乙肝疫苗免疫失败儿童病毒S基因"a"决定簇变异研究

目的 探讨江苏常州地区乙型肝炎疫苗免疫失败儿童病毒S基因“a”决定簇的变异情况。方法 对15例乙肝疫苗接种后血清表面抗原(HBsAg)阳性的儿童,采用聚合酶链反应方法(PCR)扩增其血清中HBV DNA S基因区。并对PCR产物直接标记测序。结果 15例HBsAg阳性儿童有14例血清HBV DNA阳性,其中有4例出现了S基因“a”决定簇的变异,变异率为28．6％,第126位的异亮氨酸（Ile)被苏氨酸(Thr)替代1例,第134位苯丙氨酸(Phe)被异亮氨酸替代1例。第145位甘氨酸(Gly)被丙氨酸(Pha)替代2例。结论乙型肝炎疫苗免疫失败儿童中存在s基因“a”抗原决定簇变异,江苏常州地区存在HBVS基因“a”决定簇变异的新类型。

Study on HBV DNA "a" determinant mutation in children faliued in HBV vaccination

Objective To investigate hepatitis B virus S gene "a" determinant mutation in children who failed to be protected by hepatitis B vaccine in Jiangsu Changzhou area. Methods HBV DNA S gene was amplified by polymerase chain reaction and sequenced directly. Results There were 14 samples for HBV DNA positive in all children with HBsAg positive, four mutations were detected, the mutation rate was 28.6%; one strain showed Ile-to-Thr at the 126 codon of surface antigen, one strain showed Phe-to-Ile at the 134 codon, and two strains showed Gly-to-Ala at the 145 condon of surface antigen. Conclusions: Hepatitis B virus S gene "a" determinant mutation exists in HBV vaccination immune failue children; and there are new types of S gene "a" determinant mutation in Changzhou area.