新生儿外周血单个核细胞感染乙型肝炎病毒的机制及意义

目的探讨新生儿外周血单个核细胞（PBMC）感染乙型肝炎病毒（HBV）的机制及意义。方法选择84例HBsAg阳性、HBeAg阴性的孕妇及其分娩的新生儿为研究组。16例HBsAg阴性孕妇及其分娩的新生儿作为对照。ELISA检测新生儿HBV血清学标志物（HBVM）,巢式PCR（n-PCR）检测孕妇及新生儿血清和PBMC中HBV DNA。对血清HBsAg及HBV DNA阴性、仅PBMC中HBV DNA阳性的新生儿随访1年,观察HBsAb产生及PBMC中HBV DNA存在状况。结果（1）84例孕妇血清HBV DNA阳性45例（53．57％）;PBMC中HBV DNA阳性34例（40．48％）,两者相比差异无统计学意义（x^2=2．891,P〉0．05）。血清及PBMC中HBV DNA均为弱阳性。（2）研究组新生儿感染24例（28．57％）。其中仅血清HBV DNA阳性7例,仅PBMC中HBV DNA阳性11例,血清和PBMC中HBV DNA同时阳性6例,血清及PBMC中HBV DNA均为弱阳性;新生儿血清HBsAg均阴性。对照组无新生儿感染。两组新生儿感染差异有统计学意义（x^2=4．55,P〈0．05）。（3）研究组新生儿11例（13．10％）仅PBMC中HBV DNA阳性,均为弱阳性。其母亲仅血清HBV DNA阳性5例,仅PBMC阳性2例,血清及PBMC均阳性4例。对11例中7例仅PBMC中HBV DNA阳性的新生儿随访1年。其中4例血清HBsAb阳性,PBMC中HBV DNA阴性;3例HBsAb阴性,其中2例PBMC中HBV DNA仍为弱阳性。7例血清中HBsAg及HBV DNA均阴性。结论（1）孕妇血清或PBMC中HBV DNA阳性均可导致新生儿PBMC感染。（2）感染了HBV的PBMC可在血清HBsAg和HBV DNA阴性的新生儿体内长期存在,并影响新生儿免疫接种后HBsAb的产生。

Peripheral blood mononuclear cell of neonates infected with hepatitis B virus

OBJECTIVE: To study the mechanism and significance of peripheral blood mononuclear cell (PBMC) of neonates infected with hepatitis B virus (HBV). METHODS: Eighty-four HBsAg-positive and HBeAg-negative mothers and their newborns were recruited in this study. Sixteen hepatitis B virus markers (HBVM)-negative mothers and their neonates were served as control. All these cases had no symptoms of hepatitis, serious pregnancy complications and preexisting disease. Age, gestational age and the method of delivery were matched in two groups (P > 0.05). Five ml blood samples were taken from the peripheral vein of the pregnant women before delivery and from neonates within 24 hours after birth, before inoculation of HBV vaccine (HBVac). Serum and PBMC were isolated from 2 ml and 3 ml samples respectively. The sera, PBMC and the last supernatant of PBMC washing were stored at -80 degrees C. HBVM of neonates were detected by using enzyme linked immunosorbent assay (ELISA). HBV DNA in serum, PBMC and the last supernatant of PBMC washing of mothers and neonates were detected by using a nested-polymerase chain reaction (n-PCR). Two pairs of oligonucleotide primers, the outer primer pair for first PCR and inner primer pair for second PCR, designed according to region S of HBV genome were synthesized at Shanghai Cell Biology Institute of Chinese Academy of Sciences. The neonates who were HBV DNA positive in PBMC but HBsAg and HBV DNA negative in serum were followed up for one year, HBsAb in serum and HBV DNA in PBMC were observed in the neonates. RESULTS: (1) The positive rate of HBV DNA in 84 serum and PBMC of mothers were 53.57% and 40.48%, respectively (chi(2) = 2.891, P > 0.05). All the results were weakly positive. (2) Twenty-four (28.57%) newborns in the study group were infected, including 7 who were only HBV DNA positive in serum, 11 only HBV DNA positive in PBMC and 6 in both, all the results were weakly positive. HBsAg was negative in all the newborns. None of the neonates in control group was infected with HBV. There was significant difference between the two groups (chi(2) = 4.55, P < 0.05). (3) Of all the study cases, 11 (13.10%) neonates were HBV DNA weakly positive in PBMC but HBsAg and HBV DNA negative in serum. Of their mothers, 5 were only HBV DNA positive in serum, 2 only positive in PBMC and 4 positive in both serum and PBMC. Seven of the 11 neonates were followed up for one year and at the end of follow-up, 4 were HBsAb positive and HBV DNA negative in PBMC; 3 were HBsAb negative, and among the 3 cases HBV DNA in 2 was still positive in PBMC, HBsAg and HBV DNA in serum were negative in all the 7 neonates. CONCLUSION: (1) HBV DNA positivity either in serum or in PBMC in mothers can result in infection of PBMC with HBV in their neonates. (2) PBMC infection with HBV can exist for a long time in neonates while HBsAg and HBV DNA are negative in serum, and may result in vaccination failure in neonates.