Graft-versus-host disease (GVHD) happens when the immune system mistakenly attacks healthy cells after a stem cell transplant. This can lead to serious problems like skin rashes, digestive issues, and liver damage. Extracorporeal photopheresis (ECP) helps calm GVHD by altering lymphocytes — immune cells that normally fight infections but mistakenly attack healthy tissues in GVHD. ECP removes some of these cells, treats them with ultraviolet A (UVA) light, and returns them to the body. This process changes how the immune system works, reducing the harmful attack without surgery.

For children and adults with GVHD, ECP is generally a safe, painless treatment (except for IV line placement) that helps control the immune response. Understanding what’s involved can help you or your child feel more prepared for treatment.

How Does ECP Work?

ECP uses light to change the behavior of lymphocytes. In GVHD, these immune cells mistakenly attack healthy tissues, like the skin. ECP helps by modifying their function, reducing the harmful attack.

ECP is performed in a special hospital unit or clinic. Blood is removed and cycled into a machine that separates the lymphocytes, in a process called apheresis. These cells are treated with 8-methoxypsoralen (8-MOP), which makes them more sensitive to light therapy. Next, the cells are exposed to UVA light and injected back into the body.

After ECP, the treated lymphocytes change how they work. They become less aggressive and stop attacking healthy tissues or transplanted cells.

What Should You Expect?

A healthcare provider may make specific recommendations for you or your child in the days leading up to the procedure. For example, they may advise drinking plenty of fluids and avoiding alcohol, caffeine, and high-fat foods. Following these instructions helps promote good hydration and blood flow.

Before ECP, you may need a port, a device placed under the skin for easy vein access, or a large needle may be used instead if your arm veins are suitable. A port is placed while you’re sedated, so you won’t feel pain. Your healthcare team will explain the plan beforehand.

If ECP is performed on a small child or someone with anemia (low levels of red blood cells), a blood prime may be needed first. A blood prime is a transfusion of packed red blood cells. This helps make up for the low red blood cell count. In addition, medications called anticoagulants, such as heparin or citrate, are used to thin the blood and prevent clots during the procedure.

During ECP, the person can relax in a comfortable chair and watch TV. The procedure takes two to four hours, as the healthcare team only takes a few ounces of blood at a time. Most people need multiple sessions until GVHD symptoms improve. It may take a few months of treatment before your doctor can determine if ECP is showing an effective response rate for GVHD.

ECP is performed in a dim room because 8-MOP makes the person more sensitive to light for up to 24 hours. It’s important to stay out of the sun and wear sunglasses and sunscreen throughout the day after treatment.

After ECP, a healthcare provider checks the person’s pulse and blood pressure. As long as their vital signs are OK, they’ll be cleared to go home the same day.

When Should ECP Be Used?

Both children and adults can be good candidates for ECP. For safe and successful ECP treatment, the person must have reliable vein access or the healthcare team will need access to a central venous catheter through a port. Anyone receiving ECP needs to have enough platelets and red blood cells. If the person is anemic or has a low blood count, the use of ECP may be delayed.

What Are the Risks?

ECP comes with very few risks. Because it’s done under the supervision of a qualified healthcare provider, the person is closely monitored. Nonetheless, some side effects are possible.

The main side effects of ECP are similar to the side effects of donating blood. These can include:

• Dizziness
• Fainting
• Lightheadedness
• Nausea or vomiting

If the person requires a blood transfusion before ECP, they may have side effects, such as an itchy rash (hives), back pain, fever, or shortness of breath. Additionally, the anticoagulants given before ECP can have side effects. Chills, tingling on the fingers or lips, irregular heart rate, leg cramps, and a sour taste in the mouth can develop with anticoagulants.

Some people have blood pressure changes during or right after ECP. Blood pressure may also rise when the treated cells are returned to the body. Other temporary effects may include coughing and shortness of breath.

As with any procedure that involves an IV line, there may be pain or bruising where the blood was taken. There’s also a risk of infection or mechanical issues with a central venous line. Call the doctor if the person who had ECP has a fever, arm swelling, or shortness of breath after going home. Communicating with the healthcare team about any side effects is essential to make sure there’s nothing serious to worry about.

Talk With Others Who Understand

On myGVHDteam, the site for people with graft-versus-host disease and their loved ones, people come together to ask questions, give advice, and share their stories with others who understand life with the condition.

Are you familiar with ECP therapy? If you or someone you love has had ECP, how did it affect GVHD symptoms and quality of life? Share your experience in the comments below.