Human Gene Therapy Subcommittee - AI5I9\ 
Dr. Deisseroth said they could also make data available about the degree of reduction 
possible that would still allow rapid engraftment. Dr. Mclvor asked what the total 
volume would be after the reduction. Dr. Deisseroth estimated they would use 50 
milliliters, of concentrated marrow cells; with a 10-fold increase it would be a liter with 
the supernatant. 
Dr. Parkman moved provisional approval of the protocol with the stipulation that there 
be a major revision of the consent form, including differentiation between the gene 
transfer part of the research and the other part of the research. Additional data needs 
to be provided about the level of neomycin resistance gene expression and BCR-Abl 
gene expression in colonies of cells isolated during blast crisis. Dr. Erickson seconded 
the motion. 
Dr. Walters put the motion to a vote. The motion passed by a vote of 10 in favor, 0 
opposed, and no abstentions. 
IX. PROPOSED ADDITION TO APPENDIX D OF THE NIH GUIDELINES 
REGARDING A HUMAN GENE TRANSFER PROTOCOL ENTITLED: 
HEPATOCELLULAR TRANSPLANTATION IN ACUTE HEPATIC FAILURE AND 
TARGETING GENETIC MARKERS TO HEPATIC CELLS 
Dr. Epstein said that the proposal consists of a marking protocol which is embedded in a 
larger experimental protocol regarding the use of isolated hepatic cells in the treatment 
of acute hepatic failure. It proposes injecting these cells into the circulation with the 
hope that they will reach the liver and colonize it with healthy cells from an outside 
donor. This is not autologous marking, but marking of allogeneic cells. The gene 
transfer part of the protocol proposes inserting the neomycin resistance (neo) gene into 
the cells to be transplanted to the liver. The purpose is to permit the investigators to 
follow the fate of these cells after the transplant. He cautioned that when the disease is 
an acute condition that is potentially treatable, one has to consider that the marker, if 
inserted, will be in the patient's liver cells for the rest of that patient's life. 
Dr. Epstein said it was questionable how successfully the cells can be transduced with the 
neo marker; in the animal systems it is possible to obtain 20% transduction in various 
species. However, the amount of data that is directly applicable to human hepatocytes is 
relatively scanty, and not terribly quantitative. He said this information is necessary to 
do the calculations to determine the marker frequency in the cells. He expressed 
concern about how the marking will be used to interpret the experiment when it is done. 
Although it is stated the methods for detecting expression of the marker gene by in situ 
hybridization will be worked out, these methods are not as yet available, and it is not 
clear how effective this approach will be, given the low frequency of labeled cells 
expected to be present in the liver. Furthermore, there is no information provided as to 
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