Graft-versus-host disease (GVHD) is a possible side effect of an allogeneic stem cell transplant (alloSCT), also called a donor bone marrow transplant. This type of transplant can be an effective treatment and may even cure some people with myelofibrosis.

In myelofibrosis, the bone marrow becomes cancerous and can no longer make healthy blood and immune cells. An alloSCT uses medications to destroy cancerous stem cells in the bone marrow and replace them with healthy stem cells from a donor. GVHD can develop if the new immune cells attack the recipient’s body.

If you’re considering an alloSCT for yourself or a loved one, learning about GVHD can help you feel more informed and prepared. In this article, we’ll explain what GVHD is, how it develops, and how it’s treated.

How Does an Allogeneic Stem Cell Transplant Work?

An alloSCT uses immature stem cells from a donor. After they enter the recipient’s body, the donated cells grow into mature cells that replace abnormal myelofibrosis cells.

An alloSCT is the only potential cure for myelofibrosis. However, there’s still a risk of relapse (return of the condition or symptoms). Your healthcare team may recommend an alloSCT if your myelofibrosis is progressing.

What Is Graft-Versus-Host Disease?

GVHD is a potential alloSCT complication that happens when the donor’s new immune cells see the recipient’s body as foreign and attack healthy cells. The donated stem cells are called the “graft,” and the recipient’s body is the “host.” That’s where the name graft-versus-host disease comes from.

Developing mild GVHD can be a good sign that the transplant is working to fight cancer. People who develop GVHD have lower rates of relapse.

Everyone’s cells contain a type of protein called human leukocyte antigens (HLA). A healthy immune system usually doesn’t attack the body’s own cells because it recognizes these HLA markers.

When the immune system finds germs like viruses or bacteria, it recognizes them as harmful and attacks them. HLA markers help white blood cells tell the difference between cells that belong in the body and cells that don’t.

Each person, except for identical twins, has unique HLA markers. After an alloSCT, your body contains two sets of HLA — your own and the donor’s. If the donor’s HLA is too different from yours, the donated immune cells may start to attack your healthy cells.

Can GVHD Be a Good Sign?

It may sound surprising, but mild GVHD can sometimes be a sign that the transplant is working against myelofibrosis.

The same immune response that causes GVHD can also help find and destroy cancer cells. This is called the graft-versus-tumor effect. Research shows that people who develop GVHD may have lower relapse rates than those who don’t.

How Can Graft-Versus-Host Disease Be Avoided?

Anyone who receives an allogeneic SCT is at risk of GVHD unless the donor is an identical twin. Although GVHD isn’t completely preventable, your cancer care team can take steps to lower the risk and severity.

Finding a Good Match

When the donor’s HLA closely matches yours, the risk of GVHD goes down. Your oncology team will test potential donors’ HLA to find the best match. This process is called tissue typing.

Other risk factors for GVHD include:

• Receiving stem cells from a donor who has been pregnant
• Having a donor or recipient who is an older adult
• Having a donor and recipient of different sexes
• Receiving donor cells taken from the bloodstream instead of the bone marrow
• Having a history of GVHD

Using Medications To Help Lower Risk

After the transplant, you’ll receive medications that suppress the immune system. These drugs can lower the likelihood of the new donor cells attacking your body.

GVHD can cause a wide range of symptoms, from mild to life-threatening. It may affect the skin, digestive system, eyes, and organs, including the liver and lungs.

Your healthcare team may also recommend a T-cell depleted alloSCT. T cells are white blood cells involved in the immune response that can lead to GVHD. Removing some T cells from the donor’s stem cells may lower the risk of GVHD.

What Are the Types of Graft-Versus-Host Disease?

GVHD can range from mild to severe and even be life-threatening. The two main types of GVHD are:

• Acute GVHD — Symptoms usually develop within the first 100 days after transplant. Commonly affected areas include the skin, gastrointestinal (GI) tract, and liver.
• Chronic GVHD — Symptoms can develop within the first two years posttransplant and may affect the skin, mouth, GI tract, muscles, joints, liver, lungs, or genitals.

Up to 47 percent of people who received an allogeneic stem cell transplant will develop acute GVHD. On average, symptoms begin about 25 days after transplant.

Chronic GVHD can develop between 100 and 600 days after transplant. Up to 50 percent of people who get an alloSCT will experience chronic GVHD.

What Are the Symptoms of Graft-Versus-Host Disease?

GVHD can cause a range of symptoms and affect several areas of the body. Symptoms can vary depending on the type of GVHD.

Acute GVHD Symptoms

Acute GVHD usually affects the skin. The earliest symptom is often a rash, which may be painful and itchy, and discoloration that looks like a sunburn. The rash usually starts on the ears, neck, shoulders, palms of the hands, and soles of the feet and may spread to other areas.

Other symptoms of acute GVHD may include:

• Nausea and vomiting
• Diarrhea
• Abdominal cramping
• Bloating
• Loss of appetite
• Jaundice (yellowing of the skin and whites of the eyes)

Chronic GVHD Symptoms

Chronic GVHD can affect any body system but most often involves the skin, GI tract, liver, and lungs. Common symptoms include:

• An itchy rash
• Swollen or thickened skin
• Hair loss
• Mouth sores, gum disease, or dry mouth
• Nausea, vomiting, or diarrhea
• Jaundice
• Chronic cough
• Shortness of breath or trouble breathing
• Fatigue
• Weight loss
• Dry eyes or vision changes
• Muscle pain, cramping, or weakness
• Limited range of motion
• Dryness or itching around the genitals

How Is Graft-Versus-Host Disease Treated?

GVHD can be managed with several types of therapies. The goals of treatment are to reduce the donor immune cells’ attack on the body and prevent further tissue damage.

The risk of GVHD can be reduced by using a closely matched donor and carefully controlling immune system reactions.

Corticosteroids (steroids) such as prednisone are the first medications used to treat both acute and chronic GVHD. Steroids may be given as creams, pills, IV medications, or eye drops.

If steroids don’t work well enough, other drugs may be used, including:

• Janus kinase (JAK) inhibitors — Medications such as ruxolitinib (Jakafi) block JAK enzymes involved in inflammation and immune system activity.
• Calcineurin inhibitors — Cyclosporine and tacrolimus can suppress certain enzymes that cause an immune response.
• B-cell-depleting therapies — Biologics such as rituximab may lower levels of B cells involved in immune attacks.
• Other immunosuppressants — Medications such as belumosudil, ibrutinib, methotrexate, mycophenolate, and cyclophosphamide may also help control GVHD.
• Photophoresis — This treatment uses light to calm overactive immune cells called lymphocytes.

Your healthcare team may also recommend supportive care, such as nutrition support, antimicrobials, or medications to protect bone health.

Researchers are continuing to study new GVHD treatments in clinical trials.

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