Hematopoietic Stem Cell Mobilization in Idiopathic CD4 Lymphocytopenia Patients and Healthy Controls for the Study of T Cell Maturation and Trafficking in Murine Models
The purpose of this study is to collect blood from people with "idiopathic CD4 lymphocytopenia", or ICL, and healthy volunteers. Specifically, we are interested in studying special blood cells called stem cells. Stem cells form the blood in our bodies by producing billions of new blood cells each day. Many of these blood cells help our bodies to fight infection including one group of immune cells called lymphocytes.
People with ICL have a low number of lymphocytes and are at risk of frequent infections that can be severe. We will use the blood collected in this study to conduct research in mice and in the laboratory that may provide new information about what causes ICL and what might be done to treat it. Volunteers will be compensated.
So that we can collect enough stem cells to study, participants in this study will be given injections of two medications, G-CSF (Neupogen) and plerixafor (Mozobil) before donating their blood (stem cells). These medications help to "mobilize" or move stem cells from the bone marrow into the blood stream. These medications are approved by the Food and Drug Administration (FDA) and are often given to cancer patients before a treatment called stem cell transplantation, commonly referred to as bone marrow transplant. The medications have been used to mobilize stem cells in healthy volunteers but not in ICL patients.
About 20 people (ages 18-65) will take part in this study. You are being asked to be in this study because you either have ICL or are a healthy volunteer. After screening, your total study participation time is approximately two weeks. Study procedures include physical exam; blood draws; urinalysis; sonogram of your spleen; G-CSF (Neupogen) and plerixafor (Mozobil) injections; stem cell donation by leukapheresis; and genetic testing.
For this study, we are asking you to allow us to do genetic testing on large portions of your DNA. We will compare DNA from patients with ICL to DNA from healthy volunteers to look for gene differences that may cause disease. Your genetic material can be obtained from blood, a saliva sample, or from a cheek swab which takes skin cells from the inside of your cheek. DNA can also be obtained from your skin or hair follicles. For the purposes of this study, we will use samples of stored blood that we will collect or have already collected as part of the P-mobile study.
Researchers use many methods to look for differences in genes, but two of the methods that are currently in use are whole genome sequencing and whole exome sequencing. Both methods allow us to look at a wide range of an individual's genetic material to find changes within a gene that may affect a person's health. Using these powerful testing methods means we would look for changes in all or most of your genes that could cause or contribute to ICL. Genetic testing under this protocol will not be limited to these two methods of testing and may include other methods that are available in the future.
Whole genome sequencing is the broadest method because it involves looking at all of your DNA. This includes areas of the DNA that code, or instruct the body how to function, as well as areas of DNA whose biological function is unknown . The results of whole genome sequencing are a form of code representing each of your 3 billion nucleotide pairs.
Whole exome sequencing is a more selective method in which we look only at "exons", which are the parts of your DNA that direct the body to make proteins for cell function and development. The exons are where most of your genes are located. About 85 percent of the genes known to cause diseases are located within the exons. Whole exome sequencing is an efficient method DNA testing, but it could miss a gene that is causing a problem.
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Last Updated December 20, 2013