title: Significance of isolated anti-HBc seropositivity by ELISA: implications and the role of radioimmunoassay.
abstract: Hepatitis B virus (HBV) surface antigen (HBsAg) and antibody to HBsAg (anti-HBs) are excellent markers for HBV infection and its immunity. The significance of isolated antibody to HBV core antigen (anti-HBc) seropositivity is not certain. To elucidate this, sera from 638 Chinese adult subjects, aged 18-52 years, seronegative for both HBsAg and anti-HBs, were tested for anti-HBc. Fifty-one (8%) were found to have an isolated anti-HBc seropositivity by ELISA, and all were negative for IgM-anti-HBc. The anti-HBc persisted in all subjects who attended follow-up for hepatitis B vaccination (n = 48) for a period of 8 months. These 48 subjects received 3 doses of hepatitis B vaccine (HB-VAX, 10 micrograms or 20 micrograms) at 0, 1, and 6 months: 72.9% developed a primary anti-HBs response (suggestive of a false-positive anti-HBc seropositivity), 4.2% developed an anamnestic or secondary anti-HBs response, and 22.9% did not develop an anti-HBs response. Increasing the cutoff point of the ELISA or reconfirmation with radioimmunoassay (RIA) reduced only a minor half of the false positives. This low specificity of anti-HBc ELISA/RIA, together with the high rate of anti-HBs response to hepatitis B vaccine, indicates that subjects with isolated anti-HBc seropositivity should be included in vaccination programs.
authors.affiliation: Department of Medicine, University of Hong Kong, Queen Mary Hospital.
authors.forename: C L
authors.initials: CL
authors.lastname: Lai
authors.forename: J Y
authors.initials: JY
authors.lastname: Lau
authors.forename: E K
authors.initials: EK
authors.lastname: Yeoh
authors.forename: W K
authors.initials: WK
authors.lastname: Chang
authors.forename: H J
authors.initials: HJ
authors.lastname: Lin
mesh_terms: D000293:Adolescent; D000328:Adult; D004279:DNA, Viral / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D006282:Health Personnel; D006510:Hepatitis B Antibodies / Q000097:blood*; D006512:Hepatitis B Core Antigens / Q000276:immunology*; D017325:Hepatitis B Vaccines; D006515:Hepatitis B virus / Q000276:immunology*; D006801:Humans; D008875:Middle Aged; D011863:Radioimmunoassay; D012680:Sensitivity and Specificity; D014614:Vaccines, Synthetic; D014761:Viral Hepatitis Vaccines / Q000494:pharmacology
chemical_list: D004279:DNA, Viral; D006510:Hepatitis B Antibodies; D006512:Hepatitis B Core Antigens; D017325:Hepatitis B Vaccines; D014614:Vaccines, Synthetic; D014761:Viral Hepatitis Vaccines