Nontechnical Abstract 
Acute leukemia is most successfully treated by bone marrow 
transplantation. For some patients who do not have a suitable 
donor, autologous bone marrow transplantation (AuBMT) may offer the 
only hope of cure. In AuBMT the patients own bone marrow is used 
for transplantation. While some patients appear to be cured by this 
procedure, leukemia recurs in many patients. Leukemia relapse may 
result from undetected leukemic cells in the transplanted marrow, 
insufficient transplant conditioning (i.e. leukemic cells in the 
patients body are not killed by the chemotherapy drugs or radiation 
used during the transplant) , or both. Identifying the factors 
leading to disease recurrence after AuBMT will help direct future 
treatment strategies. 
The purpose of this protocol is to determine if leukemia cells 
in the transplanted marrow are responsible, at least in part, for 
disease recurrence in relapsed patients. Patients with acute 
leukemia who are to undergo AuBMT may participate. A portion of 
their marrow will be exposed to a retroviral vector, called LNL6 , 
which contains the neomycin resistance gene. Since mammalian cells 
do not contain the neomycin resistance gene it serves as a unique 
marker gene. After the marrow is exposed to the LNL6 vector, marked 
and untreated marrow will be stored until the time of transplant, 
then infused using standard transplantation procedures. If patients 
relapse after transplantation, and their leukemia cells have the 
marker gene we will know that leukemia cells were contained in the 
transplanted marrow and contributed to disease recurrence. 
Recombinant DNA Research, Volume 15 
[507] 
