CBSE Class 12-science Answered
When an organ, such as a liver, a heart or a kidney, is transplanted from one person (the donor) into another (the recipient), the immune system of the recipient treats this organ as non-self or foreign and triggers an immune reaction, setting off a chain of events that can damage the transplanted organ. This process is called rejection and it can occur rapidly (acute rejection), or over a long period of time (chronic rejection).
Immunosuppressant drugs greatly decrease the risks of rejection, protecting the new organ and preserving its function. These drugs act by blocking the immune system so that it is less likely to react against the transplanted organ.
Immunosuppressant drugs can be classified according to their specific molecular mode of action. Cyclosporins, which act by inhibiting T-cell activation, thus preventing T-cells from attacking the transplanted organ, azathioprines which disrupt the synthesis of DNA and RNA and cell division and corticosteroids which suppress the inflammation associated with transplant rejection.
Immunosuppressants can also be classified depending on the specific organ transplant.
- For example, basiliximab (Simulect) is also used in combination with such other drugs as cyclosporin and corticosteroids, in kidney transplants.
- Daclizumab (Zenapax) is also used in combination with such other drugs as cyclosporin and corticosteroids, in kidney transplants.
- Muromonab CD3 (Orthoclone OKT3) is used, along with cyclosporin, in kidney, liver and heart transplants.
- Tacrolimus (Prograf) is used in liver transplants and is under study for kidney, bone marrow, heart, pancreas, pancreatic island cell, and small bowel transplantation.