Immunology 1: Hypersensitivity, allergy and inflammation Flashcards
What is the primary mediator in type 1 hypersensitivity reactions?
IgE
Give 3 examples of type 1 hypersensitivity reactions
Asthma
Allergic rhinitis
Eczema
Recall the pathophysiology of a type 1 hypersensitivity reaction
- Sensitisation: IgE binds mast cells and basophills
2. 2nd exposure: More IgE , cross-links –> degranulation
What is the primary mediator in type 3 hypersensitivity reactions?
Immune complexes
Give 2 examples of type 3 hypersensitivity reactions
SLE
Vasculitis
Recall the pathophysiology of a type 3 hypersensitivity reaction
Immune complex formed
Cannot traverse vessel walls
Deposition in various tissues
What is the primary mediator in type 2 hypersensitivity reactions?
Antibodies
Which immunoglobins are associated with type 3 hypersensitivity reactions
IgG
IgM
Recall the pathophysiology of a type 2 hypersensitivity reaction
Ab responds to a cell-surface or matrix-bound antigen
Give 3 examples of type 2 hypersensitivity reactions and the antigens implicated in each case
- Glomerular BM = glomerulonephritis
- AChRs = myasthenia gravis
- Intrinsic factor = pernicious anaemia
Recall 2 tests that can be used to detect type 2 hypersensitivity
Need to look for specific antibody:
Immunofluorescence
ELISA
In what disease is the ani-CCP antibody implicated?
Rheumatoid arthritis
What is the primary factor involved in type 4 hypersensitivity reactions?
T cells
Give 4 examples of type 4 hypersensitivity reactions
Chronic graft reaction
Coeliac
Graft-vs-host disease
Allergy (asthma, eczema etc BECOME type 4 chronically)
Recall the pathophysiology of type 4 hypersensitivity reactions
- T cells stimulated by Ag
- Macrophages and CD8+ T cells activated
- Th1 –> IF gamma
- Th2 –> B cell activation –> IL4,5,13
- TNF-alpha release causes tissue damage
Recall the 6 main mediators involved in inflammation
Histamine Leukotrienes Interleukins Complement TNF-alpha Interferons
In which type of hypersensitivity reaction is angiodema a key feature?
type 1
In which type of hypersensitivity reaction is urticaria a key feature?
type 2
What is urticaria and by which Ig is it mediated?
Hives - IgG
Define “atopy”
Hereditary tendency to develop hypersensitivity reactions
Recall 2 genetic factors that predispose to atopy
- IL4 gene cluster (lead to raised IgE, asthma)
2. IgE receptor gene on 11q
How does gender influence risk of atopy?
In children: more males
In adults: more females
What is the main interleukin released by eosinophil degranulation?
Il-5
Recall 3 features of the immunopathogenesis of asthma
- SMC hypertrophy
- Mucus plugging
- Subepithelial fibrosis following persistent inflammation
What is the proper name for “hay fever”?
Allergic rhinitis
Recall 3 clinical features of anaphylaxis
- Swelling of lips and throat
- Wheeze and dyspnoea
- D&V
Recall 3 tests that can be used to investigate hypersensitivity
- Skin-prick testing
- RAST
- Total IgE
What is RAST?
Rasioallerosorbent test - tests for the amount of a specific IgE in the blood
What is the main lung function test used to diagnose asthma?
Peak expiratory flow
Recall the immediate treatments used for mild and severe anaphylactic reactions
Mild: anti-histamine
Severe: adrenaline
Recall the 3 main therapies used in allergic rhinitis
- Cromoglycate (mast-cell stabiliser)
- Nasal steroid
- Anti-histamine
Recall the 2 main therapeutic approaches in eczema
- Emolliants
2. Topical steroid
Summarise the 4 steps of asthma treatment
- Salbutamol
- Beclomethasone
- Longer-acting beta-2 agonist than salbutamol
- Prednisolone
Recall the standard length of a subcutaneous course of immunotherapy
3 years
