<qa>  What is the risk of graft-versus-host disease?RATIONALE: Colony-stimulating factors such as sargramostim may increase the number of immune cells found in bone marrow or peripheral blood and may help a persons immune system recover from the side effects of chemotherapy or radiation therapy. Giving sargramostim to the stem cell donor and the patient may reduce the chance of developing graft-versus-host disease following stem cell transplantation. 