Does Having a Blood Transfusion Change Your DNA?
Recently, I went to my local American Red Cross to donate blood. Donating blood has become something of a ritual for me. I started doing it about once every three months upon hearing that it can have many potentially beneficial effects for men's health. Yet, on one visit the question dawned on me. Does having a blood transfusion change your DNA in any way?
After a through investigation, I found that the answer is not really. There are a few potential ways that blood transfusions could change your state of health. Although blood banks and the institutions tied to them; do their very best to make sure that this cannot happen. Let's dig into the topic a little further.
What Happens After A Blood Transfusion?
In a donor blood transfusion, blood from another individual (the blood donor) is driven intravenously through the veins of the recipient's body (almost always from a blood bag). To answer the question, will a blood transfusion change your DNA? We will have to look at the contents of that blood bag. Luckily, we know the answer:
- Red Blood Cells (45%)
- Plasma (55%)
- White Blood Cells & Platelets (< 1%)
Of all these components, the only component of donor blood that has a cell nucleus (and thus DNA) is white blood cells (aka Leukocytes). And as the bullet point shows their contribution to donor blood is less than 1%. To put this in perspective, while one pint of blood contains at least 4 trillion microscopic organisms; white blood may account for maybe only one billion organisms. Therefore, the actual amount of foreign DNA entering one's body through transfusion is minuscule. Moreover, this small amount of foreign DNA has almost no ability to affect the rest of your body's performance/attributes. Let's see why.
How Your Body Deals w/Foreign DNA
According to this widely cited article from the Scientific American. The human body generally treats DNA from donor blood as a "relatively innocuous interloper." The body's natural processes almost guarantee that donor DNA is "muted."
For instance, the average life cycle of a white blood cell is 3 to 4 days. And white blood cells do not replicate or divide. Almost all blood cells are produced by the bone marrow. (About 200 billion red blood cells per day, and about 5 billion white blood cells per day.) Simply put, the foreign donor DNA gets overwhelmed by the recipients own DNA. Cells containing the foreign DNA simply die off.
It is worth noting however that the length of time that donor DNA remains in someone's body seems to be related to how much blood was actually transferred from donor to recipient. Studies on female donor recipients found that for smaller scale blood transfusions, donor DNA could still be detected in the recipient's body 7-8 days after the transfusion. For large-scale blood transfusions, donor DNA could be detected in the recipient's body for up to a year and a half after the transfusion.
Exceptions To The Rule / Possible Caveats
So to answer the question, does a blood transfusion change DNA? is NO. The donor's DNA is generally degraded within the recipient's body over time, eventually disappearing altogether. This does not mean that donor DNA and donor blood cannot have an effect on the recipient's body.
Although complications from a donor blood transfusion are extremely rare due to the safety precautions that are taken by blood banks and other related services, they can happen. The symptoms of these complications can include:
- Allergic Reactions
- Iron Overproduction
- Graft Versus Host Diseases
Under the last category is something called 'febrile non-hemolytic transfusion reaction'. It is a rare reaction to donor DNA whereby the recipient's white blood cells actively attack the white blood cells in the donor blood.
It is also worth mentioning however that some blood banks address this and other conditions by taking out as many white blood cells from donor blood before storage. They do this by centrifuging the donor blood. A centrifuge will separate donor blood into its four main components: red blood cells, platelets, plasma and white blood cells. At this time the white blood cells are discarded. The blood is then further screened for virulent strains of virus and bacteria before usage.
Bone Marrow Transplants & Blood Chimeras
One way in which a person's DNA can be changed (at least in their white blood cells) permanently is through a bone marrow transplant. Traditionally, bone marrow transplants have been performed as such. Surgeons remove all the bone marrow present in the patient. Then they replace the bone marrow with donor bone marrow. Since bone marrow is responsible for producing platelets as well as red and white blood cells. Donor bone marrow will produce blood cells containing the DNA of the original donor.
In the same breath, the cells in the rest of your body will continue to have your original DNA (the one you were born with). So just like some Frankenstein creation, you will have 2 sets of DNA for the rest of your life. The popularized name for this phenomenon is human chimerism. And as it turns out it is much more common than people realize. It can even occur naturally (without a bone marrow transplant). You can read more about blood chimerism and its effects here.
Can having a blood transfusion change your DNA in any way? No. Not really. As explained before, it is possible that someone else's DNA could be present (and may even show up on tests) in your body for some time after the transfusion. But your body's natural process will prevent that "foreign" donor DNA from being expressed anywhere else in your system.
The only true way for there to be a change in the DNA contained in your blood cells would be through a bone marrow transplant. Interestingly, enough there is one case in Alaska where bone marrow transplants led to police investigators to ID the wrong perpetrator in a sexual assault crime. The details of the case can be seen here.