Transplantation

Question 1

What are the characteristics of Hyperacute graft rejection?

Answer 1

1. Occurs within minutes to hours
2. Due to pre-formed antibodies due to transfusions, multi-parity, or previous organ transplants (Type II cytotoxic hypersensitivity)
3. Antibodies bind to the grafted tissue and activate complement and the clotting cascade resulting in thrombosis and ischemic necrosis

Question 2

What are the characteristics of Acute graft rejection?

Answer 2

1. Occurs within days to weeks; the timing and mechanism are similar to a primary immune response
2. Induced by alloantigens (predominantly MHC) in the graft
3. CD4 and CD8 T cells play a role as well as antibodies (think normal immune response)
4. Immunosuppressive therapy works to prevent this type of graft rejection mainly

Question 3

What are the characteristics of Chronic graft rejection?

Answer 3

1. Occurs within months to years
2. Predominantly T cell mediated
3. Difficult to treat and usually results in graft reaction
4. Etiology not well understood, possibly triggered by viral infections

Question 4

What is the type of graft rejection with bone marrow?

Answer 4

Graft versus host disease

Question 5

What causes graft versus host disease

Answer 5

Some T-cells present in the bone marrow can attack an immunocomprimised host’s cells by becoming active against the MHC molecules

Question 6

What are the characteristics of graft versus host disease?

Answer 6

1. Widespread epithelial cell death
2. Rash
3. Jaundice
4. Diarrhea
5. Gastrointestinal hemorrhage