Friday, July 11, 2008

Bag o' platelets

The platelet transfusion went fine - we'll check my counts again on Monday to see how well it worked. Quick refresher: platelets are those blood cells primarily responsible for clotting and are measured by the thousands per microlitre (uL) of blood (e.g. 140,000, or 140 for short).

For those interested in the transfusion details, I received 4 units of irradiated, leukocyte-reduced CMV-negative platelets that were collected by apheresis. This is probably more than you'll ever want to know about platelets, but here's what I found out about all that:
  • Unlike red blood cells, platelets can only be stored for a few days, so the blood bank is constantly in need of them.
  • Platelets can be extracted from whole blood donations, or they can be collected directly from the donor using apheresis. Apheresis is a process where just one blood component is extracted while the rest of the blood is circulated back to the donor. The benefit of apheresis is that someone can donate up to 2 units of platelets per donation this way, whereas it would take 4 full donations of whole blood to make 1 unit of platelets. A donor can also donate platelets up to twice a week compared with a whole blood donation in which they have to wait 3-4 months between donations.
  • A small number of white blood cells (those that fight infection) are always present in platelet donations. Normally the body's immune system immediately kills off these donor white blood cells, but for a person with a weakened immune system there is a small risk that these white blood cells could actually overpower the body's own immune system (called graft versus host disease). Irradiation is used to render these stray white cells ineffective. They don't go away, they just don't work anymore. So, platelets are almost always irradiated for patients suffering from low white blood counts.
  • Leukocyte-reduced means that the platelets were filtered even further to reduce any white blood cells present in the donation. Leukocyte comes from the greek words leukos (white) and kytos (cell).
  • Cytomegalovirus, or CMV, is a very common virus present in over half of the US population. After a CMV infection, the virus normally lies dormant and doesn't present a problem anymore. However, it can be reactivated in people with weakened immune systems and can pose serious problems. CMV-negative means that the platelets tested negative for this virus.
  • 4 units of platelets were given for my transfusion. I found that during my marrow transplant, I'll need 120 units of platelets. Wow.
  • The threshold of thrombocytopenia (low platelets) when spontaneous bleeding might occur is a platelet count less than 5,000 - 10,000. I don't know why, but gruesome images from my favorite horror movies always pop into my head when I hear the term "spontaneous bleeding". Anyway, the recommended trigger is when it falls below 10,000. Mine was at 8,000, so my doctor consulted with the MDS specialist at the SCCA to confirm we should do a transfusion.
  • 4 units of platelets for a 200 lb person should increase the counts by 22,000.
My platelets started at 30,000 a month ago and dropped to 8,000, so getting them back up to 30,000 would be great. The downside is that the survival of transfused platelets only lasts 3-5 days (they are mature cells and don't reproduce copies of themselves like blood stem cells), so it's possible they could be back down to what they are now by next week, but we'll be entering the recovery period of the chemo soon which means the levels should be coming back up.

I also found out that the Puget Sound Blood Center has this to say about platelet donations:
If I've joined the National Marrow Donor Program Registry, is there something I can do now to help marrow transplant patients?

Yes. Become a platelet donor. Platelet donors offer immediate support to patients with cancer, leukemia and others who may need a marrow or blood stem cell transplant.
So there you go. Here's the FAQ.

And here's what a bag o' platelets looks like:

And here's what I look like getting 'em :)


josh and leslie said...

hey steve,
no other way to say it, all of this sucks! Leslie and I are looking at your blog a couple of times a week, so we can keep up w/ how things are going. we heard the recovery time for a donor is about a month, is this true do you know? we have been discussing and researching and talking to another friend of ours here who has CML. she has other health issues and so will be medicated for the rest of her life, she does not meet their requirments for a transplant, so leslie and i are thankful that you are healthy otherwise! you have been and will continue to be in our prayers, we are glad to see that you are doing so well. let us know if we can do anything else for you. later josh

Steve Rider said...

Hey guys! Yeah I know, it's all so weird. I think the recovery time for a donor is less than that. It sounds like there are 2 ways to donate marrow: directly, by way of a bone marrow biopsy, and indirectly from your blood stream.

From what I understand the 2nd way is more common now, which involves the donor taking a drug for about 5 days which causes the blood stem cells to be released into the blood stream, where they can be picked up during a blood draw later. It sounds like the donor might experience some headaches and muscle aches while they're taking the drug, but that it goes away pretty quickly after that.

More info about the donor process.