What is hyperacute rejection?

What is hyperacute rejection?

• A. Rejection that occurs within minutes to 48 hours of surgery due to pre-existing antibodies.
• B. Rejection that occurs 1 week to 6 months after transplant.
• C. Chronic inflammation and scarring that occurs over months or years.
• D. Graft attacks the host, recognizing host cells as foreign.

Answer: (A)

Hyperacute rejection is an immediate, antibody-mediated reaction to a transplanted graft. It occurs when the recipient already has antibodies against donor antigens (usually ABO or HLA). These pre-formed antibodies bind to the graft’s endothelium as soon as circulation starts, activate complement, and trigger rapid clotting and vascular injury, causing the graft to fail within minutes to about 48 hours. Prevention hinges on strict crossmatching and ABO/HLA compatibility before transplant. The other scenarios—rejection occurring days to weeks after with new immune responses, chronic rejection over months to years, or graft-versus-host disease in bone marrow transplants—reflect different processes and timeframes.

Hyperacute rejection is an immediate, antibody-mediated reaction to a transplanted graft. It occurs when the recipient already has antibodies against donor antigens (usually ABO or HLA). These pre-formed antibodies bind to the graft’s endothelium as soon as circulation starts, activate complement, and trigger rapid clotting and vascular injury, causing the graft to fail within minutes to about 48 hours. Prevention hinges on strict crossmatching and ABO/HLA compatibility before transplant. The other scenarios—rejection occurring days to weeks after with new immune responses, chronic rejection over months to years, or graft-versus-host disease in bone marrow transplants—reflect different processes and timeframes.