Graft-versus-host disease is best described as which of the following?

• A. Grafted T cells attack host tissues; occurs in bone marrow and liver transplants
• B. Preformed antibodies cause hyperacute rejection
• C. Acute rejection by host T cells
• D. Chronic fibrosis of the graft

Answer: (A)

Graft-versus-host disease happens when the donor’s immune cells, present in the transplanted tissue, attack the recipient’s tissues as foreign. This is most likely after allogeneic bone marrow or stem cell transplants (and can occur with liver transplants because passenger lymphocytes accompany the graft). The donor T cells become activated against host antigens, especially in tissues like the skin, liver, and gut, leading to rash, jaundice, and diarrhea. This is different from hyperacute rejection, which is caused by preformed antibodies in the recipient; from acute rejection, where host T cells attack the graft; and from chronic rejection, which involves gradual fibrosis and vasculopathy of the graft. So the description is donor T cells in the graft attacking the host’s tissues.