Immune Pathology 21 to 30
What is the pathogenesis of serum sickness?
- Type 3 hypersensivity
- Phase 1: Formation of immune complexes
- protein antigen, 1 week -> antibody -> blood -> Ag-Ab complexes
- Phase 2: Deposition of immune complexes
- Medium size, antigen excess most pathogenic
- high pressure filtration, glomeruli, joints
- Phase 3: Tissue injury caused by immune complexes
- Acute inflammatory reaction ~day 10
- 3 Phases
How is the tissue damage caused?
- IgG & IgM (C’ fixing Ab) bind to leukocyte Fc receptors.
- Leukocyte recruitment and activation – release proteases/lysosomal enzymes -> damage
- Deposition, activation and consumption of C’ and decreased C3 levels -> inflammatory reaction and tissue damage
What are some clinical features?
- Lymph node enlargement
- 3 of 5 to pass
What are some other examples of Type III hypersensitivity?
- Post streptococcal glomerulonephritis
- Reactive arthritis
- Arthus reaction
- Systemic lupus erythematosus
- Polyarteritis nodosa
- Other vasculitides
- Possibly membraneous glomerulonephritis
- 3 examples