12. Impaired bone marrow reserve as indicated by one or more of the following: a) History of failed stem cell collection. b) Platelet count less than 1000,000 cells/mm^3. c) Hypocellular bone marrow (less than 15% cellularity). d) Marked reduction in bone marrow precursors of one or more cell lines (granulocytic, megakaryocytic, erythroid).