collection (4) . Other investigators have shown that long term 
cytogenetic remissions can be achieved in CML with autologous 
stem cells after in vitro culture (5) . Some of these patients 
have cytogenetic remissions which lasted greater than one 
year. Our recent analysis of the survival of our autologous 
and allogeneic transplantation patients prepared with a TBI, 
VP-16, and cyclophosphamide regimen has shown that about 70% 
of the chronic phase patients are surviving a year after 
transplantation when transplanted in the chronic phase with 
allogeneic or autologous cells. If CML accelerated phase, 
blast crisis, or second chronic phase patients are prepared 
similarly and then transplanted with allogeneic marrow, 65% 
are alive one year following transplant, whereas only 35% of 
the autologous patients are alive at one year. The treatment 
mortality was 12% in 25 CML patients treated with intensive 
therapy and autologous bone marrow transplantation due to 
chemotherapy related complications. 
In this context of long term remissions after intensive 
therapy, it becomes important to determine whether the relapse 
emerges from cells remaining in the infused marrow or results 
from residual disease which xemains after systemic therapy 
used to prepare the patient for transplantation. This 
question becomes even more important to resolve and to measure 
now that methods for removing or separating Philadelphia 
chromosome positive cells from the autologous marrow and 
peripheral blood of CML patients are available (9) . These 
methods include immunochemical separations on the basis of DR 
antigens, late myeloid antigens, surface cytoadhesion 
molecules (9, 10), and potentially novel methods such as 
antisense oligonucleotide therapy. One of the problems with 
autologous transplantation in CML is the length of time 
required for hematopoietic recovery following preparative 
therapy. It has been suggested that the addition of 
peripheral blood stem cells to marrow could accelerate 
hematopoietic recovery. Some are reluctant to use peripheral 
blood due to the fear that increased numbers of Ph+ cells will 
be infused with peripheral blood stem cell preparations. 
No good animal model or in vitro model exists which would 
permit the resolution of the origin of relapse of blast crisis 
or accelerated phase cells in accelerated or blast crisis 
patients treated with intensive therapy and autologous stem 
cell transplants (residual systemic disease following TBI, VP- 
16, and cyclophosphamide or leukemia cells contaminating 
infused autologous stem cells marrow) . In addition, there is 
no way to currently measure the relative contribution of bone 
marrow versus peripheral blood stem cells to the 
reconstitution of patients following preparative therapy for 
transplant. Recently, Anderson and Rosenberg, at the NIH (11) 
have used replication incompetent retroviruses of the N2 
series, first developed by A. Dusty Miller of Seattle (12), 
designated GIN, to follow the fate of tumor infiltrating 
lymphocytes (TIL) isolated from cancer patients and reinfused 
Recombinant DNA Research, Volume 15 
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