The dynamic changes of HBV quasispecies diversity in infancy after immunoprophylaxis failure: a prospective cohort study

Background Previous works have observed that younger infants with chronic hepatitis B virus (HBV) infection are more responsive to antiviral treatment. However, the underlying mechanism remains unclear. In this study, the dynamic changes of HBV quasispecies in infants with immunoprophylaxis failure were investigated to provide virological explanations for clinical management on infantile antiviral therapy. Methods Thirteen 7-month-old infants with immunoprophylaxis failure and their mothers were enrolled from a prospective cohort, and 8 of them were followed up to 3 years old. The sequences of HBV quasispecies were analyzed by the full-length genome clone-based sequencing, and compared among mothers and their infants at different ages. Results The results revealed that the complexity, mutation frequency and genetic distance of HBV quasispecies decreased significantly at full-length, partial open reading frames and regulatory regions of HBV genome at nucleotide level in 7-month-old infants comparing with their mothers, whereas increased significantly to near the maternal level when infants grew up to 3 years old. Furthermore, similar changes were also found in Core, PreS2, RT and P regions of HBV genome at amino acid level, especially for potential NAs-resistant mutants in RT region and immune-escape mutants in Core and PreS2 regions. Conclusions This study uncovered the evolution of HBV quasispecies in infancy after mother-to-child transmission, which may provide the virological evidence for explaning that younger children are more responsive to antiviral therapy.

The Dynamic Changes of HBV Quasispecies Diversity in Infancy after Immunoprophylaxis Failure: A Prospective Cohort Study

Background: Previous works have observed that younger infants with chronic hepatitis B virus (HBV) infection are more responsive to antiviral treatment. However, the underlying mechanism remains unclear. In this study, the dynamic changes of HBV quasispecies in infants with immunoprophylaxis failure were investigated to provide virological explanations for clinical management on infantile antiviral therapy.Methods: Thirteen 7-month-old infants with immunoprophylaxis failure and their mothers were enrolled from a prospective cohort, and 8 of them were followed up to 3 years old. The sequences of HBV quasispecies were analyzed by the full-length genome clone-based sequencing, and compared among mothers and their infants at different ages.Results: The results revealed that the complexity, mutation frequency and genetic distance of HBV quasispecies decreased significantly at full-length, partial open reading frames and regulatory regions of HBV genome at nucleotide level in 7-month-old infants comparing with their mothers, whereas increased significantly to near the maternal level when infants grew up to 3 years old. Furthermore, similar changes were also found in Core, PreS2, RT and P regions of HBV genome at amino acid level, especially for potential NAs-resistant mutants in RT region and immune-escape mutants in Core and PreS2 regions.Conclusions: This study uncovered the evolution of HBV quasispecies in infancy after mother-to-child transmission, which may provide the virological evidence for explaning that younger children are more responsive to antiviral therapy.

The effects of increased dose of hepatitis B vaccine on mother-to-child transmission and immune response for infants born to mothers with chronic hepatitis B infection: a prospective, multicenter, large-sample cohort study

Background Appropriate passive-active immunoprophylaxis effectively reduces mother-to-child transmission (MTCT) of hepatitis B virus (HBV), but the immunoprophylaxis failure was still more than 5% under the current strategy. The study objective was to investigate the effects of high dose of HB vaccine on MTCT and immune response for infants born to hepatitis B surface antigen (HBsAg)-positive mothers. Methods This was a prospective, multicenter, large-sample cohort study in four sites of China, and 955 pairs of HBsAg-positive mothers and their infants were enrolled in our investigation. The infants were given 10 μg or 20 μg HB vaccine (at age 0, 1, and 6 months) plus HB immunoglobulin (at age 0 and 1 month). Serum HBsAg, antibody to HBsAg (anti-HBs), and/or HBV DNA levels in the infants were determined at age 12 months. The safety of 20 μg HB vaccine was evaluated by adverse events and observing the growth indexes of infants. Results Thirteen of 955 infants were HBsAg-positive at 12 months. Stratification analysis showed that immunoprophylaxis failure rates in the 20 μg group were not significantly different from the 10 μg group, whatever maternal HBV load was high or not. But the high dose of HB vaccine significantly reduced low-response rate (anti-HBs 10–100 IU/L) (P = 0.002) and middle-response rate (anti-HBs 100–1000 IU/L) (P = 0.022) and improved high-response rate (anti-HBs ≥ 1000 IU/L) (P < 0.0001) in infants born to mothers with HBV DNA < 5 log10 IU/mL. For infants born to mothers with HBV DNA ≥ 5 log10 IU/mL, 20 μg HB vaccine did not present these above response advantages. The 20 μg HB vaccine showed good safety for infants. Conclusions The 20 μg HB vaccine did not further reduce immunoprophylaxis failure of infants from HBsAg-positive mothers, but increased the high-response and decreased low-response rates for infants born to mothers with HBV DNA < 5 log10 IU/mL. Trial registration Chinese Clinical Trial Registry, ChiCTR-PRC-09000459

Complement Plays a Critical Role in Inflammation-Induced Immunoprophylaxis Failure in Mice

Complement impacts innate and adaptive immunity. Using a model in which the human KEL glycoprotein is expressed on murine red blood cells (RBCs), we have shown that polyclonal immunoprophylaxis (KELIg) prevents alloimmunization to transfused RBCs when a recipient is in their baseline state of heath but with immunoprophylaxis failure occurring in the presence of a viral-like stimulus. As complement can be detected on antibody coated KEL RBCs following transfusion, we hypothesized that recipient complement synergizes with viral-like inflammation to reduce immunoprophylaxis efficacy. Indeed, we found recipient C3 and C1q were critical to immunoprophylaxis failure in the setting of a viral-like stimulus, with no anti-KEL IgG alloantibodies generated in C3-/- or C1q-/- mice following KELIg treatment and KEL RBC transfusion. Differences in RBC uptake were noted in mice lacking C3, with lower consumption by splenic and peripheral blood inflammatory monocytes. Finally, no alloantibodies were detected in the setting of a viral-like stimulus following KELIg treatment and KEL RBC transfusion in mice lacking complement receptors (CR1/2-/-), narrowing key cells for immunoprophylaxis failure to those expressing these complement receptors. In-vitro studies showed complement fixed opsonized RBCs were significantly less likely to bind to B-cells from CR1/2-/- than wild type mice, potentially implicating lowered B-cell activation threshold in the presence of complement as being responsible for these findings. We thus propose a two-hit model for inflammation-induced immunoprophylaxis failure, where the first “hit” is recipient inflammation and the second “hit” is complement production/sensing. These results may have translational relevance to antigen-antibody interactions in humans.

Increased Protection of Earlier Use of Immunoprophylaxis in Preventing Perinatal Transmission of Hepatitis B Virus

Background Passive-active immunoprophylaxis against mother-to-child transmission (MTCT) of hepatitis B virus (HBV) recommends administering hepatitis B immunoglobulin (HBIG) and birth-dose hepatitis B vaccine in infants within 12 or 24 hours after birth. With this protocol, MTCT of HBV still occurs in 5–10% infants of HBV-infected mothers with positive hepatitis B e antigen (HBeAg). The present study aimed to investigate whether earlier administration of HBIG and hepatitis B vaccine after birth can further increase protection efficacy. Methods We conducted a prospective, multi-center observational study in infants born to mothers with HBV infection, in whom neonatal HBIG and birth dose hepatitis B vaccine were administered within one hour after birth. The infants were followed up for HBV markers at 7–14 months of age. Results A total of 1140 pregnant women with HBV were enrolled, and 982 infants (9 twins) of 973 mothers were followed up at 9.6 ± 1.9 months of age. HBIG and birth-dose vaccine were administered in newborn infants within a median of 0.17 (0.02–1.0) hours after birth. The overall rate of MTCT was 0.9% (9/982), with none (0%) of the 607 infants of HBeAg-negative mothers and 9 (2.4%) of 375 infants of HBeAg-positive mothers acquiring HBV. All 9 HBV-infected infants were born to mothers with HBV DNA &gt;2.75 × 106 IU/mL. Maternal HBV DNA levels &gt;2 × 106 IU/mL were an independent risk factor (odds ratio, 10.627; 95% confidence interval, 2.135–∞) for immunoprophylaxis failure. Conclusions Earlier use (within 1 hour after birth) of HBIG and hepatitis B vaccine can provide better protection efficacy against MTCT of HBV.

Quasispecies characteristic in “a” determinant region is a potential predictor for the risk of immunoprophylaxis failure of mother-to-child-transmission of sub-genotype C2 hepatitis B virus: a prospective nested case–control study

ObjectiveThis study was performed to explore the correlation between the characteristics of hepatitis B virus (HBV) quasispecies in HBV-infected pregnant women and the risk of immunoprophylaxis failure for their infants.DesignIn this prospective nested case–control study, the characteristics of HBV quasispecies in mothers whose infants were immunoprophylaxis success (control group) and those whose infants were immunoprophylaxis failure (case group) were analysed by the clone-based sequencing of full-length HBV genome and next-generation sequencing (NGS) of “a” determinant region, and were compared between the two groups.ResultsThe quasispecies characteristics including mutant frequency, Shannon entropy and mean genetic distance at amino acid level of “a” determinant region were significantly lower in case group than that in control group, using the full-length HBV genome clone-based sequencing assay. These results were confirmed by NGS assay. Notably, we discovered that the differences were also significant at nucleotide level by NGS assay. Furthermore, the risk of immunoprophylaxis failure could be predicted by analysing the three HBV quasispecies characteristics either at nucleotide level or at amino acid level of “a” determinant region, and the corresponding predictive values were tentatively set up.ConclusionsHBV quasispecies with a more complex mutant spectrum in “a” determinant region might be more vulnerable to extinct through mother-to-child-transmission (MTCT). More importantly, analysing HBV quasispecies characteristics in pregnant women with high HBV DNA load might be helpful to predict the high-risk population of immunoprophylaxis failure, and consequently provide accurate intervention against MTCT of HBV.

Pencegahan Transmisi Vertikal Hepatitis B: Fokus pada Penggunaan Antivirus Antenatal

Hepatitis B merupakan penyebab utama penyakit hati kronik dan dapat menyebabkan sirosis, gagal hati dan karsinoma hepatoselular pada 15-40% populasi. Terhitung sebanyak dua miliar penduduk dunia terinfeksi hepatitis B. Sebanyak 240 juta diantaranya mengidap hepatitis B kronik dan 780.000 jiwa meninggal karena komplikasi akut dan kronik hepatitis B. Transmisi hepatitis B berbeda di berbagai belahan dunia. Pada negara maju, transmisi hepatitis B sebagian besar melalui transmisi horizontal, sedangkan pada negara berkembang transmisi heptitis B 90% melalui transmisi vertikal. Upaya pencegahan transmisi vertikal berupa pemberian imunoglobulin mencapai tingkat keberhasilan hingga 95%, namun menyisakan sebagian kecil populasi yang mengalami kegagalan imunoprofilaksis yang berisiko untuk berkembang menjadi hepatitis B kronik. Pemberian antivirus pada saat antenatal berperan dalam mencegah transmisi vertikal pada populasi yang berisiko mengalami kegagalan imunoprofilaksis.Kata Kunci: analog nukleos(t)ida, hepatitis B, kegagalan imunoprofilaksis, transmisi vertikal Prevention of Hepatitis B Vertical Transmission: Focus on Antenatal Antiviral AdministrationHepatitis B is one of the main cause of chronic liver disease, and potentially cause cirrhosis, liver failure and hepatocellular carcinoma in 15-40% population. Globally, 2 billion people are infected by Hepatitis B. Two hundred and forty million people are suffering from chronic hepatitis B, and more than 780 000 people are dying from both acute and chronic complication of hepatitis B. In developed countries, horizontal transmission is the main mode of virus transmission, while in developing countries vertical transmission occured in 90% population with hepatitis B. Immunoglobulin administration as a prevention strategy for vertical transmission has 95% success rate, but it left 5-10% of those who has immunoprophylaxis failure to be at risk to develop chronic hepatitis B. Antiviral administration during pregnancy is considered to prevent hepatitis B vertical transmission in population at risk on developing immunoprophylaxis failure. Keywords: hepatitis B, immunoprophylaxis failure, nucleos(t)ide analog, vertical transmission