You are being asked to participate in this research study because your disease has relapsed after allogeneic bone marrow transplantation (putting normal bone marrow from one person into another that was a brother/sister, a matched family member, or an unrelated donor). This study is testing a treatment for your relapsed disease after bone marrow transplant (BMT) that uses infusions of your bone marrow donor's immune cells (system which protects the body from disease); these immune cells are white blood cells called leukocytes or lymphocytes (called T cells). In allogeneic BMT, we know that the donor's immune system (system which protects the body from disease and is comprised primarily of lymphocytes, or white blood cells) is very important for the control and elimination of leukemia after bone marrow transplantation. Many studies have shown that treatment with transfusions of the bone marrow donor's lymphocytes can lead to a complete remission in patients that have relapsed after BMT. This procedure is called donor lymphocyte infusion, or "DLI". The conventional or standard way to give donor lymphocyte infusions (referred to as DLI) is to take the lymphocytes from the blood of the original bone marrow donor blood and infuse them directly into a patient with relapsed disease without any processing of the lymphocytes.