The factors that influence HIV disease progression are not well understood. While larger amounts of circulating virus (high 'viral loads') predict future adverse clinical events, many of the clinical factors responsible for high viral loads and disease progression remain unknown. Certain clinical events and defined interventions are associated with increases in plasma viral RNA concentrations. One of these clinical interventions is immunization; immunization with several vaccines have been shown to increase plasma HIV RNA concentrations. Even though vaccination can lead to transient increases in plasma HIV concentrations, certain vaccines, including influenza vaccine, are still recommended for HIV patients because the risks of the disease targeted by the immunization are held to be greater than the immunization itself. Therefore, immunization with influenza vaccine can be considered a model, clinically indicated intervention, given at a known time which stimulates HIV replication. For influenza immunization, and for other treatments leading to increases in viral RNA concentrations, detailed knowledge of the regulatory events that mediate the increase in RNA concentrations is not available. We hypothesize that immunization with influenza vaccine, and perhaps other immune stimulatory events, lead to an increase in HIV replication through a regulatory system involving cytokines, signal transduction systems, transcription factors, effects on the cell cycle, and increased expression of additional gene products needed for viral replication, such as genes of the nucleic acid biosynthetic pathways. While experiments aimed at investigating one or another particular part of this regulatory system can be performed with traditionally available technologies, such technologies cannot provide comprehensive information concerning a large number of the regulatory events that may be involved in mediating the increase in HIV RNA concentration. In this protocol, we aim to develop the methodologies needed to determine changes in expression of many of the genes which may be involved in mediating the regulation of HIV expression in HIV-infected patients using cDNA microarray technologies. Once the methodologies are developed, such work may provide new insights into the regulatory systems controlling HIV expression in HIV-infected patients may provide new insights into the pathogenesis of HIV disease.