Grafts and Transplant rejection Flashcards
what is an autograft
a graft from self
what is a syngeneic graft
a graft from an identical twin or clone
what is an allograft
a graft from nonidentical individual of same species
what is a xenograft
a graft from another species
what is the onset of hyperacute rejection?
what about acute rejection?
hyperacute rejection occurs within minutes
acute rejection occurs within weeks to months
what is the onset of chronic rejection?
months to years
describe the pathogenesis of hyperacute rejection
pre-existing antibodies in the recipient to donor tissue causes a type II hypersensitivity reaction and activates complement
what gross pathologic features would appear as a result of hyperacute rejection
widespread thrombosis of graft vessels leading to ischemia and necrosis
what must be done if there is hyperacute rejection
remove the graft
describe the pathogenesis of acute rejection
cytotoxic lymphocytes become activated against donor MHCs leading to development of antibodies and hypersensitivity II reaction
what is seen on gross pathology after acute rejection
vasculitis of graft vessels with dense interstitial lymphocytic infiltrate
how do you treat/ prevent acute rejection
immunosuppressants
describe the pathogenesis of chronic rejection
recipient T cells perceive donor MHC as self MHC and react to whatever donor MHC’s present to them leading to cellular and humoral response
is chronic rejection reversible
no
what is graft vs. host disease
T-cells within the graft proliferate in the recipient and target recipient cells for destruction leading to severe organ dysfunction
