rejection

medicine

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Last updated

July 13, 2026

Quick Summary

Transplant rejection occurs when the recipient's immune system attacks a transplanted organ or tissue, viewing it as foreign. This is primarily driven by T lymphocytes, which identify and destroy non-self cells based on surface molecules called antigens, specifically human leukocyte antigens (HLA). While cell-mediated responses cause rejection over time, pre-existing antibodies can lead to rapid rejection. To prevent this, immunosuppressant drugs are used, which inhibit the immune response. Corticosteroids are crucial, though they increase susceptibility to infection. Careful tissue typing to match donor and recipient antigens is vital for successful transplantation.

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transplant
Rejection
Humans possess complex defense mechanisms against bacteria, viruses, and other foreign materials that enter the body. These mechanisms, which collectively make up the immune system, cannot, unfortunately, differentiate between disease-causing microorganisms and the cells of a lifesaving transplant. Both are perceived as foreign, and…
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Humans possess complex defense mechanisms against bacteria, viruses, and other foreign materials that enter the body. These mechanisms, which collectively make up the immune system, cannot, unfortunately, differentiate between disease-causing microorganisms and the cells of a lifesaving transplant. Both are perceived as foreign, and…
Read More

heart transplant
…adequate therapy to combat immune rejection of the transplanted heart led most surgeons to abandon the procedure after the initial attempts. Barnard, Shumway, and some others, however, continued to perform heart transplants, and in the 1970s cyclosporine, a compound isolated from an earth fungus, was discovered to be a very…
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…adequate therapy to combat immune rejection of the transplanted heart led most surgeons to abandon the procedure after the initial attempts. Barnard, Shumway, and some others, however, continued to perform heart transplants, and in the 1970s cyclosporine, a compound isolated from an earth fungus, was discovered to be a very…
Read More

kidney transplant
…developed to help counteract the rejection of the new organ by the body’s immune system. Because a kidney from a related donor is less likely to be rejected by the body, transplants from living relatives are more successful than those from cadavers. Nevertheless, cadavers are common sources for transplants because…
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…developed to help counteract the rejection of the new organ by the body’s immune system. Because a kidney from a related donor is less likely to be rejected by the body, transplants from living relatives are more successful than those from cadavers. Nevertheless, cadavers are common sources for transplants because…
Read More

rapamycin
…in the prevention of transplant rejection. Rapamycin is produced by the soil bacterium Streptomyces hygroscopicus. The drug’s name comes from Rapa Nui, the indigenous name of Easter Island, where the compound was originally discovered in soil samples in the 1970s.
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…in the prevention of transplant rejection. Rapamycin is produced by the soil bacterium Streptomyces hygroscopicus. The drug’s name comes from Rapa Nui, the indigenous name of Easter Island, where the compound was originally discovered in soil samples in the 1970s.
Read More