Bone Marrow Transplant Graft vs. Host

Patients with leukemia or other blood disorders sometimes need a bone marrow transplant to help treat or prevent relapse of their disease. Graft-versus-host disease (GVHD) is a possible complication of bone marrow transplant. It can be acute or chronic and is, in essence, the sign of a battle between the cancer patient (host) and the donor bone marrow (graft).

Bone Marrow

• Bone marrow is a spongy material inside bones. The marrow in certain bones, such as the hips, contains stem cells, which are responsible for producing blood cells. These blood cells include white blood cells, which fight infection, red blood cells, which carry oxygen, and platelets, which enable blood to clot. Sometimes the stem cells produce abnormal cells. In leukemia, for instance, the bone marrow produces abnormal white cells that grow too fast and do not stop growing, resulting in life-threatening anemia, bleeding and infection.

Bone Marrow Transplant

• Physicians sometimes choose to replace damaged marrow with healthy marrow via a bone marrow transplant (BMT) to treat blood cancers such as leukemia. To accomplish this, they first use chemotherapy or radiation to destroy the diseased marrow. In some instances, however, this destruction is simply a byproduct of treatment for cancer, resulting in the need for BMT. Once they have eradicated the damaged marrow, doctors introduce healthy marrow via the blood stream. If the transplant succeeds, the new marrow will engraft and start making normal blood cells.

Donor

• Some patients can provide healthy bone marrow of their own during a remission. Bone marrow harvested during this time is stored for later use, known as an autologous transplant. However, in most instances, bone marrow comes from relatives or anonymous donors (allogeneic transplant). After performing special blood tests, including DNA matching, doctors carefully review overall health, age and other pertinent factors in order to find the best possible donor match for the patient.

Graft vs. Host

• Despite precautions to find the best match available, GVHD can occur after BMT, when the graft (donated marrow) rejects the host (patient's body). It uses T cells to attack the tissues and organs of the host's body in an attempt to fend off what it sees as a foreign invasion. Acute GVHD can occur within three months of transplant and is more common in patients receiving transplants from unrelated donors. Chronic GVHD can develop many months to years after a transplant. It may occur in the skin, liver, eyes, mouth, lungs, stomach or the neuromuscular or urinary systems. UCSF Children's Hospital (ucsfchildrenshospital.org) reports a 10 to 20 percent chance of dying from GVHD.

Symptoms/Warning

• Symptoms of GVHD show in the area affected. If the eyes are involved, conjunctivitis, dryness, irritation or itching may occur. On the skin, rashes and itching may develop. Jaundice or abdominal swelling may signal liver involvement. Loss of appetite, cramping and diarrhea may indicate the stomach is affected. White patches in the mouth or sensitivity to certain foods may suggest GVHD. Patients should contact their physician immediately for any such symptoms or if they experience fever or other signs of infection.