Blood and Immune: Allergy, Hypersensitivity Flashcards
What is the most common form of immune disorder
an allergic reaction
How many people have some form of allergy
30%
Which group people has Seasonal rhinitis (hay fever) the most
Caucasians
How many New Zealanders have asthma
1 in 6
What is asthma
Immediate type allergic response where the bronchial tubes in lung narrow and thicken and inflame in response to a range of allergens or other triggers such as cold air
What is Allergic rhinitis
seasonal hay fever
When does Allergic rhinitis occur
Occurs in spring/summer due to pollen from certain flowers
What is dermatitis
Skin inflammation
what is urticaria
hives
What is the second most common site for allergic reactions
the skin
how do skin allergies occur
caused by the release of histamine into the tissue from mast cells in the skin
What is oedema
swelling
how does oedema occur
caused by leakage of fluid into the spaces between cells
main two locations of allergic reactions
mucosal regions of upper respiratory tract (nose and throat), and skin
examples of insect allergies
House dust mite, bee stings
How does penicillin cause an allergic reaction
Penicillin can interact with proteins to produce something that looks new to generate IgE response
How does jewellery cause allergic reaction
Nickel leeches out of jewellery into skin and modifies proteins in skin so that they seen new
Nickel allergies are an example of
Metal induced contact dermatitis
What is anaphylaxis
A serious complication in an allergic reaction when the mast cell activation occurs throughout the body.
what does atopic mean
at a single sight
what does systemic mean
at multiple sites
where does oedema occur in anaphylaxis
Oedema and swelling occurs at multiple anatomical sites that are distant from the original site of allergen challenge
treatment of anaphylaxis
immediate injection of epinephrine (adrenalin)
What is a type 1 hypersensitivity
Atopic allergy (IgE mediated) - Immediate
What is a type 2 hypersensitivity
Complement mediated - Medium
What is a type 3 hypersensitivity
Serum sickness (Immune complexes) Medium
Less common
Recognition of abnormal immune complexes
What is a type 4 hypersensitivity
Delayed Type (DTH) Slow response
Mediates Type I reactions
IgE and mast cells with a high affinity Fc receptor
Mediates Type II reactions
Complement
Mediates Type III reactions
Immune complexes
Mediates Type IV reactions
Adaptive immune system
What are mast cells
innate cells from myeloid lineage that reside in the skin (provide protection against complex organisms that cannot be engulfed by phagocytosis)
What does the FcεR receptor on mast cells have a high affinity too
IgE:antigen complexes
What happens when IgE antibody binds to large antigen complexes (like pollen)
it triggers local mast cells to rupture and empty their granules
What does a mast cell precoated with IgE mean
it has been primed against a particular allergen (from birth or mothers genes)
An activated mast cell produces: (5)
Histamines, leukotrienes, prostaglandins, free radicals, substance P
What does a Type I hypersensitivity
do to smooth muscles and blood vessels
causes them to constrict
What does a Type I hypersensitivity
do to mucous glands
Mucous glands produce mucus, releasing fluid causing swelling/Oedema
What does a Type I hypersensitivity
do to platelets
clotting
What does a Type I hypersensitivity
do to sensory nerves
causes nerve ending stimulation = pain
What does a Type I hypersensitivity
do to other immune cells
Recruitment of other immune cells like eosinophils
What causes body response in a type 1 hypersensitivity
vasoactive amines (histamines)
Types of Helper T cells that are involved in Type I hypersensitivity
Th1, Th2
Cytokine that causes an immature IgM-producing B cell to mature to produce IgE
IL-4
Histamines are a kind of:
vasoactive amines
What is involved in a type 2 hypersensitivity
FcR, complement and neutrophils (phagocytes)
What is in normal phagocytosis
Fc receptor for IgG or IgM
Complement receptor for complement
Process of Rhesus baby in newborns
when a pregnant woman is RhD-, but her baby is RhD+, maternal anti-RhD IgG may be produced which can cause acute haemolytic anemia in the child soon after they are born
What is Rhesus baby
This condition is caused by a blood group antigen RhD on the surface of red blood cells
Rhd genes of parents to produce Rhesus
Mother needs to be RhD - and the father must be Rhd+
What type of hypersensitivity is involved in Rhesus baby
type 2
What is Desensitisation
When an increasing dose of allergen is injected into the patient over a period of time, so that they manufacture high affinity IgG that competes with IgE.
How many patients does Desensitisation work in
about 50%
Process by which monoclonal antibodies are/were made
Mouse immunised -> mouse boosted -> spleen removed -> splenocytes fused with mouse myeloma cells -> hybridoma screened
Pros of using Mabs as therapeutic agents (4)
Highly specific, humanised, no adverse reactions, can be modified for greater potency
Cons of using Mabs as therapeutic agents (2)
Expensive, possibly serious side effects
What type of immunoglobulin is developed in response to allergens early in life that sensitises mast cells in the skin
IgE