hylkäämisreaktiona

Hylkäämisreaktio, known in English as rejection reaction, refers to a complex biological process that occurs when a recipient's immune system identifies a transplanted organ or tissue as foreign and mounts an attack against it. This immune response is a natural defense mechanism designed to protect the body from invaders, but it unfortunately complicates organ transplantation.

There are several types of rejection reactions, categorized by their timing and underlying mechanisms. Hyperacute rejection happens very rapidly, within minutes to hours after transplantation, and is usually caused by pre-existing antibodies in the recipient's blood that immediately attack the blood vessels of the graft. Acute rejection typically occurs within days to weeks or months and involves the recipient's T-cells and antibodies actively targeting the transplanted organ. Chronic rejection is a slower process that can develop over months or years, leading to gradual damage and eventual failure of the transplanted organ, often due to ongoing low-level immune responses and non-immune factors.

To prevent or manage rejection reactions, transplant recipients are usually prescribed immunosuppressant medications. These drugs work by suppressing the immune system, making it less likely to attack the foreign organ. However, these medications must be taken lifelong and can have side effects, increasing the risk of infections and other health problems. Careful monitoring of the recipient's immune status and the function of the transplanted organ is crucial throughout the post-transplant period.