Facts About Things

From posted comments, and many questions I have fielded in person, some disambiguation is long overdue, re: bone marrow/stem cell transplants.

The vast, vast, vast majority of stem cell replacement therapies involve plasma collection. You are very unlikely to be asked to donate your bone marrow. Even if you are, the donation process is entirely voluntary. If you are unwilling to donate bone marrow, then that is your business and yours alone.

I, as previously and frequently mentioned, will be getting a stem cell transplant. In the olden days of cancer medicine, admittedly not all that long ago, a bone marrow transplant would have been the only sure way of getting that done. Bone marrow transplants require minor surgery in the form of a very large needle (or two) into the back of the upper pelvis, the iliac crest. The type of transplant that I will be receiving (and the type most commonly performed) does not require this step. For my type of donation, there are four injections over four days, then dialysis. Technically, it is not dialysis, by rather a form of apheresis, where the plasma is collected through centrifuge technology. I like centrifuge technology. We'll get to that.

It seems to be difficult to find information that treats bone marrow transplants and apheretic stem cell transplants as separate topics, so I will attempt to delineate and disambiguate what I may, for ease of personal use and the allaying of fears of large, jabby needles. I myself am not particularly fond of large, jabby needles, and fully respect anyone's desire to keep clear of them, when not medically necessary.

Let's do this part in big, bold letters:

Bone marrow transplants are infrequently done.

That part is important. I feel it is doubly and triply important since I have been recruiting like crazy for www.OneMatch.ca. Obviously, bone marrow transplants would have always been relatively rare, but I mean even in the narrow context of stem cell replacement therapies. Once the only game in town, bone marrow transplants have been relegated to backburner, the bench, the reserves. They are only brought out for very specific illnesses, or due to limited facilites.

These days, the medical professionals prefer to use the aforementioned apheresis to facilitate hematopoeic transfers. Apheresis is "blood outside the body." Specifically, it is when they hook you up to an external collection machine with a centrifuge in it. This machine draws a small portion of your blood, spins it to separate the plasma and the red cells by weight, gives you back your red cells and stores the plasma before repeating the cycle, over and over, until enough plasma has been recovered for a stem cell donation. To get a cup of plasma, the machine has to process ten litres of blood, which happens to be more than your body actually contains.  It's actually roughly double the amount of blood in your standard issue, "average," human being. All that means is that you're going to be hooked up to the machine for about four hours, as it goes through your blood a few times.

I am intimately familiar with apheretic techniques, as I have been getting bi-weekly photopheresis for the last two years. Same sort of plasma collection, but then they'd administer a psoralen to the plasma, and irradiate it with high-intensity UVA before returning it all to me. It ain't so bad. The worst part of the whole thing is the heavy gauge of the needle they use to hook you up. It is a big poke, but one that takes all of two seconds to pass, as directly opposed to what is involved in a bone marrow transplant.

After apheresis, you may be quite tired for a day or so. That's it.

Questions?