Familial clustering of hepatitis B surface antigen among Panamanian Indians.

Several authors have suggested that the host genome determines the occurrence of chronic HBS Ag (hepatitis B surface antigen). In attempts to evaluate this possibility, total infection rate and the combined frequencies of HBS Ag and antibody to HBS Ag and radioimmunoprecipitation to measure antibody to HBS Ag, we tested sera from 255 Panamanian Guaymi Indians. They represented 48 families and 32 living units. Clusters of chronically antigenemic individuals were found in families. Clusters of infection were not found in families or living units. Differences in family composition (age and sex) did not explain the increased occurrence of HGS Ag. These findings support the hypothesis that some humans have an inherited susceptibility to chronic infection with hepatitis B virus after exposure.