Occult hepatitis B virus load and molecular mutation in blood donors, Huzhou / 中国输血杂志

ABSTRACT

【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) ×104 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).