HLA: Human Leukocyte Antigen
These molecules are found on the cell membrane of the white blood cells. When they come in contact with another person’s immune system they are recognised as foreign and they trigger an immune response. We speak of HISTOCOMPATIBILITY and TISSUE TYPING. The HLA system is what causes transplant rejection.

Autologous:
When a patient uses his own stored stem cells for transplant.
These cells have 100% histocompatibility.

Allogenic:
When the patient receives stem cells from a donor.
Siblings have a ¼ chance of being a perfect match for each other.
However with cord blood, in contrast to bone marrow, we only need a 4/6 correlation when we perform HLA typing on the sample.

Hematopoeitic  stem cells:
These are the stem cells that replenish the bone marrow. They develop into red and white blood cells and platelets.

Mesenchymal stem cells:
Are also present in cord blood. They develop into different cell types such as nerve cells, cardiac muscle cells, pancreatic cells, liver cells, cartilage cells…These cells have the capability of repairing damaged tissues.

Regenerative medicine:
The use of stem cells to repair damaged tissues in the body and to create new tissues for transplant.

TNC: Total Nucleated Cell Count. This is the total number of White Blood Cells (leukocytes). The stem cells will be found with the white blood cells.

Viability:
The percentage of cells with an intact cell membrane.

Graft versus Host Disease:
GVHD is a complication of allogenic bone marrow transplants in which immune cells of the transplanted marrow  recognize the recipient as foreign and mount an immunologic attack. This is very uncommon with allogenic cord blood transplants and the most important advantage of cord blood over bone marrow.