13. Transplantation And Pregnancy Flashcards
Why you have Ab against blood group B if you have blood group A f.eks
1) Carbohydrate antigens of intestinal microbiome
2) Maternal antigen exposition
3) Contact with foreign blood previously
4) Exposition by plant pollens
Autograft
Transplant from own body (e.g hair transplant)
Isograft
Transplant from monozygotic twin
Allograft
Transplant from same species
Xenograft
Transplantation from different species (e.g monkey)
Primary rejection allograft
- Necrosis
- Rejection
- Longer reaction than secondary
- Ca. 14 days
Secondary rejection allograft
- Reintroducing graft
- Necrosis
- Shorter time before rejection due to memory cells
- Ca. 5-6 days
Critical point in transplantation
1) MHC (HLA-A, HLA-B, HLA-DR)
2) Minor histocompatibility antigens
- H-Y (Y chromosome, male)
- Males preferably get grafts from other males
- HA-1 -> HA-5 (non Y chromosome)
3) Other tissue specific antigens
- ABO, Rh blood groups
- VEC (vascular endothelial cell) antigen system
- SK (Skjebred) antigen
Difference organ and bone marrow transplantation
Organ: - No cytoablation - HLA coordination important - Major complication: rejection - Success: acceptance Bone marrow - Cytoablation necessary - HLA coordination crucial - Major complication: GVHD - Success: tolerance
Types of host versus graft reactions (HVG)
1) Hyperacute rejection (minutes-hours)
- Complement activation, endoth. damage, inflammation,
- ABO, HLA, VEC incompatibility
2) Acute rejection (weeks)
- IgG binds to alloantigenic antigen
- No complement activation
- Vasculitis: IgG binds to alloantigenic endothel (Th1, CD8)
3) Chronic rejection (months)
- Fibrosis and vascular sclerosis
- CD4 T cells, macrophages
- Vessel occlusion
Hematopoietic chimera
After bone marrow transplantation
Bone marrow transplantation use
- Cancers
- Autoimmune disorders
- Other diseases
Apheresis
Harvesting stem cells from peripheral blood
GVHD (graft vs host disease) mediators
- TNF
- FasL
- Perforin-granzyme
- all from cytotoxic T cells
Types of GVHD
1) Acute
- Endothel cells damaged in skin, liver, GI system
- Delivered by graft T cells
2) Chronic
- Fibrosis + atrophy in multiple tissues
- Loss of tissue function