Significance of isolated antibody to hepatitis B core antigen determined by immune response to hepatitis B vaccination.

The immune response to hepatitis B vaccine was studied in 14 individuals with isolated, high-titer antibody to hepatitis B core antigen (anti-HBc) and examined as an indicator of this serologic pattern's significance. Four subjects demonstrated a low-titer antibody to hepatitis B surface antigen (anti-HBs) on repeated testing, and three in this subgroup had anamnestic responses (anti-HBs, 82 to 140 ratio units) after vaccination. Compared with 22 seronegative controls, the remaining ten had significantly higher anti-HBs response rates (78% vs 22%, P = .003) and median anti-HBs titers (4 vs 0 ratio units, P = .008) two weeks after vaccination. One of ten subjects had an anamnestic response, while another exhibited no response. The general pattern of anti-HBs responsiveness observed in those subjects with isolated, high-titer anti-HBc was intermediate between seronegative and anti-HBs-positive groups and may indicate a state of waning immunity after natural infection. Hepatitis B vaccination with follow-up anti-HBs testing should be done for those patients with isolated, high-titer anti-HBc to help exclude chronic infection and boost protective immunity.