title: Serological Patterns and Molecular Characterization of Occult Hepatitis B Virus Infection among Blood Donors.
abstract: BACKGROUND
  Hepatitis B infections, characterized by the presence of a viral genome without detectable hepatitis B surface antigen (HBsAg; Occult hepatitis B infection [OBI]), have been reported recently.
  
  
  OBJECTIVE
  We performed serological and molecular characterization of OBI among blood donors at Jiangsu province blood center during years 2013 and 2014.
  
  
  METHODS
  All donor samples were routinely screened by double enzyme-linked immunosorbent assay (ELISA) for hepatitis C virus (HCV), hepatitis B virus (HBV), human immunodeficiency virus (HIV), Treponema pallidum (TP), and alanine aminotransferase (ALT). Single-reactive, nonreactive, and ALT-elevated samples were pooled or resolved by nucleic acid testing (NAT). Seromarkers were examined in HBsAg-/DNA+ samples. After 1 to 12 months of follow up, seromarkers were screened again to verify OBI samples.
  
  
  RESULTS
  We studied 157119 samples from blood donors. A total of 154397 ELISA nonreactive donor samples were identified, and HBV DNA was detected in 81 samples; no samples were positive for HIV or HCV RNA. Hepatitis B virus viral loads in most donors were less than 20 - 200 IU/mL. There was only one HBsAg-positive sample. Eighty HBsAg-/DNA+ samples were evaluated further. Of these samples, 85% (68/80) were reactive for anti-HBc and 36.2% (29/800) were reactive for anti-HBc and anti-HBs; 11.3% (9/80) did not have any detectable serological markers. Twenty-nine donors were followed up. One was HBsAg ELISA positive, and of six seronegative donors, all had anti-HBc and anti-HBs, but were negative for DNA. Samples were HBV genotypes B, C and D. Mutations in the S region of HBV DNA included S114T, G119R, P120S, T125M, C139Y, T140I, C147W, T148A, A159V/G, E164D, V168A, and R169C.
  
  
  CONCLUSIONS
  Overall, we found that OBI was rare, but that the prevalence of OBI was slightly higher in Jiangsu than in other areas of China.
authors.affiliation: Jiangsu Province Blood Center, Nanjing, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Lin
authors.affiliation: The Second Hospital of Nanjing, Nanjing, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Jiangsu Province Blood Center, Nanjing, China.
authors.forename: Xinyi
authors.initials: X
authors.lastname: Tang
authors.affiliation: Jiangsu Province Blood Center, Nanjing, China.
authors.forename: Wenjia
authors.initials: W
authors.lastname: Hu
authors.affiliation: Jiangsu Province Blood Center, Nanjing, China.
authors.forename: Nizheng
authors.initials: N
authors.lastname: Jiang
authors.affiliation: Jiangsu Province Blood Center, Nanjing, China.
authors.forename: Shaowen
authors.initials: S
authors.lastname: Zhu
authors.affiliation: Jiangsu Province Blood Center, Nanjing, China.
authors.forename: Chengyin
authors.initials: C
authors.lastname: Huang
keywords: Blood Donors; Hepatitis B Virus; Infection; Molecular Characterization; Serology