The purpose of this protocol is to evaluate the safety and tolerability of an immunosuppressive agent, daclizumab, in HIV-infected adults. HIV-infected individuals with levels of plasma viremia below 30,000 copies/mL will receive daclizumab for one month. Various immunologic and virologic laboratory studies addressing the state of cellular activation and toxicity data will be collected post-enrollment. The primary study risks include factors associated with immunosuppression and fluctuation on HIV viral levels. Subjects will be compensated for participation in this study. Total enrollment for the study will be a maximum of 10 subjects.
* INCLUSION CRITERIA: 1. Documentation of HIV-1 infection by licensed ELISA test and confirmed by a Western Blot. 2. Demonstration of control of HIV viremia below the 30,000 copies/mL with a variability of less than 0.5 log of baseline two times within a week and a stable viral load for the previous 3 months. Patient may or may not be on HAART. 3. Patients with CD4 cell count greater than 400 cells/mm(3) at time of screening visit. A variability of 10% between two values is acceptable for values below 400. 4. Ability to sign informed consent and willingness to comply with the study requirements and clinic policies. 5. Age 18-65 years. 6. Willingness to travel to the NIH every 2-4 weeks 7. Need to have a primary doctor who will be taking care of the patients for their HIV infection. 8. Willingness of both women and men to use an effective means of birth control while receiving treatment through this study and 3 months following treatment. Appropriate birth control includes barrier methods, sterilization, and birth control pills. 9. Willing to designate a person for durable power of attorney on the NIH form for medical research and medical care purposes at the NIH Clinical Center. 10. Willing to undergo genetic testing for HLA and willing to have samples stored for future research EXCLUSION CRITERIA: 1. Patients who are pregnant or who are nursing infants will not be eligible. Women of child-bearing potential must have a negative pregnancy test on the day of study entry. 2. Acute or chronic liver disease, history of alcohol abuse or drug abuse that would interfere with participation in the clinical trial. 3. History of any malignant neoplasm except in situ anogenital carcinoma, adequately treated basal or squamous cell carcinoma of the skin, or solid tumors treated with curative therapy and disease free for at least 5 years. 4. History of bladder cancer. 5. Previous treatment with daclizumab. 6. Inability to comply with study guidelines. 7. Hemocytopenia: platelet count less than 80,000/mm(3), absolute neutrophil count less than 1500/mm(3), hematocrit less than 30% (in the absence of gastrointestinal bleeding or hemolytic anemia). 8. ALT/AST greater than 5 times the upper limit of normal, PT INR greater than 2 times the upper limit of normal, creatinine greater than 1.5 times the upper limit of normal. 9. Concurrent use of any other immunosuppressive therapy including systemic steroids for a duration of six weeks or more six months prior to enrollment. 10. History of use of the immunomodulatory agent such as IL-2 or interferon within the last 5 years. 11. Known allergy to murine proteins. 12. Medical illness that in the opinion of the investigator might confound results or interfere with the subject's ability to participate in the trial.