Graft-versus-host disease is a frequent complication
of allogeneic BMTs. In GVHD, the donor's bone marrow attacks the patient's
organs and tissues, impairing their ability to function, and increasing
the patient's susceptibility to infection. |
T-cells are special white blood cells
that recognize foreign matter in the body. T-cells orchestrate attacks on
bacteria, viruses and other substances foreign to the body. They can also
distinguish "self" from "non-self"-human cells that
belong in one person's body and those that do not. |
The donor's marrow also contains T-cells. When transplanted into the patient, the donor's T-cells may look at the HLA markers on the patient's cells, identify the cells as "non-self" and unleash an attack on the patient's tissues and organs. Because the patient's own immune system is suppressed prior to the transplant, it cannot launch a counterattack. This condition is called graft-versus-host disease (GVHD). The "graft" is the donated bone marrow and the "host" is the BMT patient or bone marrow recipient. |
Stage 1 (mild) : a skin rash over less than 25% of
the body. |
Acute GVHD usually occurs during the
first three months following an allogeneic BMT. T-cells present in the donor's
bone marrow at the time of transplant identify the BMT patient as "non-self'
and attack the patient's skin, liver, stomach, and/or intestines. |
Although GVHD is not yet preventable,
steps can be taken to reduce the incidence and severity of GVHD. |
Another technique sometimes used to reduce
the severity and incidence of acute GVHD is called "T-cell depletion."
Since T-cells identify foreign antigens, researchers hypothesized that removing
T-cells from the donor's marrow would decrease the incidence and severity
of GVHD. And so it did, reducing the incidence of acute GVHD in leukemic
patients from approximately 50 percent to less than 15 percent. |
Chronic GVHD usually develops after the
third month post-transplant. Scientists believe that new T-cells produced
after the donor's bone marrow has engrafted in the patient may cause chronic
GVHD. |
Chronic GVHD is usually treatable with
steroids such as prednisone, ozothioprine and cyclosporine, which suppress
the patient's immune system. Antibiotics such as Bactrim or penicillin or
both are usually taken to reduce the risk of infection while chronic GVHD
is being treated. In addition, patients may be required to wear face masks
while around other people, stay out of crowds, and avoid fresh plants, fruits
and vegetables. Patients with chronic GVHD are usually advised to avoid
vaccinations with live viruses such as German measles, tetanus, polio, etc.
until the GVHD problem is completely resolved and use of immunosuppressive
drugs ends. |
Although most patients recover from GVHD,
some symptoms may persist even after the disease has been completely resolved.
Patients who 've had GVHD usually experience long-term skin sensitivity
and must avoid prolonged exposure to sunlight, using strong sunblockers
on any exposed skin. Scarring of the skin may also occur. |
Since many patients undergoing an allogeneic
BMT experience some degree of GVHD, physicians typically discuss GVHD with
patients in detail prior to their transplant. Many patients find this discussion
overwhelming and frightening, particularly if the risks of GVHD are not
put into some perspective. Patients often do not understand that a case
of GVHD can be mild, moderate or severe, and that death, disfigurement or
permanent disability is not the usual outcome. |
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The side effects of drugs used to treat
GVHD can further stress a patient's already delicate emotional state. Depression,
confusion, anxiety, roller coaster-like mood swings, and exaggerated feelings
(anger, excitement, sadness, etc.) disproportionate to the situation are
common and can make the GVHD recovery period extremely trying for patients
and their loved ones. Keeping in mind that these side effects are tempo-
rary can help everyone involved-patient, family and friends-better cope
with this period of treatment. In rare instances, medications may be prescribed
to stabilize mood swings and reduce anxiety. |
Susan Mitchell, a BMT patient with aplastic
anemia, sums up her experience with GVHD this way: "Sometimes, as I
fought off repeated infections and looked at myself in the mirror I thought
there would be no end to my misery. But today I'm realizing a happy ending
to all of this. Every day is a little brighter and better. My GVHD is gone,
my liver is returning to normal, my skin color is back, and I don't itch
anymore. I don't do 10 km runs yet, but walking seems to suit me well for
the time being. |