introduction to immunopathology Flashcards
What is hypersensitivity?
inappropriate, over-reactive immune responses
What is autoimmunity?
directed against self antigens
What are the 4 types of hypersensitivity?
type I
type II
type III
type IV
What is type I hypersensitivity?
mediated by IgE antibodies
What is type II hypersensitivity?
binding of IgG or IgM to surface of host cells, which are then destroyed by complement or cell-mediated mechanisms
What is type III hypersensitivity?
antigen-antibody complexes deposited on host cells or tissues, leading to complement activation and inflammation
What is type IV hypersensitivity?
excess T cell activation
What happens when there is a second exposure to type I?
cross-linking of the IgE bound to mast cells via FcεRI
What happens to the gastrointestinal tract when there is re-exposure to type I?
increase fluid secretion and peristalsis
What happens to the eyes and airways after second exposure of type I?
increased mucus secretion and decrease airway diameter
What happens to the blood vessels after type I?
increased vascular permeability and vasodilation
What occurs during type II hypersensitivity?
complement activation
antibody-dependant cellular cytotoxicity (ADCC)
opsonisation
What is Haemolytic disease of the newborn?
leakage of RhD positive into maternal circulation could stimulate an immune response if mother is RhD negative
What happens to newborns caused by Haemolytic disease of the Newborn?
antibodies react and cause tissue damage
What is Myasthenia gravis?
blockage of the nicotinic acetylcholine receptor due to autoantibodies against α chain resulting in blockage of neuromuscular transmission
Myasthenia gravis can cause…?
internalisation and intracellular degradation of acetylcholine receptors
What is immune complex-mediated: Type II hypersensitivity?
persistent immune complexes deposited in blood vessels and cause inflammation
What mediates type IV hypersensitivity?
TH1 subtypes (can be TH17 and CD8)
How do we know if its type IV hypersensitivity?
antigens presented and followed by an effector phase upon re-exposure to the antigen
effector phase does not become apparent
Primary immunodeficiency is…?
genetic, recurrent, or unusual infections
Secondary immunodeficiency is…?
an external factor causing the immune system to be compromised
