What is the process of donating stem cells for allo, is there a difference between the two methods

What is the process of donating stem cells for allo? Is there a difference between the two methods?

There are two ways to donate. So one would be to do the same apheresis where you get a catheter placed into the blood vessel and then you get blood taken out. It goes through a machine to collect the stem cells and then it goes back in, just like you would do for an autologous stem cell transplant. But this procedure is done on the donor. So that is called apheresis or peripheral blood stem cell collection.

The other way to do it is to take the person to an operating room. And just like patients who will have bone marrow is done, you'll do that, but you'll do it many times. And so on average, let's say if we do a bone marrow donor on a myeloma patient just to evaluate them, we might take something like a tablespoon of bone marrow, two tablespoons of bone marrow. So if we are taking marrow to donate to someone, we'll probably be taking at least a quart or maybe two quarts. Depending. It all depends on how big the person is. So if your mom is tiny, then it's not so much. If your mom is gigantic, then it's a little bit more. So those are the two ways to do it.

If you do it where you get bone marrow taken, it's a same-day procedure, but it is a surgery. People go into general anesthesia. You can have a lot of discomfort, pain, etc. So there are different reasons why you might use one versus another. So if you think about it, most of the immune cells we have are in the blood. So when we collect blood stem cells, we actually collect immune cells with that. Whereas if we go into the bone marrow, there are much fewer immune cells. So those are more like these bone marrow blood-producing stem cells rather than immune cells. So if I take a collection from the bone marrow, maybe it has fewer immune cells in it and maybe there's less of a chance of getting graft versus host disease. That is like very theoretical. But that might be one reason to do one versus another.

The other might be, you know, the patient might say, "I want to," but there are no facilities to collect the bone marrow. Like, they just don't do that where there's facilities to collect blood. Then it's sort of, well, the choice is like doing that versus doing that. Like, there's only one choice. So that's the way it's done. But when there are dual options, a lot of it depends on the clinical trial you're on that will dictate whether you need to use one or the other.

So people have studied this extensively. And I would say, there have been studies that have shown that blood stem cells are better. A number of studies have shown that. And about an equal number of studies have shown that bone marrow is better. So I think that for an individual patient, I think they're pretty much about the same. If you ask a donor, it may be different. But if you look at the results of GvHD, disease control, all of those things, I think they're pretty much in the same ballpark.