TRANSPORT IN MAMMALS PART 7: ORGAN TRANSPLANT AND TISSUE REJECTION

Organ or tissue transplant is when a damaged or diseased organ or tissue is replaced by a healthy or functional one. This healthy or functional organ or tissue may come from another person or the patient himself.

PROBLEM:
If the healthy organ or tissue to be donated comes from another person (donor), the organ or tissue may be treated by the patient's (recipient's) immune system as foreign body. As a result the lymphocytes may respond to this transplanted organ or tissue by producing antibodies which destroy the transplanted tissue or organ. This results in TISSUE/ORGAN REJECTION.



Tissue or organ rejection may not be a problem if the tissue or organ to be transplanted comes from the patient himself. For example, a blocked coronary artery may be replaced by an artery form another part of the patient's body.

PREVENTION OF TISSUE REJECTION:

• Tissue match: the tissue of both the donor and recipient must be genetically as close as possible. Therefore the likely candidate should be the brother, sister, parents and close relatives of the patient.
• Using immuno-suppressive drugs: this drug inhibits the activity of the recipient's immune system. Problem: the patient is prone to many kind of infection and he has to continue treatment of this drug for the rest of his life.
• X-ray radiation of the bone marrow and lymphoid tissue: this method inhibits the production of blood cells which slows down the rejection process.