Detection of Australia antigen in liver biopsies by immunofluorescence.

A search for Australia antigen (AuAg) was made by immunofluorescence in 105 liver biopsies obtained from the same number of patients. No specific fluorescence was observed in 38 cases of acute viral hepatitis (19 of them seropositive for AuAg) or in 55 seronegative patients with various liver disorders or in 8 seronegative patients with histologically normal livers. However, specific fluorescence was seen in two cases: in the single case of chronic aggressive hepatitis seropositive for AuAg and in one of three cases of chronic persistent hepatitis with AuAg-positive sera. The fluorescence observed was mainly intranuclear when cellular suspensions were used, but cytoplasmic fluorescence was more prominent when observations were made on cryostat sections. The finding of AuAg by immunofluorescence in liver cells in chronic but not in acute forms of hepatitis seropositive for AuAg is consistent with the hypothesis of an important role of cellular immunity directed against infected cells in the pathogenesis of viral hepatitis.