RATIONALE: Giving chemotherapy before a donor stem cell transplant helps stop the growth of cancer cells. It also helps stop the patient's immune system from rejecting the donor's stem cells. Also, monoclonal antibodies, such as alemtuzumab, can find cancer cells and either kill them or deliver cancer-killing substances to them without harming normal cells. When the healthy stem cells from a donor are infused into the patient they may help the patient's bone marrow make stem cells, red blood cells, white blood cells, and platelets. Sometimes the transplanted cells from a donor can make an immune response against the body's normal cells. Giving cyclosporine before and after the transplant may stop this from happening. Once the donated stem cells begin working, the patient's immune system may see the remaining cancer cells as not belonging in the patient's body and destroy them (called graft-versus-tumor effect). Giving an infusion of the donor's white blood cells (donor lymphocyte infusion) may boost this effect.