Analysis of HIV Genetic Variation in Patients Before Beginning Highly Active Antiretroviral Therapy

The purpose of this study is to gain knowledge about why drug therapy sometimes stops working in people infected with the human immunodeficiency virus (HIV). This occurs in 30 to 40% of patients treated with powerful antiretroviral drugs. The study will examine how the virus becomes resistant to drug treatment through mutations (changes) and how different mutations produce new variants that are resistant to more than one drug. HIV-infected patients 18 years and older who have not been treated with antiretroviral medications and who have a relatively stable amount of virus in their blood (viral load) may be eligible for this study. Pregnant or breastfeeding women may not participate. Candidates will be screened with blood tests to determine viral load and to study the genetics of the virus. Participants will be hospitalized at the NIH Clinical Center for 10 days for daily blood sampling. (In exceptional circumstances, the sampling may be done on an outpatient basis.) After discharge, patients will be followed by weekly visits for blood tests for a total of 120 days. When antiretroviral treatment begins, the patient may do one of the following: 1. Continue on this study with antiretroviral treatment. Therapy will consist of D4T, 3TC, and efavirenz. Other drugs may be substituted for any of these that cannot be tolerated. HIV protease inhibitors will not be included in the regimen. 2. Complete participation in this study and, if eligible, enroll in another NIH protocol (AVBIO). 3. Begin standard antiretroviral therapy with a private physician. Patients for whom treatment is not yet recommended or who choose not to be treated may continue to be monitored with blood tests for a total of 18 months. (Patients who leave the study after this time may re-join when they decide to start treatment.) Participants may also undergo the following optional procedures to study the genetic variation of HIV: lymph node biopsy, spinal tap, and semen donation or female genital washin