Published: 18 Jun 2025

ICD9: 279.50      ICD10: D89.813      ICD11: 4B24

Graft-versus-host disease (GVHD) is a serious complication that can occur after a stem cell (or bone marrow) transplant.
It happens when the donor's immune cells (the graft) recognize the recipient's body (the host) as foreign and attack it.

Think of it like this: the new immune system is seeing the patient's own body and saying, "Hey, that's not right! It's foreign!" and starts attacking it.

Here's a more detailed breakdown:

Why does it happen? The donor's immune cells, particularly T cells, contain proteins (called Human Leukocyte Antigens or HLAs) that are supposed to recognize and attack foreign invaders like bacteria and viruses. Ideally, the donor and recipient HLAs are a close match. However, even with close matching, differences can still exist. These differences trigger the donor T cells to see the recipient's tissues as foreign and launch an immune attack.

Who is at risk? GVHD is most common after:
Allogeneic stem cell transplants: Transplants using cells from a donor (related or unrelated). The closer the match, the lower the risk.
Transfusions of non-irradiated blood products to severely immune-compromised patients: While rare, this can occur when a patient's immune system is so weak they can't reject the T-cells in the transfused blood. Irradiation destroys the T-cells, preventing them from attacking.

What parts of the body are affected? GVHD most commonly affects the:
Skin: Rash, itching, peeling.
Liver: Abnormal liver function tests, jaundice.
Gastrointestinal (GI) tract: Diarrhea, nausea, vomiting, abdominal pain, loss of appetite.
It can also affect other organs, including the eyes, lungs, and mouth.

What are the types of GVHD?
Acute GVHD: Develops within the first 100 days after transplant. Often involves skin, liver, and GI tract. It can be life-threatening.
Chronic GVHD: Develops after 100 days post-transplant. Can affect many organs and tissues, often mimicking autoimmune diseases. It can cause long-term problems with quality of life. Sometimes it can even be helpful, creating a 'graft-versus-tumor effect', where the donor cells attack any remaining cancer cells.

What are the symptoms? Symptoms vary depending on the organs affected and the severity of the disease. Common symptoms include:
Skin rash
Itching
Jaundice (yellowing of the skin and eyes)
Diarrhea
Nausea
Vomiting
Abdominal pain
Dry eyes
Dry mouth
Joint pain
Fatigue
Shortness of breath

How is it diagnosed?
Clinical evaluation: Based on symptoms and physical examination.
Biopsy: A tissue sample is taken from the affected organ (e.g., skin, liver, intestine) and examined under a microscope.
Blood tests: To assess liver function, kidney function, and other organ functions.

How is it treated? Treatment aims to suppress the donor immune system and reduce inflammation. Common treatments include:
Immunosuppressant drugs: Such as corticosteroids, cyclosporine, tacrolimus, and methotrexate.
Other medications: To treat specific symptoms and complications.
Extracorporeal Photopheresis (ECP): A procedure where blood is treated with a light-activated drug to suppress immune cells.
Stem cell infusions from the original donor: Can help suppress the errant immune response.

Can it be prevented? Yes, several strategies are used to prevent GVHD:
Careful HLA matching: Selecting donors with the closest possible HLA match to the recipient.
Immunosuppressant medications: Starting immunosuppressants before and after transplant.
T-cell depletion: Removing T cells from the donor graft before transplant. This reduces the risk of GVHD but can also increase the risk of infection and relapse.

What is the prognosis? The prognosis of GVHD varies depending on the severity of the disease and the organs affected. Mild GVHD may resolve with treatment, while severe GVHD can be life-threatening. Chronic GVHD can cause long-term problems with quality of life.

In summary, GVHD is a serious complication of stem cell transplantation that occurs when the donor's immune cells attack the recipient's body. Prevention and early treatment are crucial for improving outcomes.