title: T-Cell Response to Hepatitis B Core Antigen: Identification of Prior Exposure to and Confirmatory Testing for Screening for Anti-HBc.
abstract: Background. During routine donor screening in the blood bank, it is not uncommon to find isolated reactivity for anti-HBc in the absence of detectable HBV DNA in a first donation but absence of reactivity to anti-HBc in subsequent donations, suggesting a false-positive result for anti-HBc. Study Design and Methods. The blood donor population was screened between January 2010 and October 2011. We selected 2,126 donations positive only for anti-HBc from a total of 125,068 donations. During the process, OBI donors were identified, and their HBcAg-specific T-cell response was analyzed and compared to donors with chronic (HBsAg positive) and recovered (anti-HBc only) infection. We analyzed correlations between signal levels (Co/s) in the competitive assay for anti-HBc and HBV DNA detection. Results. In the 21-month study period, 21 blood donors with anti-HBc alone were identified as OBI (1 in each 5955 donors). The relevant finding was the observation that anti-HBc only subjects with Co/s ≥ 0.1 did not have either HBcAg-specific T-cells or detectable HBV DNA and OBI subjects presented with Co/s ≤ 0.1 and HBcAg T-cell response. In the subset of 21 OBI subjects, 9 donors remained positive for HBcAg T-cell response after four collections. In all 9 samples, we observed HBV DNA fluctuation. Conclusion. Our data suggest that HBcAg-specific T-cell response could be used to confirm anti-HBc serological status, distinguishing previous exposure to Hepatitis B virus from anti-HBc false-positive results.
authors: Infection Diseases Laboratory, Colsan/UNIFESP, Avenida Indianópolis, 1260 Indianópolis, São Paulo, SP, Brazil.
authors: Patricia
authors: P
authors: Araujo
authors: American Red Cross, USA.
authors: Roger Y
authors: RY
authors: Dodd
authors: Colsan, Technical and Research Department, Brazil.
authors: Flavia
authors: F
authors: Latinni
authors: Colsan, Quality Laboratory, Brazil.
authors: Renata
authors: R
authors: Souza
authors: Retrovirology Laboratory, UNIFESP, Brazil.
authors: Ricardo
authors: R
authors: Diaz
authors: Colsan, Associação Beneficente de Coleta de Sangue, Head Colsan, Brazil.
authors: Jose Augusto
authors: 0000-0001-5616-4686
authors: JA
authors: Barreto