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Genetic characterization and genotyping of hepatitis B virus ( HBV ) isolates from donors with an occult HBV infection
Author(s) -
Chamni N.,
Louisirirotchanakul S.,
Oota S.,
Sakuldamrongpanish T.,
Saldanha J.,
Chongkolwatana V.,
Phikulsod S.
Publication year - 2014
Publication title -
vox sanguinis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.68
H-Index - 83
eISSN - 1423-0410
pISSN - 0042-9007
DOI - 10.1111/vox.12178
Subject(s) - hbsag , genotype , hepatitis b virus , virology , genotyping , biology , hepatitis b , gene , orthohepadnavirus , microbiology and biotechnology , virus , genetics
Background and Objectives Screening of Thai blood donors has resulted in the detection of donors with an occult HBV infection ( OBI ), where HB s A g is undetectable, but hepatitis B virus ( HBV ) DNA is present in serum in low concentrations. This study was designed to determine whether the occurrence of OBI in donors was linked to the HBV genotype and possibly to mutations in the surface ( S ) and core ( C ) gene regions. Materials and Methods Mutations in the S and C gene regions in 48 T hai donors with OBI were mapped by sequencing. Genotyping was determined with the INNO ‐ L i PA test and by phylogenetic analysis of sequences from the S and C genes. Results The majority of OBI samples were genotype C (81·3%) with 6·3% of samples being genotype B . In addition, two genotype I isolates were identified. Mutations in the S region (100%) were found especially in loop 1 of the major hydrophilic loop ( MHL ) at positions I 110 L , T 114 S , T 126 I and S 113 T , whereas mutations in the C region (65%) were within the basal core promoter region (position A 1762 T / G 1764 A ) and precore region (position G 1896 A ). Conclusion The majority of OBI samples were HBV genotype C , although genotype I , which is newly emerging in T hailand, was also detected. The study demonstrated that OBI was probably not associated with a particular HBV genotype or with certain mutations in the S and C gene regions. However, mutations in the C gene region which could potentially impair viral replication and HB s A g production and potentially lead to OBI were identified.