Final answer:
GVHD occurs when donor immune cells from a transplant recognize the recipient's cells as foreign, affecting mainly the skin, liver, and mucosa. Close HLA matching and marrow processing to remove T cells are crucial in minimizing GVHD risks.
Step-by-step explanation:
Graft-versus-host disease (GVHD) typically affects the skin, gastrointestinal tract, liver, and eyes, and can be triggered after a bone marrow transplant or the transplantation of organs rich in lymphocytes, such as the liver. This condition occurs when the donor's T cells in the graft recognize the recipient's tissue as foreign and initiate an immune response. The affected tissues in GVHD most commonly include the skin, which may develop a rash; the liver, which can sustain damage; and the mucosa. To minimize the risk of GVHD, it's essential to closely match the human leukocyte antigens (HLAs) between the donor and recipient and to process the donated marrow to remove mature T cells.