T-Regulatory Cell Kinetics Post Transplant For Patients Undergoing Matched Sibling Stem Cell Transplantation

Patients are being asked to participate in this study because they have a cancer in their blood (such as leukemia or lymphoma) or myelodysplastic/myeloproliferative (pre-leukemia). We suggest a treatment that might help them live longer without disease than other treatment plans would. This treatment is known as a stem cell transplant. We believe this may help the patient as it allows us to give much stronger doses of drugs and radiation to kill the diseased cells than we could give without the transplant. We also think that the healthy cells may help fight any diseased cells left after the transplant.

Stem Cells are special "mother" cells that are found in the bone marrow (the spongy tissue inside bones), although some are also found in the bloodstream (peripheral blood). As they grow, they become either white blood cells which fight infection, red blood cells which carry oxygen and remove waste products from the organs and tissues or platelets, which enable the blood to clot. For the transplant to take place, we will collect these stem cells from a "donor" (a person who agrees to donate these cells) and give them to the patient. The patient has a type of blood cell cancer or other blood problem that is very hard to cure with standard treatments and they will receive a stem cell transplant (SCT). If they have a brother or sister that is a perfect match and agrees to donate, the stem cells will come from him/her. Before the transplant, two very strong drugs plus total body irradiation will be given to the patient (pre-conditioning). This treatment will kill most of the blood-forming cells in the bone marrow. We will then give the patient the healthy stem cells. Once these healthy stem cells are in the bloodstream they will move to the bone marrow (graft) and begin producing blood cells that will eventually mature into healthy red blood cells, white blood cells and platelets.

Also, we will ask permission to draw blood from the patient so that we can measure the number of certain blood cells called T regulatory cells. T regulatory cells are special immune cells that can control or regulate the body's immune response. We want to determine whether T regulatory cells are important participants in graft versus host disease (GVHD), infection and relapse. In GVHD, certain cells from the donated marrow or blood (the graft) attack the body of the transplant patient (the host). GVHD can affect many different parts of the body. The skin, eyes, stomach and intestines are affected most often. GVHD can range from mild to life-threatening. We do not know whether T regulatory cells can modify these conditions. We want to measure these T regulatory cells and learn if these cells do influence these conditions. If we learn that T regulatory cells do affect these conditions, then it may be possible to modify these cells for the benefit of transplant patients.