title: Molecular Characterization of Pre-Core/Core and S Region of Hepatitis B Virus in Hemodialysis Patients With Occult Hepatitis B Infection.
abstract: BACKGROUND
  Occult hepatitis B infection (OBI) is a major public health problem worldwide, which harbors potential risk of hepatitis B virus (HBV) transmission through blood transfusion and transplantation. OBI is characterized by the presence of HBV-DNA in the blood or liver tissue without detectable hepatitis B surface antigen (HBsAg) in the serum. An important cause of OBI is the occurrence of mutations in the HBV genome, especially in the S region.
  
  
  OBJECTIVE
  The study aims to analyze mutations in S and pre-core/core regions of HBV-DNA in hemodialysis patients.
  
  
  METHODS
  Sera of 216 hemodialysis patients were tested for HBsAg and hepatitis B core antibody (HBcAb) by ELISA. Sera of patients that tested negative for HBsAg were evaluated by PCR for the detection of HBV-DNA in the S and pre-core/core regions. In total, six PCR products were sequenced, aligned, and compared with the HBV reference sequence. Amino acid deletion and nucleotide substitution were considered mutations in S and pre-core/core regions of HBV-DNA.
  
  
  RESULTS
  Among 216 patients, 203 (93.98%) and 175 (81.01%) sera samples tested negative for HBsAg and HBcAb, respectively. Among all HBsAg-negative samples, six (2.9%) tested positive for HBV-DNA, including four (1.97%) for S and two (0.98%) for pre-core regions. All four (1.97%) samples that tested positive for the S region belonged to HBV-subtype awy. The amino acid sequence of all four samples showed the YMDD motif in position 204 (rtM204). There were three amino acid substitutions in the S region (T127P, P153L, and F170S) and one substitution in the RT region (Y135S). Moreover, two (0.98%) pre-core/core positive patients had an unexpected stop codon in position 1896.
  
  
  CONCLUSIONS
  This study indicates that 2.9% of hemodialysis patients had OBI, which is considered as a major public health problem worldwide. Moreover, we observed three mutations in S region, including T127P, P153L, and F170S, which caused OBI. This study is first to report a mutation analysis of HBV in hemodialysis patients in southwestern Iran. These results indicate that current screening tests based on HBsAg detection are not reliable for detection of HBV infection in dialysis patients.
authors.affiliation: Infectious and Tropical Disease Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran ; Department of Virology, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran.
authors.forename: Nasrin
authors.initials: N
authors.lastname: Rastegarvand
authors.affiliation: Infectious and Tropical Disease Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran ; Department of Virology, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran.
authors.forename: Manoochehr
authors.initials: M
authors.lastname: Makvandi
authors.affiliation: Infectious and Tropical Disease Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran ; Department of Virology, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Samarbafzadeh
authors.affiliation: Infectious and Tropical Disease Research Center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran.
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Rasti
authors.affiliation: Department of Virology, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran.
authors.forename: Niloofar
authors.initials: N
authors.lastname: Neisi
authors.affiliation: Department of Virology, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran.
authors.forename: Amir
authors.initials: A
authors.lastname: Pouremamali
authors.affiliation: Department of Virology, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Teimoori
authors.affiliation: Department of Virology, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IR Iran.
authors.forename: Abdolnabi
authors.initials: A
authors.lastname: Shabani
keywords: Chronic; Hemodialysis Solutions; Hepatitis B; Mutation