Welcome back MedSci readers, in part 2 of this series, I'd like to talk to you about something very personal, namely, Bone Marrow Transplants. About one year ago, a near and dear family member (we'll call this person Q) was diagnosed with leukemia, and we were all in shock. My family was a wreck for more than a month afterwards, and Q remained strong and determined to fight the disease - this is when we were first alerted to the possibility of a stem cell transplant.
Q never thought they would need a transplant - after the first round of chemotherapy, Q suddenly became much better, but sure enough, the leukemia returned. As Q's valiant battle continued, it became increasingly clear that they would need a bone marrow transplant, and as they weren't in dire circumstances, a cord-blood transplant was given to Q. The blood was insufficient, and after a month or two, the leukemia once again returned. Thankfully, a real, adult donor at about the age of 22 was found - conditions couldn't be better, with a 10/11 match for compatibility. Q received the blood transplant in July and has been recovering ever since.
But even though that makes for a nice anecdote about why stem cells can save a person's life when they most require it, it still doesn't answer the original point about how these leukemia treatments work. After meeting with Q's doctors for almost a year, the transplant has almost become a second-nature procedure to explain.
Simply put, a donor (hopefully a 100% match) removes some blood that then undergoes aphoresis, or the process whereby white blood cells are removed and only the red cells remain. Once this process is complete, the recipient (in my case, Q) receives the blood after being subjected to another round of chemotherapy in order to immunosupress and allow the red blood cells to enter the bone marrow without being attacked by the body's defense system.
This marrow transplant is, quite simply put, the most amazing revolution in leukemia treatment since the advent of chemotherapy. Assuming the patient doesn't suffer from GVHD (Graft vs Host Disease), the transplant is almost guaranteed to work provided that the match is something like Q's match. The reason that stem cell transplant success stories aren't as often heard is because most times, people die waiting for donors to show, or other times, chance a donor that isn't as compatible as they should be.
The stem cells themselves invade the bone marrow tissue and pervade through it. The body, being immuno-compromised, is unable to fight against the huge influx of red cells, and allows the new red cells to supplant the old ones. This process leads the person to completely change blood systems. The donor's blood attributes then becomes the recipient's. As a result, in another 6 months or so, Q will have to go in to get shots and vaccines all over again, as their immune system becomes akin to that of a newborn's.
Sadly, however, leukemia treatments appear to be one of the only places that stem cells are catching on - as for other cancer treatments, the possibility of stem cells coming into play seems to be one of the more interesting aspects of a cure for potentially lethal diseases.
Come back next time, when we discuss the controversy surrounding stem cells.