A/40 Flashcards
What is type 3 HS mediated by?
immune complex mediated
3 steps of type 3 HS?
- IC formation
- IC deposition
- Immune reaction
What does the IC deposition cause in type 3 HS? (3)
- fibrinoid necrosis
- necrotising vasculitis
- mirothrombi
3 examples of systemic type 3 HS
- rheumatoid arthritis
- polyarteritis nodosa
- glomerulonephritis
How is arthus reaction generated?
by serum or muscular injection of an antigen, if the subject was previously sensitized.
What does arthus reaction cause?
Localized edema, hemorrhage
What causes the tissue necrosis in T3 HS?
lysosomal leakage (degranulation), which causes inflammation
What causes edema in T3 HS?
the activation of the complement system, which increases vascular permeability
What mediates T4 HS?
T cells, either CD4 or CD8
Types of T4 HS?
- Delayed = CD4
- Cytotoxic = CD8
What presents Ag to CD4 / CD8 cells?
CD4 : MHCII complex
CD8 : MHCI complex
How do CD4 cells mature?
They mature into TH1 cells, activated by IL12 released by APC
How do TH1 cells transform?
Blastic transformation triggered by IL2 that they produce themselves
What does the blastic Th1 cell produce? (3)
- TNF
- PDGF, TGF
- INF gamma
What does the release of TGF cause in T4 HS?
fibroblast proliferation
