Flashcards in 10 Allergy Deck (17)
What is the body's response to parasitic disease?
Increased IgE levels.
Tissue inflammation with eosinophils, basophils and mastocytosis.
Presence of CD4+ T cells secreting IL4, IL5, IL13.
What is the hygiene hypothesis?
Stimulation by microbes is protective against autoimmunity.
Th1 Th2 deviation - if Th1 (infection) has nothing to work on Th2 increases.
Which genes have influences on the 'allergic' immune response? (5).
Cytokine gene cluster IL3,5,9,13
Beginning with a Th2 cell, how is mast cell degranulation achieved>
Th2 cell uses IL4 and IL13 to stimulate B cell into proliferating and producing IgE. IgE binds to sensitised mast cells which degranulate.
Mast cells have initial and late phase responses, which chemicals characterise both?
Initial: histamine, proteases, chemotactic factors (ECF, NCF).
Late: Arachidonic acid derivatives - leukotrienes, prostaglandin.
What is the atopic triad diseases?
Asthma, rhinitis, eczema.
What is rhinitis? What are the common allergens?
Allergic response in upper respiratory tract and eyes.
Animal dander, pollen, house dust mite.
Rx for rhinitis?
Antihistamines and nasal steroids.
What is allergic asthma?
IgE mediated allergy. Late phase response causes away damage. Damaged tissue becomes hyper-reactive to other stimuli e.g. fumes.
What is atopic dermatitis? Rx?
Allergy resulting in blistering, itching, cracking of skin. Major trigger is dust mite.
Rx: topical steroids and moisturisers.
What is the trinity of interplaying factors in atopic dermatitis?
Development of AD (Th2).
Which tests are available to diagnose anaphylactic reactions? (6).
Specific IgE (>0.35KuA/L)
Skin prick test (>3mm wheal).
Oral challenge (gold standard).
Basophil activation test (research, not clinical).
Component resolved diagnostics.
How is a skin prick test carried out?
Which drugs common affect this test?
-ve control (saline), +ve control (histamine), exposure.
Anti-histamines and tri-cyclic antidepressants.
What are the symptomatic therapies for anaphylactic reactions? (3).
What are the indications for immunotherapy for anaphylactic allergies? (3).
Life-threatening reaction to wasp/bee sting.
Severe hay fever.
Animal dander allergy.
What is the mechanism behind immunotherapy?
Purposeful exposure to allergen at increasing doses. Try to divert Th2 to Th1 response. Induce Treg cells and stimulate B cells to increased antibody competition.