Objective: To study the effect and mechanism of the peripheral blood mononuclear cell (PBMC) invasion by HBV on artificial immunization in newborns.
Methods: Fifty-two newborns of HBsAg positive mothers were immunized with HBIG (hepatitis B immunoglobulin) and HBVac (hepatitis B vaccine) and were followed up for 7 months. The newborns' HBV-DNA in serum and in the PBMCs was detected with nested-PCR; anti-HBs was tested with solid phase radioimmunoassay (SP-RIA). PBMCs isolated from newborn peripheral blood were incubated in the presence of PHA or purified HBsAg. Interleukin-2 (IL-2) level in culture supernatants of activated cells was detected by ELISA.
Results: The failure rate of immunization was higher in infants with positive HBV-DNA in PBMCs than those with negative HBV-DNA (P < 0.05); IL-2 level in PBMC culture supernatants was lower in former than in the latter and in normal controls (P < 0.05). The level of IL-2 in the immunization failure newborns was lower than that in the successfully immunized newborns and in normal controls (P < 0.05).
Conclusions: Intrauterine invasion of PBMCs by HBV is one of the important reasons for immunization failure in newborns. IL-2 production is closely related to the invasion of PBMCs by HBV, which may contribute to the failure of artificial immunization in newborns.