The Analysis Of Anti-HBS Titers After Primary Immunization In 1-16 Year-old Children And Primary Understanding Of Immune Escape For Mother-to-Child Transmission Of HBV

Part one: The Analysis of Anti-HBs titers after PrimaryImmunization in 1-16 Year-old ChildrenBackground: Immunization with hepatitis B vaccine is the most effective measure to prevent Hepatitis B Virus(HBV)infection.The implementation of vaccination policy significantly reduced the prevalence of HBV infection in the general population in China.This part is to analyze the change of antibody levels in 1-16 year-old children who completed the primary immunization in infant and to evaluate the necessity of administrating the booster doses.Methods: According to the tested results for HBV markers in 93,3261-16 year-old hospitalized children after primary immunization conducted in clinical laboratory center in CHCMU,analyses were performed on anti-HBs titer changes with increasing age,and the revaccination effect were evaluated in children aged 7-14.Results: The positive rates of HBs Ag and HBc Ab in 93,326 1-16year-old hospitalized children were 0.48% and 4.05%.The protective antibody levels showed a trend of an initial decrease and then an increase,1year-old group had highest seroprotection(90.31%)and 8 year-old group had the lowest(45.29%).The proportion of protective antibody levels was between 45.29% and 63.33% in the majority of groups,the percentage of high-responder was 5.03%-10.56% except 1 year-old group(23.33%),and3.33%-25.79% subjects had not seroconverted.There was no significant difference in antibody levels between girls and boys(p>0.05).Moreover,The Geometric Mean Titers(GMT)in children with confirmed revaccination history was higher than those with unknown and no revaccination history,there were significantly difference between the former and the latter two(p<0.0001)and in subjects with unknown revaccination history was also higher than those with no revaccination history,there was significant difference between them(p<0.05).Conclusion: The overall positive rate of anti-HBs was 67.10% in 1-16year-old children who completed primary immunization in infants from a large samples with consecutive age groups,the proportion of protective anti-HBs decreased from 90.31% to 45.29% for 1-8 year-old children immunized in infants,the rate increased from 45.46% to 63.33% for 9-15year-old subjects,compared with antibody of <1000 m IU/ml,the percentage of titers with 1000 m IU/ml kept relatively stable withoutshowing sharply decrease or increase in the majority groups.The anti-HBs titers will be significantly improved after revaccination,booster doses are suggested to those considered to be not seroconverted,especially children who live in school with other students or have family members with positive HBs Ag.Part two: primary understanding of immune escape formother-to-child transmission of HBVObjective: Mother-to-child transmission is the most important mode of transmission of HBV.The part mainly discusses the risk factors for children born to HBs Ag carrier mothers who developed chronic infection after active and passive immunization,and provides reference for further reducing the rates of mother to child transmission(MTCT)of HBV.Method: Mother's samples from infected mothers and children,from infected mothers and healthy children,from healthy mothers and children were collected and RNA were extracted,those were detected by RT2 Profiler PCR Array and Affymetrix Prime View Human Gene Expression Array after completing reverse transcription,and significantly difference genes were screened.Result: A total of 11 genes screened had significantly differenceamong 84 key genes involved in innate immune response,including 9up-regulated and 2 down-regulated genes.20,000 genes can be detected by Affymetrix Prime View Human Gene Expression Array,and 8 genes may be related to mother-to-child transmission of HBV,of them one was up-regulated and 7 were down-regulated.Conclusion: The differentially expressed genes which were screened by microarray involved in the innate immune response,cell signaling,cell migration,angiogenesis,apoptosis,cancer and other biological processes,they may play an important role in the mother-to-child transmission of HBV,more specimens are needed to verify those results and to explore a possible mechanism.