title: A pattern of 5-1-1 and c100-3 only on hepatitis C virus (HCV) recombinant immunoblot assay does not reflect HCV infection in blood donors.
abstract: Current criteria for a reactive (positive) interpretation on hepatitis C virus (HCV) recombinant immunoblot assay (RIBA) require > or = 1+ reactivity to at least two of the four HCV antigens present in the assay. Given that 5-1-1 is a subcomponent of c100-3, there is concern that donor samples reacting only with these two antigens (and not with c22-3 or c33c) could be incorrectly classified as positive on the basis of limited reactivity to only one HCV gene product. It is determined that 0.23 to 0.44 percent of HCV enzyme immunoassay-repeatably reactive donor sera demonstrate a pattern of 5-1-1 and c100-3 only on RIBA. Evaluation of six such donor sera using peptide enzyme immunoassays spanning the c100-3 antigen showed highly restricted reactivity to the 5-1-1 N-terminal region of c100-3, in contrast to broad 5-1-1 and c100-3 C-terminal peptide reactivity observed in the majority of donor sera with other positive RIBA patterns. HCV polymerase chain reaction and follow-up serologic evaluations of four of these donors indicated the absence of viremia or evolving seroconversion in all cases. It is concluded that, in the blood donor setting, a pattern of only 5-1-1 and c100-3 reactivity is typically not indicative of HCV infection. To avoid overinterpretation, it is recommended that RIBA grading criteria be revised to require reactivity to two or more HCV-encoded gene products.
authors.affiliation: Irwin Memorial Blood Centers, University of California, San Francisco.
authors.forename: M P
authors.initials: MP
authors.lastname: Busch
authors.forename: L
authors.initials: L
authors.lastname: Tobler
authors.forename: S
authors.initials: S
authors.lastname: Quan
authors.forename: J C
authors.initials: JC
authors.lastname: Wilber
authors.forename: P
authors.initials: P
authors.lastname: Johnson
authors.forename: A
authors.initials: A
authors.lastname: Polito
authors.forename: E
authors.initials: E
authors.lastname: Steane
authors.forename: A
authors.initials: A
authors.lastname: Zola
authors.forename: C
authors.initials: C
authors.lastname: Bahl
authors.forename: M
authors.initials: M
authors.lastname: Nelles
mesh_terms: D000595:Amino Acid Sequence; D000956:Antigens, Viral / Q000276:immunology*; D001782:Blood Donors; D016174:Hepacivirus / Q000235:genetics / Q000302:isolation & purification*; D006508:Hepatitis Antibodies / Q000032:analysis / Q000097:blood*; D006526:Hepatitis C / Q000097:blood* / Q000175:diagnosis / Q000635:transmission; D018937:Hepatitis C Antibodies; D006801:Humans; D015151:Immunoblotting / Q000379:methods; D010455:Peptides / Q000138:chemical synthesis / Q000276:immunology; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000276:immunology*; D017361:Viral Nonstructural Proteins / Q000276:immunology*
chemical_list: D000956:Antigens, Viral; C064544:C100 protein, hepatitis C virus; D006508:Hepatitis Antibodies; D018937:Hepatitis C Antibodies; D010455:Peptides; D011994:Recombinant Proteins; D017361:Viral Nonstructural Proteins