A PRELIMINARY STUDY ON
THE MECHANISM AND PROGNOSIS OF HEPATITIS B IMMUNIZATION FAILURE IN
INTRAUTERINE HBV INFECTED INFANTS
Zhu QR, Lu Q, Yu H, Duan SC,
He JW, Gu XH
Children¡¯s Hospital, Fudan University. Shanghai,
China.
Objective: In utero
Hepatitis B Virus (HBV) infection is the major cause of failure of
vaccination against hepatitis B in neonate born to HBV carrier mother. To
understand the mechanism and the prognosis of immune failure after
administration of hepatitis B vaccine (HBvac) to intrauterine HBV infected
infants.
Methods: We observed
the response to HBvac, analyzed T cell subgroups, lymphocyte proliferation
after stimulation with PHA and HBV pre-s2 Peptide, and performed
tests for genomic mutation with HBV DNA S region. 497 neonates born to HBV
carrier mothers received HBvac alone; 490 neonates, whose mothers were
injected with Hepatitis B immunogloblin (HBIG) before delivery, received
HBIG and HBvac. All infants were followed-up for 4-6 years.
Results: The study
showed that the prevalence of intrauterine HBV infection was 14.3%. The
high risk factors of intrauterine were HBsAg and HBeAg double positivity
and HBV DNA positivity in peripheral blood of pregnant women before
delivery. Inoculation with HBvac or HBIG plus HBvac at birth was effective
for children of intrauterine HBV infection, anti-HBs antibody was positive
in 56.3% and 63.4% respectively. The lymphocyte proliferation tests showed
that in intrauterine HBV infected infants there was in sufficient
cellmediated immunity and T lymphocyte was tolerant to HBV. There was HBV
mutation in intrauterine HBV infected children.
Conclusions: The major
cause of immune failure of vaccination has immune tolerance of T lymphocyte
to HBV. The HBV mutation is also an important cause of immune failure after
administration of HBvac and development of chronic hepatitis B.