The CANCER MAGAZINE
Bone marrow transplant: a consolidation therapy for blood cancers
When the manufacture of blood cells is altered by cancer, it is sometimes essential to perform a bone marrow transplant. Most often, the transplant is done from an unknown voluntary donor. It significantly increases the chances of healing.
Every year, nearly two thousand people, children and adults, with serious blood illnesses, sometimes deadly, need to be treated with a bone marrow transplant. "This gelatinous body contained in the bones plays a crucial role," recalls Professor Ibrahim Yabes-Agha, president of the French Society of Marrow Transplant and cell therapy (SFGM-TC). It is the real factory that manufactures blood: red blood cells, which carry oxygen; White blood cells, which fight against infections; and platelets, which allow wounds to heal. The bone marrow can be affected by different diseases: insufficient or too abundant cell manufacturing; Production of sick cells... It is mainly blood cancers that require the use of bone marrow transplant. The most famous blood cancer remains leukemia. It is better to speak more of leukemias in the plural, because there are different types, with various characteristics and prognosis. Leukemias in their acute form affect about five thousand people each year, mostly children and older people. They are characterized by an abnormally high number of white blood cells. We are witnessing a proliferation of cells that divide continuously before they reach maturity. The patient is weakened and his immune system no longer works: He is therefore not protected from infection.
Other affected diseases
For acute leukemias, grafting is required quite often. The same is the same for myélodysplasies, which are precancer dysfunctions of the marrow. As for lymphomas, or lymph node cancers, they sometimes require the use of grafting, but only in case of relapse, never at first intention. Finally, myeloma, or bone marrow tumours, can sometimes be affected by the graft; But more often than not, chemotherapy alone makes it possible to overcome it.
The transplant: When?
The transplant is part of a therapeutic course. It is often proposed as a consolidation treatment to avoid relapse after one or more episodes of chemotherapy and stays in sterile room to prevent any infectious risk. The principle? "The donor's bone marrow takes the place of sick cells and colonizes the patient's marrow with healthy cells," explains Professor Ibrahim Yabes-Agha. The graft is in the form of a red liquid that contains the bone marrow of the donor, ponctionnée in the bones of the pelvis or taken in its blood by Cytaphérèse *. "A transplant from another person – or allograft – greatly increases the chances of healing," says Professor Ibrahim Yabes-Agha. There are 60% long-term remissions for certain acute graft-treated leukemias, compared to only 15% in the absence of grafting. But be careful, the risk of graft reaction against the receptor must be taken into account. It is therefore essential that the HLA (Human Leucocyt antipeople) systems of the donor and the recipient are as close as possible. HLA refers to the major system of recognition of foreign cells by the immune system. The most appropriate donor is a member of the sibling, since his or her biological profile is very close to that of the patient. But in 75% of cases, there are no siblings; Or siblings do not meet the criteria to give their marrow. It is then necessary to search for a compatible donor in the registry France Marrow Transplant (RFGM) or, failing that, in the registers of foreign countries. Today, in two or three months, the teams manage to find a compatible donor. Alternatives to classical allograft it is sometimes appropriate to use umbilical cord blood taken from licensed maternity wards; This is a specific form of allograft. In fact, placental blood cells have the peculiarity of multiplying rapidly and cause a lower risk of graft reaction against the recipient because of their immature character. But in return, they take longer to colonize the recipient's organism... The graft with cord blood is therefore an alternative solution when no donor is found in the family or in the registers. Another possibility: autograft, or autologous graft. In this case, the marrow is taken from the patient himself while his illness is in remission. It is frozen and then reinjected when the time comes. This therapy is recommended for the treatment of lymphoma and myeloma, but not for leukemias, with the bone marrow of the patient proving to be too altered to be used.
* See glossary below.
Who can give?
Candidates for bone marrow donation must meet three conditions:
• Be in perfect health, some pathologies representing contraindications to the donation of bone marrow: heart or respiratory ailments, high blood pressure, diabetes, some thyroid diseases;
• Be more than 18 years old and less than 51 years old when registering, even if you can then give up to the age of 60 years;
• Agree to respond to a health questionnaire and make a blood sample to determine the donor's biological identity card (HLA typing).
Glossary
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