Allergy Flashcards
Define: Allergy
Damaging ~fatal reaction made by normal immune system against non-harmful antigens in a pre-sensitised host.
What is a cytotoxic allergic response?
IgG/IgM antibody against combined self + foreign antigen at the cell surface.
What is the onset of a cytotoxic allergic response?
Mins to hours
What does a cytotoxic allergic response cause?
Cell lysis and necrosis
What is a common antigen in a cytotoxic allergic reaction?
Penicillin
What type of allergic reaction are Erythroblastosis Fetalis and Goodpasture’s nephritis assc with?
Type 2: Cytotoxic
What is an immune allergic response?
Antibody response against soluble antigen
How long does an immune allergic response last for?
3-8 hours
What disease is associated with immune allergic responses?
Systemic Lupus Erythmatous
What is a delayed allergic response?
T cell mediated, antigen specific cytotoxicity.
What is different about Delayed response to immune and allergic?
Delayed doesn’t use antibodies.
What is the onset of delayed allergic response? (Hint: Look at it’s name)
DELAYED ~48/72 hrs
What are the common antigens for delayed allergic response?
> Metal- nickel
> Tuberculin
What disease is assc with delayed allergic response?
Contact dermititis
What activates B cells in Type 1 allergic response?
Th2 cells
What antibody do B cells make in a Type 1 allergic response?
IgE
What are the immune responses to parasitic disease? (HARD)
> Incr IgE - pathogen specific
Tissue inflammation - Eosinophilia, mastocytosis and basophil infiltration.
CD4+ T cells secreting IL4, 5, 13.
What is the Hygiene hypothesis?
Give pro-biotics to pregnant women, microbe = protective effect. Lower atopic condition probability.
What is an atopic condition?
A hypersensitive allergic response that occurs in area not touched by allergen.
What mechanisms does the Hygiene hypothesis use?
> Th1/Th2 deviation
> Antigenic competition
What does Th1 stimulate?
Infection management
What does Th2 stimulate?
Allergy
Is allergy a polygenic or monogenic disease?
Polygenic
What are allergens?
Antigens that initiate an IgE-mediated response.
How is IgE made?
Th2 make IL4 –> stimulate B cell –> Make IgE.
What is a sensitised mast cell?
Mast cell with IgE antibody.
What happens in an IgE mediated allergic response?
Basophil degranulation –> inflammatory mediator release
What is the onset of IgE mediated allergic response?
15-30 mins - fast
What does the late phase response of IgE allergic response release?
Arachidonic acid –> Leukotrienes and Prostaglandins.
What are the roles of the Th2 cell?
> Multiple cytokine release
Part of innate inflammatory response
Drives Ig production
What three diseases form the Atopic triad?
> Asthma
Rhinitis
Eczema
What symptoms does Rhinitis give?
> Blocked nose
> Runny nose - assc w/ eye symptoms
What is the treatment of Rhinitis? (Hint: hayfever)
Anti-histamines and nasal steroids
What are the symptoms of Asthma?
> Airway constriction
Airway inflammation
Hypersensitivity
What does the late phase response of asthma do to the airways?
Damage, makes them hypersensitive to non-allergens (e.g fumes)
What are the three things used to treat allergic responses?
> Anti-histamines
Steroids
Adrenaline (life saving)
What is the specific therapy for allergic responses?
Immunotherapy (sub cut. or sub ling.)
What GI symptoms can a food allergy cause?
> Vomiting
> Diarrhoea
What respiratory symptoms can a food allergy cause?
> Bronchospasm
> Rhinitis
What cutaneous symptoms can a food allergy cause?
> Urticaria (hives)
> Angioedema
What is the most serious symptoms of a food allergy?
Anaphylaxis
