隐匿性乙型肝炎病毒感染可通过密切接触传播

目的探索一名出生时乙肝疫苗免疫成功后仍感染乙肝病毒的小孩的感染来源。方法采集小孩及其父母的血标本进行HBV血清学标志物和病毒载量检测,使用酚氯仿法提取HBV DNA,PCR扩增HBV S基因,将扩增产物进行克隆并测序,利用Mega 5.0和Bioedit 7.0对测序结果进行分析。结果父亲和母亲均为隐匿性乙型肝炎病毒感染,父亲、母亲、儿子的PCR产物分别获得12、11和9个克隆株。父亲克隆株的血清型为adrq+,ayw1,ayw,ayr,基因型为C2、B、B/C;母亲克隆株的血清型为ayw1,adw2,adwq+,基因型为C5、B、B/C、C/G;儿子克隆株的血清型为adrq+,基因型仅为C2。S基因序列进化发生树显示,儿子的所有克隆序列与父亲大多数的克隆序列聚集在一起,而与母亲的克隆序列没有聚集。来自儿子和父亲的S基因克隆序列有相同的氨基酸突变模式(T118K、T123N、G145A)。结论儿子乙型肝炎病毒感染的来源是父亲,提示隐匿性乙型肝炎病毒感染可通过家庭密切接触传播。

Occult HBV infection may be transmitted through close contact

Objective To search for the infectious source of hepatitis B virus from a child, who had received the standard vaccination regimen at birth and produced protective antibody. Methods Serum samples were obtained from a child and his parents. Sera were tested for HBV serological markers and viral loads. HBV DNA was extracted using phenol-chloroform .The surface gene of HBV was amplified by nested PCR and the amplicons were cloned and sequenced. Phylogenetic analysis was carried out using Mega 5.0 and Bioedit 7.0. Results Both parents had occult infections. Twelve, eleven and nine clones, from the father, mother and son, respectively, were sequenced. Serotypes adrq +, ayw1, ayw,ayr and genotype B, subgenotype C2, a recombinant B/C were identified in the father. Serotypes ayw1, adw2, adwq+ and genotype B, subgenotype C5 ,two recombinants B/C、a recombinant C/G were identified in the mother. The adrq + was the only serotype in son. Subgenotype C2 was the only genotype identified in son. A phylogenetic tree showed that all of the child’s sequences and most of the father’s sequences clustered together. However, none of mother’s sequences clustered with those of the child. The surface antigens gene from the child and his father had the same amino acid substitution patterns (T118K, T123N and G145A). Conclusions The father was the source of the son’s HBV infection, suggesting that occult HBV infection may be transmitted through close contact.