Risk of rejection

• Rejection happens when your body doesn't recognise and accept your new lungs as a part of you.
• You will be on lifelong immunosuppressant medication to stop your immune system from attacking the new lungs.
• There are three different types of rejection: acute, antibody, and chronic.

When one organ is replaced with a new one from another person, there is always a risk that your body won’t recognise and accept it as part of you. Instead, your body sees your new lung(s) as a foreign, something that didn’t come from you, and tries to fight it. This is called ‘rejection’. Rejection episodes are common and can happen any time after your transplant.

The normal role of your immune system is to protect your body from infection and foreign germs. It prevents germs entering the body and fights any that do get in. It is continuously working to keep us healthy.

Unfortunately the immune system cannot distinguish between good foreign and bad foreign lungs. The donor lung(s) have unique genetic markers on them that are recognised by your immune system as not belonging to your body. It sends out a message to recruit an army of cells to attack the new lung(s). These markers on the donor lungs will never change. Your immune system will never recognise the lung(s) as its own, and will continue to try attacking them forever.

There are three different types of rejection.

Acute rejection

Acute rejection happens in 30 to 50% of patients in their first year after transplant. Sometimes patients don't experience any symptoms, while others might have increased shortness of breath with coughing or wheezing.

Acute rejection can be detected through lung function tests. We will need to do a biopsy of the lung using a bronchoscope (camera) to help diagnose it.

Acute rejection may be treated with steroids, depending on the severity. Missing doses of immunosuppression medication or not having the right levels can contribute to acute rejection. Therefore, we will review your immunosuppression medication to see if it needs to be changed, and consider other contributing factors like uncontrolled acid reflux.

Antibody mediated rejection

Antibodies are proteins created by the body that fight infection. Sometimes they mistake your new lung(s) for an infection, attacking and damaging the lung(s). This is called antibody mediated rejection.

Blood tests and scans may help us to diagnose this. We sometimes treat this with a change to immunosuppression dose or type, or by giving additional medications.

Chronic rejection

Sometimes rejection becomes chronic, meaning it will never be fully cured. Chronic rejection causes wear and tear of the lung(s), like a rapid aging process. We may use different terms or abbreviations to define the type of chronic rejection:

Chronic rejection is diagnosed using breathing tests, CT scans and tests to rule out other causes for a drop in lung function. We can only diagnose chronic rejection when we rule out every other cause, including infection.

Potential treatments may include adding a medication called azithromycin, radiotherapy, treating infections and reflux. Unfortunately, having another transplant is rarely an option as it is a much higher risk surgery, with worse outcomes compared to the first lung transplant.

To help prevent your body from rejecting the new lung(s), you will be given medications that suppress your immune system. These are called ‘immunosuppressant’ medications. They essentially trick your body into seeing your new lung as part of you. They also increase your risk of getting new infections.

We will start you on these medications during the surgery through a drip. This needs to start straight away so your body doesn't start to attack the 'foreign lungs'. You will need to take the medication for the rest of your life, because your immune system will never recognise the new lung(s) as its own and will continue to try and attack the lung(s) forever.

Rejection can still occur even if you’re taking all of your medicines. The risk of rejection increases if you

• miss doses of your immunosuppressants
• take your immunosuppressants at the wrong time
• change doses of your immunosuppressants yourself without consulting the transplant team

It’s very important to take all of your tablets exactly as they are prescribed for you.