Alternate Names: Graft rejection; Tissue/organ rejection
Causes and Risks: The immune response protects the body from potentially harmful substances ("antigens") such as microorganisms, toxins, and cancer cells. The immune system distinguishes "self" from "foreign" and reacts against substances it recognizes as foreign. The presence of foreign blood or tissue in the body triggers an immune response that results in blood transfusion reactions and transplant rejection.
Blood and tissue contain identifying proteins on the surface that aid in distinguishing "self" from "foreign" tissues. These proteins can act as antigens that trigger the immune response, and antibodies are formed against foreign antigens. Tissue is "typed" according to the antigens it contains (Histocompatibility antigens).
No two people (except identical twins) have identical tissue antigens. Therefore, organ and tissue transplantation almost always causes an immune response against the foreign tissue (rejection), which results in destruction of the transplant. "Tissue typing" ensures that the organ or tissue is as similar as possible to the tissues of the receiving person. This is performed because greater antigen difference causes more rapid and severe rejection.
A few exceptions occur. Corneal transplants are rarely rejected because they have no blood supply, so lymphocytes and antibodies do not reach the cornea to cause rejection. Identical twins have identical tissue antigens, so transplantation between identical twins almost never causes rejection.
Prevention: ABO (blood group) and HLA (tissue antigen) typing before transplantation ensures a close antigenic match.
Suppression of the immune system is usually necessary for the rest of the transplant recipient’s life to prevent rejection.
Symptoms:
- reduced organ function
- pain in the location of the organ
- fever
- general discomfort, uneasiness, or ill feeling (malaise)
Note: Symptoms vary with the specific organ or tissue.
Signs and Tests: There may be tenderness on palpation over the organ (particularly the kidneys). Signs of reduced organ function are often present. A biopsy of transplanted organs confirms rejection. Routine biopsy is often performed to detect rejection early, before symptoms develop. An X-ray, CT scan, or other procedure may indicate inflammation, swelling, or reduced organ function.
Tests that may be performed related to this disorder include:
Treatment: The goal of treatment is to maintain the integrity and functioning of the transplanted organ or tissue.
Suppression of the immune response is used for both treatment and prevention of transplant rejection. Corticosteroids such as prednisone are used to reduce the immune response. The dosage may be very high during treatment of acute rejection episodes and then reduced to a lower "maintenance" dose to prevent rejection. Immunosuppressant medications include azathioprine and cyclosporine. Monoclonal antibodies specifically reduce the activity of T lymphocytes, which are the primary immune system cells responsible for transplant rejection. Occasionally, radiation is used to suppress the immune system.
Prognosis: The outcome varies. Some organs and tissues are more successfully transplanted than others. Rejection may be reversed with treatment or may progress despite treatment. Immunosuppression must continue for the rest of the person’s life.
Complications:
- loss of function of the transplanted organ/tissue
- side effects of medications, may be severe (see the specific medication)
Call your health care provider if transplanted organ or tissue shows reduced function, or other symptoms of transplant rejection occur. Also, call your health care provider if medication side effects develop.
