[Frequency of antigen associated to hepatitis due to virus B (HBAg) and of antibody (HBAc) in healthy subjects and during of course of acute and chronic hepatitis. Radioimmunologic study].

Among the several methods employed for the detection of hepatitis B antigen (HBAg) and hepatitis B antibody (HBAb), radioimmunoassay is considered to be the most sensitive and specific. This paper describes a radioimmunoprecipitation test (RIP) for HBAg and HBAb standardized in our laboratory; it consists of a double-antibody precipitation test in a micro-titer system employing 125I-labeled HBAg. The test is compared with double immunodiffusion (ID) and with counterimmunoelectrophoresis (CEP) in the detection of HBAg and HBAb in healthy persons and in patients with acute and chronic liver disease. RIP is 20,000 times more sensitive than ID and 2,500 times than CEP when HBAg is tested, and 40,000 times more sensitive than ID and 10,000 times than CEP for the antibody detection. Moreover the method is reproducible and specific for HBAg and HBAb. With this test the frequency of HBAg in healthy persons was 0% in subjects without any known contact with antigenic material, 0.80% in hospital personnel and 1.17% in high risk personnel (laboratory technicians, blood products workers, ecc.). In acute viral hepatitis the frequency of HBAg was 90% at the admittance to the hospital and 70% at the dimission, while CEP detected a frequency of 85% and 20% respectively. In chronic liver disease the frequency of HBAg with the RIP method was 83.3% in chronic persistent hepatitis, 42.8% in chronic aggressive hepatitis, 23% in cryptogenic cirrhosis and 16.6% in alcoholic cirrhosis. The frequency of HBAb detected with RIP was 4.50% in subjects without any known contact with antigenic material, 6.45% in hospital personnel, 0.41% in high risk personnel, 20% in acute viral hepatitis at the admittance to the hospital and 50% at the discharge, 25% in chronic persistent hepatitis, 14.2% in chronic aggressive hepatitis, 15.3% in cryptogenic cirrhosis and 50% in alcoholic cirrhosis. The high frequency of antibody in healthy persons with no history of hepatitis or parenteral exposure to blood transfusion suggests a widespread diffusion of hepatitis B infection and the possibility of a nonparenteral route transmission. The frequency of HBAg and HBAb in chronic liver disease as detected by a very sensitive method rises the question of a possible role of hepatitis B virus in the pathogenesis of the disease.