母婴阻断失败乙型肝炎病毒基因序列分析

The analysis of hepatitis B virus genetic characterization from immuned children and their mother

目的通过随访调查和病毒基因检测，了解母婴阻断后的效果，并研究突破母婴阻断的乙型肝炎病毒基因序列特征，了解病毒母婴传播特点。方法2003年开始收集临床乙型肝炎病毒表面抗原阳性母亲血清及婴儿血清75对，检测血清学感染指标，取其中母亲与婴儿皆为阳性的血清提取乙型肝炎病毒，扩增包括preS和S基因在内的基因序列片段，序列测定后与标准基因型别比较，确定病毒基因及血清型别，及母婴间病毒核苷酸差异率，及确定a抗原决定簇的氨基酸替代突变率，与免疫成功组进行比较。结果经血清学检测后共得到母婴血清皆为阳性者4对，包括一对双胞胎，扩增出乙肝病毒基因序列，其中4个乙型肝炎病毒基因型为B型，1个乙型肝炎病毒基因型为C型，其中1对双胞胎婴儿在“a”抗原决定簇出现T143M变异，其余扩增母婴阻断成功病例43例，37例为B型，6例为C型，其中a抗原决定簇发生变异的有3例。结论母婴阻断失败的儿童中大部分与母亲的基因序列相同，a抗原决定簇变异的比率高于成功组母亲，但差异无统计学意义。

Objective In order to investigate the characterization of mother to children transmission, the sequences of HBV were analyzed to offer the information about the effect of interrupt. Methods The sera of 75 mother with positive HBsAg are collected from 2003, and the ELISA was performed to determine the HBV infection of the child. The Large S sequence of HBV including preS and S gene are amplified and sequenced. The genotype was determined with the standard genotype sequence. The mutation ratios of group successsfully interrupted and failed compared. Results The sera of 4 pairs mother-children were HBsAg positive, including one twins. The virus genes are successful amplified. Four of HBV genotype is B and one is C. Gene of twins has mutation of T143M. 43 HBV of successfully interrupted group were sequenced. There are 37 of genotype B and 6 of genotype C. Three have the mutation in ＂a＂ dominant, and the percentage is 7%. Conclusion Most failed interrupted child have the same sequence with their mother, and the ratio is higher than the mother of successful group, however there have no statistical significance.