This is an investigational study. The FDA has authorized the use of the HuM195-Gelonin conjugate in research only. Fludarabine has been previously approved for treatment of chronic lymphocytic leukemia by the FDA. The injectable solution of busulfan is a new preparation that has been approved by the FDA for allogeneic transplantation for chronic myelogenous leukemia (CML). The use of these drugs in this study is investigational. Up to 24 patients will be enrolled on this study. All will be enrolled at UTMDACC.