title: Comparison of neutralization profiles for anti-HCV reactive donor samples with or without detectable HCV RNA.
abstract: OBJECTIVE
  At Japanese Red Cross (JRC) Blood Centers, all donated blood is screened for hepatitis C virus (HCV) by serological and nucleic acid amplification testing. Donor plasma that tested reactive for anti-HCV by serological test is disqualified even if the donor tests negative for HCV RNA. These test results reflect both true-positive results because of past HCV infection and false-positive results because the cross-reactivity of plasma IgG, which current testing methods are unable to distinguish. To characterize these antibody test results, we examined the neutralizing activity of these plasma samples.
  
  
  METHODS
  Donor plasma samples that tested reactive for anti-HCV by serological test but negative for HCV RNA (n = 43) were analysed for determining their neutralizing activities measured by the inhibition of the cellular entry of pseudoparticles harbouring HCV envelope glycoproteins (HCVpp).
  
  
  RESULTS
  Strong and broad neutralizing activities against HCVpp entry similar to the samples that tested reactive for anti-HCV serological test and positive for HCV RNA (considered to be derived from individuals with chronic HCV infection) were observed in three of 43 plasma samples from donors who tested anti-HCV reactive but HCV RNA negative.
  
  
  CONCLUSIONS
  By examining the neutralizing activities of plasma samples, we identified individuals with a past HCV infection from those in whom we were unable to confirm HCV infection according to the current testing algorithms of JRC, which do not perform anti-HCV confirmatory tests.
authors.affiliation: Japanese Red Cross Kinki Block Blood Center, Osaka, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Kuroishi
authors.affiliation: Japanese Red Cross Kinki Block Blood Center, Osaka, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yasui
authors.affiliation: Japanese Red Cross Kinki Block Blood Center, Osaka, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Matsukura
authors.affiliation: Japanese Red Cross Kinki Block Blood Center, Osaka, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Tani
authors.affiliation: Japanese Red Cross Kinki Block Blood Center, Osaka, Japan.
authors.forename: R A
authors.initials: RA
authors.lastname: Furuta
mesh_terms: D000914:Antibodies, Viral / Q000097:blood*; D001782:Blood Donors; D045744:Cell Line, Tumor; D057809:HEK293 Cells; D016174:Hepacivirus / Q000235:genetics / Q000276:immunology*; D006801:Humans; D009500:Neutralization Tests / Q000379:methods*; D021141:Nucleic Acid Amplification Techniques; D012367:RNA, Viral / Q000097:blood / Q000235:genetics
chemical_list: D000914:Antibodies, Viral; D012367:RNA, Viral
keywords: HCV testing; blood donor; hepatitis C virus neutralizing antibody