HIV Expression in Patients With Low Viral Load on Highly Active Antiretroviral Therapy (HAART)

This study will investigate low-level viral loads in HIV-infected patients taking highly active antiretroviral therapy (HAART). Although HAART reduces viral levels and restores immune function to some degree, it does not cure HIV infection. The virus persists even at levels below that which it can be detected. This study will examine where this residual virus comes from in order to better understand the infection and the effectiveness of therapies. In addition, the study will 1) evaluate the ability of a new test to detect the virus at low levels; and 2) determine whether adding the protease inhibitor Kaletra to the HAART treatment regimen for patients with a low viral load will further decrease their viral load. HIV-infected patients 18 years of age and older may be eligible for this study. Patients involved in the viral load test will be recruited from an NIAID HIV study in which they are already participating. Three groups of patients will be enrolled: those with a viral load of less than 50 copies/ml plasma, those with 51-500 copies/ml, and those with 501-5000 copies/ml. Patients involved in the Kaletra trial must have been taking HAART for 6 months or more and have less than 50 viral copies/ml plasma. They will be screened for this study with a history, physical examination, and routine laboratory tests. Participants in the viral load test evaluation will donate 70 ml of blood up to four times. No more than one sample will be collected per day. Participants in the Kaletra trial will have blood samples drawn on two successive days and will then be randomly assigned to one of two treatment groups. One group will begin Kaletra therapy (four capsules two times a day) immediately; the other will undergo observation for 4 weeks before starting Kaletra. Depending on what group they are in, patients will provide blood samples for viral load measurements and clinical samples according to the following schedule: Immediate Kaletra One sample each during weeks 1, 2, and 3, of therapy and two samples during week 4. Delayed Kaletra One sample each during weeks 1, 2, and 3 of observation and two samples during week 4. After starting therapy, one sample will be collected each week during weeks 1, 2, and 3 of therapy and two samples during week 4. In both groups, after the last dose of medicine on day 28, Kaletra therapy will be complete. At the end of therapy, additional blood will be collected for viral sampling as follows: one sample each during weeks 1, 2, and 3, and two samples during week 4 after Kaletra therapy.