Organ rejection

Organ Rejection

Organ rejection (pronunciation: /ˈɔːrɡən rɪˈdʒɛkʃən/) is a complex biological process that occurs when the immune system of a transplant recipient identifies the transplanted organ as foreign and attempts to eliminate it.

Etymology

The term "organ rejection" is derived from the English words "organ", referring to a part of the body that performs a specific function, and "rejection", which means to refuse to accept, consider, submit to, take for some purpose, or use.

Types of Organ Rejection

There are three main types of organ rejection: hyperacute rejection, acute rejection, and chronic rejection.

• Hyperacute rejection occurs within minutes to hours after transplantation. It is caused by pre-existing antibodies in the recipient's blood that react with antigens in the donor organ.

• Acute rejection typically occurs within days to weeks after transplantation. It is caused by the recipient's immune system recognizing the donor organ as foreign and attacking it.

• Chronic rejection occurs over months to years and is characterized by gradual loss of organ function. The exact cause is not well understood, but it is thought to involve both immune and non-immune factors.

Related Terms

• Immunosuppression is the medical suppression of the immune system to prevent organ rejection.

• Graft-versus-host disease (GVHD) is a complication that can occur after a bone marrow or stem cell transplant, where the donated cells attack the recipient's body.

• Transplant tolerance is the state in which a recipient's immune system does not react against the transplanted organ.

• Allograft is a transplant of an organ or tissue from one individual to another of the same species with different genotype.

See Also

• Transplantation
• Immunology
• Histocompatibility

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