Australia antigen is intimately associated with a hepatitis virus. It is found in the blood of many individuals who have acute viral hepatitis and in some patients with chronic diseases (ie, some forms of leukemia, Down's syndrome, etc) who have a form of chronic anicteric hepatitis. It is also found in relatively high frequency in apparently normal people living in the tropics, and in even higher frequency in patients with lepromatous leprosy who reside in these areas. Patients with lepromatous leprosy who have the antigen in their blood do not have acute hepatitis, but do have slightly elevated serum glutamic pyruvic transaminase levels. We could not detect any clinical or biochemical evidence of liver abnormality in the apparently normal individuals with Australia antigen.
Blumberg BS, Melartin L. Australia Antigen and HepatitisStudies in Asymptomatic People and Lepromatous Leprosy Patient. Arch Intern Med. 1970;125(2):287–292. doi:10.1001/archinte.1970.00310020093010