Antibody-mediated rejection (AMR) after kidney transplant

What is antibody-mediated rejection (AMR)

After your kidney transplant, there's a chance your immune system, your body's defense system, will try to attack your new kidney. Antibody-mediated rejection (AMR) is a type of kidney transplant rejection. It happens when your immune system makes antibodies that attack your new kidney. Antibodies are a type of protein in your blood that help your immune system fight infections. Instead of just fighting off germs, these proteins see the kidney as "foreign" and start attacking it, even though it's there to help you. AMR is a serious transplant complication and one of the leading causes of kidney transplant failure.

There are three types of AMR:

1. Hyperacute rejection: happens right after surgery  
2. Active AMR: happens when antibodies actively attack the kidney, which can lead to sudden kidney problems
3. Chronic active AMR: develops slowly, lowering kidney function over time

People who have AMR are at a higher risk for rejection episodes and may even lose their new kidney if it is not treated.  

What causes AMR?

AMR happens when your immune system makes antibodies that see your new kidney as "foreign" and try to attack it. The main cause is donor-specific antibodies (DSA), which are antibodies that target your donor's kidney. Not everyone with DSA develops rejection, but having these antibodies can raise your risk.  

Some things can raise your risk for AMR, such as having a previous transplant or getting blood transfusions. These things can expose your immune system to proteins from someone else's body. Your immune system may make antibodies against those proteins, and the antibodies can stay in your blood and attack your kidney. AMR can happen soon after a transplant, or even many years later. That is why regular follow-up and monitoring with your health care team are important to keep your new kidney healthy.  

What are the symptoms of AMR?

Antibody-mediated rejection (AMR) does not always cause noticeable symptoms at first. Some people feel fine while the rejection is happening, which is why regular follow-up tests are so important. When symptoms do appear, they can signal changes in how your kidney is working and may need quick medical attention. Possible signs and symptoms may include:

• Urinating (peeing) less than usual
• Foamy pee
• Swelling in your legs, feet or hands
• Pain over the new kidney
• Feeling very tired (fatigue)
• High blood pressure, or hypertension

Severe forms can also cause an increase in creatinine, a waste product in your blood and fluid buildup. This can cause shortness of breath, cough or fever. 

How do doctors treat AMR?

Depending on your needs, your doctor and health care team may use several different treatments to lower harmful antibodies and calm your immune response to protect your new kidney from further damage. There are no FDA-approved treatments for AMR. If the rejection persists and the kidney function doesn't improve, you may need to start on dialysis or be re-evaluated for another transplant. Work with your doctor and care team to develop a treatment plan that works for you.  

How can I protect my kidney transplant?

You can take steps to protect your kidneys, lower your risk of rejection and keep your kidney working well for as long as possible. Staying connected with your health care team, taking your medicines as prescribed and practicing healthy habits can all play a role in keeping your kidneys healthy.  

• Take your medicines exactly as your doctor tells you. Missing doses can lead to rejection.
• Keep up with follow-up doctor visits and necessary blood work to monitor your health and find any changes early.
• Ask your doctor and care team about donor-specific antibody testing before and after transplant.
• Ask your care team about cell-free DNA testing post-transplant for surveillance of your kidney health.
• Follow a kidney-friendly eating plan. You can ask your doctor to refer you to a dietitian who can help you make a healthy eating plan that will work for you and your new kidney.
• Stay active on most days of the week. Talk to your doctor about what exercises and types of physical activity are safe for you.
• Avoid any medicines or supplements unless approved by your doctor or transplant team.

If you are taking immunosuppressant medicines that prevent your body from rejecting your kidney transplant, you may be at a higher risk for infections.

You can help avoid infections by:

• Washing your hands often
• Avoid being around people who you know are sick
• Covering your mouth and nose when sneezing or coughing
• Following food safety practices, such as cooking meat to the correct temperature and storing food properly.

If you're waiting for a kidney transplant, consider kidney paired donation programs which make kidney transplant an option for people who have a family member or friend who is willing to donate a kidney but is not a match for them. 
 

Mental and emotional health

Hearing that your body may be rejecting your new kidney can be stressful and scary. Remember that you are not alone. With regular monitoring, treatment and support, many people continue to live healthy lives after AMR. Talk to a mental health professional who can give you tools and resources to manage anxiety, fear or depression.  Consider joining a support group for transplant patients who understand what you're going through.

Learn more about managing your mental health  

Clinical trials and research

Since there are no FDA-approved treatments for AMR, researchers are studying new treatments in clinical trials, a type of medical research or study that involves people. Joining a clinical trial helps advance care for future transplant patients.

If you're interested or want to learn more, ask your doctor:

• Am I eligible for a clinical trial?
• What are the risks and benefits?
• How can I find a clinical trial near me?

Learn more about clinical trials