Immunological studies of Australia antigen carriers with and without liver diseases.

Examination of the cell-mediated and the humoral immune systems was carried out in two groups of persistent carriers of Australia antigen. Group A included eleven blood donors with an entirely normal liver histology and without previous history of liver disease. Group B included seven patients with an initial acute `viral' hepatitis verified by biopsy. Subsequent biopsies revealed progression to chronic persistent hepatitis in three cases, to chronic aggressive hepatitis in three, and a suspicion of chronicity in one of the patients. The patients in group B had significantly higher serum concentration of IgM and significantly lower serum concentration of complement C4 than the healthy carriers in group A. No differences were found between the two groups with respect to the presence of autoantibodies or the antibody response to vaccination with keyhole limpet haemocyanin. Delayed-type cutaneous reactions to 2,4-dinitrochlorobenzene, haemocyanin and PPD were equal in the two groups. The PHA-induced lymphocyte transformation was significantly lower in the group of patients with chronic hepatitis as compared to the healthy carriers, but none of the groups showed a statistically significant difference from a control group of eight laboratory technicians. It is concluded that a general immunodeficiency state is not a prerequisite for developing persistent Au-antigenaemia. The slightly impaired T-cell response to PHA found in patients with persistent Au-antigenaemia and chronic liver disease may be related to the liver disease rather than to the Au-antigen carrier state.