Transplantation

Question 1

Hyperacute graft rejection

Answer 1

occurs within minutes to hours

Due to pre-formed antibodies (type II hypersensitivity)

Question 2

Acute graft rejection

Answer 2

occurs within days to weeks
Induced by alloantigens (predominantly MHC) in the graft
Both CD4 and CD8 T cells play a role as well as antibodies

Question 3

Accelerated acute graft rejection

Answer 3

occurs within days, the timing and mechanism are similar to a memory response

Question 4

Chronic graft rejection

Answer 4

occurs within months to years

Predominantly T cell mediated