Hypersensitivities Flashcards
What are common sources of allergens?
inhaled materials, injected materials, ingested materials
What is a hypersensitivity reaction?
undesirable reactions produced by the normal immune system, including allergies and autoimmunity
Hypersensitivity requires a ___________ state of the host.
pre-sensitized (immune)
Clinical timing of Type I, II, III, and IV hypersensitivity?
I - within minutes if prior sensitized
II & III- within hours if prior sensitized
IV- 2-3 days if prior sensitized, delayed
What cells are involved in Type I hypersensitivity?
Mast cells
Basophils
Eosinophils
What cells are involved in Type III hypersensitivity?
Neutrophils (some mast cells too)
What cells are involved in Type IV hypersensitivity?
Th1, CTLs, macrophages
What Ig classes are involved in Type I hypersensitivity?
IgE
What Ig classes are involved in Type II hypersensitivity?
IgG, IgM
What Ig classes are involved in Type III hypersensitivity?
IgG, IgA
What Ig classes are involved in Type IV hypersensitivity?
none
Clinical syndrome involved with hypersensitivity type I?
allergies
asthma
anaphylaxis
Clinical syndrome involved with hypersensitivity type II?
Cytolysis of antibody coated cells leads to anemia, thrombocytopenia, or neutropenia
Clinical syndrome involved with hypersensitivity type III?
Immune complex deposits on capillaries, complement activation leads to immune complex disease (vasculitis, glomerulonephritis, arthritis)
Clinical syndrome involved with hypersensitivity type IV?
granulomas or cellular apoptosis induced by CD8 cells
How is disease caused in Type I hypersensitivity?
By inflammatory molecules releases from mast cells.
Mediated by IgE attached to Mast Cells.
Clinical signs of allergic disease are independent of the allergens entry route. True or false?
False
What causes allergic anaphylaxis? How does this affect smooth muscle?
Inflammatory molecules released by mast cells
Animals may die due to contraction of critical smooth muscle (those lining the bronchi)
What are the two purposes of Type I Hypersensitivity?
Self eliminate / self cure round worms in the gut
Eliminate allergen (antigen) from muco-cutaneous surfaces.
What are the clinical signs of the body trying to eliminate allergens from muco-cutaneous surfaces?
Mucus formation, runny nose, sneezing, itching, coughing, vomiting, diarrhea
What are the consequences of the body trying to eliminate allergens from muco-cutaneous surfaces?
smooth muscle contraction - bronchoconstriction
vascular permeability - edema formation
IgE microgram quantities in the blood and shortest half-life
What are the mechanisms of tissue injury and disease in Type I?
mast cell derived mediators
cytokine-mediated inflammation
What are the effector cells for Type I?
mast cells, basophils, eosinophils
