I’ve been a blood donor for over twenty years. The other day a doctor called me and asked me if instead of my normal quarterly donation, I’d be willing to give a few extra hours of my time along with a chunk of white blood cells. I said yes.
There’s this transplant patient at a hospital in Stockholm. Like all such patients this person, let’s call her Joan (I have no idea what her real name is), is on immune suppressant drugs to keep her body from tossing out the transplanted organ. She now seems to have contracted a difficult infection. Unfortunately she’s developed antibodies against run-of-the-mill donated blood that would work in most cases. So in order to give Joan white blood cells to beat the infection, you can’t just look at the AB and Rh factors, you need to look at tens of genetic markers until you find a rare match. Me, in this case.
For me, it’s three visits to the hospital. Monday morning, they first checked my health, which turned out to be very good. Then they drew some of my blood and mixed it with Joan’s in a tube to see if it would provoke an immune response. When it did not, they injected me with filgrastim. This is a synthetic analogue of the hormone G-GSF, granulocyte-colony stimulating factor. In the body, G-CSF is secreted here and there, and it causes the bone marrow to make granulocytes and stem cells and release them into the bloodstream. Granulocytes are a category of white blood cells, the immune system’s foot soldiers.
After the doctor and nurse had seen that the injection didn’t cause me to keel over, they sent me off with some dexamethasone pills to take Monday evening. This is a steroid similar to the hormone cortisone, which has a wider range of functions, one of which is apparently to get those granulocytes out into my blood quicker.
The doctor warned me that I might feel a little creaky in the evening from the sudden flooding of my system with unneeded white cells. And I did, like if I had the flu coming on distantly. But I consoled myself with the thought that I was still in much better shape than Joan. This morning I was back at the hospital and got hooked up to a centrifuge. They’re taking blood out of my left arm, spinning it up in the centrifuge until it separates into layers by density, grabbing the bottom part of the layer of white blood cells (the youngest ones), and then sending the rest back into my right arm. They’ll keep at this for two hours, then shoot me up with more filgrastim and send me off with some more dexamethasone, for the whole procedure to be repeated tomorrow morning.
Why am I a blood donor? Why am I doing this complicated thing for Joan, whom I’ll never meet? Well, because I’ve been helped many times by modern medicine, I believe in solidarity and I’ve been taught to feel good about myself when I’m altruistic. And really, it doesn’t cost me much to help out here.
If you want to be all Darwinist, then you can actually say that I’m acting in my evolutionary self-interest. Joan and I are genetically similar. In helping her stay alive, I improve the chances of my genes spreading in the population. Joan is a transplantee and might neither have any kids nor be in any shape to bear them in the future, what do I know. But maybe she has nieces and nephews, whose evolutionary environment will be a bit less harsh if their aunt is around to help feed, protect and raise them. And then they may go on to have five kids each who share a lot of my genes. Anyway, me and Joan are blood kin now.