1. Patients with impaired bone marrow reserve, as indicated by one or more of the following: a) Prior myeloablative therapies with autologous bone marrow transplantation (ABMT) or peripheral blood stem cell (PBSC) rescue b) Platelet count < than 100,000 cells/mm3 c) Hypocellular bone marrow (less than 15% cellularity) d) Marked reduction in bone marrow precursors of one or more cell lines (granulocytic, megakaryocytic, erythroid)