title: Prevalence and clinical relevance of occult hepatitis B virus infection in patients on the waiting list for kidney transplantation.
abstract: BACKGROUND
  Occult hepatitis B virus (HBV) infection can be defined as the long-lasting persistence of viral genomes in the liver tissue, and sometimes also in the serum at low levels of viremia in individuals with undetectable HBV surface antigen (HBsAg). Viral replication can be reactivated by immunosuppressive therapies or immunologic diseases, leading to the development of typical hepatitis B.
  
  
  METHODS
  All patients on the waiting list for renal transplantation at the only 2 transplant centers in our region (Piemonte, Italy) were checked for the presence of occult HBV infection by an highly sensitive quantitative HBV-DNA polymerase chain reaction (PCR) assay (nested PCR); the only exclusion criterion was HBsAg-positivity. The enrollment lasted from October 1, 2006, to May 31, 2007. The prospective follow-up will continue for 5 years.
  
  
  RESULTS
  HBV-DNA sequences were detected in blood samples from 10 of 300 cases examined (3.3%), being more frequent among Asian (1/3; 33.3%) and African (1/16; 6.25%) subjects as compared with the Caucasians (8/281; 2.8%; P = .011), among anti-hepatitis C virus (HCV) positive versus HCV negative patients (3/32 [9.3%] vs 7/268 [2.6%]; P = .004) and mainly among patients with a previous history of overt liver diseases (3/22 [14%] vs 7/278 [2.5%]; P = .019). HBV-DNA sequences became undetectable at 1 month after renal transplantation in 3 patients; the follow-up is in progress for these and the other patients.
  
  
  CONCLUSIONS
  Occult HBV infection occurs in patients undergoing renal transplantation. Longer observation and prospective studies will clarify the clinical impact of this occult infection on transplant outcomes and the possibility of viral reactivation related to immunosuppressive therapy.
authors.affiliation: Department of Clinical and Experimental Medicine, Amedeo Avogadro University, Novara, Italy. strattanefro@hotmail.com
authors.forename: P
authors.initials: P
authors.lastname: Stratta
authors.forename: E
authors.initials: E
authors.lastname: Bruschetta
authors.forename: R
authors.initials: R
authors.lastname: Minisini
authors.forename: M C
authors.initials: MC
authors.lastname: Barbè
authors.forename: C
authors.initials: C
authors.lastname: Cornella
authors.forename: G
authors.initials: G
authors.lastname: Tognarelli
authors.forename: T
authors.initials: T
authors.lastname: Cena
authors.forename: C
authors.initials: C
authors.lastname: Magnani
authors.forename: R
authors.initials: R
authors.lastname: Fenoglio
authors.forename: K
authors.initials: K
authors.lastname: Toffolo
authors.forename: A
authors.initials: A
authors.lastname: Airoldi
authors.forename: M
authors.initials: M
authors.lastname: Pirisi
mesh_terms: D004279:DNA, Viral / Q000032:analysis / Q000097:blood; D005260:Female; D006509:Hepatitis B / Q000453:epidemiology* / Q000276:immunology; D006515:Hepatitis B virus / Q000235:genetics*; D006801:Humans; D007558:Italy / Q000453:epidemiology; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D015995:Prevalence; D011446:Prospective Studies; D014850:Waiting Lists
chemical_list: D004279:DNA, Viral