معهد البحوث الطبيه

Medical Research Institute

Department: Immunology and Allergy Semester: Spring

Degree: Diploma in Allergy Academic year:2019/2020

Course title: Allergology I Time allowed:180 minutes

Course code:1708608 Date:25 /7/2020

Final Exam Total marks: 60

THE EXAM CONSISTS OF “TWO” QUESTIONS IN “--”PAGES

All questions to be answered

Question No.1: (30 Marks 0.5 for each)

Choose the correct answer:

1) Characteristics of Cytotoxic Hypersensitivity does not include

a) Directed against cell surface or tissue antigen

b) Cell damage is mediated by cytotoxic T cells

c) Characterized by complement cascade activation

d) The reaction time is minutes to hours.

2) Eosinophilia in allergic diseases such as allergic rhinitis or asthma is driven by allergen

activated Th2 cells. Which cytokine is the most critical cytokine mediating increased

eosinophils differentiation, activation and survival?

a) IL-4

b) INF-gamma

c) IL-5

d) Eotaxin

3) The following conditions are due to type II reaction EXCEPT

a) Autoimmune hemolytic anemia

b) Good Pasteur disease

c) Lupus nephritis

d) Hemolytic disease of the new born

4) The followings are examples of generalized Type III reaction EXCEPT

a) Serum sickness

b) Systemic luprus

c) Drug reactions

d) Arthus reaction

5) The classical example of Type IV reaction is

a) Arthus Reaction

b) Montoux reaction

c) Prausnitz-Kustner test

d) None of the above

6) 30 year-old systems analyst presents for evaluation of a bee sting allergy. He describes an

episode in which he was stung on the forearm by a bee and, within 5 minutes, experienced

pruritus, urticaria, and mild wheezing. The effector cell in this type of hypersensitivity is a(n)

a) Eosinophil

b) mast cell

c) megakaryocyte

d) neutrophil

7) The late phase of the allergic response

a) Occurs 30 minutes after exposure to allergen

b) Is due to histamine-induced vasodilatation and increased vascular permeability

c) Is mediated primary by eosinophils and Th2 T cells recruited from the blood

d) Is mediated by macrophages and Th1 T cells recruited from the blood

8) Which statement is false? Characteristics of Allergens are typically:

a) Proteases-like proteins

b) Are typically soluble and can easily cross mucosal membranes

c) Are most effective at high concentrations

d) Are multivalent antigens

9) Which of the following is/are important in producing IgE antibodies

a) Allergen concentration

b) The production of TH2 cytokines

c) Genetic predisposition

d) All of the above

10) Inhalant allergens include all of the following EXCEPT

a) House dust mite allergens

b) Tree and grass Pollens

c) Mammalian denders

d) Crustacean tropomycine

11) What is true about mast cell location?

a) Usually intravascular

b) Abundant in bone marrow

c) Increased density in exposed skin

d) Rare in the GIT

12) Mast cell activation occurs through:

a) Direct binding of pathogens or their components by pathogen associated molecular

b) pattern (PAMP) receptors located on the MC surface

c) Binding of opsonized bacteria or their products by complement receptors or

immunoglobulin receptors

d) Recognition of endogenous peptides produced by infected or injured host cells

13) Mark the incorrect answer:

a) Allergen sensitization is a primary immune response that involves the binding of

specific IgE to MC

b) Endotoxins can act on MCs via TLRs inducing the secretion of TNF-alpha

c) Sensitized MCs may amplify the allergic response by acting as antigen presenting cells

to further drive allergen specific Th2 proliferation

d) Preformed MC cytoplasmic granule associated mediators include heparin, tryptase

TNFα, and leukotrienes

14) Chemokines produced by mast cells include all EXCEPT

a) Eotaxin

b) RANTES

c) Prostaglandins

d) MCP-1

15) In the allergic reaction:

a) IL-5 inhibits eosinophil mobilization from the bone marrow

b) IL4 up-regulates FcεR1 and allows eosinophil recruitment

c) RANTES recruits monocytes-macrophage lineage cells

d) MPC-1 induces histamine release from basophils

16) The Th2 cell- mast cell- eosinophil axis means:

a) Stem cell factor produced from eosinophils allows MC activation.

b) MCs regulate stem cell factor release.

c) Th2 cytokine- stimulated MCs express inflammatory mediators that can activate

eosinophils

d) All of the above

17) Der p 10

a) It is a tropomycine that occurs as a cross-reactive allergen in invertebrates and, in

particular, in seafood, where it has been described as an important allergen responsible

for severe systemic anaphylaxis

b) Of mite allergic patients, 5.6% shows IgE binding to rDer p 10.

c) Der p 10 generally has low allergenic activity but can induce strong basophil

degranulation in certain patients

d) All are correct

18) Der p 11, Indicate the incorrect statement

a) a mite paramyosin that plays more of a secondary role in patients with a respiratory form

of house dust mite allergy,

b) it is a major allergen in patients with atopic dermatitis

c) The prevalence of serum IgE reactivity to rDer p 11 on immunodot assay ranged from

41.7% to 66.7% in different allergic patient groups, whereas it was rare in non-atopic

patients with urticaria (18.8%) and in normal individuals (8%).

d) Is a major mite allergen identified in its feces.

19) All are true of Tropomycin EXCEPT

a) Regulates muscle contraction, also present in non-muscle cells

b) Identified as food allergens in crustaceans, molluscs and the fish parasite Anisakis

simplex

c) Identified as inhalant allergens in arthropods (mites, cockroaches)

d) Vertebrate tropomyosins seem to be highly allergnic

20) All are true of the allergens Lipocalins EXCEPT

a) Transporters for small hydrophobic molecules, such as lipids, steroids, odorants and

pheromons

b) Eight-stranded anti-parallel b-barrel

c) Constitute the vast majority of mammalian dander allergens (inhalant allergen)

d) Example of Lipocalines are Der p 10, Bla g 7, Pen a 1 (shrimp), Hel as 1 (snail),

Hom a 1 (lobster)

21) The following leukotriene is a potent chemotactic agent

a. LTB4

b. LTC4

c. LTD4

d. LTE4

22) The following drugs inhibit histamine release

a. Beta adrenergic drugs

b. Cromolyn and nedocromil

c. Betahistine

d. Chlopheneramine maleate

23) The following is an agonist for H1 receptor

a. Histidine

b. Adrenaline

c. Chlorpheramine maleate

d. Betahistine

24) Antihistamines NOT have the following property

a) They block histamine receptors

b) They can displace histamine molecules connected to receptors.

c) They have higher affinity of histamine for H1 receptors.

d) They prevent further histamine binding.

25) H1- receptors antagonists reduce or eliminate all the following effects of histamine

EXCEPT

a) Contraction of endothelium, increasing of vascular permeability;

b) Contraction of smooth muscle of bronchi, GIT, uterus;

c) Excitement of CNS.

d) Chemotaxis of mast cells

26) H1- receptors antagonists are NOT classified According to

a) Selectivity to histamine H1 receptor

b) Ability to block histamine release

c) Ability to cross blood brain barrier

d) Cardiotoxicity

27) Third generation H1 receptor antagonists have the following properties, EXCEPT

a) Anti-inflammatory effect

b) Antihistaminic and Antiallergic effects

c) Rapid but short acting effects.

d) Absence of blockade of other types of receptors (cholinergic-, Serotonin-receptors).

28) The main disadvantage of Second generation H1 receptor antagonists is that they are

a) Selective H1 blockers

b) Metabolized by cytochrome P-450 enzyme system

c) Non penetrable through blood/brain barrier (have no sedative action).

d) Absence of blockade of other types of receptors (cholinergic-, Serotonin-receptors).

29) FcεRI complex has all the following properties EXCEPT:

a) consists of α, β and γ- chains

b) It binds IgE with high affinity

c) Its level is higher in connective tissue mast cells

d) Allergen cross-linking IgE attached to FcεR1 triggers release of granules from cell.

30) The following are cytokines released by mast cells and their main actions, the action of one

of these cytokines is NOT correct, which one?

a. TNF α, IL-1 and chemokines (Pro-inflammatory cytokines)

b. IL-4 (promotes the switching of B cells to IgE production)

c. IL-5 (promotes the differentiation and activation of basophils)

d. IL-13 (stimulates mucus secretion by airway epithelial cells).

31) The early and late allergic skin reactions share in all of the following EXCEPT

a. Edema

b. Erythema and warmth

c. Induration

d. Burning sensation and itching

32) The main characteristic of late allergic skin reaction over the acute one is the presence of:

a. Dermal edema, characterized by separation of collagen bundles

b. Degranulated mast cells

c. Local vasodilation

d. Influx of eosinophils, basophils, and neutrophils

33) A neighbor calls you at 6 AM from a drug shop in Alexandriaa, an hour before he is

departing on a six hour fishing trip. He wants advice on "anything" he could take to help

prevent sea sickness. He reads off a short list of medications that the store has available.

You realize that several of them would probably be effective if taken well before departure.

However, amongst the medications mentioned, the least likely to be effective in preventing

sea sickness would be:

a. dimenhydrinate

b. diphenydramine

c. loratidine

d. promethazine

34) H2 histamine receptor subtype is distributed in:

a) Smooth muscle, endothelium and brain

b) Gastric mucosa, cardiac muscle, mast cells and brain

c) Presynaptically in brain, mesenteric plexus and other neurons

d) All of the above

35) Most tissue histamine is sequestered and bound in:

a) Granules in mast cells or basophils

b) Cell bodies of histaminergic neurons

c) Enterochromaffin-like cell of the fondus of the stomach

d) All of the above

36) These categories of histamine H1 antagonists are noted for sedative effects, EXCEPT:

a. Piperidines; i.e. Loratadine, Fexofenadine

b. Ethanolamines (aminoalkyl ethers); i.e. Dimedrol, Clistin

c. Ethylenediamines; i.e. Suprastine

d. Phenothiazines; i.e. Diprazine, Promethazine

37) Which category of histamine H1 antagonists is noted for the best antiemetic action?

a) Alkylamines (propylamines); i.e. Brompheniramine

b) Ethanolamines (aminoalkyl ethers); i.e. Doxylamine

c) Piperazines; i.e. Hydroxyzine, Cyclizine

d) Ethylenediamines; i.e. Suprastine

38) A 19 year-old woman suffering from nausea and vomiting related to a migraine headache

was given an i.v. infusion of "Drug X" in a local Emergency Department. During the

infusion, she complained of extreme pain at the site where the i.v. line was inserted. Soon

thereafter she developed circulatory problems at the site of injection, which then over

several weeks progressed to gangrene, which required amputation of her arm in stages.

What most likely was Drug X?

a) bromopheniramine

b) chlorpheniramine

c) diphenhydramine

d) promethazine

39) Histamine can be released by different "triggers" including tissue injury and immune

activation caused by the detection of foreign antigens. However, a few drugs are also capable

of directly causing histamine release by displacing the bound form of histamine stored within

mast cells. An example of a drug producing this type of histamine reaction is:

a) cephalexin

b) cimetidine

c) epinephrine

d) morphine

40) Which category of histamine H1 antagonists is noted for the highest local anesthetic effect?

a) Alkylamines (propylamines); i.e. Brompheniramine

b) Piperidines; i.e. Loratadine, Fexofenadine

c) Ethylenediamines; i.e. Suprastine

d) Phenothiazines; i.e. Promethazine

41) Which category of histamine H1 antagonists is recognized for as second-generation

antihistamines?

a) Alkylamines (propylamines); i.e. Brompheniramine

b) Piperidines; i.e. Loratadine, Fexofenadine

c) Ethylenediamines; i.e. Suprastine

d) Phenothiazines; i.e. Promethazine

42) These histamine H1 antagonists are recognized for as second-generation antihistamines,

EXCEPT:

a) Astemizole

b) Loratadine (Claritin)

c) Cetirizine (Zyrtec)

d) Suprastine

43) Which of the following histamine H1 antagonists is a long-acting (up to 24-48 h)

antihistamine drug?

a) Diazoline

b) Diprazine

c) Suprastine

d) Dimedrol

44) Which of histamine H1 antagonists is noted for the ulcerogenic effect?

a) Diazoline

b) Loratadine

c) Suprastine

d) Dimedrol

45) Children who have an egg allergy should not get which of these vaccines?

a) MMR

b) Flu

c) Polio

d) None of the above

46) Dust mites are a common trigger for indoor respiratory allergies. Where are you most likely

to find them in the home?

a) Carpet

b) Beds

c) Drapes

d) All of the above

47) All are true Regarding The major food allergens EXCEPT

a) Water-soluble glycoproteins that range in molecular weight from 10,000 to 67,000 Da.

b) Have no known unique biochemical or immunochemical characteristics.

c) They tend to be resistant to heat and acid treatment

d) Sensitive to proteolysis and digestion.

48) Oral Allergy Syndrome is characterized by all of the following EXCEPT

a) Characterized by the acute onset of oropharyngeal pruritus following the ingestion of

raw fruits and vegetables by patients with a history of seasonal allergies.

b) It is a form of type III hypersensitivity reaction to ingested fruits and vegetables

c) manifested by oral pruritus and occasionally by mild edema of the lips, tongue, palate,

and throat

d) The syndrome is attributed to initial sensitization to airborne seasonal pollens

49) Allergic eosinophilic esophagitis (AEE) are characterized by all of the following Except

a) Characterized by infiltration of the esophagus, stomach and/or intestinal walls with

eosinophils, basal zone hyperplasia, papillary elongation, absence of vasculitis and

peripheral eosinophilia in about 50 % of patients

b) It is an IgE mediated disease

c) In children symptoms similar to gastroesophageal reflux and in adult’s dysphagia and

impaction is common

d) Diagnosis is based on endoscopic findings and biopsy (>15-20 eosinophils per High

Power Field)

50) Celiac disease is characterized by all of the following Except

a) Extensive enteropathy leading to malabsorption

b) Associated with an immune reaction to wheat, rye and barley

c) Highly associated with HLA-DRB8

d) anti-transglutaminase IgA, Anti-gliadin IgA are usually positive.

51) Drug induced Maculopapular exanthema (MPE) are characterized by all of the following

EXCEPT

a) Represent a late-phase reaction of immediate hypersensitivity

b) infiltration of T cells in dermis and epidermis

c) The mononuclear cell infiltrate is composed of CD3+ T cells with a predominance of

CD4+ T cells in the perivascular dermis,

d) Infiltrating T cells are cytotoxic to keratinocytes and orchestrate an inflammatory

process, which is often eosinophil rich.

52) Pathophysiology of bullous drug eruptions are characterized by all of the following EXCEPT

a) Preferential activation of drug-specific CD8+ T cells in in the skin of patients with

drug induced bullous exanthem

b) Higher activation of circulating T-cells (CD4 and CD8)

c) Represent a delayed type hypersensitivity reaction to drugs

d) Usually develops within 24 hour of drug intake

53) Indicate the false statement

a) Drug provocation tests can be positive in allergic and non allergic drug reactions

b) Sulphidoleukotrienes (LTC4 and its metabolites LTD4 and LTE4) produced upon in

vitro stimulation of blood leukocytes (predominantly basophils) by drugs could be

quantitatively measured to depict drug allergy

c) About 10% of patients with severe drug hypersensitivty may develop another drug

allergy to a structurally not related compound

d) Cross-reactivity between penicillins and cephalosporins are very evident in the

development of delayed type hypersensitivity reactions

54) Allergy to radiocontrast media (CM)

a) More frequent with non-ionic dimer CM.

b) Repeated exposure to the same CM is essential for induced immediate and delayed

reactions to appear i.e sensitization step.

c) Intradermal skin tests with a battery of CM can be positive with immediate and

delayed reactions. The highest sensitivity is seen 2-6 months after the reaction

d) Cross-reactivity is very uncommon in delayed type reactions,

55) Allergy to Chemotherapeutic agents

a) Some cases may be due to non-immune mediated release of histamine or cytokines

while, Some cases are immune mediated

b) Patients can tolerate re-exposure after pretreatment with steroids and antihistamine,

and slow re-administration of the drug

c) Reaction rates may vary with different forms of the drugs, e.g. pegylated

d) All are correct

56) A 10-year-old boy who has hypertension needs a contrast study of his kidneys. He is allergic

to shrimp, and his parents are worried that he will have a reaction to the iodine content in

the radiocontrast media .

Of the following, the MOST appropriate management is to :

a) perform allergy tests for radiocontrast media

b) pretreat the child with antihistamines immediately before the procedure

c) reassure parents that the risk of reaction is negligible

d) undertake a food challenge with shrimp to confirm the diagnosis

57) A 4-year-old child has atopic dermatitis due to severe allergies to dust, animal dander, and

many kinds of pollens. Mediators released from which cell type are

responsible for the clinical manifestations immediately following exposure to these

substances?

a) B cells

b) Macrophages

c) Mast cells

d) Th1 cells

58) A mother brings her 1-year-old son to your office because she thinks he is allergic to grass

pollen. He has had intermittent rhinitis for several months. It is December, and the family

lives in the northeast United States. Both parents have seasonal allergic rhinitis .

Of the following, your BEST advice to the mother is to :

a) begin a long-acting antihistamine to control the boy’s symptoms

b) explain that he does have allergies, but he cannot be treated until he is older

c) explain that it is not allergy because of the boy’s age and exposure history

d) refer the boy to an allergist for testing for sensitivity to grass pollens

59) You are seeing a 4-year-old girl in the emergency department for treatment of an episode of

anaphylaxis. She is currently taking amoxicillin for treatment of otitis media. She had just

finished lunch today and taken her medication when she experienced respiratory difficulties,

urticaria, and general discomfort. Lunch included foods she normally eats, except for a new

brand of chicken noodle soup and plain M & M's for dessert. She does not like eggs, and when

she has eaten them in the past, she spat them out.

Of the following, the MOST likely cause of her reaction is:

a) drug allergy

b) food allergy

c) food poisoning

d) viral urticarial

60) Food Protein-Induced Enterocolitis Syndrome (FPIES). Indicate the false statement

a) FPIES is a non-IgE mediated food allergic disorder that involves severe, repetitive vomiting within 2-4 hours after food ingestion.

b) The first line of treatment in FPIES is administration of intravenous fluids to counteract fluid loss from vomiting and diarrhea.

c) Epinephrine autoinjectors Could be the first line of treatment for patients with FPIES . d) Since FPIES does not present with classic allergic symptoms involving the skin or respiratory

tract, it is frequently misdiagnosed in the emergency setting. Therefore, it is helpful to provide the patient with an emergency letter that describes the symptoms and management.

Question no. 2: 15 short assay (30 marks,2 marks each)

1. Structure of Ig E

IgE is one of five isotypes of human immunoglobulins: IgG, IgA, IgM, IgD, and IgE. All immunoglobulins are composed of two light chains and two identical heavy chains. The heavy chain differentiates the various immunoglobulin isotypes. The heavy chain in IgE is epsilon. IgE is a monomer and consists of four constant regions in contrast to other immunoglobulins that contain only three constant regions. Due to this extra region, the weight of IgE is 190 kDa compared with 150 kDa for IgG. IgE has no hing region The C-epsilon-2 constant domain is unique to IgE, while the C-epsilon-3 region binds to the low- and high-affinity IgE receptor. Of note, the anti-IgE monoclonal antibody omalizumab also binds to the C-epsilon-3 region, so the binding of omalizumab to IgE decreases the amount of "free" IgE available for binding to IgE receptor-bearing cells, including mast cells and basophils.

2. IgE RECEPTORS

There are 2 receptors for IgE:

The low-affinity IgE receptor (FcεRII; CD23) expressed on the surface of B cells, as well as

other hematopoietic cells, and

The high-affinity IgE receptor (FcεRI). FcεRI is expressed on mast cells and basophils as

tetramers (αβγ2) and on antigen-presenting cells, at much lower levels, as trimers (αγ2).

Expression of the β chain in mast cells and basophils results in increased FcεRI surface expression

and amplifies signaling through the receptor. FcεRI not occupied by IgE has a half-life on the

mast cell surface of 24 hours in vitro, whereas receptors bound to IgE appear to be expressed for

the life of the cell.

The density of human basophil FcεRI expression correlates directly with serum IgE levels, where

binding of IgE stabilizes the receptor at the cell surface. Similarly, the density of human mast cell

FcεRI levels correlates with free IgE levels in vitro.

The FcεRI subunits have no known enzymatic activity but rather signal through associated

cytoplasmic tyrosine kinases. The α chain of FcεRI binds to the Fc portion (C3 domain) of IgE

and consists of an extracellular domain, a transmembrane domain, and a short cytoplasmic tail

with no signaling motifs. The β subunit consists of 4 transmembrane domains with a single

immunoreceptor tyrosine–based activation motif (ITAM) and is associated with Lyn kinase. The

γ subunits form a disulfide-linked dimer, and each subunit contains an ITAM. After aggregation

of FcεRI by multivalent antigen recognized by bound IgE, Lyn phosphorylates tyrosine residues

in the ITAMs of the β and γ subunits. The tyrosine-phosphorylated γ subunit then recruits Syk

kinase. Syk activates a number of downstream signaling events associated with mast cell or

basophil activation. Syk-deficient basophils and mast cells do not degranulate after FcεRI

aggregation. Syk is the target for a number of experimental therapeutic agents.

The low-affinity IgE receptor FcεRII (CD23) is a Ca-dependent lectin that is expressed on B cells,

as well as T cells, Langerhans cells, macrophages, monocytes, eosinophils, and platelets. The

receptor consists of a large extracellular domain with the lectin head that binds IgE, a single

transmembrane domain, and a short cytoplasmic tail. Like the FcεRI receptor, expression of CD23

is upregulated by IgE and IL-4.8 CD23 can be shed from the membrane into a soluble form,

sCD23, by endogenous proteases (a disintegrin and metallopeptidase 10-ADAM10)9 and

exogenous proteases, including the dust mite major allergen Der p 1. CD23 activation mediates

IgE regulation, differentiation of B cells, activation of monocytes, and antigen presentation.

Increased expression of membrane-bound CD23 on B cells and resultant soluble CD23 is seen in

patients with allergic disorders. CD23 expression on B cells is reduced with allergen

immunotherapy. Polymorphisms in the gene encoding CD23 have been reported to be associated

with the risk of asthma exacerbation.10 An α-CD23 mAb, lumiliximab, has been tested in vitro,

where it leads to a reduction in TH2 responses and reduced IgE synthesis. Lumiliximab has been

studied in a phase I trial in allergic asthma and is undergoing a phase II trial for the treatment of

chronic lymphocytic leukemia.

3. Compare and contrast the various types of mast cells

4. Give a brief account on Tryptase

➢ Mast cell tryptase is released upon activation of mast cells, along with histamine,

heparin , chymase, and carboxypeptidase

➢ It is the most abundant human mast cell protein and exists in two forms that show 90

percent homology: alpha and Beta tryptases.

➢ The biologic function of tryptase has not been completely defined, but it appears to

activate protein cascade systems, enhance vasopermeability and alter airway smooth

muscle reactivity.

➢ Tryptase has the capability to Cleave fibronectin , vasoactive intestinal peptide, and

➢ kininogens. Also a growth factor for epithelial cells and fibroblast. The total tryptase

level in Blood is used as an indirect parameter of mast cell burden and mast cell

activation.

➢ Baseline tryptase levels are generally elevated in patients with systemic mastocytosis

(SM).

➢ Increased serum tryptase levels are also observed within 15minutes of onset of

anaphylaxis with a peak level seen at 1 to 2 hours, although this is not consistent.

5. Give a brief account on Chymase

Chymases (EC 3.4.21.39, mast cell protease 1, skeletal muscle protease, skin chymotryptic

proteinase, mast cell serine proteinase, skeletal muscle protease) are a family of serine proteases

found primarily in mast cells, though also present in basophil granulocytes (e.g. alpha chymase

mcpt8). They show broad peptidolytic activity and are involved in a variety of functions. For

example, chymases are released by mucosal mast cells upon challenge with parasites and parasite

antigens promoting an inflammatory response, and chymase mcp1 and mcp2 are used for marker

for mast cell degranulation in parasite infection such as Nematode,Trichuris muris. Chymases are

also known to convert angiotensin I to angiotensin II The vasoactive properties produced by

angiotensin II may contribute to transient hypertension in some individuals during mast cell

activation reactions and play a role in hypertension and atherosclerosis.

Because of its role in inflammation it has been investigated as a target in the treatment of asthma.

6. Give a brief account on sampling for indoor allergen and its interpretation

of the results

Needed equipment: Dust collector and a vacuum cleaner or a high volume pump. a. A composite sample or single samples from specific area may be taken. b. Room Selection: The best single predictor for overall allergen exposure is the

living room floor (NSLAH), next would be the bedroom floor. For meaningful results, follow other studies. For certain allergens, kitchens and bathrooms may be better.

c. Suggested sampling area is one square meter (m2). However, estimates are appropriate, when sampling along baseboards, nooks & crannies (e.g. kitchens).

d. A minimum of 100 mg dust is required for analysis. Interpretation of Results: Guidelines for mite allergen levels (Der p 1): <2µg/g dust = Low: Not sufficient to cause symptoms 2-10 µg/g dust = Moderate: Risk for sensitization and bronchial hyperactivity >10 µg/g dust = High: Risk for acute allergic asthma attack Suggested threshold level for cockroach: Measurement is in Units per gram. 2 U/g dust of Bla g 1 and/or Bla g 2 >2 U/g dust = risk for sensitization Guidelines for cat allergen levels (Fel d 1): <1µg/g dust = Low: Not sufficient to cause symptoms 1-8 µg/g dust = Moderate: Risk for sensitization and bronchial hyperactivity >8 µg/g dust = High: Risk for acute allergic asthma attack There are no established risk factors for Dog, Rodent, and Fungal Allergens. For dog allergens (Can f 1), suggested risk for sensitization at >10 µg/g dust.

7. Establishment of Pollen calendar for Alexandria. Its significance and its

methodology

Airborne pollens for Alexandria can be measured and reported as a “pollen count.” There are numerous methods for sampling the air. The two basic methods are passive and active sampling. Passive sampling simply collects particles from the air onto slides, plates, or traps by the force of gravity. This method is heavily biased toward the large particles and is not commonly used. In active sampling, particles are actively removed from the air by a mechanical or electrical device. The most commonly used active air-sampling devices are impaction devices that work by accelerating an airstream onto a sampling surface. This enables the particles to break free of the airstream and “impact” onto the collecting device. It is more difficult for smaller particles to break free of the airstream; therefore, measuring smaller particles, particularly fungal spores, is more difficult. Two commonly used impaction devices are the Rotorod sampler and the Burkard spore trap. The Rotorod sampler consists of two plastic rods that are coated with silicone grease and rotated rapidly around a fixed circumference by an electric motor. The collector rods are then removed, stained, and analyzed under light microscopy. Pollen grains are identified by light microscopy at 400× magnification. The number of particles per cubic meter of air (p m −3 ) is calculated from the volume of the atmosphere sampled. It has been shown to be more than 90% efficient at capturing pollen particles approximately 20 μm in diameter. The Burkhard spore trap consists of plastic tape or a standard microscope slide coated with silicone adhesive that is moved past an air intake orifice at a fixed speed. The tape or slide is stained and analyzed under light microscopy. The total particle recovery per day (p m −3 ) can then be calculated. The Rotorod is less expensive than the Burkhard spore trap. The Burkhard spore trap has a greater acceleration velocity and is more efficient at collecting particles smaller than 10 μm (primarily fungal spores). The pollen grains collected on the slides can be categorized by their surface characteristics. The outermost layer of the pollen grain, the exine, is prominently sculptured and may show apertures as circular pores, elongate furrows, or both. The pollen grains with pores alone are classified as porate and those with furrows alone as colpate; those with both are termed colporate. Depending on the number of apertures, pollens are labeled as monoporate, tricolpate, and so forth. When numerous apertures are present, the prefix “peri-” is used. “Stephano-” is used to refer to equatorial pores or furrows (Fig. 2.1 ). This nomenclature is used to help identify particular pollens. Approximately 30 grains of pollen per cubic meter of air is required to cause an allergic reaction. Because of priming, the amount of pollen grains required to initiate symptoms at the beginning of the season is greater than at the end. An average person inhales about 10 m 3 of air per day, which would result in approximately 300–500 pollen grains per day to sustain an allergic reaction. The amount of allergen per pollen grain is variable and difficult to quantify. For ragweed pollen, it has been estimated there is 5 ng of Amb a 1 per pollen grain. This would result in the inhalation of approximately 2.2 μg of Amb a 1 on a daily basis during the ragweed season.

8. Measures for avoiding indoor allergens

9. Compare and contrast primary vs. secondary pollutants, giving examples

of each

Air Pollution

Chemicals added to the atmosphere by natural events or human activities in high

enough concentrations to be harmful

• Two categories

Primary Air Pollutant

Harmful substance that is emitted directly into the atmosphere

Secondary Air Pollutant

Harmful substance formed in the atmosphere when a primary air pollutant reacts with

substances normally found in the atmosphere or with other air pollutants

Examples of Primary Pollutants:

➢ Car exhaust, smokestacks (CO, SO2, NO)

➢ Particulate material (soot, ash)

➢ Toxic metals (lead, mercury)

➢ Volatile organic compounds (VOCs) (methane, propane, CFCs, etc.)

Examples of secondary pollutants:

➢ Atmospheric acids (H2SO4,HNO3)

➢ Photochemical oxidants (NO2)

10. Histamine receptors

a) H1 receptors are located on epithelial cells as well as vascular and perivascular

cells and mediate vascular permeability and instability.

b) H2 receptors are present on epithelial cells in the gastrointestinal tract and are

associated with gastric hypersecretion.

c) H3 receptors are found in the brain and gastrointestinal tract and may be

associated with

d) certain neurologic effects such as headache.

e) H4 receptors are present on eosinophils and mast cells but their significance is still

unknown

11. Give a brief account on the main characteristics food allergen classes.

Class 1 food allergens:

– Primary sensitizers – Sensitization may occur through the gastrointestinal tract – Water-soluble glycoproteins – Molecular weights ranging from 10 to 70 kD – Stable to heat, acid and proteases

Class 2 food allergens (cross-reactive): – Generally plant-derived proteins – Highly heat-labile – Difficult to isolate – No good, standardized, extracts are available for diagnostic purposes –

Major class 1 food allergens

• Cow's milk:

• Caseins (, ,), -lactoalbumin, -lactoglobulin, serum albumin

• Chicken egg: Ovomucoid, ovalbumin, ovotransferrin

• Peanut: Vicillin, conglutin, glycinin

• Lentil Vicilin

• Soybean: Glycinin, profilin, trypsin inhibitor

• Shrimp: Tropomyosin

• Fish: Parvalbumins

• Fruits and other vegetables (apple, apricot, peach, plum, corn)

• Lipid transfer proteins (LTPs) Class 2 food allergens (Cross-reactive and associated with oral allergy syndrome, latex-fruit syndrome)

• Pathogen-related protein 2 group (glucanase): Latex, avocado, banana, chestnut, fig

• Pathogen-related protein 3 group (chitinase):

Latex (Hev b6), avocado • Pathogen-related protein 5 (thaumatin-like):

Cherry, apple, kiwi • Birch Bet v1 homologues (pathogen-related proteins 10):

Apple, cherry, apricot, peach, pear, carrot, celery, parsley, hazelnut • Birch Bet v2 homologues (celery-mugwort-spice syndrome) profilin:

Latex, celery, potato, pear, peanut, soybean

12. Pseudoallergy

Pseudoallergy, or nonallergic hypersensitivity, mimics immediate-type allergic reactions

clinically without evidence of underlying immunological mechanisms. The most common

triggers of pseudoallergic reactions are aspirin and other nonsteroidal antiinflammatory drugs

(NSAIDs), as well as some food ingredients and additives, such as salicylates, benzoates, and

tartrazine. These reactions do not involve IgE sensitization and can, therefore, occur on first

exposure. Pseudoallergic reactions are dose-dependent and usually occur with chemically

nonrelated substances. The diagnosis is difficult because skin tests and serology are

uninformative. Diagnosis of nonallergic hypersensitivity is based on a distinctive clinical pattern,

time course, clinical signs, and response to elimination of the cause. In the appropriate clinical

context, pseudoallergy can be confirmed with oral challenge tests.

13. Leaky gut syndrome

IgG mediated allergy is a non acute condition. Symptoms often appear delayed, only after hours or days after the consumption of the concerned food. Positive blood tests are sometimes without symptoms. It may also take weeks or months after sensitization until the first symptoms appear. This is due to the necessity of a sensitized organ or tissue where immune complexes adhere and are destroyed. During the destruction of these immune complexes the surrounding tissue is also damaged and after a certain time, specific symptoms may occur. IgG food allergy is a low grade inflammatory condition which becomes symptomatic, if it turns into a chronic inflammatory condition. This occurs when the concerned foods are consumed on a regular basis, e.g. more than 2-­­3 times a week. While IgE mediated allergic reactions are limited to a few symptoms, IgG mediated allergy may lead to or maintains any chronic inflammatory process

every chronic inflammatory disease articulations, glandular diabetes, hypothyroidism intestinal lesions, Crohn disease, celiac disease, irritable colon cutaneous manifestations : atopic eczema, pruritus, acne migraine, chronic headache psychic disorders -­­ depression chronic fatigue (CFS) overweight, obesity, hypertension malabsorption syndrome autoimmune diseases fibromyalgia respiratory disease, asthma chronic non-­­infectious rhinitis chronic iron deficiency

Conditions leading to increased gut permeability

➢ bacterial and viral infections ➢ Parasites and Candida albicans ➢ Conservation agents ➢ Colorants ➢ heavy metals ➢ environmental toxins ➢ stress Interferon--­g, TNF--­a

DIAGNOSTIC TOOLS TO ESTIMATE THE RISK FOR INCREASED GUT

PERMEABILITY AND THE ASSESSMENT OF INTESTINAL INFLAMMATION

Determination of sIgA in stool is a valid tool to estimate the ability to produce sufficient sIgA

necessary for the defense against pathogenic agents.

Decreased values of sIgA indicate a higher risk for allergic conditions and increased risk for

gastro--‐intestinal infection and colonization of candida albicans.

Increased values of sIgA indicate an ongoing fight against those agents and may indicate the

presence of those agents in the intestine. Specific treatments may enhance sIgA production.

Indications:

Recurrent infectious diseases

Food and air born Allergies

Candidosis

Food intolerance

Alpha-­1-­anti-­trypsine

α--‐1--‐AT, is a protease produced by the liver. α--‐1--‐AT is normally not present in the gut or

only at low concentrations. Presence of α--‐1--‐AT indicates an increased gut permeability, as a

loss from proteins from blood to the gut lumen. Vice versa the migration of proteins and

pathogens from the gut to the blood is also increased.

A second reason for increased α--‐1--‐AT is the regulation of inflammatory processes in the gut.

Therefore the interpretation of increased α--‐1--‐AT should always be performed in conjunction

with Calprotectin.

Calprotectin

Is a stable marker for gastro--‐intestinal inflammation.

Calprotectin is a calcium-­‐binding protein of the cytoplasm of granulocytes. It represents

about 5% of the protein content of neutrophil granulocytes and 60% of the cytosol. It is resistant

against the degradation of proteases and is one week stable in the stool. Calprotectin is a

sensitive inflammation marker which is not influenced by drugs, food or enzymatic metabolism.

Calprotectin is known for its ability to discriminate between IBD and IBS.

In IBD Calprotectin values are well above 50 µg/ml, known as the cut-­‐off value for IBD But

values for Calprotectin below 50 µg/ml are not necessarily meaningless or to be considered as

healthy. Values between 10µg/ml and 50 µg/ml may indicate low-­‐grade intestinal

inflammation as caused by food allergy.

14. Epigenetic factors in development of allergic diseases

One of the most challenging questions in this regard relates to the biochemical mechanism of

how exogenous environmental trigger factors modulate and modify gene expression,

subsequently leading to the development of chronic inflammatory conditions. Epigenetics

comprises the umbrella of biochemical reactions and mechanisms, such as DNA methylation

and chromatin modifications on histones and other structures. Recently, several lifestyle and

environmental factors have been investigated in terms of such biochemical interactions with the

gene expression-regulating machinery: allergens; microbes and microbial compounds; dietary

factors, including vitamin B12, folic acid, and fish oil; obesity; and stress

Nucleotide sequence modification

Insertion

Deletion

Substitution

Recombination

Mutation

Loss of function

Gain of function

Structural and chemical modification

DNA folding/coiling

Phosphorylation

Methylation

Histone acetylation

Histone acetylation and methylation

Alters the rate of transcription

Alters protein expression

DNA methylation

Adding a methyl group to specific cytosine bases in DNA

Suppresses gene expression

Causes of histone changes and DNA methylation

Environmental exposures

Tobacco smoke

Traffic pollution

Alterations in early-life environment

Maternal nutrition

Transgenerational epigenetic effects mediated by DNA methylation

Grand maternal smoking increasing the risk of childhood asthma in their grandchildren

Sex-specific transmission

Paternal allergic disease predisposing male offspring to development of allergic disease

Maternal disease predisposing female offspring

Animal models

Mice exposed to in utero supplementation with methyl donors exhibit enhanced airway

inflammation after allergen challenge, a phenotype that persists in the second generation despite

the absence of further exposure

Effect of environmental exposures relevant to allergic disease

Prospective studies of large birth cohorts with information on maternal environmental

exposures during pregnancy are likely to provide important insights into the role of epigenetic

factors in the heritability of allergic disease.

15. Types of food additives

1. Preservatives (to give food a longer shelf-life) The Sulphites used to preserve

processeed meats, and dried fruit According to the FDA, about 5 percent of asthmatics

are sensitive to sulfites. Sodium nitrite, &benzoic acid These agents are added to food

products and occur naturally in, cinnamon, tea and berries. They may cause urticaria,

asthma and angioedema. (E 210 - E 219 )

2. Colourings (make food visually more attractive). :

Colourings (make food visually more attractive). (tartrazine) is used to color beverages,

candy and other foods. Nitrates and Nitrites - give meat a pink colour to look more

attractive and found in frankfurters They can trigger hives, urticaria, asthma and

generalized allergic reactions. ( E 100 - E 180 )

3. Antioxidants: (prevent fat rancidity)

Synthetic phenolic antioxidants prevent this spoilage happening but can trigger asthma,

rhinitis and urticaria. (E320 – 321) Flavour enhancers (to enhance palatability).

Aspartame: a low calorie sweetener can trigger urticaria and itchy hives. Monosodium

Glutamate (MSG) which can trigger the "Chinese Restaurant Syndrome" of headache and

burning plus tightness in the chest. ( E 620 - E 635 )

4. Emulsifiers and stabilisers Stop oil and water components separating, as in ketchup and

mayonnaise, Occasionally cause adverse reactions.

5. Naturally occurring substances in food .

Vaso-active amines. Natural Histamine, Serotonin and Tyramine occur in some cheeses,

fish, sausage, red wine, chocolate and pickled vegetables can induce cramping, flushing,

headache and palpitations in a dose related manner.

Caffeine found in foods, medication, tea, coffee and Coca-Cola induces dose dependent

agitation, palpitations, nausea and tremors.

6. Salicylates (aspirin-like naturally occurring chemicals).Salicylates induce urticaria,

asthma and nasal polyps. They are found in Curry powder, paprika, dried

thyme, oranges, apricots, honey, berries and fruit skins, tea and almonds. Salicylate

sensitive individuals also tend to have adverse reactions to benzoates and tartrazine