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Efficacy of immunization of high-risk infants against hepatitis B virus evaluated by polymerase chain reaction
T Matsumoto1, K Nakata, K Hamasaki
1First Department of Internal Medicine, Nagasaki University School of Medicine, Japan.
Insights
Hepatitis B Virus (HBV) immunization effectively prevents mother-to-child transmission in high-risk infants. However, specific HBV S gene mutations can lead to immunization failure and persistent infection.
Area of Science:
- Virology
- Immunology
- Genetics
Background:
- Hepatitis B virus (HBV) poses a significant risk for mother-to-child transmission.
- High-risk infants require effective immunization strategies to prevent HBV infection.
- Polymerase Chain Reaction (PCR) is a sensitive tool for detecting viral genomes.
Purpose of the Study:
- To evaluate the efficacy of immunization against HBV in high-risk infants.
- To identify HBV DNA and analyze viral S gene sequences in infants who received immunization.
- To investigate potential reasons for immunization failure.
Main Methods:
- Utilized Polymerase Chain Reaction (PCR) to detect HBV DNA in serum samples from immunized infants.
- Analyzed the DNA sequences within the S gene of detected HBV genomes.
- Monitored infants for HBV DNA positivity and clinical hepatitis over a one-year period.
Main Results:
- Two out of 29 high-risk infants tested positive for HBV DNA one year post-immunization.
- One infant with wild-type HBV DNA cleared the infection, while the other developed persistent infection with clinical hepatitis.
- The persistent HBV infection was associated with nucleotide substitutions in the S gene's "a" determinant, affecting viral protein expression.
Conclusions:
- Standard HBV immunization is largely effective in preventing mother-to-child transmission in high-risk infants.
- Amino acid substitutions in the S gene's "a" determinant may be linked to the failure of conventional HBV immunization.
- Further research is needed to understand and overcome vaccine escape mutations in HBV.
Abstract:
The polymerase chain reaction (PCR) is a rapid and very sensitive method to detect viral genomes. In the present study, the efficacy of immunization against hepatitis B virus (HBV) of high-risk infants was evaluated by PCR. Twenty-nine infants born to 24 HBeAg-positive carrier mothers were given hepatitis B immune globulin (HBIG) at birth and thereafter received repeated inoculations of plasma-derived vaccine or HBIG, or both, within 1 year. Serum samples at 1 year following immunization were stored at -40 degrees C for later analysis using PCR to detect HBV-DNA. When HBV genomes were detected in infants, the DNA sequences in the S gene of HBV were determined. Of 29 infants, 2 were positive for HBV-DNA at the 1 year following immunization; one had the HBV containing only the wild-type sequence in the S gene and became negative for HBV-DNA during the follow-up period. In contrast, another had the HBV, which contained nucleotide substitutions that altered the expression of the common group-specific determinant "a" of the S gene and resulted in clinical hepatitis with viral persistence. PCR analysis suggests that immunization against HBV prevents effectively high-risk infants from mother-to-child transmission. Even then, however, it is possible that amino acid substitutions in the "a" determinant of the S gene are associated with failure of conventional immunization against HBV.