Alemtuzumab Plus Peripheral Stem Cell Transplantation in Treating Patients With Chronic Lymphocytic Leukemia

RATIONALE: Monoclonal antibodies such as alemtuzumab can locate tumor cells and either kill them or deliver tumor-killing substances to them without harming normal cells. Peripheral stem cell transplantation may be able to replace immune cells that were destroyed by chemotherapy or radiation therapy. Combining monoclonal antibody therapy, chemotherapy, radiation therapy, and peripheral stem cell transplantation may kill more tumor cells. PURPOSE: Phase II trial to study the effectiveness of alemtuzumab plus peripheral stem cell transplantation in treating patients who have chronic lymphocytic leukemia.