Use of Labeled Glucose to Study Lymphocyte Replication and Survival in HIV-Infected Patients

Overview

This study will examine how quickly white blood cells called CD4 lymphocytes replicate (divide) and how long they live in both HIV-infected and non-infected people by measuring how quickly the genetic material (DNA) of cells is replicated. To do this, participants will receive infusions of glucose, a non-radioactive form of a type of sugar. Cells normally use glucose to make various products needed for cell growth and replication, including cell DNA. Measuring how much glucose cells incorporate into their DNA can provide important information about cell replication. This rate of incorporation will be examined and compared in HIV-infected people and in healthy, normal volunteers. HIV-infected patients and non-infected healthy volunteers 18 years of age and older may be eligible for this study. Candidates will be screened with a medical history, physical examination, chest X-ray, electrocardiogram (EKG) and blood tests. Participants will be given a continuous infusion of glucose at a dose of up to 60 grams (about 2 ounces) per day for up to 5 days. The glucose will be delivered through a catheter (thin plastic tube) placed in an arm vein. Blood samples will be collected as often as daily in the first week following the infusion and then from twice a week to once a month for up to 4 years. Alternatively, patients may undergo leukapheresis a procedure for collecting quantities of lymphocytes up to 10 times during the first month after the infusion, and possibly later as well, but no more often than once every 2 weeks. For this procedure, whole blood is collected through a needle in an arm vein. The blood circulates through a machine that separates it into its components. The white cells are removed and the rest of the blood is returned to the body either through the same needle or through a second needle in the other arm. Participants may be asked to receive up to four glucose infusions. There will be at least a 2-week interval between infusions. Participants who have more than three leukapheresis procedures within 3 weeks will have at least 6 weeks between infusions. Participants will be followed periodically in the outpatient clinic for evaluation and tests. This study may provide a better understanding of how HIV causes disease and progressive weakening of the immune system and how therapies affect immunity.

Understanding the rate of lymphocyte replication and destruction in HIV-infected patients, as well as the effects of therapy on lymphocyte replication should lead to a better understanding of the mechanisms behind the immunodeficiency induced by HIV. To examine this directly, up to 100 HIV-infected patients will receive up to 5 days of continuous infusions with \[6,6-(2)H(2)\]-glucose, a nonradioactive, stable isotope of glucose that is safe to administer. The deuterium is incorporated into DNA via metabolism of glucose to ribose and incorporation into nucleotides. The rate of incorporation can be measured in subpopulations of cells to determine the rate of replication of those cells. Fifty HIV-uninfected persons will also be enrolled in the protocol to allow a determination of lymphocyte kinetics in individuals with normally functioning immune systems or immune systems that may have been affected by other diseases. All participants in this study will be reimbursed for the inconvenience and discomfort associated with study participation.