Chapt. 4: Indoor and Outdoor Allergens and Pollutants Flashcards
What is the primary composition of allergens in and outside the home?
Proteins
Major route of exposure both inside and outside the home
Inhalation
Submicronic particles are more likely to be associated with rhinitis or asthma?
Asthma
The main source of outdoor allergen exposure?
Pollens and fungi
Most significant allergen sources in the home?
Mites, cockroaches, pets such as dogs and cats
Atopic dermatitis and anaphylaxis are associated with what food allergen sources?
Peanuts, milk and fish
Rhinitis and asthma are associated with what aeroallergens?
pollens and house dust mites
Meaning of allergen?
describes any of those that are capable of stimulating the production of specific IgE in a genetically predisposed individual
Most clinically significant route of exposure to allergens?
Respiratory tract
Meaning of allergenic?
describes the IgE-inducing property of an allergen
The terms allergen, allergenic, and allergenicity are synonymous with what terms?
antigen, antigenic, and antigenicity
Meaning of cross-reactive allergen?
because of a significant sequence homology (common epitopes), a patient will produce an IgE response to a primary allergen and also react to a related one.
What are some cross-reactive allergens?
tropomyosins in mites, snails, cockroaches, shellfish
In pollens and distantly related fruits what are the common allergens?
profilins
What is the OAS (oral allergy syndrome)/PFS (pollen food syndrome)?
Patients who are sensitized to pollen via inhalation and react to distantly related fruits.
What are the most complex glycoprotein mixtures allergens?
pollens, fungal spores, seeds and mites
What are the least complex glycoprotein mixtures allergens?
animal danders, urine and from occupational sources
What is the percentage of polysensitization?
70%. Monosensitization often precedes polysensitization.
Meaning of “major” allergen?
Allergens in a particular source that are recognized by >50% or more of allergic individuals. The remaining ones are “minor”.
What is important to the aerosolized particles, the aerodynamic or the absolute size?
The aerodynamic size.
What size particles will give rise to nasal symptoms as opposed to asthma?
> 10 um. Submicronic particles enter the bronchi and give rise to lower airways inflammation, resulting in asthma
Size will also affect what property of the allergen?
The length of time the particles are suspended in the atmosphere, and thus the exposure
How to express pollen and fungal spores?
Number of grains/spores/m3 per 24hours or pollen index of developing symptoms using the terms “low” “moderate” “high” “very high” and “extreme”
What are haptens?
LMW chemically reactive compounds which are allergenic
What are the most common haptenic compounds in clinical practice?
The beta lactam antibiotics such as the benzyl penicillins.
Every protein allergen contains a number of potential epitopes, which are also known as antigenic determinants. what are these?
These represent linear amino acid sequences or adjacent sections of a sequence that engage with either the B cell receptor or its soluble antibody form or the T cell receptor sitting on the surface of a lymphocyte.
What is the number of amino acid residues comprising a B cell epitope that interacts with the actual binding site of a B cell receptor or allergen-specific IgE?
5 amino acid residues
Are lipids allergenic?
Do not appear to be, although the lipid content of some sources such as pollens may play an adjuvant role in sensitization.