Allergy 2 Flashcards
Whats chemical sensitivity?
- Acquired Intolerance of airborne chemicals
Examples of chemical sensitivity?
- Products of combustion
- Perfumes and fragrances
- Products for Cleaning
- Pesticides
- Food additives and caffeine
- Paints and other solvent
Symptoms of chemical sensitivity are similar to…
…that of a classical allergy
Chemical sensitivity can be related to…
…fibromyalgia, chronic fatigue syndrome and, in some cases, post-traumatic stress disorder.
What organ systems are involved in chemical sensitivity?
- Respiratory system
- Nervous system
Classical allergy is also known as…
…type I hypersensitivity
Classical allergies range from…
…hay fever to food allergy.
Classical allergy is an […] condition, which is mediated by […] route.
Classical allergy is an acquired condition, which is mediated by IgE route.
Classical allergies induces inflammation via…
…the release of histamine from mast cells
Classical allergies can be …
…atopic (immediate) or non-atopic (delayed) in response
Possible symptoms of allergy?
- Allergic Rhinitis: – Most common clinical expression of atopic hypersensitivity
- Allergic asthma– Allergen exposure results in bronchoconstriction
- Allergic Gastroenteropathy– Localized IgE reactions in the gut to an ingested food
- Urticaria– Diffuse hives or wheals
- Angioedema– localized tissue swelling that can occur in soft tissues throughout the body
Whats anaphylaxis?
A sudden and severe allergic reaction
Anaphylaxis occurs within…
…minutes of exposure
Anaphylaxis is marked by…
… swelling of the throat or tongue, hives, and trouble breathing.
During anaphylaxis, what is at risk?
Life is at risk and time is critical
Anaphylaxis can lead to death within…
… 15 minutes if treatment is not received
Methods of IgE Allergy Testing?
- Skin prick testing
- Elimination/Challenge diets
- Antibody testing – Didn’t work for my sesame allergy
- Hydrogen breath test (lactose)
- Coeliac test (gut biopsy)
What are the two major types of anaphylaxis?
1) IgE mediated
2) Non-IgE mediated
Whats IgE mediated anaphylaxis?
- True anaphylaxis that requires an initial sensitizing exposure, the coating of mast cells (and basophils) by IgE, and the explosive release of chemical mediators upon re–exposure.
Whats Non-IgE mediated anaphylaxis?
- These reactions, the so called “anaphylactoid” reactions, are similar to those of true anaphylaxis, but do not require IgE.
– Usually caused by the direct stimulation of the mast cells and basophils.
– The same mediators as occur with true anaphylaxis are released and the same effects are produced.
Mast cells may be triggered by other stimuli such as…
…exercise, emotional stress, chemicals.
Non–IgE mediate Anaphylaxis does not require…
…sensitization
IgE (atopic) allergies most often
develop in…
…childhood
The genes of every child come…
…50% from the mother and 50% from
the father
half the proteins in the child are derived from…
…the father
The genes of every child come 50% from the mother and 50% from
the father.
* So half the proteins in the child are derived from the father
* This is a potential problem as the mothers immune system can…
…attack cells showing paternal derived proteins. Particularly since IgG can cross the placenta.
babies immune systems are…
…Th2 cell rich
So babies immune systems are Th2 cell rich and thus…
…drive IgE antibody producing cells
In most cultures kids are exposed to…
…lots of micro-organism from birth stimulating Th1 cells to develop and thus restoring the Th1/Th2 balance.
But if the environment is too
clean then this balance is…
…restored only slowly
When a B-cell is stimulated to change its antibody type, it is the…
…Th2 cells that direct the
change.
- Resulting in classic IgE type allergy
It is thought that the immature immune system of babies can be
‘educated’ by …
…food antigens present in the
mothers milk
What are Th0 ?
virgin/naive T-helper cells
Th1 and Th2 helper cells differentiate from …
…virgin/naive T-helper cells (Th0)
With frequent type 1 hypersensitivity, virgin T helper cells encouraged to…
…differentiate as Th2 cells
Low levels of Th1 cells mean
suffers get …
…more systemic infections (e.g. bronchitis) and take longer to recover/heal.
Mast cells are very…
…long lived.
Memory B cells can last…
…50+ years
IgE stimulated allergy thus tend to…
… reoccur even after long periods of exclusion of the allergenic food from
the diet.
If one or two B cells bind the food allergen, but not enough to trigger a reaction then …
…cells called T reg cells can instruct the B cell to suppress the response to the allergen.
Giving the sufferer very small amounts of the allergenic food – not enough to cause a reaction! – can lead to an…
…increase in the number of T reg cells
Giving the sufferer very small amounts of the allergenic food – not enough to cause a reaction! – can lead to an increase in the number of T reg cells and so the…
…suppression of the reaction when greater quantities of allergen is encountered.
What are the two types of intolerance?
1) Non-allergy intolerance
2) IgG based allergy
Whats a non-allergy intolerance?
This is where the digestive system is lacking an enzyme
Whats an IgG based allergy?
Caused when food gets through to the blood in a less than completely digested state
Non-allergy intolerance is where the digestive system is lacking an enzyme. For example,…
… The enzymes that digests lactose (lactase) for instance
Lactose passes through to the…
…lower gut
Lactose passes through to the lower gut where it is digested by …
…microbes living in the gut
Some gut bacteria are friendly such as…
…vitamins and energy
Some bacteria will produce…
…gas, causing bloating
Other bacterias will produce…
…diarrhoea and malaise
What are Allergy-related food intolerances (Food-specific IgG related) ?
An actual food allergy, indicated by the
production of antibodies to the food allergen, and by the release of histamines and other chemicals into the blood
Many adverse reactions to foods do not involve…
…IgE antibodies
Many adverse reactions to foods do not involve IgE antibodies.
- They are called…
…food “sensitivities” or “intolerances.”
Many adverse reactions to foods do not involve IgE antibodies
- They are called food “sensitivities” or “intolerances.”
- Other immune mechanisms are used instead such as…
…IgG antibodies, immune complexes, or cell-mediated reactions are involved instead.
Allergy-related food intolerances can happen…
…quickly or can be delayed for two to
seventy-two hours or longer.
IgG are the most […] and […] antibody.
IgG are the most common and smallest antibody.
IgG allergy are the only…
…immunoglobulin to cross placenta
IgG are involved in fighting…
…the disease.
IgG is similar to…
…IgE
Other than mast cells, IgG antibodies can bind to several other cell types such as…
…Macrophages, monocytes and polymorphonuclear leukocytes (including neutrophils).
IgG antibody can bind to …
…mast cells (and thus anaphylaxis), but are usually free in the blood
Often the reaction is less intense as these other cells types do not have the
same ability as mast cells to…
…amplify the immune response.
(You have a reaction, but it is mild – perhaps barely noticeable – you just feel rough)
Expression of food intolerance may be influenced by…
- Physical exertion
- Stress
- Level of inflammation
- Increased permeability of the gut
Probiotics are…
… bacteria known to be beneficial
Probiotics help prevent…
… bad organism from adhering and causing problems such
as candidosis
There is evidence to suggest that
good bacteria can:
– Reduce the risk of cancer
– Lower serum cholesterol
– Reduce the severity of food allergies
– Stimulate the immune system
– Are anti-inflammatory
Allergens that cause food intolerance are often…
…repetitive in structure
Allergens that cause food intolerance are often repetitive in structure.
- They are often …
…storage proteins in seeds, eggs or foods such as milk used to transport nutrients
virgin B cells can be partially activated by…
…binding of more that one surface antibody to the antigen.
If large amounts of any type of food is eaten that gets in to the body (via leaky gut for instance) then any virgin B cells reacting to the food could …
… be activated
Because the B cell is not fully activated means that…
…the reaction is not necessarily fixed
About 95% of IgG-mediated reactions are…
…not fixed.
