title: The status of humoral immunity in occult HBV infection in south-eastern Iranian patients.
abstract: BACKGROUND
  Occult hepatitis B infection (OBI) is characterized as a form of hepatitis in which, despite of absence of detectable HBsAg, HBV-DNA is present in patient's peripheral blood. The aim of this study was to investigate components of humoral immunity during OBI as a possible measure of how patients respond to Hepatitis B viral infections.
  
  
  METHODS
  In this study, HBsAg-/anti-HBc+/HBV-DNA+ samples were assigned as OBI cases and SRID techniques were performed to measure levels of circulating antibodies (IgG, IgM and IgA) as well as C3, C4. In addition, complement system function was assessed by CH50.
  
  
  RESULTS
  Our results showed that the serum levels of IgG and C4 were significantly lower in OBI patients, while IgM and C3 were higher in patients when compared to healthy controls. Serum levels of IgA and CH50 were not significantly different between OBI patients and controls.
  
  
  CONCLUSIONS
  Based on these results, it could be concluded that although OBI patients produced elevated levels of IgM there may be a problem converting and progressing this response to generate enough IgG to overcome HBV infection.
authors.affiliation: Department of Microbiology, Hematology and Immunology, Faculty of Medicine, Rafsanjan University of Medical Sciences, Rafsanjan, Iran. kazemi24@yahoo.com
authors.forename: Mohammad Kazemi
authors.initials: MK
authors.lastname: Arababadi
authors.forename: Ali Akbar
authors.initials: AA
authors.lastname: Pourfathollah
authors.forename: Abdollah
authors.initials: A
authors.lastname: Jafarzadeh
authors.forename: Gholamhossein
authors.initials: G
authors.lastname: Hassanshahi
authors.forename: Ali
authors.initials: A
authors.lastname: Shamizadeh
authors.forename: Behzad Nasiri
authors.initials: BN
authors.lastname: Ahmadabadi
authors.forename: Derek
authors.initials: D
authors.lastname: Kennedy
mesh_terms: D000328:Adult; D005260:Female; D006509:Hepatitis B / Q000097:blood / Q000276:immunology*; D006801:Humans; D056724:Immunity, Humoral; D007492:Iran; D008297:Male