title: Characterization of occult hepatitis B virus infection from blood donors in China.
abstract: Prevalence and characteristics of occult hepatitis B virus (HBV) infection (OBI) of genotypes B and C prevalent in China have not been extensively explored. Characterization of OBI strains obtained from Chinese blood donors was based on clinical and serological analyses, follow-up testing, and sequence analyses. Twenty-eight samples from 165,371 HBV surface antigen (HBsAg)-negative plasmas were confirmed HBsAg negative and DNA positive(HBsAg(-)/DNA(+)), of which 22 were classified as OBIs and 6 as window period infections. The OBI incidence was 1:7,517 in blood donors, whose ages ranged between 20 and 45 years (median, 28 years). OBI donors had normal alanine aminotransferase (ALT) levels and low viral loads ranging between unquantifiable amounts and 178 IU/ml (median, 14 IU/ml). Sequences from 21 basic core promoter/precore (BCP/PC) regions, five whole genomes, and two additional pre-S/S regions from OBI strains were compared to genotypes B and C HBsAg(+) reference strains. Eighty-six percent (6/7) of OBI strains were genotype C. Deletions, insertions, stop codons, and substitutions were detected in 15/21 (71%) core regulatory elements of OBI strains. Critical mutations were found in the core proteins of 5/5 OBI strains in parallel with random substitutions in pre-S/S proteins from 6/7 (86%) OBI strains. Critical mutations in core regulatory elements and core proteins might affect OBI genotype B and C strain replication. That there were few S protein substitutions suggests a minor role of the host immune defenses in OBI occurrence.
authors.affiliation: Department of Transfusion Medicine, Southern Medical University, Guangzhou, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zheng
authors.forename: Xianlin
authors.initials: X
authors.lastname: Ye
authors.forename: Ling
authors.initials: L
authors.lastname: Zhang
authors.forename: Wenjing
authors.initials: W
authors.lastname: Wang
authors.forename: Lifang
authors.initials: L
authors.lastname: Shuai
authors.forename: Anqi
authors.initials: A
authors.lastname: Wang
authors.forename: Jinfeng
authors.initials: J
authors.lastname: Zeng
authors.forename: Daniel
authors.initials: D
authors.lastname: Candotti
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Allain
authors.forename: Chengyao
authors.initials: C
authors.lastname: Li
mesh_terms: D000328:Adult; D001782:Blood Donors; D002681:China / Q000453:epidemiology; D016000:Cluster Analysis; D004279:DNA, Viral / Q000097:blood* / Q000235:genetics; D005260:Female; D005838:Genotype; D006509:Hepatitis B / Q000175:diagnosis* / Q000453:epidemiology* / Q000473:pathology / Q000821:virology; D006510:Hepatitis B Antibodies / Q000097:blood; D006514:Hepatitis B Surface Antigens / Q000097:blood; D006515:Hepatitis B virus / Q000302:isolation & purification*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D017422:Sequence Analysis, DNA
chemical_list: D004279:DNA, Viral; D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens