An approach for the analysis of relapse and marrow reconstitution after
autologous marrow transplantation using retrovirus-mediated gene transfer
DR Rill, RC Moen, M Buschle, C Bartholomew, NK Foreman, J Mirro , RA Krance, JN Ihle and MK Brenner
Department of Hematology-Oncology, St Jude Children's Research Hospital,
Memphis, TN 38101.
Autologous bone marrow transplantation (ABMT) is widely used as treatment
for malignant disease. Although the major cause of treatment failure is
relapse, it is unknown if this arises entirely because of residual disease
in the patient or whether contaminating cells in the rescuing marrow
contribute. Attempts to purge marrow of its putative residual malignant
cells may delay hematopoietic reconstitution and are of uncertain efficacy.
We now describe how retrovirus-mediated gene transfer may be used to
elucidate the source of relapse after ABMT for acute myeloid leukemia and
to evaluate the efficacy of purging. Clonogenic myeloid leukemic blast
cells in patient marrow can be transduced with the NeoR gene-containing
helper-free retrovirus, LNL6, with an efficacy of 0% to 23.5% (mean,
10.5%). Transduced colonies grow in selective media and the presence of the
marker gene can be confirmed in individual malignant colonies by polymerase
chain reaction. If such malignant cells remain in harvested "remission"
marrow, they will therefore be marked after exposure to LNL6. Detection of
the marker gene in the malignant cells present at any later relapse would
be firm evidence that residual disease contributed to disease recurrence,
and would permit rapid subsequent evaluation of purging techniques. The
technique also marks normal marrow progenitors from patients with acute
myeloblastic leukemia. These colony-forming cells can be detected in
long-term marrow cultures at a frequency of 1% to 18% for up to 10 weeks
after exposure to the vector. Animal models and analysis of probability
tables both suggest that these levels of marking in vitro are sufficient to
provide information about the mechanisms of relapse and the biology of
marrow regeneration in vivo. These preclinical data form part of the basis
for current clinical studies of gene transfer into marrow before ABMT.
Volume 79,
Issue 10,
pp. 2694-2700,
05/15/1992
Copyright © 1992 by The American Society of Hematology
