What are the methods for stem cell transfer?

Allogenic transplantation
This is the transplantation, when deemed appropriate, of stem cells harvested from the patient’s siblings, relatives, or other people who are non-relatives.

Autologous transplantation
This is the transplantation of stem cells taken from the patient’s own for the treatment of some blood disorders. 

Syngeneic transplantation
This is the transplantation of stem cells taken from one of the monozygotic twins to the other.

How are stem cells collected?

Harvesting stem cells from the bone marrow

A blood count and blood values of the person is examined prior to harvest of bone marrow. Tests on the liver, kidney, and blood are carried out to be sure of the general health status.

Allogeneic bone marrow transplantation is performed in the operation theater. Special needles are used to puncture a point right on the top of the hip bone and all blood cells in the bone marrow are taken. This blood is equivalent to approximately one unit of blood, it is then sent to the laboratory for separation and purification of the stem cells. 

Stem cells are separated by the apheresis device. After a count is made and the percentage of live cells are determined, it is calculated whether there are enough number of cells for the person who will receive the transplantation. If it is suitable then a preparation is made for transfer. The bone marrow of the donor will begin production again.  

There are misconceptions regarding bone marrow transplantation that the donor will be harmed bu the procedure. Similar to those who avoid liver or kidney transplantation, there may be people who may not wish to donate bone marrow based on this wrong information. The procedure gives no harm to the donor. However, people under age 2 or above 60 are not accepted as donors for bone marrow. 

Stem cell harvest from the placenta

Since 1989, stem cells from the cord blood are being used with an increasing frequency. The placenta, formerly discarded and named as the couple of the baby in the public, is actually a rich source of stem cells.

Immediately after delivery of the baby, the obstetrician grasps the connection (cord) between the mother and the baby with a clamp. The baby is separated once the cord is clamped. In the meanwhile a cannula is inserted into the cord and blood is withdrawn from the placenta. In the meanwhile care is taken to massage the placenta and collect all the stem cells in the blood.

In the laboratory, the stem cells are isolated from the blood followed by tissue typing. The material is examined for its health and the presence of any contamination. It is stored if it is found to be appropriate. This is because in some conditions there may inadequate number of cells, microbiologic contamination, and clotting which all render the storage of stem cells unnecessary. The family is informed all about this. If it is found to be worth preservation and the family has approved it, the stem cells are stored.

Transplantation method of the future

α –β T CELL DEPLETED CELL TRANSPLANTATION

A very special method of transplantation performed in only a few centers throughout the world is the bone marrow – stem cell transplantation in which dangerous cells (α –β  T cell) are decreased. This transplantation is a candidate for completely solving the problem of finding a donor, and is the transplantation method of the future.   

In this method, dangerous cells and NK (natural killer) cells are isolated, while the blood stem cells are given to the patients in mega (very high) doses. The advantages of this method are:

  • Less lethal reactions (GVHD)
  • Effective fight against cancer
  • Shorter stay in the hospital

In this type of transplantation a 12/12 tissue match is not considered essential, and your mother, father, half matched sibling, or your child can be a donor for you even if you do not have a complete match.

ALO ACIBADEM
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Tuesday, February 20, 2018 10:58:46 AM