Graft versus host disease (GvHD)

What is GvHD?

GvHD stands for ‘graft versus host disease’. The word ‘graft’ means your donor’s cells, and ‘host’ means you.

After your stem cell transplant, your donor’s cells will form your new blood and immune system. But there are still small differences between your newly developing immune system and other cells in your body. As a result, your new immune system may harm some of the cells in your body because it sees them as ‘different’. This is what we call GvHD.

Why does GvHD develop?

Normally, your immune system’s role is to keep your body safe from infections caused by bacteria, viruses and fungi that are not part of you. It also scans your body’s own cells and removes any that don’t appear to be ‘normal’, such as those turning into cancer cells.

If your new immune system starts targeting and attacking a lot of your body’s existing cells, this can cause unwanted complications and side effects. At its worst, too much GvHD can be life-threatening.

However, some GvHD can be a good thing because it means:

• your newly formed immune system is working
• your working immune system is likely to be attacking any remaining or returning disease cells.

You might also hear this called ‘graft versus leukaemia effect’ or ‘graft versus tumour effect’.

Why might I get GvHD?

GvHD can affect anyone who has had a stem cell transplant using a donor’s cells, also known as an allogeneic transplant. In extremely rare cases, people can get mild GvHD from a transplant using their own stem cells too.

There’s generally a higher rate of GvHD among:

• people who have received stem cells from an unrelated donor – even if they are a perfect human leukocyte antigen (HLA) match.
• people whose stem cell donor is related to them, but not a perfect or near-perfect HLA match, also known as a ‘mismatched transplant’.

Medical professionals do not yet fully understand GvHD, making it difficult to predict who will get it and who won’t. People often experience very mild symptoms, but for others, GvHD can feel more severe and can affect their quality of life.

When am I most likely to get GvHD?

You can get GvHD at any time, so it’s important to report any post-transplant symptoms to your team. However, people most commonly experience GvHD when:

• Your immune cells start to come back and appear in your blood. This is usually a few weeks after your transplant.
• Your medical team reduces the medication that suppresses your immune system. This is usually a few months after you go home. As your immune cells become more active, they might notice there’s a difference in your body’s cells and start an attack.
• You have a donor lymphocyte infusion (DLI). This is a top-up of donor cells which you might get if your new immune system needs a boost.

What are the signs of GvHD?

The signs of GvHD can vary massively. More importantly, people most often experience symptoms caused by GvHD in certain organs or parts of the body, such as your:

• skin
• stomach and gut
• liver
• inside the mouth (oral)
• eyes and around the eyes
• lungs and breathing function
• muscles and joints
• genital area.

How will I know if I have GvHD?

As not all symptoms are specific only to GvHD, you might have a test to confirm the GvHD diagnosis. Your medical team might perform tests like:

• A biopsy, a procedure where a small sample of tissue is taken.Doctors might do this test for skin or liver GvHD.

• Using a small camera inside your body to look closely at the affected organ. Doctors might do this test for stomach or lung GvHD.

Although many GvHD symptoms are quite general and can feel mild, it’s still important you tell your transplant team as soon as possible.

What are the symptoms and treatments for different body parts?

Although everyone has their own experience of GvHD, there are some common symptoms and treatments for certain body parts and organs.

Are there different types of GvHD?

There are four types, or ‘classes’, of GvHD:

• Acute: starts within 100 days of your transplant.
• Chronic: starts more than 100 days after your transplant.
• Progressive: when acute GvHD progresses to chronic GvHD.
• Overlap: when features of acute and chronic GvHD happen together.

Once classed, medical professionals then give the GvHD a grade which they use to guide treatment and help monitor improvements. The grade is based on your symptoms and the number of organs involved.

Some transplant centres slightly adapt the grading system they use, so it’s best to check how they measure yours.

What is extracorporeal photopheresis (ECP)?

ECP is a treatment that aims to destroy the white blood cells that cause GvHD. It does this by combining a medication called methoxypsoralen (8-MOP) with ultraviolet (UV) light.

Doctors can use ECP for both acute and chronic classes of skin liver and oral GvHD.

How does ECP treatment work?

If you have ECP to treat your GvHD, the procedure will look something like this:

1. Doctors will attach you to a machine that removes your blood through a cannula and drip.
2. This machine separates the white blood cells from your blood, while returning the rest of the blood to your body.
3. Your white blood cells are then exposed to UV light and 8-MOP to destroy the cells that cause GvHD.
4. The machine returns the treated white blood cells to your body.

How long does ECP treatment take?

ECP treatment can take between one and two hours. You might start by having two appointments per week, every fortnight. However, depending on your response, your treatment cycles are likely to reduce over time.

It also depends on your class and grade of GvHD:

• ECP for acute GvHD responds quite quickly.
• ECP for chronic GvHD can take six months or more before any improvement.
• In some cases, ECP treatment can last 12 to 18 months, or longer.

If you get a referral for ECP, it might feel quite daunting due to the length of treatment. Some people want to delay it as long as possible, but the timing of ECP is crucial for it to be most effective.

If your doctor suggests a referral for ECP, it’s essential you consider it carefully. Leaving GvHD untreated for too long could reduce the effectiveness of ECP.

Tips for safely managing GvHD

While everyone can have a different experience of GvHD, it might help to read our tips from healthcare professionals and people who have gone through it before:

• Take your medication exactly as advised. Always take your immunosuppression medication – this is among the most important medication you’ll need to take. If you have nausea, vomiting or diarrhoea, or are unable to take your medication, you must tell your doctor or clinical nurse specialist (CNS).
  
• Report any change in your GvHD to your transplant team immediately. Do not leave it until your next appointment, as GvHD can quickly get worse. Call your CNS or a member of your transplant team – they can advise over the phone and in most cases will save you a trip to the clinic.
  
• Keep your team updated if you go into hospital. If you’re admitted to another hospital, you must ensure they contact your transplant centre. This will allow them to advise the hospital on how best to manage your GvHD.
  
• Watch out for signs of infection. As some treatments for GvHD and immunosuppression can put you more at risk of infection, please be wary of symptoms – especially if you’re taking these medications for long periods. Report any change in temperature to your transplant team immediately.
  
• Be wary of related effects. Depending on the organ involved, GvHD and its treatments can have knock-on effects. You might need to be referred to other healthcare professionals such as a dietician or physio. It’s important you follow their advice to eat a healthy diet, prevent weight loss, manage fatigue and maintain fitness.

What if I'm admitted to another hospital with GvHD?

Many GPs and local hospitals may not have had much experience of treating GvHD.

If you need to visit your GP, or are admitted to your local hospital while receiving treatment for GvHD, it’s important to remember the following advice:

• Tell them all the medications you are on and the treatment you are receiving for GvHD.
• Make sure they contact your transplant centre. Give them the relevant contact numbers or contact the transplant centre directly yourself.
• If the doctors would like to change any of your GvHD medication, they need to first discuss this with your transplant centre.
• You should never suddenly stop taking immunosuppression or steroid medication. If doctors suggest this, ensure they have first spoken to your transplant centre. These types of medication should only be reduced gradually, over a number of days.

If you’re referred to a specialist in the local hospital for your GvHD – like a dermatologist for your skin, for example – check your transplant centre is aware of the referral. It’s important the specialist has some knowledge of GvHD.

Difficult feelings while living with GvHD

In most cases, your medical team can quite easily treat and resolve GvHD. However, in cases where GvHD begins to affect your wellbeing, this in turn could affect your quality of life. As well as coping with the effects of GvHD, certain aspects might also affect both your physical and mental health and wellbeing.