Organ Donation

Organ donation is the act of physically removing an organ or a tissue from donor and placing it into the recipient. The organs that can be transplanted are many including heart, intestine, kidney, liver, skin and bone marrow amongst others.

A new organ can be required in case one fails or is affected by a disease. For example, if someone has a fatal liver problem, a transplanted liver can save their life. Before an organ can be transplanted inside a recipient, a long process of organ matching takes place: the donor and the recipient’s blood types are matched, the process of tissue typing takes place and the donors are selected. The donor and the recipient must share the same blood group because otherwise, the recipient’s antibodies in the blood will react against by attacking the antibodies on the introduced blood. The tissues also need to be the closest match possible in order to diminish the chances of rejection.

There aren’t two people on this planet, apart from identical twins, that share exactly the same types of tissues. Tissue typing is a group of procedures to determine the histocompatibility antigens (molecules found on all the cells of the body, each person has a unique set of them) on a person’s cells or tissues. Human Lymphocyte Antigens (HLA) are the most used antigens for histocompatibility. They are grouped in two classes: Class I are found on all cells, Class II are found only on B- lymphocytes, macrophages, monocytes, dendritic cells and endothelial cells. The process of typing is performed on blood samples, easily withdrawn from a vein. Specific antibodies in the blood sample will react to specific antigens. Specific antibody preparations bind to specific histocompatibility antigens. There are specific laboratory instruments used to detect specific antibodies binding to cells. Class II antigens can be discovered by the mixed lymphocyte reaction (MLR) or the polymerase chain reaction (PCR). In the first one, lymphocyte duplication happens when there is a mismatch and it can be detected by a specific assay. The second one is a DNA test that can determine the presence or absence of antigens by looking whether there are genes for the antigens. Tissue typing reduces greatly the chances of rejection by the immune system of the recipient, even though he/she will have to take immunosuppressant drugs, which reduce the strength of the immune system, for the rest of his/her life.

The donors are selected based on their age, habits and medical history. They must be 25 or over, they must be tobacco-free for at least 4 weeks prior to donation, they must comply with requests of drug screenings and they must be healthy individuals (people with heart diseases, diabetes, lung problems and cancer cannot donate organs).