Liver Fibrosis in HIV-Infected Patients With Elevated Liver Enzymes on Antiretroviral Therapy

* INCLUSION CRITERIA: Age 18 years or older. Ability to understand and willingness to provide written informed consent. Willingness to undergo liver biopsy. Willingness to comply with study requirements and procedures including storage of blood and liver tissue samples for use in future studies of HIV, AIDS, immune function, hepatic diseases, or other related diseases. Established HIV diagnosis (documentation of HIV-1 infection by licensed ELISA testing and confirmed by Western Blot). For the antiretroviral cohort on combination antiretroviral therapy for at least 12 months with stable regimen for at least 3 months prior to enrollment. Chronically elevated transaminases for at least 6 months documented by an elevated AST and/or ALT on the following 3 occasions within the 12 months prior to enrollment: 1. Screening; 2. Less than 6 months (24 weeks) prior to enrollment (distinct from screening); 3. More than 6 months prior to enrollment. Note: Occasions must be at least 8 weeks apart. Specific screening lab criteria: * AST and/or ALT greater than upper limit of normal; * Absolute neutrophil count greater than 750/mm(3); * PT/PTT within normal range; * Platelets greater than 50,000/uL; * Hemoglobin greater than or equal to 10 mg/dL; * Creatinine less than or equal to 2.0 mg/dL; * Negative serum or urine pregnancy test for females of childbearing potential. Willingness to avoid medications that contain aspirin for 7 days PRIOR to liver biopsy and nonsteroidal anti-inflammatory drugs for 3 days PRIOR to liver biopsy. Willingness to avoid medications that contain aspirin for a week AFTER liver biopsy. Willingness to avoid other medications or herbal supplements (e.g., gingko biloba) which may increase the risk of bleeding before and after liver biopsy, as directed by the study team. Willingness to restrict activity for 72 hours after liver biopsy. Have a primary care physician. HIV monoinfected individuals who have had a previous liver biopsy to evaluate chronically elevated transaminases on antiretroviral therapy or for another indication may be allowed to enroll in the study for the purposes of obtaining additional information on predictors of liver disease and to observe the natural history. In such instances, investigators will attempt to access this tissue for review. EXCLUSION CRITERIA: Chronic hepatitis B infection (defined as positive HBsAg or hepatitis B viral load greater than 10,000 copies/ml). Hepatitis C infection (defined as positive HCV viral load) or history of treatment for chronic hepatitis C. Acute Hepatitis A infection (defined as HAV IgM positive). Suspected rhabdomyolysis (e.g., markedly elevated AST with elevated CPK). Known or suspected autoimmune hepatitis. Known or suspected biliary diseases, such as primary biliary cirrhosis or sclerosing cholangitis. Known or suspected Wilson's disease, alpha-1-antitrypsin deficiency, celiac disease. History of primary hemochromatosis, glycogen storage disease, amyloidosis, or cystic fibrosis. Clinical evidence of decompensated liver disease (e.g., jaundice, ascites, esophageal varices, or hepatic encephalopathy). Active clinical pancreatitis. Chronic renal disease. Morbid obesity (BMI greater than or equal to 40), if judged to be a contradiction to percutaneous liver biopsy AFP greater than or equal to 100 ng/mL. Hepatoma or hepatocellular carcinoma. Pregnancy. Active opportunistic infection (except oral thrush) or neoplasm (except Kaposi's sarcoma, skin cancer, or cancer of the cervix or anus, unless known or suspected liver metastasis). Severe psychiatric disorder that would interfere with adherence to protocol requirements. Individuals who have a stable psychiatric condition may be eligible. Decompensated cardiac or pulmonary disease limiting physical activity (e.g., New York Heart Association Heart Failure Class 2 or higher). History of unexplained bleeding. Allergy to lidocaine. Current use or a history of treatment with interleukin-2, interferon-alpha or other investigational agent(s) within 6 months of protocol screening. However, antiretroviral medication obtained through expanded access programs are permitted. Current use or a history of treatment with a systemic corticosteroid, immunosuppressive or cytotoxic agent within 90 days of protocol screening. However, volunteers receiving no more than one day of corticosteroid therapy in the 90 days prior to screening will be eligible. Any medical condition for which an investigator believes liver biopsy may be contraindicated.