title: Characteristics of escape mutations from occult hepatitis B virus infected patients with hematological malignancies in South Egypt.
abstract: OBJECTIVE
  To investigate the prevalence and virological characteristics of occult hepatitis B virus (HBV) infections in patients with hematological malignancies in South Egypt.
  
  
  METHODS
  Serum samples were collected from 165 patients with hematological malignancies to monitor titers of HBV DNA, hepatitis B surface antigen (HBsAg), and antibodies to HBV core (anti-HBc) and surface antigens. Serum samples negative for HBsAg and positive for anti-HBc were subjected to nucleic acid extraction and HBV DNA detection by real-time polymerase chain reaction. DNA sequences spanning the S region were analyzed in cases with occult HBV infection.In vitrocomparative study of constructed 1.24-fold wild type and S protein mutant HBV genotype D clones was further performed.
  
  
  RESULTS
  HBV DNA was detected in 23 (42.6%) of 54 patients with hematological malignancies who were HBsAg negative, but anti-HBc positive, suggesting the presence of occult HBV infection. The complete HBV genome was retrieved from 6 occult HBV patients, and P120T and S143L were detected in 3 and 2 cases, respectively. Site directed mutagenesis was done to produce 1.24-fold genotype D clones with amino acid mutations T120 and L143. Thein vitroanalyses revealed that a lower level of extracellular HBsAg was detected by chemiluminescence enzyme immunoassay (CLEIA) with the clone containing T120 mutation, compared with the wild type or the clone with S143L mutation despite the similar levels of extracellular and intracellular HBsAg detected by Western blot. Southern blot experiments showed that the levels of intracellular HBV DNA were not different between these clones.
  
  
  CONCLUSIONS
  Occult HBV infection is common in patients with hematological malignancies and associated with P120T and S143L mutations. 120T mutation impairs the detection of HBsAg by CLEIA.
authors.affiliation: Abeer Elkady, Department of Clinical and Chemical Pathology, Medical School of South Valley University, Qena 83523, Egypt.
authors.forename: Abeer
authors.initials: A
authors.lastname: Elkady
authors.affiliation: Abeer Elkady, Department of Clinical and Chemical Pathology, Medical School of South Valley University, Qena 83523, Egypt.
authors.forename: Sayuki
authors.initials: S
authors.lastname: Iijima
authors.affiliation: Abeer Elkady, Department of Clinical and Chemical Pathology, Medical School of South Valley University, Qena 83523, Egypt.
authors.forename: Sahar
authors.initials: S
authors.lastname: Aboulfotuh
authors.affiliation: Abeer Elkady, Department of Clinical and Chemical Pathology, Medical School of South Valley University, Qena 83523, Egypt.
authors.forename: Elsayed
authors.initials: E
authors.lastname: Mostafa Ali
authors.affiliation: Abeer Elkady, Department of Clinical and Chemical Pathology, Medical School of South Valley University, Qena 83523, Egypt.
authors.forename: Douaa
authors.initials: D
authors.lastname: Sayed
authors.affiliation: Abeer Elkady, Department of Clinical and Chemical Pathology, Medical School of South Valley University, Qena 83523, Egypt.
authors.forename: Nashwa M
authors.initials: NM
authors.lastname: Abdel-Aziz
authors.affiliation: Abeer Elkady, Department of Clinical and Chemical Pathology, Medical School of South Valley University, Qena 83523, Egypt.
authors.forename: Amany M
authors.initials: AM
authors.lastname: Ali
authors.affiliation: Abeer Elkady, Department of Clinical and Chemical Pathology, Medical School of South Valley University, Qena 83523, Egypt.
authors.forename: Shuko
authors.initials: S
authors.lastname: Murakami
authors.affiliation: Abeer Elkady, Department of Clinical and Chemical Pathology, Medical School of South Valley University, Qena 83523, Egypt.
authors.forename: Masanori
authors.initials: M
authors.lastname: Isogawa
authors.affiliation: Abeer Elkady, Department of Clinical and Chemical Pathology, Medical School of South Valley University, Qena 83523, Egypt.
authors.forename: Yasuhito
authors.initials: Y
authors.lastname: Tanaka
keywords: Escape mutation; Hematological malignancies; Occult hepatitis B infection