Role of HBs Ab in development of hepatitis.

24% of a healthy control population had antibody to hepatitis-B surface antigen (HBsAb) detectable by passive haemagglutination. The frequency was higher in other population groups in proportion to the intensity of contract with individuals or material positive for HBsAg. Data obtained during an outbreak of type-B hepatitis indicate that immunity to the disease is directly dependent on the titre of circulating HBsAb. A close relationship was found between the presence of HBsAb and liver dysfunction in carriers of HBsAg. This supports the hypothesis that immune response to the antigen may be necessary for the development of liver damage in type-B hepatitis. Nevertheless, since a good antibody response to HBsAg was found in uraemic patients, in whom hepatitis had a clinical course quite different from the population at large, it is thought that immune mechanisms other than the humoral response may account for the pathogenesis of the disease.