| If you receive a blood transfusion or an organ
transplant does your body change due to the DNA in
the blood and tissue? Will it ever be the same as
|Question Date: 2018-09-12|
My lab works on transplantation and how your
body and immune system responds to a transplanted
tissue. The answer to your question is yes,
a body definitely changes following a transplant,
and it is due to differences in the DNA between
the recipient and the donor.
Primarily, the host always has an immune
response to the transplanted tissue because it
recognizes those differences, so most people are
on very strong drugs called
immunosuppressants, which block the immune
system from killing the transplanted tissue, for
the rest of their lives. This is bad because then
the patient is also not responding to normal
infections. In addition, many times the
transplanted tissues contain what are called
blood forming stem cells, which are the
cells that make your blood. The donor stem cells
can begin to make blood, and the recipient
actually has blood made from them, and is now a
'chimera', made of tissues of two
After an organ transplant, the body will change
due to the function of the organ. The
function of the organ is instructed by the DNA in
cells that make up the organ. DNA is contained
within the nucleus of the cells in your body.
The exception is red blood cells that do not
have a nucleus (and so do not have DNA. A
blood transfusion can include only red blood cells
which would mean that no new DNA would be added to
your body. The addition of the organ will change
your body (hopefully for the better) and the
effect on your body is most likely not reversible.
The DNA in the cells of the transplanted organ
will NOT be added to the DNA in the cells
of your other organs.
Interesting question. The key to understanding
the answer is to remember that DNA stays in the
nucleus of the cell. So if you get a kidney
transplant, and someone took a DNA sample of your
kidney, it would have the donor’s DNA. But the
rest of your DNA would still be yours. Well,
almost all of it. There will be some cells in the
kidney, like blood cells or damaged kidney cells.
The DNA from these may end up in your blood
stream, but the DNA won’t move into other cells.
Your red blood cells don’t have any nuclei when
they mature, but your white blood cells do. These
days blood is usually separated into different
components based on what a patient needs. They can
even take just a particular component of the blood
from a donor. (When I give
platelets--which are fragments of a
specific cell and help blood to clot— they put the
red and white blood cells and the plasma right
back into me.) So let’s say you got a transfusion
of red cells, then they did a DNA test on your
blood. The only cells with DNA at all would be
the few white cells. There might be a few
cells in the sample that had the donor’s DNA, but
most would be your own.
Here’s an interesting thing, though. Blood
cells are made in bone marrow. Some people
have diseases like leukemia that may need to be
treated by destroying a person’s own bone marrow,
and replacing it with donor bone marrow. This
person will then be making blood cells with the
donor’s DNA. This has been a plot point in some
mysteries. The rest of the person’s tissues would
still have their own DNA.
When a person gets an organ transplant, they
need to find a donor with similar DNA. Why
do you think that’s important?
Thanks for asking.
Well, you're better than you were before, if you
needed a transfusion or an organ transplant; so
you wouldn't want to be the same as before.
1. Yes, some of the other DNA can stay in your body:
DONOR DNA IS DETECTED IN RECIPIENT BLOOD FOR YEARS
AFTER KIDNEY TRANSPLANTATION USING SENSITIVE
FORENSIC MEDICINE METHODS.
You can read here
2. You don't even need to have a transplant to
have different types of DNA in your body. Here
are some strange stories:
3. Maybe I have DNA from my son in my brain!
Scientists autopsied the brains of 59 dead women
and found Y [male] chromosomes in 37 of the women!
They think it got there when they were pregnant
with their sons!
This question doesn't have a simple answer.
If the DNA of the transplanted blood and tissue is
too different from your own, then your immune
system will conclude that it's an invading
infection and will try to destroy it. The
resulting internal warfare can even kill you. For
this reason, doctors are very careful to make sure
that the blood or other tissue being donated is
genetically compatible with the recipient.
If the tissue being transplanted is bone
marrow, then your blood will be changed
because bone marrow is what makes new blood. If
it's a blood transfusion, then the transplanted
blood will remain while it's still in you, but
will be flushed out of your body as blood is
constantly being replaced from your bone marrow
and you will go back to what you were before. If
it's anything else, then the transplanted organ
will be new, but the rest of your body will not.
All of the cells in a person's body contain the
same genetic code because they originated from the
same founder cell way back in fertilization. Each
time cells divide, they transfer a copy of the
genetic code to a daughter cell. Whenever our
bodies need new cells, cell divisions occur and
pass along our genetic information. However (and
this is very important), not all of the cells
in our body are capable of dividing.
Cancers occur when cells that should never
divide begin dividing uncontrollably. Evolution
has given us a delicate balancing act - if we
don't have enough dividing cells, we can't
regenerate dying cells in important organs, but if
we have too many, the consequences are extremely
dangerous. This is why we have small populations
of pluripotent cells specific to each organ
that generate cells only when needed.
Red blood cells (RBCs), the important component
of blood transfusions , are made in bone
marrow, where stem cells divide to create
new RBCs. Because stem cells are not
transferred in a donation, the RBCs given to
the patient will not divide and continue to spread
donor DNA. (Additionally, RBCs are a unique type
of cell because they actually lack a nucleus!)
However, some patients do need bone marrow
transplants, especially following treatment for
cancer. As mentioned before, cancer occurs when
stem cells go crazy - therefore, treatments like
radiation and chemotherapy are used to stop
cell division that has gotten out of control.
This treatment is effective at killing cancer
cells, but it also kills healthy stem cells like
those in bone marrow. Sometimes patients have
their own bone marrow harvested before treatment
and put back in their body afterwards. If they
receive a bone marrow donation, the donor's
stem cells will divide and produce cells with
foreign DNA - depending on how many of the
host's stem cells survived during radiation,
the patient may continue to produce foreign DNA
throughout their life! If the donor is
healthy, it is unlikely that this genetic change
will have negative effects on the recipient.
To summarize, transplants and transfusions will
only continue to create cells with foreign DNA if
they contain stem cells.
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