title: Age- and gender-specific distributions of hepatitis B virus (HBV) genotypes in Japanese HBV-positive blood donors.
abstract: BACKGROUND
  There are an increasing number of reports on the hepatitis B virus (HBV) genotype distribution in acute or chronic HBV-infected patients in Japan; however, reports on the HBV genotype of blood donors are few. To compare the HBV genotypes of hepatitis B surface antigen (HBsAg)-positive blood donors with infected patients, all the HBsAg-positive donors' genotypes were determined.
  
  
  METHODS
  Data on Japanese blood donors from October 2006 to September 2007 were obtained from the Japanese Red Cross database. The number of available samples was 1979, and the HBV genotypes were determined in 1887 samples. The six major genotypes of HBV (A-F) were determined by enzyme-linked immunosorbent assay. The presence of the immunoglobulin M (IgM) antibody against the HBV core antigen was determined by enzyme immunoassay among all HBsAg-positive donors.
  
  
  RESULTS
  A significant difference in the HBV genotype distribution between donors and patients was in the C/B genotype ratio. The ratios were low in blood donors (2.0-3.9) and high in patients (5.3-18.2). The genotype B ratio increases from 13.8% in teenage donors to 42.4% in those in their 50s; however; the genotype C ratio decreases from 83.1% in teenage donors to 55.1% in those in their 50s. In both IgM antibody against hepatitis B core antigen and nucleic acid test-positive donors, genotypes A and B were restricted to male donors.
  
  
  CONCLUSIONS
  The age-specific distribution of HBV genotypes in Japanese blood donors was observed in the B/C genotype ratio. The gender-specific distribution of HBV genotype A, which originated from the US or Western countries, was observed in male Japanese donors.
authors.affiliation: Japanese Red Cross Saitama Blood Center, 1370-12 Takahagi, Hidaka-shi, Saitama-ken, Japan. yoshikawa@saitama.bc.jrc.or.jp
authors.forename: Akira
authors.initials: A
authors.lastname: Yoshikawa
authors.forename: Yuko
authors.initials: Y
authors.lastname: Gotanda
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Masako
authors.initials: M
authors.lastname: Tanaka
authors.forename: Harumichi
authors.initials: H
authors.lastname: Matsukura
authors.forename: Toshio
authors.initials: T
authors.lastname: Shiraishi
authors.forename: Keiji
authors.initials: K
authors.lastname: Matsubayashi
authors.forename: Emi
authors.initials: E
authors.lastname: Kon
authors.forename: Ko
authors.initials: K
authors.lastname: Suzuki
authors.forename: Hisao
authors.initials: H
authors.lastname: Yugi
mesh_terms: D017677:Age Distribution; D001782:Blood Donors; D001803:Blood Transfusion; D005260:Female; D005838:Genotype; D006515:Hepatitis B virus / Q000235:genetics*; D006801:Humans; D007564:Japan; D008297:Male; D021141:Nucleic Acid Amplification Techniques; D017678:Sex Distribution