Post Transplant Donor Lymphocyte Infusion

Inclusion Criteria: * Patients (age \> or = 1 years) with a diagnosis of relapse after related or unrelated allogeneic stem cell transplantation for a hematological malignancy. * For CML, relapse will be defined as any cytogenetic evidence of a Philadelphia chromosome or persistence of BCR/ABL rearrangements by molecular testing on at least two measurements over a 6 month interval. If cytogenetics are normal and there is PCR evidence of a BCR/ABL fusion, patients will be eligible if they have evidence of a quantitative increase in CML measured either by quantitative PCR or by fluorescent in situ hybridization (FISH). * For non-CML, relapse will be defined based on disease specific morphologic criteria from a bone marrow biopsy and aspirate or recurrence of disease specific cytogenetics. For disease specific definition of relapse, see appendix 3. Relapse can be determined morphologically with less than 5 percent blasts if definitive relapse can be determined. Equivocal results for relapse should result in a repeated test after an appropriate time interval (suggested 1 month) to determine eligibility. Post-transplant lymphoproliferative diseases (often referred to as EBV-associated lymphomas) are NOT eligible for this protocol. * For Chronic Phase CML patients only * \- must have failed (no response in 3 months or incomplete response at 6 months) or refused treatment with Gleevec * \- if no prior DLI, CML patients will first have DLI- if relapse occurs after DLI, DLI with chemotherapy per this protocol will be offered * Patients must be within one year of identification of relapse or if beyond that time period, must have at least 10% donor DNA by RFLP or cytogenetics. * Same allogeneic donor (sibling or URD) used for transplantation is available for lymphocyte donation. * No severe organ damage (by laboratory or clinical assessment) as measured by: * \- blood creatinine ≤ 2.0 mg/dL * \- liver function tests \< 5 x normal * \- left ventricular ejection fraction \> 40% (testing required only if symptomatic or prior known impairment). * \- pulmonary functions \> 50% (testing required only if symptomatic or prior known impairment). Oxygen saturation (\>92%) can be used in child where PFT's cannot be obtained. * \- chest x-ray without evidence of active infection * Off prednisone and other immunosuppressive agents (given for any reason) for at least 3 days prior to DLI infusions. * Performance status ≥ 60% * Women must not be pregnant or lactating. The agents used in this study may be teratogenic to a fetus and there is no information on the excretion of agents into breast milk All females of childbearing potential must have a blood test or urine study within 2 weeks prior to registration to rule out pregnancy * Women of childbearing potential and sexually active males are strongly advised to use an accepted and effective method of contraception * Patient must given written informed consent indicating understanding of the nature of the treatment and its potential risks Exclusion Criteria: * Concurrent signs of acute or chronic graft-versus-host disease requiring ongoing treatment at the time of relapse will be ineligible. * Patients being treated for GVHD with prednisone, cyclosporine, Imuran or other immunosuppressive medications are not eligible until these medications are discontinued for at least 2 weeks without a flare of GVHD. * Active CNS leukemia * Active fungal infection or pulmonary infiltrates (stable prior treated disease is allowable) * HIV positive