Graft-versus-host disease (GVHD) may happen after stem cells or other blood-forming cells from a donor (the graft) have been transplanted into your body (the host). The donor's cells include some immune cells. These cells can attack your body.
The transplant may be done to treat leukemia or other forms of cancer. Your bone marrow, which has been damaged by cancer, is first destroyed with high-dose chemotherapy or radiation. Healthy cells from a donor are then put into your body through an intravenous (I.V.) line. Over time, these cells become new, healthy bone marrow.
There are two kinds of stem cell transplants:
- Allogeneic. The cells come from a matched or a partially matched donor. In many cases, this may be a related family member. But stem cells may also come from an unrelated donor who has the same tissue type as you. Unless the donor is your identical twin, the donor's cells won't be a perfect match with yours. This can cause GVHD. It can lead to severe organ damage and death.
- Autologous. The cells come from your own body and are saved. When your own cells are put back into your body, GVHD won't happen.
There are two types of GVHD:
- Acute. This type usually happens within 100 days of a transplant. It involves the skin, gastrointestinal (GI) tract, and liver.
- Chronic. This type usually happens 100 days or more after the transplant. It involves the same body systems as the acute type but also affects the eyes, lungs, genitals, and joints. Chronic GVHD may take years to go away and can even be a lifelong condition.
You may experience either type of GVHD or both of them.