献血人群隐匿性乙型肝炎病毒载量和分子突变分析

Occult hepatitis B virus load and molecular mutation in blood donors,Huzhou

目的了解湖州地区无偿献血人群中隐匿性HBV感染(OBI)的流行状况,分析OBI者的病毒载量和分子特征。方法采用ELISA和NAT对本站2018年10月~2020年2月45 368份献血者标本进行HBV感染筛查。以HBsAg阴性、NAT阳性献血者作为实验组;以同期HBsAg阳性、NAT阳性的标本作为对照组。抽提2组的血清病毒核酸,以实时荧光PCR定量检测HBV DNA拷贝数并比较2组差异。巢式PCR对病毒S区基因进行扩增和测序,并与HBV野生型参考序列比对,确认基因分型及S区分子突变特征。结果最终确认36份为隐匿性HBV感染(0.08%,36/45 368);其中有8份DNA载量低于检出限,其余28份的HBV DNA均值为(42.3±1.24)IU/mL明显低于对照组均值水平(3.32±1.94)×10^(4)IU/mL(P<0.05)。测序结果显示,28份OBI标本中,20份为B型(71.43%),其余8份均为C型(28.57%)。OBI者在HBsAg抗原决定簇内的氨基酸变异率显著高于MHR区(P<0.05)。结论本地区献血人群OBI者病毒载量较低,以基因型B型为主,主要变异位点在HBsAg抗原决定簇(124~147)区。

Objective To investigate the prevalence of occult hepatitis B virus infection(OBI) among blood donors in Huzhou, and to analyze the viral load and molecular characteristics of OBI. Methods 45 368 blood samples were screened by enzyme linked immunosorbent assay(ELISA) and nucleic acid testing(NAT) for HBV infection from October 2018 to February 2020 in our center. HBsAg-/NAT+ blood donors were studied as experimental group, contemporary HBsAg+/NAT+ donors as the control. The serum viral nucleic acids of the two groups were extracted, and HBV DNA copies were detected by real-time PCR, the differences between the two groups were compared. The S region gene of the virus was amplified and sequenced by Nested PCR, then compared with the reference sequence of HBV wild type, in order to confirm the genotyping and molecular mutation characteristics of S region. Results 36 samples were confirmed as OBI(0.08%, 36/45 368). The HBV DNA load of 8 samples was lower than the detection limit, and the average HBV DNA load of other 28 samples was(42.3±1.24) IU/mL, which was significantly lower than that of the controls(3.32±1.94) ×10^(4) IU/mL(P<0.05). Among the 28 OBI samples, 20 were type B(71.43%), and 8 were type C(28.57%). The frequency of amino acid variation in HBsAg epitopes was significantly higher in OBI than in MHR(P<0.05). Conclusion The viral load of OBI blood donors in Huzhou, mainly genotype B, is low, and the variation sites were mainly focused in HBsAg epitope and amino acid region(124~147).