food allergy.pdf hypersensitivity antigens

Allergy food

1. SadudeeBoonmee, MD
Division of Allergy and Immunology
Department of Pediatrics
King ChulalongkornMemorial Hospital

2. Topic outline
•Introduction
•Important protein families
•Allergen from animal origin (Egg, CM)
•Allergen from plant origin (Soy, wheat
and peanut)

3. Currently available tests detect only sensitization,
not clinical allergy, cannot predict prognosis and severity
Nature
Allergenic
source
contain a mixture of allergenic and
non-allergenic molecules

4. Introduction
•Specific IgEdetermined using allergen extracts as test
allergens have to 2 type of problem
1. the difficulty of starndardizingthe allergens
used as substrates ( differ in allergenicity
variability of allergen source)
2. can not differentiated between primary
sensitization and immunological cross-reactivity
Borreset.al,PediatricAllergy and Immunol2011;22:454-461.

5. Introduction
•Both skin prick testing and specific IgEblood
testing employ heterogeneous protein
preparationsnot always the best indicators
of clinical reactivity
•Componenttesting designed to pinpoint
the allergen source when cross-reactive
allergen components are present.
Borreset.al,PediatricAllergy and Immunol2011;22:454-461.

6. Introduction
•Identifying whether the sensitization is
genuine in primary (species-specific) or if it is
due to cross-reactivityto similar protein
structure may help to evaluate the risk of
reaction on exposureto difference allergen
source
Clinical and Experimental Allergy;2010 ,40: 896-904

7. 1.Almost anything containing proteins can be
an allergen source
-each allergen source contains many different
allergenic protein (allergen component)
-each allergen component commonly has several
different epitopes
-epitope is the actual three-dimensional binding
site for an antibody
Basic of allergen component
Clinical and Experimental Allergy;2010 ,40: 896-904

8. 2. Protein stability
-allergen that stable to heat and digestion
are more likely to cause severe reaction
-allergen that heat and digestion labile are
more likely to be tolerateedor only cause
mild/local symptom
Basic of allergen component
Clinical and Experimental Allergy;2010 ,40: 896-904

9. 3. Allergen component name
-the first 3 letter of the genus, follow by the first
letter of the species and the number indicating
the order of allergen identification
-Latin designation of peanut is
Arachishypogaeathus Arah 1 designated
allergen number 1 from peanut
Basic of allergen component
Clinical and Experimental Allergy;2010 ,40: 896-904

10. •Production technique of allergen component
can be
-biotechnological in “recombinant” from
-“purified” from (original source)
Basic of allergen component

11. Important allergen families
•Most allergen component belong to a limited
number of protein families
•IgEantibodies in the same protein family
often cross-reactive, and classifying allergen
component into protein families can
answering question on cross-reactivity

12. Important allergen families
LTP (non-specific Lipid Transfer Protein, nsLTP)
-A protein stable to heat and digestioncausing reactions also to
cooked foods.
-Often associated with systemic and more severe reactions in
addition to OAS.
-Often associated with allergic reactions to fruit and vegetables in
southern Europe.
Storage proteins
-Proteins found in seeds serving as source material during the growth
of a new plant.
-Often stable and heat-resistant proteins causing reactions also to
cooked foods.
Plant allergen

13. Important allergen families
Profilin
-An actin-binding protein showing great homology and cross-reactivity even
between distant related species.
-Recognized as a minor allergen in plants and plant related foods.
-Seldom associated with clinical symptoms but may cause demonstrable or even
severe reactions in a small minority of patients.
CCD
-Cross-reactive carbohydrate determinants are seldom associated with clinical
symptoms but may cause demonstrable or even severe reactions in a small
minority of patients.
PR-10 protein,BetV1 homologue
-A heat labile protein, cooked foods are often tolerated.
-Often associated with local symptoms such as oral allergy syndrome
(OAS).
-Often associated with allergic reactions to fruit and vegetables in
northern Europe.

14. Important allergen families
Lipocalin
-Stable proteins and important allergens in animals
-Allergen components displaying limited cross-reactivity between
species.
Parvalbumin
-A major allergen in fish.
-A marker for cross-reactivity among different species of fish and
amphibians.
-A protein stable to heat and digestion causing reactions also to
cooked foods.
Animal allergen

15. Tropomyosin
-An actin-binding protein in muscle fibres.
-A marker for cross-reactivity between crustaceans, mites and
cockroach.
Serum albumin
-A common protein present in different biological fluids and solids e.g.
cow’s milk and beef, eggs and chicken.
-Cross-reactions between albumins from different animal species are
well known, for example between cat and dog and cat and pork.
Important allergen families

19. Allergen of animal origin

20. Allergen component in egg white Gal d 1, 2, 3, 4
Egg (Gallus domesticus)
Clinical& experimental allergy; 2010: 40: 1442-1460
Gal d 5 alpha-livetin(serum chicken albumin)

21. Gal d 1(ovumucoid)
-10% of total egg white protein
-stability against to heat and digestion by
protease (strong disulfide bonds) capacityto
stimulate a specific immune response
-sIgEAbto Gal d 1 helpful in prognosis
and diagnosis of egg allergy
-High concentration of ovomucoid-sIgE
associated with persistent egg allergy
(raw or cooked egg )
-Low concentration of ovomucoid-sIgE
associated with tolerance to heated egg
Egg (Gallus domesticus)
Clinical& experimental allergy; 2010: 40: 1442-1460

22. Gal d 2 (ovalbumin)
-heat-labile, IgE-binging epitopes on
OVA might be detroyedafter heating 
less allergenic
-children who have sIgEprimary to OVA
likely to tolerate heated egg
Egg (Gallus domesticus)
Clinical& experimental allergy; 2010: 40: 1442-1460

23. Gal d 3(ovotransferrin)
-nonhemeiron-binding
-heat-labile allergen
-sIgEAbto ovotransferrinin Dxof egg
allergy not been determined
Gal d 4 (lysozyme)
-lysozyme commomlyused as a food
preservative(antibacterial)
-egg allergic pt. who sensitized to lysozyme
may react when exposuredto such product
Egg (Gallus domesticus)
Clinical& experimental allergy; 2010: 40: 1442-1460

24. Allergenic component in egg yolk : Gal d 5
Gal d 5 (alpha-livetin) =chicken serum albumin
-bird-egg syndrome
Vitellenin(apovitelleninI)
apoproteinB (apovitelleninVI)
Egg (Gallus domesticus)
Role in egg allergy
remain unclear
Clinical& experimental allergy; 2010: 40: 1442-1460

25. •Objective: to evaluate the clinical usefulness and added
diagnostic value of measurements of IgEantibodies to egg
white, ovalbumin, and ovomucoidin children with egg allergy.
•Methods: 108 children age 14 mo–13 y (median age, 34.5 mo)
with suspected egg allergy underwent double-blind, placebo
controlled food challenges with raw and heated egg.
•The outcomes of the challenges were related to the serum
concentration of specific IgEantibodies and total IgEby using
ImmunoCAP
JACI 2008;122:583-588

26. •Pt. devidedinto 3 group ( immediatedreactions to OFC)
-Group A (n=38) : positive challenge for heated egg white
-Group B (n=29) : tolerated heated egg white, positive
challenge to raw egg white
-Group C (n=41) : tolerated both heated and raw egg white
•Serum of all pt. obtain before food challenge
-sIgEegg white, sIgEto ovalbumin, sIgEto ovomucoid, total
IgEImmunoCAP
JACI 2008;122:583-588

27. Results
JACI 2008;122:583-588
Heated EW + Raw EW + Heated & raw EW -
Heated EW + Raw EW + Heated & raw EW -

28. JACI 2008;122:583-588
Heated
EW +
Raw
EW + Heated & raw EW -
Heated
EW +
Heated
EW +
Heated
EW +
Raw
EW +
Raw
EW +
Raw
EW +
Heated & raw EW -
Heated & raw EW -
Heated & raw EW -

30. children allergic to raw egg white
(ie, groups A and B vsgroup C; A)
children allergic to heated egg white
(ie, group A vsgroups B and C; B).
sIgEAbto egg white well in diagnosis of reactions to raw egg
white
-positive decision point was 7.4 kUA/L
-negative decision point was 0.6 kUA/L
sIgEAbto ovomucoidshowed the best results in
patients who react to heated egg white
-positive decision point was 10.8 kUA/L
-negative decision point was 1.2 kUA/L

31. •Quantification of sIgEto OVM could be useful in guiding
physician in decision whether to perform a challenge or not
•OVM > 11 kUA/L high risk of reaction to heated and raw
egg
•OVM < 1 kUA/L low risk of reaction to heated egg (pt. may
react to raw egg)
Clinical implications: Measurement of specific IgE
antibodies to egg white and ovomucoidmight be
helpful in guiding evaluations of children for allergy to
raw egg or heated egg (eg, in cakes/cookies).
JACI 2008;122:583-588

32. Cow’s milk (Bosdomesticus)
Whey
Caseins
CurrOpinAllergy ClinImmunol11: 216-221
Caseins= 80% of total protein
βlactoglobulin(β-LG) not present in human milk
Major allergen in milk

33. α-lactoglobulin(Bosd 4)
-Functional subunit of whey lactose syntase
-controversial role in milk sensitization
-80% of CMPA react to Bosd 4
β-lactoglobulin(Bosd 5)
-most abundant whey protein
-Pt. have allergic reaction toβ-lactoglobulin13-76%
Bovine serum albumin (BSA) (Bosd 6)
-cow’s milk and beef allergy
-CMPA pt. have positive to BSA 0-88%
(only 20% have clinical reaction)
Cow’s milk (Bosdomesticus)
CurrOpinAllergy ClinImmunol11: 216-221

34. Bovine immunoglobulins(Bosd 7)
-in blood, tissue fluid, secretion
-seldom cause clinical symptom in CMPA
Caseins (Bosd 8)
-α
s1-caseins,α
s2-caseins, β-caseins, κ-caseins
-polysensitizationto many caseins fraction
usually observed (closely epitope or cross-
sensitization )
-α
s1-caseins major allergen inducing strong
immediatedor delayed allergic reactions
Cow’s milk (Bosdomesticus)
CurrOpinAllergy ClinImmunol11: 216-221

35. •Objective
: to calculate the frequency of accidental
exposure reactions in children allergic to cow’s
milk during a 12-month period
: to analyze clinical characteristics and
circumstances surrounding the reactions
: to identify risk factors for severe reactions
(J Allergy ClinImmunol2009;123:883-8.)

36. •Methods
: 88 children allergic to cow’s milk (44 boys; median age,
32.5 months)
: cross-sectional study at age >= 18 mo
: Systematized questionnaire about accidental
exposure (reactions were classified as mild,
moderate, and severe)
: sIgEto cow’s milk & casein titers were determined
periodically as clinical indicated in F/U visit
(J Allergy ClinImmunol2009;123:883-8.)

37. •Result
mo
Five of the 6 children had asthma
Severe reaction 15%
(J Allergy ClinImmunol2009;123:883-8.)

38. P, Percentile.
Mann-Whitney U test: #/{P 5 .044; #/kP< .01; /P 5 .044; /**P < .01.
*P value: comparison between severe AARs versus mild or moderate AARs or no reaction.
Fisher test.
Mann-Whitney U test.
§x2 Test.
Conclusion: Reactions to accidental exposure are frequent in
children with cow’s milk allergy. The proportion of severe
reactions was 15%. The risk factors for severe reactions
included very high levels of specific IgEto cow’s milkand
caseinand asthma.
(J Allergy ClinImmunol2009;123:883-8.)

39. fir
-Retrospective studies of 52 patients (3 to 114
months) withproven CMA by DBPCFC
-All Ptwere rechallengeat least once , some were
rechallenge2 or 3 time
-32 (61.5%) patients became tolerant in the analysed
time period.
-Serum was collected at all time point prior to OFC 
analysedfor
B. Ahrens, et.al,Clinical & Experimental Allergy, 2012 () –

40. B. Ahrens, et.al,Clinical & Experimental Allergy, 2012 () –

41. •Result
sIgECM
18
mo
33 mo
Children with initial sIgECM
below 5.0 kU/L 4 time
likely to tolerant
B. Ahrens, et.al,Clinical & Experimental Allergy, 2012 () –

42. B. Ahrens, et.al,Clinical & Experimental Allergy, 2012 () –
18
mo
Children with initial low
(<0.3ISU/L) sIgEto αlactalbumin,
βlactoglobulin(Bosd 5.0102),
κcasein and αs1-casein7.2,
2.7, 3.8 and 2.7 time likely to
tolerantrespectively
•Conclusion
•Children became tolerant earlier if their specific IgE-antibody
levels against the α-lactalbumin, and β-lactoglobulin(Bos
d5.0102), αs1-casein and, κ-casein were low
•CM-specific IgEis a good prognostic marker for persistence of CM

43. Allergen of plant origin

44. Allergen component in soy : Glym 4, 5 and 6
Glym 4
-PR-10 protein family (Bet v 1 homologue)
-pollen-associated soy allergy mainly discribed
in adult with mild symptoms
(primary sensitization to birch pollen)
-cross-reactive to Arah 8
-In Europe approximately 2/3 of pt. allergic to
soy are allergic to peanut
Soy (Glycine max)
Clinical& experimental allergy; 2010: 40: 1442-1460

45. Glym 5 and 6
-most important in primary sensitization to soy
protein (via GI tract) esp. in children
-sensitization rate to
Glym 5 36%
Glym 6 43%
Glym 5 and Glym 6 are diagnostic marker for
severe allergic reaction to soy
Clinical& experimental allergy; 2010: 40: 1442-1460
Soy (Glycine max)
In soy allergic pt.

46. Paper soy2paper
•Aim: to identify relevant soybean allergens and correlate the
IgE-binding pattern to clinical characteristics in European
patients with confirmed soy allergy
•Methods: The IgEreactivity in 30 sera from subjects
(Switzerland, Denmark and Italy)—with a positive double-
blind, placebo-controlled soybean challenge (n = 25)
or a convincing history of anaphylaxis to soy (n = 5) was
analyzed by ELISA or CAP-FEIA
J Allergy Clin Immunol 2009;123:452-8.

47. The 2 soybean major storage proteins
-Glym 5 (β-conglycinin: 3 subunits)
: α(67kd)
: α ‘ (71 kd)
:β(50 kd))
-Glym 6 (glycinin: 5 different subunits)
: G1 (A1aB1b, 53.6 kd)
: G2 (A2B1a, 52.4 kd)
: G3 (A1bB2, 52.2 kd)
: G4 (A5A4B3, 61.2 kd)
: G5 (A3B4, 55.4 kd)
•IgEreactivitiesmajor storage Protein (8 subunits) of the
proteins were correlated to the clinical characteristics of our patient group
to investigate the potential use as biomarkers for severe allergic reactions
to soybean.
J Allergy Clin Immunol 2009;123:452-8.

48. Clinical implications:
Component-resolved diagnosis
with purified Glym5 and Glym6
is potentially applicable for
identifying subjects at risk of
experiencing severe soy-related
allergic reactions.
J Allergy Clin Immunol 2009;123:452-8.
Glym 5 +ve= 13/30 (43%)
Glym 6 +ve= 11/30 (37%)
Glym 5 otGlym 6 +ve=16/30(53%)

49. Tri aA_TI, Tri a 18, Tri a gliadin, Tri a 19 (Ѡ-5 gliadin)
and high molecular weigh glutenin
Tri a 14
-Lipid transfer protein
-heat resistance and lack of cross-reactivity to
pollen
-major allergen in pt. living in southern Europe
and significant in baker’s asthma
Tri a 18
-Hevb 6 homologue (latex component)
Wheat (Triticiumaestivum)
Clinical& experimental allergy; 2010: 40: 1442-1460

50. Tri a 19 (Ѡ-5 gliadin)
-associated with risk of IgE-mediated reaction to
wheat
-risk of wheat-dependent exercise induce
anaphylaxis
Wheat (Triticiumaestivum)
Clinical& experimental allergy; 2010: 40: 1442-1460

51. Tri aA_TI(alpha-amylase/tyrpsininhibitor)
-wheat allergen in raw and cooked food
-play role in wheat-depedentexercise induce
anaphylaxis
High molecular weigh glutenin
-associated with wheat-dependent exercise
induce anaphylaxis
Tri a gliadin
-primary wheat sensitization (low-risk of pollen cross-reactivity)
Wheat (Triticiumaestivum)
Clinical& experimental allergy; 2010: 40: 1442-1460

52. •Aim: to examine whether ω-5gliadinis a clinically relevant allergen in
children with hypersensitivity reactions to ingested wheat.
•Method
: Sera were obtained from 40 children (mean age, 2.5 years; range,
0.7-8.2 years) with suspected wheat allergy (AD a/o GI a/o
respiratory symptoms
: Wheat allergy Dxwith open or DBPC oral wheat challenge.
: Wheat ω-5 gliadinwas purified by reversed-phase
chromatography,andserum IgEantibodies to ω-5 gliadinwere
measured by ELISA
: In vivo reactivity was studied by SPT.
: Control sera were obtained from 22 children with no
evidence of food allergies
J Allergy ClinImmunol2001;108:634-8

53. •Result
Immediated
Delayed
J Allergy ClinImmunol2001;108:634-8
-16/19(84
%)
detected
IgEto Ѡ-5
gliadin
-6/7 SPT
+veto Ѡ-5
gliadin
-not detected
IgEto Ѡ-5 gliadin
-2/2 SPT –veto
Ѡ-5 gliadin

54. J Allergy ClinImmunol2001;108:634-8
Conclusion: The results of this study
show that ω-5 gliadinis a significant
allergen in young children with
immediate allergic reactions to
ingested wheat. IgEtesting with ω-5
gliadincould be used to reduce the
need for oral wheat challenges in
children.

55. Morita,etal. AllergologyInternational.2009;58:493-498

56. -most common food associated with fatal
allergic reaction in western country, the
prevalence also increase in Asia
-13 peanut allergen have been identified
-5 peanut component are clinically
relevant and available
Arah1, 2, 3, 6, 8, and 9
Peanut (Arachishypogaea)
Clinical& experimental allergy; 2010: 40: 1442-1460

57. Ara h 1, 2, and 3
-majorpeanut allergen (peanut seed storage protein)
-associated with primary sensitization
-pt. with peanut allergy are sensitized to
Arah 1 35-95%
Arah 2 75-100%
Arah 3 20-55%
-stable to heat and digestionrisk of reaction to
cooked or roast food
Peanut (Arachishypogaea)
Clinical& experimental allergy; 2010: 40: 1442-1460

58. Arah 1
-cross-reactive to nut and legume [lentil,pea,
and soy(Glym 5)]
Arah 2
-marker for primary sensitization to peanut and
risk marker for severe allergic reaction
-cross-reactive to lupine and tree nut
(eg. almond and brazil nut)
Arah 3
-cross-reactive to soybean, pea, and tree nuts
Clinical& experimental allergy; 2010: 40: 1442-1460
Peanut (Arachishypogaea)

59. Arah 6
-high homology to Arah 2
Arah 8
-PR-10, Bet V 1 homologue
-heat-labile proteincooked food often tolerated
-primary sensitization through pollen : birch,cedar
-cross-reactive to lupine and soy (Glym 4)
Arah 9
-Lipid transfer protein (LTP)
-associated with severe OAS and systemic reaction
-primary sensitization probably due to primary
sensitization to peach or other LTP-containing fruits
Peanut (Arachishypogaea)
Clinical& experimental allergy; 2010: 40: 1442-1460

60. •Aim
-To establish by oral food challenge the proportion of
children with clinical peanut allergy among those
considered peanut-sensitizedby using skin prick tests
and/or IgEmeasurement
-To investigate whether component-resolved diagnostics
using microarray could differentiate peanut allergy from
tolerance.
•Method
-The Manchester Asthma and Allergy study 
unselected population based birth cohort
-participants recruited prenatally and F/U prospectively
at age 1, 3, 5 and 8 yr( questionnaire, SPT, sIgE)
J Allergy ClinImmunol2010;125:191-7

61. 85 were sensitized to
peanut
13 OFC
J Allergy ClinImmunol2010;125:191-7

62. J Allergy ClinImmunol2010;125:191-7

63. J Allergy ClinImmunol2010;125:191-7
Green : peanut tolerant
Yellow : peanut allergy
-Peanut allergy fold change = 6.06 expression level 66.7 time higher than
negative control
-Peanut tolerant fold change = 0.28 expression level 1.2 time higher than
negative control
Clinical implications: Measurement of IgEresponse to
major peanut allergen Arah 2 is more useful in predicting
clinical peanut allergythan currently used skin or blood
tests based on whole extract.

64. Advantage of CRD
•Quantifying IgEantibodies to a single allergen
protein component rather than a
heterogeneous allergen preparation
•Providing a unique component-specific IgE
antibody profile of the patient for
personalized medical care
• Supporting a molecular-level understanding of
the patient’s individual constellation of
symptoms

65. Advantage of CRD
• Better characterize the patient’s sensitization patterns
• Better understand the clinical risk for reactions in a
patient
• Determine the presence of cross-reactivity between
allergens
• Facilitate food challenge testing with increased
knowledge of what to expect
• Select appropriate patients for specific immunotherapy
and customize treatment
Advantage of CRD

66. Allergen Components as severity markers
Peanut Ara h 1, 2 and 3
Soy Gly m 5 and 6
Wheat Omega-5-gliadin
Milk Bos d 8 (casein)
Egg Gal d 1 (ovomucoid)

68. Important allergen
Arah 1, 2, 3, 8 and 9 (peanut)
• IgEabs to Arah 1, 2, 3 and 9 (LTP) are associated with
peanut reactions, which in many cases can be severe.
• IgEabs to Arah 8 (PR-10) are usually associated with
milder, local symptoms such as OAS, origintingfrom birch
sensitzation.
Ovumucoid(egg white)
• IgEabs to ovomucoidare associated with persistent egg
allergy and usually neither raw or cooked is tolerated.

69. Omega-5 gliadin(wheat)
• IgEabs to omega-5 gliadin(Tri a 19) in adults are associated with a
risk of exercise-or NSAIDs-induced reactions in connection with
wheat ingestion.
• IgEabs to omega-5 gliadinin children are associated with a risk of
immediate reactions to wheat.
Glym 4,5 and 6 (soy)
• Glym 5 and 6 are associated with clinical reactions to soy.
Glym 5 -Arah 1 and Glym 6 -Arah 3 share homologoues
structures.
• IgEabs to Glym 4 (PR-10) are usually associated with milder, local
symptoms such as OAS, originating from birch sensitzation.
Important allergen