those elicited by attenuated P. falciparum sporozoites.

Molecular analysis of HLA class II associations with hepatitis B virus clearance and vaccine nonresponsiveness

Clearance of acute hepatitis B virus (HBV) infection is associated with a vigorous CD4+ T-cell response focusing on the core protein. HLA class II glycoproteins present viral peptides to CD4+ T cells and influence the immune responses. HLA-DRB1*1301/2 have been associated with viral clearance, and HLA-DRB1*0301 is associated with nonresponse to vaccination with envelope proteins. Binding affinities of overlapping peptides covering the core and envelope proteins of HBV were measured to HLA glycoproteins encoded by HLA-DRA1*0101,-DRB1*0101 (HLA-DR1), HLA-DRA1*0101,-DRB1*0301 (HLA-DR3), HLA-DRA1*0101,-DRB1*0701 (HLA-DR7) and HLA-DRA1*0101,-DRB1*1301 (HLA-DR13) molecules and compared with published peptide-specific CD4+ T-cell responses. There are more high-affinity ligands (IC50 < 1 micromol/L) derived from the core protein than the surface antigen (P < .04 for HLA-DR1/7/13), but there was no increase in the number or the affinity of ligands for HLA-DR13. Clusters of particular core peptides bound to multiple HLA types, explaining the immunodominance of these regions for T-cell responses. Within the envelope protein, the low-affinity ligands (IC50 < 10 micromol/L) are found mainly in the surface antigen, with a marked paucity of ligands for HLA-DR3 (HLA-DR3 vs. non-DR3; P < .05) consistent with the lower vaccination responses for this HLA type. Of all peptides tested, 8 to 10 bound mainly to one HLA type, allowing a substantially greater breadth of response in heterozygotes. In conclusion, these data offer a mechanistic explanation for the dominant response to the HBV core protein during infection and support the direct involvement of the HLA-DRB1 gene in vaccine nonresponsiveness but not altered susceptibility to viral persistence.

Non-responsiveness to hepatitis B surface antigen vaccines is not caused by defective antigen presentation or a lack of B7 co-stimulation

The mechanisms causing non-responsiveness to hepatitis B surface antigen (HBsAg) vaccines in man remain elusive. The increased incidence of non-responsiveness in subjects with HLA-DR3(+) or -DR7(+) haplotypes suggests that immune response mechanisms governed by genes of the MHC are involved. Homozygotes for these two haplotypes are found almost exclusively in the non-responder (NR) population. It is conceivable that antigen-presenting cells (APC) of NR are defective in the uptake of HBsAg and that they are unable to present this Ag adequately. Previously, we demonstrated that DR2(+), DR7(+) and DP4(+) NR were able to present HBsAg. In the present paper we demonstrate that six DR0301(+) NR, five of which are homozygous for this marker, were able to take up, process and present HBsAg to HBsAg-specific, DR0301-restricted T cell lines. Non-fractionated peripheral blood mononuclear cells (PBMC) from the DR0301(+) NR did not proliferate to HBsAg in vitro, whereas they proliferated vigorously upon stimulation with tetanus toxoid, thus ruling out the presence of a generalized immunodeficiency. We therefore conclude that HLA-DR0301(+) NR vaccinees are not deficient in their HBsAg-presentation. Because it was demonstrated that recently activated T cells can apparently bypass the requirement for B7, we may have overlooked the role of the B7-co-stimulation in our set-up that used HBsAg-specific T cell lines. Therefore we examined the expression of B7 co-stimulatory molecules on NR-APC. CD86 was normally present on these cells and was not down-regulated after culturing the PBMC in the presence of HBsAg. We conclude that CD86 expression on CD14(+) monocytes of DR0301- and DR07-homozygous poor responders is not deficient and cannot be the mechanism underlying the non-responsiveness of these subjects.

Anti-HBs cellular immune response in kidney recipients before and 4 months after transplantation

Patients with renal failure represent a population at risk for hepatitis B, since only 50 to 60% of them develop protective humoral responses after vaccination. As this could be due to an altered regulation of cellular immune responses, the objectives of the present study were to evaluate the proliferative abilities of lymphocytes from patients with chronic renal failure after stimulation in vitro with a mitogen (pokeweed mitogen [PWM]) or HBsAg. In order to differentiate between the immunodeficiency associated with renal failure and that due to immunosuppression posttransplantation, the same subjects were tested before and 4 months after kidney transplantation. The lymphoproliferation assay used was performed by flow cytometry, which is based on sequential analysis of the cell cycle and which allows analysis of cytokine production. Serologically, the group of 36 patients tested comprised 22% nonresponders, 30% poor responders, and 48% responders. Lymphocyte growth was observed for all patients after stimulation with PWM, indicating that these cells had the capacity to proliferate in vitro. The level of lymphoproliferation in response to PWM was significantly reduced after transplantation, yet both before and after transplantation, all serologic nonresponders developed cellular responses to at least two vaccines. No correlation between humoral and cellular responses was shown. Proliferating cells were lymphocytes, which mostly secreted interleukin 4 (IL-4) and IL-10 for the three serologic groups. This study suggests that even when repeated vaccination fails to induce significant antibody levels in patients with renal failure, specific HBs cellular responses develop, and these may prove to be efficient in protecting these patients against hepatitis B.

[Association of humans leucocitary antigens with humoral nonresponsive to hepatitis B vaccine in chronic hemodialysis patients]

Vaccination using surface antigen from hepatitis B virus has not been successfully responded by hemodialysis patients. The present study was aimed at assessing a possible relationship between human leukocyte antigens and the low production of protective antibodies (anti-HbS) against the surface antigen from hepatitis B by patients with chronic renal failure submitted to hemodialysis programs. The antigens HLA-DR and HLA-DQ were identified in 76 hemodialysis patients through classic microlymphotoxicity. Our results showed that 34.2% of the patients were non-responsive to the vaccine VHB. The most frequent HLA specificity were: HLA-DR3, DR-7 and DQ2 with a significant association for HLA-DR3 (p=0.0025; OR 5.1; IC 95% 1.36-19.10). Such data suggest an association between genes from HLA class II antigens and the humoral non-response to the vaccine VHB.