Tumor rejection

Question 1

Mechanisms for hyper acute rejection

Answer 1

preformed antibodies to graft (e.g ABO)

Question 2

Morphology of hyperacute rejection

Answer 2

cyanosis and gross molting
aterial fibrinoid necrosis
capillary thrombotic oculsion

Question 3

Time course of acute graft rejection

Answer 3

less than 6 months

Question 4

Mechanism of acute rejection

Answer 4

CD4 t cells against the donor antigens

humoral and cellular immune response

Question 5

morphology of acute rejection

Answer 5

humoral: c4 deposition (classical and mbl), pmns, necrotizing vasculitis
cellular: lymphocytes n the interstitium and endothelium

Question 6

timecourse of chronic rejection

Answer 6

months to yrs

Question 7

mechanisms of chronic rejection

Answer 7

chronic, low grade immune response (usually cd8) refractory to immunosuppressants

Question 8

morphology of chronic immune response

Answer 8

vascular wall thickening and luminal narrowing

interstitial fibrosis and parenchymal atrophy

Question 9

Onset for hyperacute rejection

Answer 9

mins to hrs