This study will collect white blood cells and plasma for research on how the immune system controls HIV infection. The immune system of a very small group of HIV-infected patients, called non-progressors, has been able to control HIV for long periods without antiretroviral therapy. Some immune system-related genes important for this control have been identified in these patients. This study will examine the contribution of HLA genes B*57+, B*27+ and A*01+ to HIV disease in progressors and long-term non-progressors. (HLA type is a genetic marker of the immune system.)
HIV-infected patients 18 years of age and older with HLA types B*57+, B*27+ and/or A*01+ may be eligible for this study.
Participants will undergo apheresis-a method for collecting larger quantities of certain blood components than can safely be collected through a simple blood draw-by one of the following two methods:
- Automated pheresis - Blood is drawn through a needle placed in an arm vein and spun in a machine, separating the blood components. The white cells are extracted and the red cells, with or without plasma (liquid part of the blood), are re-infused into the donor through the same needle or a needle in the other arm. An anticoagulant (medication to prevent blood from clotting) is usually added to the blood while in the machine to prevent it from clotting during processing.
- Manual pheresis - One unit (1 pint) of blood is drawn through a needle placed in an arm vein, similar to donating a pint of whole blood. The red blood cells, with or without plasma, are separated from the rest of the blood and re-infused to the donor through the same needle. Manual pheresis will be done only when a person's estimated total blood volume or red cell count is too low to safely permit removal of blood through a pheresis machine. An adult small in size or markedly anemic, for example, may fall into this category.
Some of the blood collected through apheresis may be stored for future studies of HIV disease and immune function and for HLA testing, a genetic test of markers of the immune system. Some of the blood may be used to screen for different types of viral liver infections, such as hepatitis A, B, C, D, E, F, or G.
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In an attempt to elucidate the mechanism(s) of immune-mediated restriction of HIV viral replication, we aim to study four groups of individuals: 1) HIV-infected long-term nonprogressors (LTNP), who appear to control HIV primarily through virus-specific cellular immunity; 2) HIV-infected patients who have broadly cross neutralizing antibody activity against HIV; 3) HIV-infected patients receiving antiretroviral therapy who will undergo a treatment interruption; and 4) the family members of patients exhibiting immunologic control of HIV infection. Although most of our previous efforts have focused on investigating the virus-specific immune responses in a unique group of patients termed LTNP who control HIV by cellular immune-mediated mechanisms, more recently, another group of rare individuals who naturally develop broadly cross neutralizing antibody activity against HIV isolates have also been identified in our laboratory. Passive transfer studies in nonhuman primates have demonstrated that neutralizing antibodies detectable in a subject at the time of challenge can protect from infection. We aim to recruit more of these patients in an effort to further characterize and compare their virus-specific cellular and humoral immune responses with those in individuals experiencing progressive infection. In addition, it is necessary to define whether putative correlates of immune mediated restriction of viral replication are a cause or an effect of HIV viremia. To this end, we are enrolling patients who will be discontinuing their antiretroviral regimen and examine virologic and immunologic parameters during the treatment interruption. Through this arm of the study, we will attempt to further characterize the mechanisms by which HIV evades and/or suppresses an effective anti-viral immune response and to identify features of the virus or the patients' immune responses that are associated with virologic control following treatment interruption. As we attain greater insight into differences between these patient groups, we hope to perform genetic studies that would enable us to more precisely identify susceptibility or protective genes, which could be potentially used to construct a familial pedigree. We anticipate that all of these findings will contribute to an enhanced understanding of the nature of effective HIV-specific humoral and cellular immunity, which will help focus future vaccine design efforts. For our studies, it will be necessary to obtain larger quantities of plasma or mononuclear cells than can be safely obtained by simple phlebotomy. These components can be easily and safely obtained using apheresis procedures in the Clinical Center Apheresis Unit. This protocol is designed to conform to the requirements of the Apheresis Unit for donors to have leukapheresis or plasmaapheresis procedures.