3. Will the reconstituted immune system reject as foreign the correct protein 
or cells producing it? Unlikely, since an ADA protein is made in most cases of 
ADA(-) SCID : it simply has a very short half-life. Furthermore, the presence 
of inactive ADA protein can be measured in the patient's cells prior to 
treatment. 
4. Will the new cells cause autoimmune disease - attacking either the 
affected cells or other "normal" cells in the body? Answer unknown. 
5. Possibility of using this procedure for other genetic diseases: will the 
other bone marrow derived cells, i.e.. red blood cells or macrophages 
(scavenger cells) also grow with a selective advantage even though they are 
apparently unaffected in ADA deficiency? To what other tissues might these 
cells be able to deliver functioning proteins? 
BENEFITS OF KNOWLEDGE: 
1. May be able to reduce severity of disease or cure the child treated. 
2. Ability to treat other children with ADA (-) SCID, possibly earlier in life, 
even in utero . reducing the duration of time the children suffer from symptoms 
of the disease or its treatment. 
3. Extension of treatment concepts to other genetic diseases. 
4. Treatment of cancers using high doses of chemotherapy (which 
otherwise would destroy blood cells) by treating marrow with drug 
resistence genes 
INVOLVEMENT OF RESEARCH SUBJECT 
Why patient is being invited to participate 
Child has ADA(-)SCID and no compatible donor [expound on benefits, limitations 
and risks of other currently available treatments.] 
PROCEDURES AND DURATION OF STUDY 
1. Preliminary screening procedures-incl uding HLA typing and their cost to 
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Recombinant DNA Research, Volume 12 
