Cellular immunity in children with successful immunoprophylactic treatment for mother-to-child transmission of hepatitis B virus.
BACKGROUND
The administration of hepatitis B immunoglobulin followed by hepatitis B vaccine can result in a protective efficacy of almost 90% in mother-to-child transmission of hepatitis B virus (HBV). However, little is known about immunity against HBV infection in children after immunoprophylactic treatment. We tried to assess the association between T-cell responses and viremia in children after successful prophylactic treatment.


METHODS
Thirteen children and their 8 HBV carrier mothers (8 families), who were positive for human leukocyte antigen (HLA)-A24, were enrolled in this study. All of the 13 children received immunoprophylactic treatment and became negative for hepatitis B surface antigen (HBsAg) after birth. HBV-specific cytotoxic T lymphocyte (CTL) responses were evaluated using IFNgamma - enzyme-linked immunosorbent spot (ELISPOT) and major histocompatibility complex class I peptide pentamer assays. Serum HBV DNA was measured by real-time PCR.


RESULTS
Significant HBV-specific T-cell responses were detected in 2 (15%) of the 13 children by ELISPOT. However, the frequency of HLA-A24-HBV-specific CTLs was very low in both HBV carrier mothers and children using pentamers. Of the 13 children, 4 (31%) were positive for serum HBV DNA. However, the levels of serum HBV DNA were 100 copies/ml or less. One of the 2 children in whom significant HBV-specific CTL responses were detectable was positive for serum HBV DNA.


CONCLUSIONS
HBV core and polymerase-specific T-cell responses were detected and a low-dose viremia was observed in children after successful immunoprophylaxis treatment. Although the presence of viremia was not related to HBV-specific T-cell responses, CTLs might play a role in the control of HBV infection in children born to HBsAg-positive mothers after immunoprophylactic treatment.
Komatsu
Haruki
H
Department of Pediatrics, Yokohama Eastern Hospital, 3-6-1 Shimosueyoshi Tsurumi Yokohama, Kanagawa 230-0012, Japan. haruki-komatsu@chive.ocn.ne.jp
Inui
Ayano
A
Sogo
Tsuyoshi
T
Hiejima
Eitaro
E
Tateno
Akihiko
A
Klenerman
Paul
P
Fujisawa
Tomoo
T
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004279:DNA, Viral / Q000097:blood; D005260:Female; D006509:Hepatitis B / Q000276:immunology* / Q000517:prevention & control*; D006510:Hepatitis B Antibodies / Q000627:therapeutic use*; D017325:Hepatitis B Vaccines / Q000008:administration & dosage*; D006515:Hepatitis B virus / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D006801:Humans; D007111:Immunity, Cellular; D007223:Infant; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control*; D007371:Interferon-gamma / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D044967:Serum / Q000821:virology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014766:Viremia; D055815:Young Adult
D004279:DNA, Viral; D006510:Hepatitis B Antibodies; D017325:Hepatitis B Vaccines; D015395:Histocompatibility Antigens Class I; D007371:Interferon-gamma