What is rejection
Normally, our body’s defense mechanism or the immune system protects us against any foreign body such as viruses, bacteria etc. So when a kidney from the other person is transplanted, the body may recognize it as a foreign invader and therefore attack it to get rid of it. This is called as rejection. To prevent the body from rejecting the new kidney the patient is given immunosuppressants or anti-rejection drugs. These medications help to suppress the body’s natural immune response, so that it is not able to identify the new kidney as foreign.
I. Hyperacute rejection
Despite the use of immunosuppressants, one or more episodes of rejection often occur shortly after transplantation (hyperacute rejection). It is a rare condition and may occur within minutes or hours after the transplant. Graft (kidney) loss is irreversible. It is caused by a reaction initiated by the presence of preformed antibodies (formed as a result of previous blood transfusion, pregnancy or a transplant) against the donor HLA. It results in immediate and irreversible damage to the newly transplanted organ, which must be removed. However, this condition has become rare as now antibody screening tests are done prior to kidney transplant operation.
II. Acute rejection
Acute rejection is most likely to occur in first 3-6 months after the transplant. More than 50% of patients experience at least one episode. But this does not mean that the recipient will lose the kidney. Rejection can usually be stopped by increasing the dose of the immunosuppressant, changing the type, or using more than one immunosuppressant. Most of the patients respond well to treatment and 90% of episodes are reversed. However, some episodes can occur years later especially if the recipient does not take the immunosuppressant medications as prescribed by the doctor.
The following signs help to recognize an acute rejection episode:
- Weight gain greater that two pounds (approx. 1 kg) in one day or four pounds (approx. 2 kgs) in a week.
- Fever (100o F)lasting for more than 2 days. Fever is also indicative of infection.
- Decrease in urine output.
- Tenderness over the transplant site.
- Flu-like symptoms may include chills, aches in joints and muscles, or generalized sense of not feeling well.
- Additional signs includeincreased bloodpressure, pain or burning during urination, blood or odor in the urine, coughing or shortness of breath, nausea or vomiting, headache, irritability, weakness.
- Abnormal kidney function test such as increase in creatinine and BUN (Blood urea nitrogen) levels.
In most cases, rejection can be controlled if treated promptly. Therefore, it is imperative to contact your transplant team or doctor immediately if you experience any of these rejection symptoms. Rejection can be finally confirmed only by renal biopsy. Biopsies are performed at regular intervals after transplantation.
In some cases Cyclosporin (one of the immunosuppressants) may cause a decline in kidney function in a manner similar to rejection. This is called as Cyclosporin nephrotoxicity. In such cases rejection is confirmed by a kidney biopsy.
III. Chronic rejection
Chronic rejection usually occurs in transplanted kidneys which have already suffered early damage from acute rejection. It commonly starts an year after a transplant rejection and progresses slowly. There is a gradual and progressive rise in the creatinine levels in blood associated with proteinuria (excretion of protein in urine) and high blood pressure. Chronic rejection may also result from recurrent nephritis (inflammation of kidneys) or cyclosporin nephrotoxicity. The condition does not respond to increased immunosuppression.