Analysis of HIV-1 Replication During Antiretroviral Therapy

Overview

This study will determine if the level of virus in HIV-infected patients taking antiretroviral medications for prolonged periods decreases or persists at a stable level. It will also examine whether new gene changes (mutations) occur during drug suppression. HIV-infected patients who are 18 years of age or older, have been enrolled in another NIH protocol, have been suppressed on antiretroviral therapy and have very low levels of virus in their blood may be eligible for this 5-year (or more) study. Participants come to the NIH Clinical Center about every 6 months for a physical examination, routine and research blood tests and leukapheresis to collect white blood cells for T cell analysis. For leukapheresis, blood is collected through a vein much like donating whole blood, but the blood is directed through a machine that separates and extracts the white cells and returns the rest of the blood components to the patient. Patients may also have an optional third clinic visit each year for another blood draw.

Combination antiretroviral therapy for human immunodeficiency virus serotype 1 (HIV-1) infection has resulted in profound reductions in viremia and is associated with marked improvements in morbidity and mortality. Therapy is not curative, however, and prolonged therapy is complicated by drug toxicity and the emergence of drug resistance. How drug resistance emerges during suppressive antiretroviral therapy remains poorly understood. Investigating the characteristics of HIV-1 replication during suppressive antiretroviral therapy will yield important insights in understanding the emergence resistance, and requires patients who have suppressed viral RNA levels. Prior National Institutes of Health (NIH) protocols have made important observations regarding the kinetics of HIV-1 decline in response to therapy, the levels of HIV-1 viremia during suppressive therapy, and the nature of HIV-1 genetic diversity prior to and following initiation of antiretroviral therapy. In the process, these studies have generated a useful cohort of patients with suppressed viral RNA levels, who have been extensively characterized from a virologic and immunologic standpoint. Similarly, patients from other NIH protocols have been followed for prolonged periods before and after therapy has been initiated, and they also have stored sample sets that would be useful in new studies of HIV replication. The HIV Drug Resistance Program (DRP) has studied samples from protocols 00-I-0110 and 97-I-0082 to develop a number of new, sensitive laboratory techniques to measure and quantitate genetic variation and to investigate immune response parameters. To further advance understanding of HIV-1 replication during suppressive antiretroviral therapy and the emergence of drug resistance, we propose a new protocol to study these 2 patient cohorts (from the above cited protocols) and selected patients in other protocols with a new series of studies. The primary objective of this protocol is to investigate the virologic and immunologic characteristics of HIV-infected individuals undergoing antiretroviral therapy. Upon implementation, this new protocol will provide human subjects protection for samples collected under the two prior protocols, whether patients enroll in the new study or not.