Mechanism of peripheral blood mononuclear cell invasion by HBV on artificial immunization in newborns

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.