DNA in transplant patients?

Question

I am taking a human development class. We just learned about DNA, but it was a minor part of the class. I asked about what happens when a patient receives organs, blood, skin, or bone marrow transplants. If a DNA test were performed, and any of the donated cells were tested, they would have the donor's DNA.

What happens long term? I know that blood cells only last about 180 days and they don't replicate, so they would be gone. What about cells produced by donated bone marrow? Will they carry the DNA of the donor or the recipient? What about the skin? Will it grow and spread the donor DNA?

My prof is more into the psychology of development and did not know the answer to this.

Thanks!

Answer 1

In one case, a liver donors cells replaced the recipients bone marrow.  This is unusual and you will see a variety of intermediate states, many not as benign as this case.  A dangerous condition, graft vs. host disease, occurs when donor immune cells proliferate and attach the recipient.

Answer 2

Here are some background tidbits:

1. Each person's DNA is slightly different.

2. The main function of a cell is to produce protein.

3. You are made out of protein and since your DNA is different from others, the proteins you're made out of are slightly different from others.

4. Viruses and bacteria are also made out of protein.

5. Your body responds to foreign proteins (such as bacteria, viruses and someone else's organ) by making chemicals called antibodies (actually enzymes) that destroy the foreign proteins.  This is the function of your auto-immune system.

The result of all of that is that when a person gets an organ transplant, the new organ's cells continues to make the same proteins they always made and your body will make antibodies to destroy the new organ.  Therefore, the recipient of an organ transplant must take anti-rejection drugs (called cyclosporins).  

The donor organ (skin included) does not "spread" its own DNA, it remains within the cells of the donated organ.

Answer 3

All donor cells would always have the donor's DNA and all their progeny will have the same DNA.

So all blood cells produced by donated marrow, skin from a graft, donated kidneys, ect will always have another individuals DNA.

Answer 4

We become chimeras.  Yahoo usually wont let me post the wikipedia link, so you can go there and search chimera and get some good info.

The transplanted organ will have the dna of the donor, while the rest of the body has its own dna.  This is why transplant patients have to remain on immunosuppression, so that the immune system doesnt attack the new organ.  This is behind the reason why patients still have graft v host disease.

I am a stem cell transplant patient, as in bone marrow transplant.  My donor was unrelated.  My bone marrow and blood carry the dna of donor, while the rest of my body has my own dna.  My blood type also changed.  Before transplant I was o+ and now am a+.

This situation is featured on many crime shows such as Law and Order and CSI.  The criminal is a stem cell transplant patient, so the blood evidence they left at the scene does not match the cheeck swab they took to compare.  Most people think that is just tv, but it is infact real.