BENEFITS 
The benefits of this study would be that we could leam whether if treating the marrow with 
growth factors makes it grow back faster and makes the risk of infection smaller and you/your 
child’s hospital stay shorter. Stem cell section may also mean that only normal marrow cells and 
not cancer cells are given back to you/your child. This information might help you/your child. 
Otherwise, what we leam might lead to better treatment for other patients. 
RISKS 
Stem cell Choosing 
We hope that stem cell chosing will mean that only normal blood making cells are returned to 
you/your child and we hope the growth factor treatment will make them grow faster. The major 
risk is that only a few stem cells are selected and the marrow will be slower than normal to 
recover. This might increase the risk of infection and bleeding. It is possible that the marrow 
would not recover at all. In that case we will give back the portion of your/your child’s marrow 
that was frozen without treatment. 
Marking 
No bad effects have been seen in animal studies using these markers or in more than 30 people 
treated with marker genes here or at other institutions. Still, there may be risks. It is possible 
that the mouse virus might "recover" in the cell and be able to grow; it might even cause cancer. 
We think this is very unlikely but we cannot rule it out yet. 
BONE MARROW TRANSPLANT 
You (your child) will rest for one day after the chemotherapy. Then the bone marrow that was 
taken out before will be put back through an IV catheter. So that we can study the marked cells, 
we will take a little extra blood after the marrow is put back. The extra blood taken will be 
about 20 mL (1 tablespoon) once or twice a week for 6 weeks. We will also take extra blood 
monthly for 6 months, every six months for 2 years, and then once a year for 2 years. 
LONG-TERM FOLLOW UP 
We will follow your (your child’s) progress over a long period. You (your child) will need to 
be examined yearly after the transplant. After the first 4 years this can be done by your (your 
child’s) local doctor. A teaspoon of blood will be taken at each exam. 
SIDE EFFECTS 
Stem Cell Selection 
May delay or prevent the graft from taking. May increase the risk of infection or bleeding. 
Virus - No known side effects. 
(Possibly could cause a few antibiotics such as neomycin or amikacin not to work or the virus 
could "recover" and grow or could make cells cancerous) 
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Recombinant DNA Research, Volume 19 
