Hypersensitivity Flashcards
what are hypersensitivity disorders
incorrect immune response causing damage to self - includes allergy and autoimmune disease
which type of hypersensitivity is each disorder
I - immediate hypersensitivity
II - direct cell effects
III - immune complex mediated
IV - delayed hypersensitivity
type I hypersensitivity causes what
allergy
what causes allergy to arise
IgE mediated response to external antigen (allergen)
what are examples of allergens
foods, asthma, pollen, eczema, drugs
what is the hygiene hypothesis
that increasing cleanliness can lead to increased allergy in children - prevention of Th1 cells differentiating into Th2 cells
does the first exposure to an allergen cause an allergic reaction
No, second exposure causes reaction. B cells produce IgE and allergen is cleared but on second encounter of allergen histamine is released from IgE
what is the immediate response of exposure to an allergen
muscle spasm
mucosal inflammation
inflammatory cell infiltrate
what is the management of allergy
allergen avoidance
anti-inflammatory
block mast cell activation
type II hypersensitivity involves activation of what
IgM or IgG antibodies reacting to surface antigens
what are two examples of type II hypersensitivity
blood transfusions
Good Pastures syndrome
what is Good Pastures syndrome
autoimmune disease affecting kidneys and lungs.
due to genetic susceptibility and environmental triggers
what is the treatment for Good Pastures syndrome
ICS, smoking cessation
what are three functions of antibodies
act as opsonins for phagocytosis
activates NK cells and eosinophils
activates complement system
what is the bodys response to type III hypersensitivity
leukocyte accumulation and inflammation
what is an example of type III hypersensitivity
hypersensitivity pneumonitis/extrinsic allergic alveolitis
what type of conditions cause extrinsic allergic alveolitis
farmers lung, malt workers lung, cheese workers
what organisms commonly cause EAA
aspergillus - inhalation of mould etc can leave deposits within the bronchioles and alveoli
what is the treatment of EAA
antigen avoidance
reduce inflammation through ICS
reduce production of antibody through immunosuppression
what is a side effects of immunosuppression/anti-TNF therapy
reactivation of latent TB
type IV hypersensitivity is delayed type true/false
true
how long does it take after exposure to experience symptoms from EAA
4-6 hours
how long does it take after exposure to experience symptoms from an allergen
immediate, minutes to an hour
how long does it take after exposure to experience symptoms from type IV hypersensitivity
days
what are examples of non-autoimmune type IV hypersensitivity
sarcoidosis
TB
which lymphocyte causes type IV hypersensitivity
T cells
what is the pathophysiology of type IV hypersensitivity
inhalation of antigen causes macrophages and T cells in the parenchyma causing granuloma formation
what is the management of sarcoidosis
many patients spontaneously improve
can treat with ICS to block T cell activation
