Bone Marrow Transplant

What is bone marrow?

Bone marrow is, where it is actually, it's the tissue that sits in the middle of the largest bones in the body. And it's the tissue in the body which makes the cells of the blood. So the red cells that carry oxygen around the body, the white cells that fight infection, the platelets are there to help blood clot, they are all made in this tissue and it is basically the jellylike stuff which fills the middle of the major bones.

Who needs a bone marrow transplant?

People who need bone marrow transplants are usually people who have serious life-threatening diseases of the blood. And in general, those patients have cancers of the blood such as leukaemia or lymphomas. In some cases it could be patients who have immune deficiency diseases. They have inherited a deficiency in immune cells and so they need to have replaced normal immune cells. In some cases it can be an auto immune disease or other disease which stops the patients normal bone marrow producing blood cells, and that person, if they can't produce their own blood cells, will die unless they get a transplant of the cells able to make new blood cells from somebody else. The majority of people who get bone marrow transplants though, are people with cancers of the blood.

Why do you need more donors and who can become a donor?

The compelling need for more donors for the register is that you have to match the tissue type between the donor and the patient, because if you don't do that then the patient is likely to die from a disease where the immune system of the donated cells reacts against the patient and can kill the patient. So you need to get the matching. And genes that you match for are variable within the population and they act as if like unique identifiers for individuals within the population. So, your chances of finding a matching donor are actually quite low and it could be one in 10,000, one in 100,000 individuals in the population have the potential to act as a donor for any particular patient in need. So that means you need a large pool of donors. It becomes like a lottery and you've got a small chance of finding a matching donor. So, you just need more potential donors to make your chances of getting a winning ticket in that lottery greater. At the moment, we have somewhere in the region of 400,000 donors, there's a bit less than that in the Anthony Nolan Trust register. And we're still having patients for whom we don't find matching donors. So, we need to find more donors. We need to have more people who are prepared to make that commitment to help potentially save somebody's life.

Why can't the patient's family help instead?

Well if there's a matching family member then they can, and there's basically a 1 in 4 chance that a brother or sister could be a match for you and that would be the best match, for any patient, would be a matching brother or sister. But if you haven't got a matching brother or sister, if you're a single child in a family or your brothers and sisters don't happen to match then you have to find somebody else, so you have to look in the general population for somebody whose going to be a good match for you.

Why do men make the best bone marrow donors?

There's a couple different reasons for that. One simple reason is the amount of bone marrow you can get from a donor is often related to the size and the weight of the donor and men are generally bigger than women and you can get more bone marrow from a man than you can from a woman. The success of the transplant, to a certain extent, is related to the amount of the donation you can give; the more you can give the more likely it is to be successful. There are some other reasons as well. One important reason is that female cells can respond to male cells in a way which can cause problems. If you had a female donor for a male transplant, male cells won't respond to female cells in the same way; so male donor into a female patient wouldn't have the same problems. So males are more like universal donors; there are fewer problems in male donors. And then finally, you can't donate if you're pregnant and for a period of a year after you've given birth. And so if you're a female volunteer donor, there may be periods when you're not able to donate and so if you happen to be a match during that time, you can't donate and so it's more efficient, in a way, to have male donors because they're always going to be available to donate to any patient in need.

How many people need bone marrow transplants in the UK each year?

In general terms, the register gets about 100 requests a month for donors. Not all of those will come from the UK, but there will be about 100 a month routinely. The number of transplants done per year is a bit less than that. On average, each year we would provide just over 300 donors for transplants. There may be other transplants that are taking place with donors from other registers, but that gives you a ballpark figure for the number of transplants done every year and for the number of requests for donors.