Rejection

Definition

Rejection is the immune system's response to a foreign object or tissue, such as a transplanted organ, that is recognized as non-self and triggers an attack to eliminate it. This is a critical concept in the context of organ transplantation and the body's defense mechanisms.

5 Must Know Facts For Your Next Test

1. Rejection is the primary complication and leading cause of failure in organ transplantation procedures.
2. The immune system recognizes the transplanted organ as foreign and mounts an attack, known as an acute rejection response.
3. Acute rejection typically occurs within the first few weeks or months after a transplant and can be life-threatening if not properly managed.
4. Chronic rejection is a gradual, long-term process that can occur months or years after a transplant, leading to gradual organ dysfunction.
5. Immunosuppressive drugs are crucial in preventing and managing rejection by suppressing the immune system's response to the transplanted organ.

Review Questions

• Explain the role of the immune system in the rejection of a transplanted organ.
  • The immune system plays a central role in the rejection of a transplanted organ. When a foreign organ is introduced into the body, the immune system recognizes it as non-self and mounts an attack against it. This is because the transplanted organ contains different antigens, or molecules on the surface of its cells, that the body's immune cells identify as foreign. The immune system then activates a series of responses, including the production of antibodies and the recruitment of immune cells, to try to eliminate the perceived threat posed by the transplanted organ. This immune response is known as rejection and can lead to the failure and rejection of the transplanted organ if not properly managed through the use of immunosuppressive drugs.
• Describe the different types of rejection that can occur in organ transplantation and their characteristics.
  • There are two main types of rejection that can occur in organ transplantation: acute rejection and chronic rejection. Acute rejection typically occurs within the first few weeks or months after a transplant and is characterized by a rapid, aggressive immune response against the transplanted organ. This can be life-threatening if not properly managed. Chronic rejection, on the other hand, is a gradual, long-term process that can develop months or years after the transplant. In chronic rejection, the immune system's ongoing attack on the transplanted organ leads to gradual dysfunction and deterioration of the organ over time. Recognizing and differentiating between these two types of rejection is crucial for healthcare providers to implement appropriate treatment strategies and prevent the ultimate failure of the transplanted organ.
• Evaluate the importance of immunosuppressive drugs in the management of organ transplant rejection and discuss their potential limitations.
  • Immunosuppressive drugs are essential for the successful management of organ transplant rejection. These medications work by suppressing or weakening the immune system's response to the transplanted organ, preventing the body from mounting an attack and rejecting the foreign tissue. Without the use of immunosuppressive drugs, the likelihood of organ rejection and transplant failure would be significantly higher. However, the use of these drugs is not without its limitations. Prolonged use of immunosuppressants can lead to an increased risk of infections, cancer, and other side effects, as the weakened immune system is less able to defend against these threats. Additionally, some patients may develop resistance or intolerance to certain immunosuppressive medications, requiring the use of alternative drugs or dosing regimens. Careful monitoring and management of these medications by healthcare providers is crucial to balance the benefits of preventing rejection with the potential risks associated with immunosuppression.

Related terms

Immune Response: The body's defense system that recognizes and responds to foreign substances or pathogens to protect against infection and disease.

Antigens: Molecules on the surface of cells that the immune system identifies as foreign or non-self, triggering an immune response.

Immunosuppression: The process of suppressing or weakening the immune system, often used to prevent rejection of a transplanted organ.