Low Dose IL-2, Hematopoietic Stem Cell Transplantation, IL2 for GVHD

Participation in this protocol will last about 1 year. To participate in this study, the patient will need to have undergone a stem cell transplant. Before the treatment starts, investigators would like to test the patient's blood blood for the number of regulatory T cells already present before beginning IL-2. Treatment Plan: Before the conditioning treatment for the transplant, 30 to 40 ml (6 to 8 teaspoonfuls) of blood will be collected from the patient for regulatory T cell analysis. Approximately same amount of blood will also be collected on day 0 (the day of the transplant), and at the following times after the transplant: day 7 (the day the IL-2 will most likely start) then weekly for another eleven weeks, then monthly for 8 months. On approximately day 7 following the transplant, if the patient is well and meets the eligibility requirements, the IL-2 injections will begin. These will be given subcutaneously (as a small injection just under the skin) three times per week for 6 weeks. The injections may also been given through a special catheter, called an Insuflon catheter, that is placed just under the skin for a week at a time. The first dose must be given in the hospital, but the remaining doses can be given at home. The patient will be taught how to give the injections to him/ herself. If the patient's body has no serious toxicities from the IL-2 and has not developed severe GVHD, the patient can continue to get the injections the same way for an additional 6 weeks. If at any time the patient develops severe GVHD or serious toxicity related to the IL-2,the injections will be stopped. If the patient's disease returns (relapse) or he or she does not engraft (accept the donor graft), the patient will be removed from the study. The patient's labs will be followed closely while he/she is receiving the IL-2 injections, as well as heart, kidney and lung functions; however, these are all standard tests that the patient will receive after transplant regardless of participation in this study.