I. INTRODUCTION 
In a world or country that was completely rational, th ere would be little concern 
about the safety of somatic gene therapy of human disease with retrovirus vectors. How- 
ever, in the United States of America in 1986, the introduction of such new technologies 
is controversial. Near hysteria marks much public response to the AIDS epidemic which 
is caused by a virus in the same family as the viruses proposed for human treatments. 
Thus, consideration of such therapy needs to be discussed in detail. 
The use of retrovirus vectors for somatic therapy of human genetic diseases can 
be looked at as a novel improvement on present means of drug delivery or as the in- 
troduction of a potentially dangerous technology. Although as scientists and physicians, 
we may believe that the first characterization is correct, I am convinced that we must act 
as if the second characterization is correct. We must design our vector systems and 
protocols so that even quite unrealistic fears about safety can be allayed. 
The general plan now being discussed for somatic gene therapy of human dis- 
ease with retrovirus vectors is to use a modified retrovirus vector containing a gene that is 
absent or mi sanctioning in the patient to infect bone manrow cells from the patient and 
then retransplant the infected cells into the patient (Anderson, 1985; Parkman,1986). 
Such therapy involves only somatic cells and not germ-line cells. 
A. Conce rns 
Whose safety are we concerned with? Firstly, the new therapy should not harm 
the patient Possible types of harm to a patient from somatic gene therapy of human dis- 
ease with retrovirus vectors arc induction of cancer, induction of harmful mutations, ex- 
posure to massive amounts of publicity, and other general concerns. Relevant questions 
to consider are whether or not these concerns are lessened when the patient has an ex- 
tremely severe, life-threatening disease and whether or not the concerns are heightened 
when the patient is a minor. 
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