Transplant rejection

Definition

Transplant rejection is a process in which a transplant recipient's immune system attacks the transplanted organ or tissue. See also: Graft-versus-host disease

Alternative Names

Graft rejection; Tissue/organ rejection

Causes

Your body's immune system usually protects you from substances that may be harmful, such as germs, poisons, and cancer cells.

These harmful substances have proteins called antigens on their surfaces. As soon as these antigens enter the body, the immune system recognizes them as foreign and attacks them.

In the same way, an organ that is not matched can trigger a blood transfusion reaction or transplant rejection. To help prevent this reaction, doctors "type" both the organ donor and the person who is receiving the organ. The more similar the antigens are between the donor and recipient, the less likely that the organ will be rejected.

Tissue typing ensures that the organ or tissue is as similar as possible to the tissues of the recipient, but the match is usually not perfect. No two people (except identical twins) have identical tissue antigens.

Doctors use a variety of drugs to suppress the immune system and prevent it from attacking the newly transplanted organ when the organ is not closely matched. If these drugs are not used, the body will almost always launch an immune response and destroy the foreign tissue.

There are some exceptions, however. Cornea transplants are rarely rejected because the cornea has no blood supply. Immune cells and antibodies are not able to reach the cornea to cause rejection. In addition, transplants from one identical twin to another are almost never rejected.

There are three types of rejection:

• Hyperacute rejection occurs a few minutes after the transplant, if the antigens are completely unmatched. The tissue must be removed right away so the recipient does not die. This type of rejection is seen when a recipient is given the wrong type of blood.
• Acute rejection may occur any time from the first week after the transplant to 3 months afterward. Everyone has some amount of acute rejection.
• Chronic rejection takes place over many years. The body's constant immune response against the new organ slowly damages the transplanted tissues or organ.

Symptoms

• The organ's function may start to decrease
• General discomfort, uneasiness, or ill feeling
• Pain or swelling in the area of the organ (rare)
• Fever (rare)
• Flu-like symptoms, including chills, body aches, nausea, cough, and shortness of breath

The symptoms depend on the transplanted organ or tissue. For example, patients who reject a kidney may have less urine, and patients who reject a heart may have symptoms of heart failure.

Exams and Tests

The doctor will examine the area over and around the transplanted organ, which may feel tender to you (especially with a kidney transplant).

There are often signs that the organ isn't working properly, such as:

• High blood sugar (pancreas transplant)
• Less urine released (kidney transplant)
• Shortness of breath and less ability to exercise (heart transplant)
• Yellow skin color and easy bleeding (liver transplant)

A biopsy of the transplanted organ can confirm that it is being rejected. A routine biopsy is often performed to detect rejection early, before symptoms develop.

When organ rejection is suspected, one or more of the following tests may be done before the organ biopsy:

• Abdominal CT scan
• Chest x-ray
• Heart echocardiography
• Kidney arteriography
• Kidney ultrasound
• Lab tests of kidney or liver function

Treatment

The goal of treatment is to make sure the transplanted organ or tissue works properly, and to suppress your immune system response. Suppressing the immune response can prevent transplant rejection.

Many different drugs can be used to suppress the immune response. The medication dose depends on your condition. The dose may be very high while the tissue is being rejected. Then the dose may be lowered to prevent rejection from happening again.

Outlook (Prognosis)

Some organ and tissue transplants are more successful than others. If rejection begins, drugs that suppress the immune system may stop the rejection. Most people need to take these drugs for the rest of their life.

Even though potent drugs are used to suppress the immune system, organ transplants can still fail because of rejection.

Single episodes of acute rejection are easy to treat and rarely lead to organ failure.

Chronic rejection is the leading cause of organ transplant failure. The organ slowly loses its function and symptoms start to appear. This type of rejection cannot be effectively treated with medicines. Some people may need another transplant.

Possible Complications

• Certain cancers (in some people who take strong immune suppressing drugs for a long time)
• Infections (because the person's immune system is suppressed)
• Loss of function in the transplanted organ/tissue
• Side effects of medications, which may be severe

When to Contact a Medical Professional

Call your health care provider if the transplanted organ or tissue does not seem to be working properly or if other symptoms occur. Also, call your health care provider if medication side effects develop.

Prevention

ABO blood typing and HLA (tissue antigen) typing before a transplant helps to ensure a close match. You will usually need to take medicine to suppress your immune system for the rest of your life to prevent the tissue from being rejected.

Being careful about taking your post-transplant medications, and being closely watched by your doctor may help prevent rejection.

References

Eghtesad B, Miller CM, Fung JJ. Liver transplantation management. In: Carey WD, ed. Cleveland Clinic: Current Clinical Medicine. 2nd ed. Philadelphia, Pa: Saunders Elsevier; 2010.

Barry JM, Jordan ML, Conlin MJ. Renal transplantation. In: Wein AJ, ed. Campbell-Walsh Urology. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 40.

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