Term
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Definition
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Term
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Definition
| Grafts from an identical twin. |
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Term
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Definition
| Grafts from the human species. |
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Term
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Definition
| Grafts from a different species. |
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Term
| Cornea transplant comes from - |
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Definition
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Term
| Lung transplant comes from - |
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Definition
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Term
| Heart transplant comes from - |
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Definition
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Term
| Liver transplant comes from - |
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Definition
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Term
| Bone marrow transplant comes from - |
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Definition
| Needle aspiration from a living donor. |
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Term
| Kidney transplant comes from - |
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Definition
| Living donor, or cadaver. |
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Term
| Pancreas transplant comes from - |
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Definition
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Term
| Blood transplant comes from - |
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Definition
| Transfusion from a living donor. |
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Term
| Skin transplant comes from - |
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Definition
| Usually yourself (autologous) - typically burn victims. |
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Term
| Limiting factors of transplantation: |
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Definition
Not enough supply/donors.
ABO incompatibility.
HLA incompatibility. |
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Term
| Why is it important to match HLA and MHC antigens for transplantation? |
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Definition
| To avoid cell-mediated and/or humoral responses to foreign HLA or MHC antigens. |
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Term
| How many rejections for allografts? |
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Definition
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Term
| Allograft first-set rejection is what type of response? |
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Definition
Primary immune response.
Revascularization: leukocytes arrive by 3-7 days.
Full rejection by 10-14 days. |
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Term
| Allograft second-set rejection is what type of response? |
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Definition
Secondary immune response: immunologic memory.
Rejection begins by 3-4 days.
Full rejection by 5-6 days. |
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Term
| Revascularization occurs with what rejection set of an allograft? |
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Definition
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Term
| First-set rejection process: |
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Definition
Day 1: Graft.
Days 3-7: Revascularization.
Days 7-10: Cellular infiltration.
Days 10-14: Thrombosis and necrosis (damages blood vessels, blood clots, necrotic tissue) |
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Term
| Second-set rejection process: |
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Definition
Day 1: Graft.
Days 3-4: Cellular infiltration.
Days 5-6: Thrombosis and necrosis (Necrotic tissue and blood clots) |
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Term
| Cells involved in allograft rejection: |
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Definition
CD4+ and CD8+ populations are involved.
Increased levels of INF-Gamma.
Dendritic cells (involved in rejection and tolerance)
Pretreatment with donor cells can promote tolerance. |
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Term
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Definition
Tissues that are genetically similar.
Generally indicating allograft acceptance. |
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Term
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Definition
| Genes closely linked, such that they are inherited as a group (MHC) |
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Term
| Most vigorous rejection is due to: |
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Definition
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Term
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Definition
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Term
| HLA consists of how many alleles from each loci? |
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Definition
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Term
| Loci of MHC Class I genes: |
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Definition
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Term
| Loci of MHC Class II genes: |
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Definition
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Term
| Everybody has how many haplotypes? Where do they come from? |
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Definition
| Two. One from mother, one from father. |
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Term
| Stage 1 of allograft rejection is: |
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Definition
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Term
| What happens in the sensitization stage of allograft rejection? |
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Definition
T cells of the recipient proliferate in response to antigens on the graft.
- Both CD4+ and CD8+ cells react.
- Donor APC's migrate to lymph nodes and stimulate host T cells there.
- Host APC's (dendritic cells) can migrate into graft and endocytose foreign antigens -- dendritic cells can cross-present endocytic antigens in the context of MHC I. |
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Term
| What is direct allorecognition? |
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Definition
When donor APC's (allogenic APC) migrate to lymph nodes and stimulate host T cells (alloreactive T cell) there.
-T cell recognizes unprocessed allogenic MHC molecule on graft APC's. |
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Term
| What is indirect allorecognition? |
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Definition
When host APC's (dendritic cells) migrate into graft and endocytose foreign antigens.
- T cell recognizes processed peptide of allogenic MHC molecule bound to self MHC molecule on host APC. |
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Term
| Stage 2 of allograft rejection is: |
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Definition
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Term
| What is involved in the effector stage of allograft rejection? |
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Definition
Host immune system attacks the graft (Type IV - delayed hypersensitivity)
- CTL-mediated cytotoxicity.
- Compliment mediated antibody response.
- ADCC.
TH cells play a key role:
- IL-2: T cell proliferation and CTL response
- IFN-Gamma: DTH response, increased MHC II expression
- TNF-Beta: Increased cytotoxicity. |
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Term
| What are the clinical types of graft rejection? |
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Definition
Hyperacture rejection.
Acute rejection.
Chronic rejection. |
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Term
| When does hyperacure rejection take place? |
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Definition
| Less than 24 hours after graft - can happen in minutes. |
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Term
| When does acute rejection take place? |
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Definition
Weeks after graft.
Usually begins about 10 days post-transplant, with full rejection after 10-14 days. |
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Term
| When does chronic rejection take place? |
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Definition
| Months to years after graft. |
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Term
| What triggers hyperacture rejection occur? |
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Definition
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Term
| What cells make acute rejection occur? |
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Definition
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Term
| What type of immune response is chronic rejection? |
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Definition
| Humoral and cell-mediated. |
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Term
| What happens when chronic rejection is cell-mediated? |
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Definition
| Lymphocyte infiltration of graft. |
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Term
| What happens when chronic rejection is humoral? |
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Definition
| Rejection vasculitis; associated with development of donor specific HLA antibodies. |
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Term
| What is histocompatibility testing for? |
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Definition
- To determine ABO and HLA type of patients and donors.
- Selection of donor tissues with minimal difference between donor and recipient.
- Look for evidence of prior sensitization.
- Identify incompatible transplants by in vitro crossmatching. |
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Term
| Does the patient need immunosupprives therapy of the donor is a perfect HLA match? |
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Definition
| Yes because other minor histocompatibility antigens will likely differ and can eventually cause transplant rejection. |
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Term
| To avoid hyperacute rejection: |
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Definition
| Use ABO compatible blood. |
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Term
| Where are blood group antigens expressed? |
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Definition
| RBC's, epithelial cells, and endothelial cells. |
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Term
| To avoid acute or chronic rejection: |
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Definition
Use donor tissue with similar or identical HLA antigens as recipient.
If patient has evidence of prior sensitization, avoid using organs/tissues with those HLA antigens. |
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Term
| Matching solid organs - what is priority? |
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Definition
ABO incompatibility - HLA matching is secondary priority.
Solid organ transplants almost always have to be ABO identical. |
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Term
| Matching stem cell/bone marrow transplants - what is priority? |
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Definition
HLA matching - ABO is secondary priority (ABO antigens are not found on stem cells - therefore, no hyperacture rejection)
If HLA is not matched there can be graft rejection, as well as rejection of patient by graft. |
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Term
| What happens in Graft vs. Host Disease (GVHD)? |
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Definition
Lymphocytes from the donated graft attack allogenic antigens of the recipient.
50-70% of bone marrow transplants are affected by GVHD.
Symptoms:
- Skin reactions.
- GI hemorrhaging.
- Liver failure.
- Splenomegaly. |
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