Molecular characteristics of hepatitis B infection with low level HBsAg and nucleic acid testing non-reactive results in blood donors / 中国输血杂志

ABSTRACT

【Objective】 To investigate HBV infection with low level of HBsAg and nucleic acid testing(NAT) non-reactive results in blood donors, and analyze molecular characteristics. 【Methods】 Low level HBsAg but NAT-nonreactive samples were collected and tested for HBsAg by Abbott chemiluminescent microparticle immunoassay (CMIA)., HBsAg, anti-HBs, HBeAg, anti-HBe and anti-HBc were further detected by Roche electrochemiluminescence immunoassay(ECLI). BCP/PC and S regions were also amplified by Nested-PCRs and qPCR for HBV DNA quantity were adopted simultaneously. 【Results】 Of 100 363 donations, 60(0.054%) low level HBsAg and NAT-nonreactive blood samples were enrolled the study. In which, 54/60(90%) and 57/60(95%) were WanTai HBsAg ELISA and DiaSorin HBsAg ELISA reactive respectively. Of 33 cases genotyped, genotype B were 87.9%( 29/33), including adw2 96.6%(28/29) and adw1 3.4%(1/29), C was observed in 4(12.1%) with sero-type adrq+. Mutations in S gene of genotype B such as Q101R, Q129H, T131I, M133L/T, F134L, G145R, V168A, L175S and V177A were observed as notable mutations, which can affect HBsAg diagnosis. A high frequency mutation C1799G(87.5%, 21/24)were detected in BCP/PC and would reduce the replication of virus. The median viral load measured by qPCR was 49.6(0~628)IU/mL. 【Conclusion】 A small part of donations with low-level HBsAg and NAT-nonreactive can not be deferred by one isolated ELISA screening assay. It is necessary to apply more sensitive and specific HBsAg assays and NAT in blood screening, and improve the ability to detected mutants.