Organ Transplantation
Organ transplantation is the transfer of an organ from the body of the donor to the body of the recipient. This occurs as the recipients organs may fail to function and require a replacement from a donor in order to sustain life. The recipient requires a transplant due to being born with a structural abnormality of an organ, born with a disease that causes an organ to fail or develop a disease that caused an organ to fail.
Organs and Tissues able to be Transplanted
Organs and Tissues able to be Transplanted
- Hear
- Heart Valves
- Liver
- Lungs
- Kidney
- Pancreas
- Intestines
- Cornea
- Skin
- Bones
- Bone Marrow
- Connective Tissue
All cells have MHC markers, known as major histocompatibility complex, that are marker proteins located on the surface of cells. As they are genetically composed from the individual, it is said these MHC markers are unique allowing the immune system to identify them as self. MHC markers are used to identify whether a cells is self or non-self. These markers allow the body to recognise non-self cells triggering a response to attacked them. In order for an organ transplant to occur, tissue typing must be completed by both a donor and recipient prior to organ transplants. Tissue typing is used to see if a donor and recipient have similar MHC markers. This is important as the better matched the MHC markers are, the less chance of rejection of the organs.
Organ Rejection
It is common for an organ transplant to be rejected by the body of the recipient. This is due to all mammalian cells having a MHC which is a group of proteins that act as an antigen on their surface which are unique to that individual. When tissues are transplanted these markers cause them to be identified as non-self and T cells and macrophages attack them. If a donor organ is transplanted into a recipient, T Cells will recognise the organ tissue as being foreign and present the antigen to B Cells. The complimentary B Cell binds to the antigen, begins to replicate rapidly into B Plasma Cells and B Memory Cells. B Plasma Cells release antibodies which targets the antigen so that the foreign cells are attacked. As the antigens are being attacked, this can cause the donor organ to be affected. As the cells of the organ have been recognised as foreign they are attacked which results in the organ not fulfilling its function. This is known as organ rejection.
Immunosuppressive drugs are drugs that prevent T Cells from directly attacking the antigen and therefore not presenting the antigen to B cells. These drugs must be taken by the recipient for the rest of their live to ensure that the T cells do not attack the cells of the donor organ, therefore preventing organ rejection. As immunosuppressive drugs act directly against T Cells, this decreases the overall function of the immune system, increasing chances of the body being exposed to infections or diseases. If the drug is not taken regularly then the immune system is no longer supressed and increases defence mechanisms, but this means that organs cells will be attacked as they are non-self and foreign to the body.
It is common for an organ transplant to be rejected by the body of the recipient. This is due to all mammalian cells having a MHC which is a group of proteins that act as an antigen on their surface which are unique to that individual. When tissues are transplanted these markers cause them to be identified as non-self and T cells and macrophages attack them. If a donor organ is transplanted into a recipient, T Cells will recognise the organ tissue as being foreign and present the antigen to B Cells. The complimentary B Cell binds to the antigen, begins to replicate rapidly into B Plasma Cells and B Memory Cells. B Plasma Cells release antibodies which targets the antigen so that the foreign cells are attacked. As the antigens are being attacked, this can cause the donor organ to be affected. As the cells of the organ have been recognised as foreign they are attacked which results in the organ not fulfilling its function. This is known as organ rejection.
Immunosuppressive drugs are drugs that prevent T Cells from directly attacking the antigen and therefore not presenting the antigen to B cells. These drugs must be taken by the recipient for the rest of their live to ensure that the T cells do not attack the cells of the donor organ, therefore preventing organ rejection. As immunosuppressive drugs act directly against T Cells, this decreases the overall function of the immune system, increasing chances of the body being exposed to infections or diseases. If the drug is not taken regularly then the immune system is no longer supressed and increases defence mechanisms, but this means that organs cells will be attacked as they are non-self and foreign to the body.