Immunotherapy With NK Cell, Rituximab and Rhu-GMCSF in Non-Myeloablative Allogeneic Stem Cell Transplantation

The goal of this clinical research study is to find out if giving a boost of natural killer (NK) cells from a donor combined with Rituxan (rituximab), can help to control disease in patients who have already received an allogeneic stem cell transplant. The safety of this treatment will also be studied. Participants have recurrent chronic lymphocytic leukemia (CLL) or lymphoma after non-myeloablative stem cell transplantation. Primary Objectives: 1.0 To determine the safety of Natural Killer (NK) cells and Rituximab + rhu-Granulocyte-macrophage colony-stimulating factor (GMCSF) in patients with persistent or recurrent B-cell lymphoid malignancies after non-myeloablative stem cell transplantation. 2.0 To determine factors associated with response.