- Allergy = The immunological response of the human body to foreign substances, also known as allergens. Mostly IgE
mediated.
o 150 million Europeans
o Prediction: in 2025, 50% of all Europeans will suffer from an allergy
o Most common types
▪ Allergic rhinitis (aeroallergens)
▪ Food allergy
▪ Allergic asthma
▪ Insect sting allergy
o Symptoms
▪ Sneezing/runny nose
▪ Itching eyes/skin rash
▪ Wheezing/coughing/shortness of breath
▪ Swelling of lips/tongue/eyes/face
▪ Abdominal pain, vomiting, diarrhea
▪ Anaphylaxis
- Allergy or not:
o Someone ate a candy bar containing peanuts and is, a few minutes after, experiencing swelling of the tongue,
lips and face → yes
o Someone ate bread, containing gluten. They experience bloating, obstipation and abdominal pain. Their body
contains high amounts of IgA. → no, celiac disease, autoimmune disease
o Someone had a glass of milk and experiences diarrhea, abdominal pain and bloating after a few hours. → no,
lactose or milk intolerance
o Someone had a glass of milk and experiences redness of the skin and abdominal pain after a few minutes. →
yes
o Someone has been experiencing a rash, dizziness, fatigue and headaches on regular basis. After carefully
screening when these symptoms occur, they came up with the following products: fish, strawberries,
avocado, chocolate, cheese. → no, histamine intolerance
- Immune system
- In allergies the T-cells are important
o Every type of immune cell has a different function
in you body. Based on the signals from the
environment, your body will switch to a certain type.
In case of allergy Th1 and Th2 (T helper cells).
▪ If you have too little Th1 cells for a longer time,
you can develop diseases like rheumatism, psoriasis,
MS, Crohn’s disease, arthrosis, diabetes-type 1.
▪ If you have too little Th2 cells for a longer time,
you can develop allergies, HIV and during pregnancy
you have higher Th2 count in you body (?).
, - Immunological pathway of allergy
o Antigen presenting cell (APC).
▪ Dendritic cells / macrophages: If something that isn’t supposed to be in your body enters, these
cells will eat it → phagocytosis → small piece(s) of the antigen will be presented → these pieces will
be recognized by the T-cells (adaptive immune system).
If you’re already primed to develop an allergy, T-cells will differentiate into Th2 cells.
Th2 cells will release cytokines (IL-4 and IL-13) → activates B-cells, that are able to produce IgE
(characteristic of an allergy, also tested) when they turn into plasma cells → will crosslink to mast
cell → degranulation → allergic symptoms
Memory B-cells and memory T-cells.
o Whenever your body makes a mistake in detecting a food compound and recognizes it as something bad, it
will create a memory, and therefore your body will respond to it every time in the same manner.
o Two categories
▪ Sensitization phase: First time you come into contact with a food allergen. Nothing happens, you
need re-exposure to get the symptoms. Also with mosquito bites.
▪ Allergic reaction: Nex time your exposed to the allergen.
- Allergy: an increasing problem
- The cost of allergy
o Price level 2019 and EU-28: 69 billion euros! →
NL 2.3 billion/year
▪ Societal costs and hospital costs, but also recalls
cost billions a year.
- If the recall damage in the EU is similar to the US, then about 70 billion euros industrial damage of food recalls, of
which 40% is due to allergens → 28 billion / year
Societal costs of allergy → 69 billion / year
Total allergy costs: 97 billion / year
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