HEPATOCELLULAR TRANSPLANTATION AND TARGETING GENETIC MARKERS TO HEPATIC CELLS 
electrophoresis and isoelectric focusing and could be used to distinguish polymorphic 
proteins arising from the graft from those of the host. Polymorphism in liver specific, 
serum proteins would be particularly informative markers if they could be detected in 
the recipient's serum since they could provide a non- invasive measure of the viability 
and differentiation of the transplanted cells. Unfortunately, such polymorphism are 
rare and may be obscured by transfusions of plasma from unrelated individuals. We are 
assessing the applicability of this method for assessing hepatic grafts in OLT in a 
separate protocol ("Clinical course and management of hepatic transplantation". Dr. 
George Ferry, P.I.). 
F. Evaluation of rejection. 
Rejection of orthotopic liver grafts is the most difficult clinical problem after 
transplantation. Immune rejection of hepatocytes has been observed to be a severe 
problem in animal experiments and a phenotypic response to transplantation has been 
dependent upon cyclosporin immunosuppression in many experiments (Cobourn, et al, 1987; 
Ricordi, et al, 1989a; 1989b; Maganto, et al, 1988; Canton, et al, 1987; Ebata, et al., 
1987; Makowka, et al., 1986; Demetriou, et al., 1986; Darby, et al., 1986). There is 
no data to predict the severity of rejection of hepatocyte grafts in human subjects (see 
section III.D). We will presume that immune rejection of hepatocytes will be similar 
to that observed in OLT, and we will treat patients with the same immune suppression 
protocols currently used for OLT including pretreatment with high dose cyclosporin and 
long-term maintenance on this drug. This protocol is described in memo of October 31, 
1990 from Fred Ledley, M.D. to the GCRC in response to their questions. 
Two sets of studies will be performed to assess the severity of rejection. First, 
the presence of the marker gene in transplanted hepatocytes may be useful for 
quantitatively monitoring the course and severity- of this rejection. We may be able to 
use quantitative identification of the marker gene in serial biopsy samples to monitor 
the course of rejection, and to decrease the patient's exposure to potentially dangerous 
immunosuppressive drugs if rejection is found to be less severe. As described above, 
this may be particularly beneficial in patients in whom HCT could provide a "bridge" to 
recovery of their own cells providing evidence that would enable immunosuppression to 
be discontinued. Second, we will monitor the appearance or levels of several immune 
markers thought to be associated with rejection including: soluble IL-2 receptors, 
soluble CD-4, CD-8, tumor necrosis factor, and will perform lymphocyte phenotyping for 
activation markers. If possible, measurement of donor specific immune activation will 
be performed. If this protocol, on a limited number of patients, establishes the 
technical feasibility of HCT, future studies will be designed explicitly to assess the 
immunological issues inherent in heterologous hepatocyte transplantation using adequate 
numbers of patients and controls. 
It should also be noted that there is no reason to believe that cyclosporin would 
have a detrimental effect on HCT. In fact, cyclosporin has been described to have a 
trophic effect on hepatocyte proliferation (Mazzaferro et al , 1990). 
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