Health And Wellness Center: Bone marrow transplant

A bone marrow transplant involves the administration of a small fraction of precursors

What is a bone marrow transplant?

A bone marrow transplant involves administering to the patient suffering from a small fraction of precursors or progenitors of normal blood in order to restore blood formation (hematopoiesis) eliminated by the effect of previously administered drugs or ionizing radiation. This is therefore fully reconstitute the hematopoietic or blood-forming system of the body, injecting some cells with multiple capabilities called stem cells (stem cells English) present in normal bone marrow.

Ultimately, the goal of a hematopoietic transplant, which is the medical term, is the elimination of the underlying disease in the patient with full restoration of their hemopoietic functions (or blood-forming) and immune (or defense) of agency.

Main types of transplant

1. According to the relationship between the donor and the recipient we differentiate between:

Autologous transplantation: when the patient acts as his own source of stem cells.

syngeneic transplantation: when there is a complete genetic identity between donor and recipient, ie, when transplantation is performed between monozygotic twins. It is the most common and one can easily understand situation.

Allogeneic transplantation: when between the donor and recipient are genetic differences. The donor is usually a sibling of the patient, but may be an unrelated donor (usually volunteers included in international registrations). It is important to note that a person has only about one-third as likely to have a compatible donor among relatives.

2. According to the origin of stem cells:

Originally stem cells obtained from bone marrow by direct puncture and aspiration of bone marrow or marrow, which was then injected to the patient vein. Recently, it has been found that in normal blood stem cells are also, though less than in bone marrow. Therefore, today stem cells are obtained from peripheral blood, prior administration of substances or stimulating factors that mobilized by passing from bone marrow into the blood, where they are captured by a machine that separates them. Finally, it is also possible to obtain stem from umbilical cord blood and placental cells.

Who can benefit from this type of transplant?

Bone marrow transplantation is an effective treatment for an increasing number of diseases. Today there are many patients who can benefit from these techniques.

Current indications transplantation of blood-forming stem cells are multiple:

Malignant tumors of the blood, such as different types of leukemia, multiple myeloma, non-Hodgkin lymphoma, Hodgkin's disease.
Acquired disorders of hematopoiesis, such as severe aplastic anemia and paroxysmal nocturnal hemoglobinuria the.
Immunodeficiencies.
Congenital blood disorders such as thalassemia or Fanconi anemia.
Other congenital disease, severe and rare metabolism, such as mucopolysaccharidosis or Gaucher disease.
Solid tumors requiring intensive cancer treatment.

In allogeneic transplants (where the donor and recipient have genetic differences) potential recipients should otherwise be healthy and preferably with less than 55 years old. Given the possible complications that may arise, will require the donor and recipient have an HLA (Human Leukocyte Antigens or human leukocyte antigens, a sort of "ID" of cells of each individual) as compatible as possible. This limitation restricts the availability of potential donors, a brother being the one that most likely will have to present a compatible HLA system.

In autologous transplants much less immune disorders that allogeneic transplants because the donor and recipient are the same person occur.

How transplant performed?

First phase: obtaining cells

Stem cells are obtained bone marrow with the donor under general anesthesia by multiple bone punctures in the iliac crests of the pelvis bone. about 1 liter of medullary blood, the recipient patient through a central venous catheter is injected is obtained. The procedure is well tolerated and requires only painkillers after surgery. Major complications are rare.

Obtaining stem cells from the peripheral blood is performed in a less harmful or aggressive to the donor through a simple puncture in the veins of the forearms (like when we go to get an extraction for a blood test). Donor blood then flows through a machine that separates different types of blood cells. Stem cells are deposited in a bag transfundirlas the sick, and the donor will return the remaining blood elements. Thus stem cells twice that obtained with the procedure of bone marrow aspiration. This technique does not require anesthesia, hospitalization is shorter and is cheaper, so that, at present, has almost completely replaced the bone marrow puncture.

Second phase: transplant

In allogeneic transplantation, the recipient is treated with high doses of chemotherapy and / or radiotherapy to remove and condition your bone marrow. One day after completing this treatment the transplant is performed, infusing through a vein stem cells from the donor. After a period of suppression (aplasia) of the bone marrow, which lasts from 1 to 3 weeks hemopoietic system restoration occurs, although it may not be complete for several months.

In autologous transplantation, the recipient (ie the patient) it is performed collecting bone marrow stem cells or peripheral blood while the disease is in remission, ie inactive. Such cells are processed and frozen in liquid nitrogen. It is then prepares and a day after conditioning the patient is injected with the hematopoietic precursors.

Complications of bone marrow transplantation.

Complications of hematopoietic stem cell transplantation due to the side effects of suppressive therapy conditioning bone marrow and immune disorders due to genetic differences between donor and recipient.

Common complications:

alopecia or hair loss
general tiredness
inflammation of mucous different
produced by different types of germs and infections
a characteristic disease called chronic graft-versus-host (only in allogeneic transplants) characterized in the acute phase, skin disorders, abdominal pain with profuse diarrhea and jaundice or yellowing of the skin involvement liver. In the chronic phase multiple alterations of different organs appear.

Late complications of transplantation (among others):

sterility
hypothyroidism
sepsis or spread of infections
waterfalls
other psychological disorders.

Both types of transplants are associated with high occurrence of other diseases or complications, and involve high mortality rates:

for autologous transplant recipients mortality is estimated 5% to 20%
if brothers in allogeneic transplantation, 20% to 30%
in allogeneic transplants volunteers, mortality can be up to 45%.

Monitoring and surveillance of these patients

Unlike recipients of solid organ transplantation, recipients of hematopoietic transplants do not require immunosuppression (ie, have their immune system suppressed or depressed defense) long, and the drug is usually given for this purpose, cyclosporin a, may be interrupted after about 6 months after transplantation.

regular monitoring of the patient with regular blood tests is necessary and it becomes necessary psychological support plan by the medical team that performed the transplant, family and friends for a normal adjustment to everyday life. Occasionally it may be necessary counseling and psychiatric treatment.

Despite the many possible complications, most transplant patients return to work and to an active life without continuation treatment. Looking to the future, which is already being present, gene therapy in cancer treatment is seen as a technique to solve many medical problems today are untreatable.