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How do immunosuppressant drugs help prevent organ transplant rejection?
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transplant
British surgeon Andrew Ready flushing a donated kidney during a transplant at Queen Elizabeth Hospital, Birmingham, England, 2006.
Immunosuppressant drugs prevent organ transplant rejection by inhibiting the immune system, specifically targeting the mechanisms that identify and destroy foreign tissue.12
Transplant rejection is primarily driven by T lymphocytes, which recognize antigens on the donor organ as "nonself" and initiate a cell-mediated attack. Immunosuppressants work through several key pathways:3
- Calcineurin Inhibitors: Drugs like cyclosporine and tacrolimus block intracellular signaling pathways in T cells, effectively preventing them from activating and attacking the graft.1
- Antiproliferative and Antimetabolic Agents: Medications such as sirolimus and mycophenolate mofetil inhibit the activation, proliferation, or DNA synthesis required for T cell function.1
- Antibody Therapies: Various monoclonal and polyclonal antibodies target specific proteins or receptors on the surface of T cells to neutralize their activity.1
By suppressing these immune responses, the drugs allow the recipient's body to accept the transplanted organ. Over time, some patients may achieve a state of adaptation toward the graft, potentially allowing for a reduction in medication dosage.124