[Anti-core antibody in HBsAg negative subjects].

: Hepatitis B core antibody was detected by radioimmunoprecipitation test using core antigen radiolabelled with 3H-TTP. Core antigen was prepared from Dane particles isolated from plasma of asymptomatic carriers of HbSAg. Sera samples from 286 blood donors found to be HBsAg negative by RIA, 31 patients with chronic hepatitis HBsAg negative and 12 subjects with a past history of acute viral hepatitis B who became HBsAg negative since 2 to 5 years, were tested for anti-HBc and anti-HBs presence. Co-existence of anti-HBc and anti-HBs was found in 32.8% blood donors, 29% chronic hepatitis patients and in all subjects with a past history of disease. Moreover an average of 8.4% of blood donors and 6.4% of chronic hepatitis patients were anti-HBc positive in absence of anti-HBs. The possible significance of anti-HBc as a useful tool for epidemiologic studies is discussed.