Pathophys 4: Immune Responses to Transplantation
Order by
10 terms
Terms | Definitions |
|---|---|
 MHC class I | expressed by must nucleated cells -> present antigen to CD8+ T cells |
| MHC class II | expressed by limited subset of cells (dendritic/langerhans/macrophages/b cells/activated T cells/stimulated endothelium) -> present antigen to CD4+ T cells |
| Tissue matching | made at 3 loci -> HLA-A, HLA-B and HLA-DR |
| Hyperacute allograft rejection | minutes to hours after anastomosis of graft -> binding of preformed antibodies to graft antigens -> followed by tissue damage (type II hypersensitivity) -> no treatment available -> can test recipient serum for antibodies that react with donor lymphocytes using flow cytometry to prevent |
| Accelerated allograft rejection | days to weeks after grafting -> small amounts of preformed antibodies or antibodies produced after grafting (type II hypersensitivity) |
| Acute allograft rejection | weeks to months after grafting -> recognition of graft antigens by allospecific T cells followed by cytotoxicity (CD8 cells)) or release of inflammatory lymphokines (CD4 cells) -> type IV hypersensitivity -> causes tissue damage, hemorrhage and necrosis -> can give pulse steroids or anti-T cell antibodies (OKT-3) to treat |
| Chronic allograft rejection | months to years after grafting, unknown mechanism, probably mixture of type IV and type II processes -> fibrosis, atrophy, vascular intimal thickening -> no satisfactory therapy available |
| Graft Vs host disease (GVHD) | immunologically competent cells/precursors are transplanted into an immunodeficient recipient and the transferred cells recognize alloantigens in the host (usually to HLA) -> match HLAs to prevent or deplete donor of T cells |
| Acute GVHD | days-weeks post transplant -> rash, destruction of bile ducts (jaundice), gut mucosal ulceration (bloody diarrhea) -> lesions are Pauci-cellular, CTLs and cytokines as effectors |
| Chronic GVHD | cutaneous fibrosis and destruction of skin appendages, cholestatic jaundice, esophageal and GI strictures, lymphodepletion, autoimmunity possible |
First Time Here?
Welcome to Quizlet, a fun, free place to study. Try these flashcards, find others to study, or make your own.