Blood Transfusions and DNA

Question : It has been stated that DNA is only found in white
blood cells as opposed to red blood cells. If a person receives whole
blood, which contains red cells, through a transfusion, is it possible
that DNA from the doner will mix or combine with the recipient’s DNA?

A followup question would be if a person receives a bone marrow
transplant, is it possible that DNA from the doner will affect the DNA of
the recipient? This effect being that the DNA would merge or one become
dominate over the other.

A more simple question – Is it possible that the DNA of one person will
mix or merge with the DNA of another person if a doner receives a whole
blood transfusion or a bone marrow transplant? Since bone marrow produces
blood cells, would the transplanted bone marrow produce cells with the DNA
of the doner or produce cells with the DNA of the recipient?

Answer : There are mutliple questions here, each of which would require quite a bit of explanation to respond completley. First off, reb blood cells as alluded
to, have no nucleus and no DNA. They do have rna….which is a nuclear
informational molecule. White blood cells do nave nuclei and a full
compliment of chromosomes. Red blood cells have a life span of about 120
days. White cells have highly variable life spans once released from the
bone marrow into the circulation…from hours to years. The subject is
complicated by the nature of cells…in that they divide to form “daughter”
cells. The original cell no longer is an entity. In transplantations of
tissues, be they a transfusion or a marrow transplant or organ transplant
the donor tissue if it does not come from the individual must meet certain
compatability criteria prior to transplantation. In peripheral
blood….blood in the circulation, this is somehat routine since it is the
first transplantation of human tissue to become routine. The donor cells in
a blood transfusion…which is a transplant, to my knowledge do not
generally remain detectable for long periods but simply die to be replaced
by the recipient’s own cells. This is not the case in bone marrow
transplantsan where stem cells seed into the recipient’s bone marrow to
produce their cells indefinatley…if the recipient does not reject the
transplant because of a lack of tissue compatability. There is also a chance
that the donor cells will “reject the new home” and attack the recipients
body. This is called a ” graft verses host response.” In any case, if the
new marrow is successful in seeding the marrow, the recipient will typically
have the donor’s DNA in all the decendents of the transplanted cells. The
dna from these cells does not generally “mix” with the DNA of the recipients
cells. Nor does it replace the DNA of the cells in other tissues of the
recipient.


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