T-Cell Response to Hepatitis B Core Antigen : Identification of Prior Exposure to and Confirmatory Testing for Screening for Anti-HBc

Abstract EN

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.