Standardization & Preparation of Allergen Extracts 2022

Question 1

1. A 10-year-old patient comes into your office with perennial rhinitis. Skin testing is ordered to evaluate for allergies to common aero-allergens. A process is used to ensure the skin test
extracts are accurate and precise.
What is the best process?
A. Equivocation
B. Extraction
C. Standardization
D. Sterilization

Answer 1

1. C, Standardization, p. 467.
   Of the answer choices, standardization would be the chosen method. Standardization is the
   process by which reference extract is selected and methods and procedures are developed
   quantitively to compare a test extract to establish equivalence

Chapter 29: Standardization and Preparation of Allergen Extracts
Middleton’s Allergy Principles and Practice, 9th Edition

Question 2

2. Which of the following are cross-reactive with Timothy grass?
A. Aceracea (maple, box elder)
B. Chloridoidea (Bermuda)
C. Panicoidea (Bahia)
D. Poodieae (perennial rye)

Answer 2

2. D, Poodieae (perennial rye), p. 468.
   Timothy grass belongs to Pooideae group which includes Lolium (aka perennial rye). Other
   grasses that cross react are poa annua (blue grass), dactylis (orchard), festuca, and vernal.
   Chloridoidea and Panicoidea are grasses that do not cross react. Aceraceae are trees. See table 29.1.

Chapter 29: Standardization and Preparation of Allergen Extracts
Middleton’s Allergy Principles and Practice, 9th Edition

Question 3

3. What are two methods for collecting pollens from source materials?
A. Cutting and wetting method
B. Drying and glycerin method
C. Growing and salvaging method
D. Vacuum and water setting method

Answer 3

3. D, Vacuum and water setting method, p. 467-8.
   Vacuum method is a widely used and efficient method of collecting pollen from plants that
   grow in pure stands like grasses and weeds. The water setting method is performed by placing
   freshly cut stems and flowers in flasks containing water in an enclosed room or green house
   before pollination and then collecting pollen. Other methods include cutting and drying.

Chapter 29: Standardization and Preparation of Allergen Extracts
Middleton’s Allergy Principles and Practice, 9th Edition

Question 4

4. When performing allergy tests, which extract should not be mixed due to risk of
degradation?
A. Cockroach, dust mites, mold
B. Dog, cat, cockroach
C. Grass, tree, cat
D. Tree, grass, dog

Answer 4

4. B, Dog, cat, cockroach, p.473.
   Dog, cat, and cockroach cannot mix. Fungal and cockroach extracts with pollen or dander
   extracts should be avoided. Proteases from fungal and cockroach extracts can lead to enzyme
   degradation when mixed with pollen and dander extracts and decrease stability. This is the
   main reason why they should not mix.

Chapter 29: Standardization and Preparation of Allergen Extracts
Middleton’s Allergy Principles and Practice, 9th Edition

Question 5

5. What is the family of small extracellular proteins that mammalian allergenics such as cat (Fel
d 1) and cattle (Bos D 2) belong to?
A. Lipid transfer proteins
B. Lipocalin
C. PR-10
D. Profilins

Answer 5

5. B, Lipocalin, p. 469.
   Allergenic source materials such as from rodents (Mus m 1) and dog (Can f 1) and cat (Fel d 1)
   belong to a family of small extracellular proteins called lipocalins

Chapter 29: Standardization and Preparation of Allergen Extracts
Middleton’s Allergy Principles and Practice, 9th Edition

Question 6

6. A 10-year-old boy who lives on farm presents with year-round allergies. His family currently travel between Ecuador and their home in South Dakota. His mother has noticed that his symptoms improve when they are in South Dakota.
   What is a likely allergen causing his symptoms?
   A. Amb a 1
   B. Blot t 2
   C. Tri a 14
   D. Mus m 1

Answer 6

6. B, Blot t 2, p. 469.
   Blomia tropicalis (Blot t 2) is noted to be part of mites that can be found in tropical and
   subtropical regions. It can be found in homes at densities equal to Dermatophagoides species.

Chapter 29: Standardization and Preparation of Allergen Extracts
Middleton’s Allergy Principles and Practice, 9th Edition

Question 7

7. A 30-year-old park ranger presents to your clinic with a history of severe anaphylactic
   reactions. He complains that several hours after he eats lunch, he starts having episodes of
   hives and wheezing. One of these attacks required a visit to the emergency department where
   he was given an epinephrine injection to resolve. He cannot pinpoint what he is allergic to since these events have happened 3-4 hours after eating.
   What is the most likely epitope that is causing his reactions?
   A. Albumin
   B. α(2, 3)-fucose
   C. Galactose alpha-1, 3 galactose
   D. Glucosamine

Answer 7

7. C, Galactose alpha-1, 3 galactose, p. 469.
   Galactose alpha-1, 3 galactose has been linked to severe and atypical anaphylactic reactions. It
   is a mammalian oligosaccharide epitope that is present on several proteins in mammalian
   tissues including muscles.

Chapter 29: Standardization and Preparation of Allergen Extracts
Middleton’s Allergy Principles and Practice, 9th Edition

Question 8

8. What are common unit labels for non-standardized allergen extracts?
A. Bermuda grass (BAU/mL)
B. Birch (protein nitrogen units)
C. Ragweed (Amb a 1 units)
D. Yellow hornet (μg protein)

Answer 8

8. B, Birch (protein nitrogen units), p. 470-1.
   Non-standardized extracts are formulated based on w/v or protein content alone (protein
   nitrogen units) while standardized extracts are formulated based on potency tests and use units AU/mL, BAU/mL, or μg of protein.

Chapter 29: Standardization and Preparation of Allergen Extracts
Middleton’s Allergy Principles and Practice, 9th Edition

Question 9

9. Which insect venom protein can be extracted using whole-body extracts therapy?
A. Fire ant
B. Honeybee
C. Wasp
D. White faced hornet

Answer 9

9. A, Fire ant, p. 470-1.
   Fire ant venom proteins have been found to be present in sufficient concentrations in whole
   body extracts to be suitable for diagnostic allergens and therapeutic extracts.

Chapter 29: Standardization and Preparation of Allergen Extracts
Middleton’s Allergy Principles and Practice, 9th Edition

Question 10

10. What is the method used by Center for Biologics Evaluation and Research (CBER) to
determine biologic potency of extracts?
A. ID50EAL
B. IEF
C. Sterile filtration
D. W/V extraction

Answer 10

10. A - ID50EAL, p.473
    ID50EAL (intradermal dilution for 50 mm sum of erythema) determines the bioequivalent allergy units and can be used to compare allergenicity of extracts from different sources.

Chapter 29: Standardization and Preparation of Allergen Extracts
Middleton’s Allergy Principles and Practice, 9th Edition