Espallardo, Irish Mae T

What Bone Marrow Does

All your blood cells are made in your bone marrow. When you're born, all your bones have marrow. As you age, your bones stiffen, and only your hips, torso, and cranium have marrow.

There are three types of blood cells:

Red blood cells provide oxygen and

nutrients to the body and remove waste products from organs and tissues White blood cells are the major part

of the immune system. They fight viruses, bacteria, and fungi.

Platelets are the cells that clot to

stop bleeding.

In diseases like leukemia and lymphoma, a cell in the bone marrow becomes cancerous. Usually, it stops at an immature stage of development, then begins reproducing. Cancerous cells lose their ability to die when they're supposed to (a process calledapoptosis). Thus, they begin either to crowd out other cells in the bone marrow or in the blood stream or both.

Treatments for Leukemia

There are two major types of leukemia, chronic and acute. Acute leukemia progresses quickly and requires extreme and rapid intervention. Usually that is chemotherapy and possibly a bone marrow transplant, which will be explained in a moment.

Chronic leukemia is more slow-moving. It is treated with medications. If I understand correctly (and I might not because I have acute leukemia), doctors normally don't treat it with a bone marrow transplant because the transplant and preparation for it are more likely to be fatal than the leukemia is!

I'm going to focus on acute leukemia.

Untreated, acute leukemia can kill in weeks. I saw a statistic that said that in 1966 the mean survival time was 40 days from diagnosis. Personally, I needed a transfusion of blood 19 days after I was diagnosed. Based on the decline of my blood cells, I'm pretty sure I would not have lived more than 6 weeks after my diagnosis if I had not been treated.

The proliferation of cancerous marrow and blood cells are initially treated with chemotherapy. The treatment destroys blood cells and marrow cells. The patient is given blood treated with radiation to remove all white blood cells. The red blood cells keep the patient alive.

The idea is to destroy pretty much all the white blood cells, which are almost always the ones that are cancerous, and most of the marrow cells. The hope is that in the process all the cancerous cells will be destroyed.

Once chemotherapy is over, the marrow is allowed to grow back and begin producing blood again. Hopefully, at this point, the marrow and blood system will be restored without cancer.

Often the chemotherapy is repeated three or four times to ensure destruction of all the cancer cells.

Chemotherapy is dangerous. For two to three weeks the patient has no white blood cells, making him or her extremely vulnerable to infections. Extreme care is maintained to keep the patient safe, and antibiotics and other prophylactic medications are given.

In many cases, this is enough to cure the leukemia, and the patient lives the rest of his or her life completely healthy.

If the patient relapses, then the next step is a bone marrow transplant. Also, in some forms of leukemia the risk of relapse, and the danger associated with it, is so high that a transplant is warranted even before relapse occurs.

Bone Marrow Transplant

If chemotherapy doesn't work or is known not to be enough, then there is one step further that treatment can go. The bone marrow can be replaced by someone else's.

This can be done in two ways. One way is called a stem cell transplant, and it's basically a "short cut" for the donor. I'll explain that in the next section.

In a bone marrow transplant, bone marrow is extracted from the hips of the donor. About a hundred tiny holes are made through the skin into the hip bone with a special tool that punches a small hole in the bone. A needle is inserted through the hole (it's possible the needle is part of the tool) and bone marrow is sucked out of the bone.

Bone marrow is mostly liquid. It looks a lot like blood.

The holes in the skin are so small that no stitches are needed. The bone heals up in about a week. I'm told that the donor will feel like a mule kicked them in the rear end, and they'll hurt for about a week.

The process, at least of the transplant itself, is much easier on the recipient. About a quart of marrow is pulled from the donor, and it is given to the recipient intravenously.

Yes, that's right. The donor spends a few minutes (I'm told), getting the bone marrow by IV.

That is what is so amazing. The bone marrow simply goes in a vein, and it takes care of the rest from there. It makes its way to the bones and takes up residence as the new bone marrow. From there it produces an entirely new blood system. In fact, it is possible for the recipient's blood type to change!

The recipient's blood type can change because the doctors do not match the donor for blood type. Instead, if the donor is a sibling (brother or sister), there are six places on the recipient and donor's DNA that have to match. If the donor us unrelated, then there are four more things to consider. I actually don't know whether those four things are four more DNA spots.

I'll explain partial matches below. I'll also explain the dangerous and difficult preparation that the recipient has to go through in order to receive the transplant, but first let's explain a "stem cell" transplant.

Stem Cell Transplant

A stem cell transplant is just a different way to replace the bone marrow. It's an easier route for the donor.

In a stem cell transplant, the donor is given a series of growth hormone shots over several days. This causes the bone marrow to rapidly produce the hematopoeitic stem cells that are the precursors to all the blood cells. So many stem cells are produced that some stem cells are forced out of the marrow and into the blood stream.

After five days or so, the donor is hooked up to a machine that removes blood through a vein on the donor's arm. The blood is run through the machine, which somehow removes the stem cells. Once the stem cells are removed, the blood is put back into the donor in his or her other arm.

The stem cells are then taken to the recipient and given by IV just as the bone marrow would be. It works exactly the same way, just as amazing.