Bone Marrow Transplant !

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Whats it all about ?
Bone Marrow is the spongy tissue found in the cavities of the body's bones, where all the body's blood cells are produced.

Every type of blood cell in the marrow begins its life as a stem cell. The stem cells then divide and form different cells that make up your blood and immune system. These include white cells that fight infection (leukocytes), red cells that carry oxygen (erythrocytes), and platelets which are clotting agents. Without bone marrow, and the disease fighting blood cells it produces, your immune system will be severly impared and you will have little defense against even the most common infection.

The goal of a bone marrow transplant is to cure many different types of cancer and disease. The type of transplant depends on who donates the marrow.

Allogeneic transplant--The person giving the bone marrow or stem cells is a genetically matched family member (usually a brother or sister).

Unrelated allogeneic transplant (MUD) --The person donating marrow is unrelated to the patient. Chances of finding an unrelated compatible donor from the general population depends on the uniqueness of tissue type. Genetic and ethnic background can also affect the likeihood of finding a donor.

Syngeneic transplant--The person donating the bone marrow or stem cell is an identical twin.

Autologous transplant--The patient donates his/her own bone marrow or stem cells prior to treatment for re-infusion later.

Peripheral blood stem cell transplant--The patient or a donor donates stem cells collected from the circulating blood system instead of from bone marrow. The only difference with this kind of BMT is the source of the stem cells and how they are collected.

Allogeneic, unrelated and syngeneic are most commonly used in persons with diseases affecting the bone marrow, like leukaemia, aplastic anemia, and some lymphomas. The basic idea here is to replace the unhealthy marrow with healthy marrow.

Sometimes a disease like leukemia interferes with stem cell growth, causing cells to stop developing or to become defective, or, in some cases, both. Eventually these immature blood cells enter the bloodstream causing the affected person to become seriously ill. A bone marrow transplant offers the gift of like to patients whose marrow is diseased. The transplant is the transfer of healty marrow from a donor to the patient. The key factor is that the healthy marrow contains healthy stem cells.

Sometimes a patient can give his own marrow back to himself. This is called an autologous BMT. It is often hard to understand how a sick person could be their own donor and be healthy again. The autologous transplant (or rescue as it is often known) isn't necessarily performed because there's something wrong with the bone marrow or the stem cell production. It is preformed because the dosage of chemotherapy and radiation needed to kill the cancer is so high it will destroy the patients existing bone marrow. Without this marrow there is no immune system and the patient willl eventually die. Instead, the patients own marrow, collected (harvested) prior to chemo and radiation, is reinjected and the immune system is reestablished. Meanwhile, the hope is that the cancer tumours and cells have been destroyed.

Bone marrow transplantation is a lot different from other types of organ transplants. For one thing, there is no surgery on the day of the proceedure. The new marrow doesn't have to be placed inside an incision or stitched into place. It is fed into the body intravenously, like a blood transfusion. Many patients and their familes find the actual day of the transplant a bit of an anticlimax. The patient receives the harvested stem cells through and IV and they find their way to the marrow space in the bones. If the transplant goes well, stem cells from the new marrow will begin producing life-sustaining blood cells. In the case of a bone marrow transplant, this takes two to four weeks. In a peripheral stem cell transplant, the stem cells will begin reproducing generally within two weeks.

Stem cells or bone marrow from a donor

In this type of transplant stem cells or bone marrow are donated by another person (a donor). Doctors call this an allogeneic transplant or an allograft. It is used as part of the treatment for cancers which are in the bone marrow, such as leukaemias and myeloma. It can also be used to treat some rare non-cancerous diseases of the bone marrow.

Treatment with chemotherapy is given to destroy the cells in your bone marrow. Afterwards bone marrow donated by someone else (a donor) is given to you. This means that you have a source of healthy bone marrow, which will also help you to recover from the effects of the high-dose treatment you have had. The most suitable donor is usually a brother or sister whose bone marrow is a close match to your own. Occasionally it is possible to use bone marrow or stem cells from an unrelated donor if tests have shown that his or her white blood cells are a good match with yours.

When stem cells or bone marrow from a donor are given into the body the donor cells can sometimes attack the cancer cells. The donor cells can also cause a reaction in the body known as graft-versus-host disease (GVHD).

An allogeneic transplant is a serious and complicated procedure. This intensive treatment is carried out in specialised transplant units in specialist hospitals.