I walk the half mile from my school to MD Anderson. It could be the 3rd time or the 300th time. I lost track long ago. I call my dad to let him know I'm on my way over. "I'll update you when you get here." Uh-oh. That can't be good. Normally, I get some sense of what is going on. But nothing this time. And we haven't even met with the stem cell doc yet. The donor, my dad's brother, is running into a brick wall from the perspective of a donor. His platelet counts are too low to donate.
But really, that's only half the problem. It's compounded by the fact that he hasn't been able to muster enough stem cells to even hit 1 million cells after a good week of attempts. They want 4 million cells. They can get by with 3 million but even that has some qualifications. You can imagine that if you collect all 3 million at once, there'd be less stress and handling on the cells. But if takes 6 collections, well, some of the cells aren't going to be viable so you don't really have 3 million live cells. It'd be like going to the grocery one item at a time or all at once.
So they sent him home to recuperate. The hope, and I mean hope in the philosophical sense of the word as this is anything but a diagnosis, is that his brother battled a cold a couple weeks back and perhaps that's limiting the response of his bone marrow to kick out enough stem cells (and platelet cells). We shall see in due time. If that's true, then he should give a good collection in a couple of weeks. If not, then it's time to hit the national registry to attempt to find a match there.
If you're like me, then you may be wondering why they don't just go directly into the bone marrow to collect the cells they need. I asked the stem cell doc that very question. First, if they can't collect peripherally via the blood, then the collection tends not to be adequate from the bone marrow. One predicts the other. But equally important is the fact that stem cells collected from the blood tend to produce better outcomes (at least in MDACC's hands) than stem cells from the bone marrow. So it'd be better to collect peripherally from an unrelated donor than from the marrow of a related donor. As to the why, that's complicated and I'm too tired to go into it now (exams start next week for me). Besides, it'd be esoterically boring to all but the most hard core science geek. I'm going to go drink some boxed wine and watch South Park before drifting off to sleep. It's been a long day.