what an amazing month! my bone marrow transplantation rotation was one i have been looking forward to, and it exceeded my expectations. very few cancer centers in the world can offer the number and varied types of stem cell transplantation that m.d. anderson can.
caring for paients who are in the peri-transplant period is challenging to say the least. with no innate protection to infection, these patients can be among the sickest in the hospital. but, it is ultimately rewarding to see the patients who get discharged from the hospital and return to clinic in complete remission.
i want to say a little more about the importance of bone marrow transplantation. (understand that every bone marrow transplant is actually a stem cell transplant. very naive stem cells have the ability to reestablish all the elements of a recipient’s bone marrow. the stem cells used for bone marrow transplantation are not the embryonic stem cells that are so controversial.) the national marrow donor program (nmdp) is the national program responsible for matching unrelated donors to patients who need a stem cell transplant and don’t have a related donor. the nmdp matches, collects, and distributes stem cells for over 200 transplants each month.
please realize that over 70% of patients who need a tranplant do not have a matched related donor. let me put it into perspective just how difficult it is to have a sibling donor. the formula to determine if one of your siblings is a suitable stem cell match is 1 minus 0.75 raised to the power of the total number of full siblings you have. let’s say i needed a transplant. my likelihood of dawn or keri being a suitable match is 1 – 0.75 raised to the power of two, which is 1 – 0.5625, which is 0.4375 or 43.75%. if neither would be a match, i would have to rely on the nmdp. i know your next question is if parents and children can donate to one another. the simple answer is yes, but understand that this is in no way an ideal situation since each of us gets half of our genes from our mother and half from our father. a parent-child donation is only half-matched which opens up an entirely new set of problems.
please realize how important the services of the nmdp are. if you are interested in becoming a donor, please visit http://www.marrow.org for instructions on how to become a donor. the process of getting on the list is very simple, it only requires a swab of inner cheek to collect some mucosal cells for genetic profiling. you can do the entire process online, and the kit is mailed to you to do your own cheek swabs. however, this kit process means extra cost for the nmdp, so there is a cost to the potential donor for this process. if you watch the website for traveling collection stations that may visit your area, there is usually no cost to be put on the list if you visit them in person.
so what happens if you are a match? your stem cells can be harvested by the process that i described in my blog entitled “a long-awaited return to the o.r.” thankfully, the collection process has gotten much more simple. now, we can give you a medication by injection 5 days prior to your stem cell collection to increase the number of stem cells that are floating around in your bloodstream. then, you go through a process not very unlike being on a dialysis machine that filters out these stem cells from your bloodstream and returns all the mature blood cells to the donor at the same time. this process takes about 5 hours and usually has to be done on two consecutive days in order to get enough cells for donation.
one final word on cord blood, the blood that is in the umbilical cords of newborns. parents can now choose to donate the umbilical cord and placenta to the nmdp for stem cell collection. this causes no harm to mother or child. in fact, the umbilical cord and placenta which contain a huge amount of stem cells are usually just thrown away. three or four ounces of blood are taken from the umbilical cord prior to its being discarded, and this blood is sent to the nmdp. if the cord blood is a match to a waiting recipient, the nmdp won’t need to come back to your baby to do any further tests or procedures. the cord blood has the stem cells in it that are needed for the actual donation. the only minor change is that this process requires that the mother also be tested for any infectious disease (hiv, hepatitis, etc.) by a normal blood draw while she is in the hospital. mothers probably won’t even realize that an extra blood draw is being done.
my blog is becoming a public service announcement.