Immunohistochemical study of delta antigen in an American metropolitan population

Delta antigen, a transmissible agent associated with hepatitis B virus, has been detected primarily in Italian patients. The preservation of delta-antigen in formalin-fixed, paraffin-embedded liver tissue enabled us to study the prevalence of this agent in our material. Using the peroxidase-antiperoxidase method, delta-antigen was found in 2 of 65 consecutive biopsy specimens of patients with HBsAg-positive liver disease. In addition, delta-antigen was demonstrated in 2 of 14 autopsy specimens from HBsAg-positive patients. Of the delta-antigen-positive patients, one was Italian, one was a polytransfused American-born Italian and two were American homosexuals. All four delta-Ag-positive patients had chronic active hepatitis. In one patient, the agent persisted for 5 years while chronic active hepatitis reverted to chronic persistent hepatitis during prednisone therapy. These findings suggest that transmission of delta-antigen follows that of hepatitis B virus infection, although it is relatively uncommon in New York City.