Cohort II: At study entry a patient history and physical exam is performed, and volunteers complete a questionnaire. Volunteers with a rising plasma HIV RNA during the first three visits will have frequent sampling of blood and physical exams for two years. Volunteers continue to be followed thereafter once every 6 months through 5 years of study duration. Volunteers are offered the opportunity to participate in a lymphoid tissue substudy and/or the lymphoid kinetics substudy. These substudies require hospitalizations of 24 hours or less for tissue biopsies and glucose infusion. Compensation for travel and for the inconvenience of study participation is provided