Aani Immuno: Hypersensitivity Flashcards
Mnemonic for remembering the types of Hypersensitivity Reaction?
ACID
- Allergic - IgE
- Cytotoxic (ab mediated) - IgG or IgM
- Immune complex mediated -IgG or IgM
- Delayed - T cell mediated
Which Abs are involved in Type 1 Hypersensitivity Reaction?
IgE
Which Abs are involved in Type 2 Hypersensitivity Reaction?
IgG or IgM
Which Abs are involved in Type 3 Hypersensitivity Reaction?
IgG or IgM
Symptoms of Type 1 Hypersensitivity reaction?
Angiodema, Rash, Urticaria, Wheeze, Diarrhoea, Rhinoconjunctivitis, Anaphylaxis
4 Most common Type 1 Hypersensitivity reaction in Children?
- Asthma
- Allergic Rhinitis (hayfever)
- Eczema
- Food
What is atopy?
Triad eczema, asthma, hayfever. Predisposition to developing allergic hypersensitivity reactions.
Can a baby get a peanut reaction the first time they’ve had peanuts?
No, you need to be sensitised first. IgE sensitised.
what is Oral allergy Syndrome? (OAS)
When exposure to pollen can induce food allergy e.g. Birch Pollen Allergy Syndrome.
IgE are directed to proteins in fruit/nuts following respiratory exposure to birch pollen
what are the types of allergic rhinitis?
Seasonal (grass pollen etc)
Perennial (pets, house dust mites)
Occupational (latex, lab animals)
How long does it take for Acute Urticaria to resolve?
Wheals resolve within 6 weeks. If they last longer than 6 weeks, this is Chronic Urticaria
What is anaphylaxis?
A severe systemic allergic reaction
What are the symptoms of anaphylaxis?
Respiratory: Wheeze, cough, throat swelling, breathing difficulty
Hypotension: Faint/raised HR
Skin: Erythema, Urticaria, Swelling, Itch
Why does anaphylaxis happen?
Following exposure to allergen, you get IgE mediated mast-cell degranulation. You can also get Non-IgE mediated anaphylaxis
Common causes for IgE mediated Anaphylaxis?
Wasps
Peanuts
Latex
Penicillin
Common causes for Non-IgE mediated Anaphylaxis?
NDAIDs
IV Contrast medium
Opioids
Which tests are used in Allergy?
Skin Prick Test
RAST
Complement Resolved Diagnostics
Challenge Test
What is the criteria for diagnosing Anaphylaxis?
Amina Said So
Airways affected (Life threatening breathing impairment)
Sudden onset/rapid progression
Skin involvement
Management of Anaphylaxis?
8 things
IM Adrenaline 500 micrograms 100% Oxygen Raise legs Hydrocortisone 100mg IV Inhaled bronchodilators Antihistamine e.g. Chlorphenamine Refer to allergy specialist IV Fluids
What is an important criteria for the Skin Prick test to work?
Must stop antihistamines for 48 hours before test
If you cannot stop your anti-histamines what can you do instead of the skin prick test?
RAST.
What does RAST do?
Measures IgE made against a certain allergen
What is the gold standard investigation for food allergy?
Challenge Test
What can you measure in the blood to check if anaphylaxis has occured?
Mast Cell Tryptase. (Peaks at 1-2 hours. Goes back down by 6 hours).
It is a protein released by mast cells that have undergone degranulation
Other differentials for anaphylaxis?
Pheochromacytoma Anxiety ACE inhibitors (low BP) Inhaled foreign body Chronic Urticaria
Which antigen is attacked by an Ab in the following type 2 hypersensitivity disease:
Haemolytic Disease of the Newborn
Antigen on neonatal erythrocytes e.g. A, B, Rh
Which antigen is attacked by an Ab in the following type 2 hypersensitivity disease:
Goodpasture’s Syndrome
Glomerula basement membrane of Collagen 4
Which antigen is attacked by an Ab in the following type 2 hypersensitivity disease:
Graves Disease
TSH receptor
not just TSH
Which antigen is attacked by an Ab in the following type 2 hypersensitivity disease:
Churg Strauss Syndrome
Medium & Small Vessels
Which antigen is attacked by an Ab in the following type 2 hypersensitivity disease:
Wegener’s Granulomatosis
Medium & Small Vessels
Which antigen is attacked by an Ab in the following type 2 hypersensitivity disease:
Pernicious Anaemia
Intrinsic Factor
or
Gastric Parietal Cells
Which antigen is attacked by an Ab in the following type 2 hypersensitivity disease:
Pemphigus Vulgaris
Epidermal Cadherin
Which antigen is attacked by an Ab in the following type 2 hypersensitivity disease:
Autoimmune Thrombocytopaenic Purpura
Glycoprotein 2a/3b on platelets
Which antigen is attacked by an Ab in the following type 2 hypersensitivity disease:
Chronic Urticaria
Allegerns e.g. drugs, bites etc
Which antigen is attacked by an Ab in the following type 2 hypersensitivity disease:
Autoimmune Haemolytic Anaemia
Blood Group Antigens on Erythrocytes
What is Evans syndrome?
Autoimmune Haemolytic Anaemia + Immune Thrombocytopaenic Purpura
Which antigen is attacked by an Ab in the following type 2 hypersensitivity disease:
Myasthenia Gravis
Acetylcholine receptor
Which antigen is attacked by an Ab in the following type 2 hypersensitivity disease:
Microscopic Polyangitis
Pauci-immune necrotizing small vessels
Which antigen is attacked by an Ab in the following type 2 hypersensitivity disease:
Acute Rheumatic Fever
M proteins on Group A Strep
Which specific test(s) can be carried out for:
Myasthenia Gravis
- Anti Ach R Abs
- Tensilon Test
- Abnormal EMG
Which specific test(s) can be carried out for:
Goodpasture’s Syndrome?
- Anti GBM Ab
2. Smooth linear line visible on IF staining (IgG deposits on BM)