title: Molecular characterization of occult hepatitis B cases in Greek blood donors.
abstract: The use of sensitive nucleic acid testing for hepatitis B virus in blood donors revealed a number of HBV DNA(+) cases among HBsAg(-) donors, a status known as occult HBV infection. The purpose of this study was the serological and molecular characterization of occult HBV infection in Greek blood donors. A prospective study was undertaken in order to identify occult HBV infection cases in blood donors. As part of the routine screening of blood donations in Greece, blood units were screened individually by a multiplex HIV-1/HCV/HBV nucleic acid assay. Initially reactive samples were retested with discriminatory assays. HBV DNA(+)/HBsAg(-) samples were tested further for HBV serological markers and HBV DNA was quantified by real-time PCR. Molecular characterization was performed by sequencing the envelope and polymerase genes of HBV. Preliminary screening revealed 21 occult cases with the following patterns: anti-HBc only: 7 donors, anti-HBc/anti-HBs: 7 donors, anti-HBc/anti-HBe: 5 donors, anti-HBc/anti-HBs/anti-HBe: 2 donors. In all cases, the HBV DNA load was <351 IU/ml. Sequencing was successful in 10 donors (classified within genotype D) revealing several amino acid substitutions related to diagnostic escape and antiviral resistance. HBsAg diagnostic failure and low viral replication in occult HBV infection carriers could possibly be attributed to multiple changes in envelope and polymerase regions, respectively.
authors.affiliation: Department of Hygiene and Epidemiology, Athens University Medical School, Athens, Greece.
authors.forename: Antigoni
authors.initials: A
authors.lastname: Katsoulidou
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Paraskevis
authors.forename: Emmanouil
authors.initials: E
authors.lastname: Magiorkinis
authors.forename: Zissis
authors.initials: Z
authors.lastname: Moschidis
authors.forename: Catherine
authors.initials: C
authors.lastname: Haida
authors.forename: Eleni
authors.initials: E
authors.lastname: Hatzitheodorou
authors.forename: Agoritsa
authors.initials: A
authors.lastname: Varaklioti
authors.forename: Anastasia
authors.initials: A
authors.lastname: Karafoulidou
authors.forename: Maria
authors.initials: M
authors.lastname: Hatzitaki
authors.forename: Lilian
authors.initials: L
authors.lastname: Kavallierou
authors.forename: Athanasia
authors.initials: A
authors.lastname: Mouzaki
authors.forename: Evaggelia
authors.initials: E
authors.lastname: Andrioti
authors.forename: Chrysanthi
authors.initials: C
authors.lastname: Veneti
authors.forename: Athanasia
authors.initials: A
authors.lastname: Kaperoni
authors.forename: Eleftheria
authors.initials: E
authors.lastname: Zervou
authors.forename: Constantina
authors.initials: C
authors.lastname: Politis
authors.forename: Angelos
authors.initials: A
authors.lastname: Hatzakis