T-Regulatory Cell Kinetics, Stem Cell Transplantation, REGKINE

Before the transplant we will test the patients blood for viruses which can cause problems after the transplant. These viruses include Hepatitis B, (which causes liver damage), cytomegalovirus, (which causes lung disease) and HIV (which causes AIDS). If the patient is positive for the AIDS virus, they will not be able to undertake the transplant. The patient will be given 6 doses of chemotherapy with a drug called Ara C in high doses (every 12 hours) which will begin 8 days before their stem cell transplant. Then, another chemotherapy drug called cyclophosphamide will be given in high doses by vein for two days on the 7th and 6th days before their transplant. A drug called MESNA will be given with cyclophosphamide. MESNA is used to decrease the side effects caused by cyclophosphamide. Radiation treatment will be given to the entire body on each day for 4 days before the transplant. This will be done 2 times a day for 4 days. The chemotherapy and radiation treatment will last 8 days. The patient will receive extra radiation treatment if they have certain diseases (central nervous system (CNS) disease, testicular disease or other focal (localized) disease). The day after the radiation treatment is completed; the patient will receive the healthy stem cells by vein. Once in the bloodstream, these stem cells will go to the bone marrow and should begin to grow In prevention of GVHD, the patient will also receive medicine called FK506 as well as low dose methotrexate. The FK506 will be given intravenously (through the vein) initially starting 2 days before the transplant and later by mouth (when they are able to take oral medications). This drug will be given each day for several weeks. Four doses of low dose methotrexate will be given intravenously. The methotrexate will be given on the day after the transplant, 3, 6 and 11 days after the transplant. If the GVHD cannot be controlled with FK506, other medicines may need to be given. Your doctor will describe these medicines at that time. After the patient has their stem cell transplant, we would like to collect some blood at different time points after the transplantation in order to study how regulatory T cells work and grow after a stem cell transplant. To study how these cells are working in the system, blood samples will be taken each month for six months, at nine months, at one year, 2 years and 3 years following transplant. Approximately 6-8 teaspoons of blood will be collected each time. The total blood drawn for this study over three years should not exceed 1 and 3/4 cups. This amount is considered safe in adults. The amount of blood collected will be decreased in children and/or in patients where this amount of blood collection would not be appropriate. If the patient has a central line, the blood will be taken from it, so that extra needle sticks should not be needed. If the patient does not have a central line, they will need to have one placed. This will be a separate procedure for which the patient will sign a separate consent form. The patient will need to come to the clinic on the days of blood drawing and to be seen at Texas Children's Cancer Center.