Hepatic involvement in patients with human immunodeficiency virus infection: discrepancies between AIDS patients and those with earlier stages of infection. The effect of human immunodeficiency virus (HIV) infection on type and severity of liver disease was studied in 61 HIV-positive patients who did not have AIDS and in 45 AIDS patients. Liver biopsies revealed viral hepatitis in 12 of 18 non-AIDS patients but in only 4 of 34 AIDS patients (P less than .0005, Fisher's exact test). Acute, non-A non-B, and chronic active hepatitis B were seen exclusively in the non-AIDS group; however, chronic persistent hepatitis B was seen in both groups. In 9 of 18 AIDS patients intra vitam liver histopathology established diagnoses of opportunistic infections or tumors. Tissue reaction to certain pathogens, such as hepatitis B virus, mycobacteria, and cryptococci, seems to be milder in AIDS patients than in others who are HIV positive or the expected reaction of the normal host. This is likely because of impaired cell-mediated immunity in patients with advanced HIV disease. 