immune stuff

Question 1

transplant rejection

hyperacute rejection

occurs within minutes to hours

what kind of HSR is it

Answer 1

antibody mediated type II

pre-existing recipient antibodies react to donor antigen

activate complement

presents: widespread thrombosis of graft vessels –> ischemia/necrosis

Question 2

acute transplant rejection occurs

weeks (within 3 months) of the transplant

what type of HSR

Answer 2

cell mediated (type IV)

cytotoxic T lymphocytes recognize foreign MHC 1

humoral: similar to hyperacute, except antibodies develop after transplant.
presents: vasculitis of graft vessels w/ dense interstitial lymphocytic infiltrate
prevention: immunosuppressants

block (IL-2) bc it stimulates proliferation of all T cells.

Question 3

chronic rejection

months to years.

pathogenesis?

Answer 3

mediated by T cells and antibodies

- cytotoxic T cells treat transplant cells as self cells presenting non self antigen.

CD4+ T cells respond to recipient APCs presenting donor peptides, including allogeneic MHC.

Both cellular and humoral components

type II and IV hypersensitivity rxns.

presents w/ vascular damage, fibrosis, irreversible

-

Question 4

Graft versus host disease

whats happening

Answer 4

grafted T cells proliferate and attach host.

presents:

maculopapular rash

• (ears, hands trunk, can look like SJS)
• hemolysis and jaundice
• hepatosplenomegaly
• GI/ abd pain N/V/D