Graft-versus-host disease (GVHD) is a condition where donated immune cells attack the transplant recipient’s body, treating it as foreign. It’s one of the most common and serious complications after an allogeneic stem cell or bone marrow transplant, where cells come from a donor rather than the patient themselves. The condition can range from mild skin rashes to life-threatening organ damage, and it affects the skin, gut, liver, lungs, eyes, and other tissues.
Why Donor Cells Attack the Body
Every cell in your body carries surface proteins called human leukocyte antigens (HLA) that act like an identification badge. Your immune system uses these proteins to distinguish your own cells from invaders. When you receive a stem cell transplant from a donor, the donated cells come equipped with their own immune cells, particularly T-cells, which are trained to recognize threats.
The problem is that even with careful donor matching, the recipient’s HLA proteins rarely match the donor’s perfectly. The donated T-cells encounter the recipient’s cells, read their surface proteins as foreign, and launch an immune attack. This is the core of GVHD: the transplanted immune system treats the recipient’s healthy tissues the same way it would treat an infection or a tumor. The donated T-cells activate, multiply, and migrate through the body, damaging whatever tissues they identify as “nonself.”
Doctors and patients accept this risk because those same aggressive donor T-cells also attack any remaining cancer cells in the recipient’s body. This beneficial side, called the graft-versus-leukemia effect, is actually one of the main reasons stem cell transplants work as a cancer treatment. Studies have shown that when donor T-cells are removed from the graft to prevent GVHD, cancer relapse rates increase. So transplant medicine walks a fine line: enough immune activity to destroy cancer, but not so much that it destroys healthy tissue.
Acute vs. Chronic GVHD
GVHD comes in two forms that behave quite differently. The traditional dividing line is 100 days after transplant: symptoms appearing before that point are classified as acute, and those appearing afterward as chronic. In practice, the distinction is now based more on the type of symptoms than strict timing. Some patients develop acute-type symptoms well past the 100-day mark (called late-onset acute GVHD), and some develop an overlap syndrome with features of both.
Acute GVHD typically targets three organ systems: the skin, the gastrointestinal tract, and the liver. A skin rash is often the first sign. Gut involvement shows up as persistent diarrhea, nausea, and weight loss. Liver involvement causes a buildup of bilirubin in the blood. Severity is graded on a scale from I to IV based on how many organs are affected and how badly, with grade IV being the most dangerous.
Chronic GVHD is a different beast. It can affect nearly every organ system and often resembles autoimmune diseases like lupus or scleroderma. It tends to develop more slowly and can persist for months or years.
How Chronic GVHD Affects the Body
The skin is the most commonly affected organ in chronic GVHD. Symptoms range from dry, itchy rashes and changes in skin color to a more serious tightening and hardening of the skin that can restrict joint movement or make it difficult to open your mouth fully. Some people develop brittle nails, hair loss, or damage to sweat glands that makes it hard to tolerate heat.
Eye involvement is also common. Chronic GVHD can damage tear glands, leading to dry, gritty, burning eyes, sensitivity to light, blurry vision, and crusting on the eyelids. The lungs can be affected too, through a condition called bronchiolitis obliterans syndrome, where the small airways become inflamed and scarred. Lung GVHD is particularly concerning because it often has no obvious symptoms in its early stages, making regular screening important.
Other areas that can be affected include the mouth (dryness, sores, sensitivity), the joints, and the genitals. Because it can involve so many body systems at once, chronic GVHD often requires monitoring by multiple specialists.
How Common Is It?
Rates of acute GVHD have dropped significantly over the decades thanks to better donor matching and improved prevention strategies. Before 2010, nearly half of allogeneic transplant recipients developed moderate to severe acute GVHD. In more recent years, that number has fallen to about 16% for moderate-to-severe cases, and roughly 4% for the most severe forms. That’s a major improvement, though the condition remains a leading cause of complications after transplant.
Chronic GVHD is still common and carries real long-term risk. Among patients diagnosed with chronic GVHD, the rate of death from causes other than cancer relapse reaches about 22% within five years. The most frequent cause of those deaths is organ failure or infection directly linked to chronic GVHD itself, accounting for roughly 38% of non-relapse deaths. Lung involvement is a particularly strong predictor of worse outcomes.
Prevention Strategies
Every allogeneic transplant recipient receives preventive medications, typically starting around the time of transplant. The standard approach combines two types of immune-suppressing drugs. One is a calcineurin inhibitor (such as tacrolimus or cyclosporine), which blocks a key signaling pathway that T-cells need to activate. The other is a drug that slows the rapid multiplication of immune cells. These medications are given together for weeks to months after transplant, then gradually tapered if GVHD doesn’t develop.
HLA matching between donor and recipient remains the single most important factor in reducing GVHD risk. Siblings who share the same HLA type are ideal donors. When no matched sibling is available, unrelated donors from registries are screened for the closest possible match. Even with a perfect match on the major HLA markers, minor protein differences can still trigger GVHD, which is why preventive medications are always used.
Treatment When GVHD Develops
Corticosteroids are the first treatment for both acute and chronic GVHD. They broadly suppress the immune response and are effective for many patients, particularly those with milder disease. The challenge comes when GVHD doesn’t respond to steroids, a situation called steroid-refractory disease.
For steroid-refractory acute GVHD, ruxolitinib became the first FDA-approved treatment in 2019. It works by blocking specific signaling molecules that drive the inflammatory immune response. In the clinical trial that led to its approval, patients with moderate to severe acute GVHD who had failed steroid therapy showed meaningful improvement. It’s taken as a pill twice daily, which is simpler than many transplant-related treatments that require IV infusions.
Treatment for chronic GVHD often involves longer courses of immune suppression and may require multiple medications targeting different parts of the immune system. Because chronic GVHD can affect so many organs, treatment plans are often tailored to whichever body systems are involved. Some patients need treatment for months, others for years.
Living With GVHD
For many transplant survivors, GVHD becomes a chronic condition that shapes daily life. Skin involvement may mean avoiding sun exposure and using careful moisturizing routines. Eye dryness can require frequent use of artificial tears and protective eyewear. Lung involvement means staying alert to respiratory infections and maintaining physical activity to preserve lung function. Regular self-checks of your mouth, eyes, skin, joints, and genitals help catch new symptoms early, when they’re easier to manage.
Physical function matters more than many patients realize. In studies of chronic GVHD outcomes, patients who could walk farther and maintain higher activity levels had significantly better survival. Staying as physically active as your condition allows isn’t just about quality of life; it’s directly linked to long-term outcomes. The balance between managing immune suppression, watching for infections, and maintaining normal activities is the central challenge of life after transplant with GVHD.