Apple Allergy

Allergen Data Collection: Apple (Malus domestica)
Internet Symposium on Food Allergens 1(3): 103-119 (1999) [http://www.food-allergens.de]

1 Prevalence of Apple Allergy


Country / Subjects	Sensitivity to	References
*Denmark, Hellerup* 101 birch and/or hazelnut allergic patients	apple extract 8% apple peel, fresh 28% (SPT)	Andersen et al. 1978
*Finland, Helsinki* 73 birch pollen allergic patients	apple 63 % (case history) apple pulp 43 % and apple seed 59% (SPT)	Lahti et al. 1980
*Finland, Oulu* children with atopic dermatits	apple 0% and 13% in patients 1-3 years and 3-15 years of age (n=14 and 32) (SPT)	Hannuksela 1987
*France, Toulouse* 142 food allergic children	apple 0.7 % (labial food challenge)	Rance & Dutau 1997
*Germany, Berlin* 167 pollen and food sensitive patients	apple 93 % and 84 % (SPT and case history)	Jankiewicz et al. 1996
*Germany, Frankfurt* 80 patients with pollen associated food allergy	apple 41% (SPT, RAST)	Boehncke et al. 1998
*Germany, Hamburg* 30 patients with pollen associated food allergy	apple 87 % (EAST)	Möller et al. 1997
*Italy, Milan* 262 fruit and/or vegetable allergic patients	apple 53 % (clinical history)	Ortolani et al. 1988
*Italy, Milan* 100 fruit and/or vegetable allergic patients	apple 45 % (clinical history)	Ortolani et al. 1989
*Japan* 171 birch pollen allergic patients	apple 13 % (RAST)	Yamamoto et al. 1995
*Netherlands, Rotterdam* 79 tree-pollen allergic patients	apple 65%, 68%, and 44% (SPT, RAST, and case history)	de Groot et al. 1996
*Spain, Salamanca* 84 mugwort sensitive patients without other pollen sensitizations	apple 1.2% (RAST)	Garcia-Ortiz et al. 1996
*Sweden, Uppsala* 128 pollen allergic patients a) birch pollen b) grass / mugwort pollen	a) apple 90% b) apple 46% (SPT, controls = 17% positive)	Dreborg & Foucard 1983
*Switzerland, Vaudois* 111 patients with pollen- associated food allergy	apple 83 % (RAST)	Bircher et al. 1994
*Switzerland, Zurich* 402 food allergic adults	apple, kiwi 1.5 %	Wüthrich 1993
*USA, Long Beach, CA* 137 patients with latex allergy	apple 2 % (convincing history of possible IgE mediated symptoms occurring within 60 minutes of ingestion)	Kim & Hussain 1999
*USA, Ohio* 148 respiratory- allergic children with reproduced symptoms after food challenge	apple 2 % (open challenge)	Ogle et al. 1980
*USA, Rockville, MD* 34 patients allergic to tree pollens	apple 71 % (SDS-PAGE immunoblot)	Hsieh et al. 1995

2 Symptoms of Apple Allergy

Symptoms & Case Reports References

systemic reactions
anaphylaxis (7), exercise-induced anaphylaxis (5)
cutaneous symptoms
angioedema (1, 4, 11), urticaria (1, 6, 7, 11)
gastrointestinal symptoms
glottis edema (11), tongue edema (11), itching in mouth (1, 4, 8), itching in throat (1, 8), swelling of lips (8), tingling in mouth (1, 4), vomiting (11), oral allergy syndrome* (2, 3, 6, 7, 9, 10), in general (6)
respiratory symptoms
allergic rhinitis (1), asthma (4, 6, 11)
* symptoms, which could be involved in oral allergy syndrome: local symptoms as intra-oral and lip-irritation, angioedema and systemic symptoms as rhino-conjunctivitis, urticaria-angioedema, asthma, and anaphylaxis (3)
(1) Kremser & Lindemayr 1983
(2) Pastorello et al. 1987
(3) Ortolani et al. 1988
(4) Ortolani et al. 1989
(5) Anibarro et al. 1994
(6) van Ree et al. 1995
(7) Fernandez-Rivas et al. 1997
(8) Möller et al. 1997
(9) Wüthrich 1997
(10) Wüthrich et al. 1997
(11) Sánchez-Monge et al. 1999

Percentage of reactions
Oral allergy syndrome 82%, with additional systemic symptoms 17%, extra-oral symptoms 18% in 139 apple-allergic patients (1)
Onset of symptoms within 5 min after food ingestion in > 50% of patients with oral allergy syndrome and within 30 min in > 90% (1)
In 10 apple allergic patients without related pollinosis: 64% anaphylaxis, 27% oral allergy syndrome, and 18% urticaria (2)
(1) Ortolani et al. 1988
(2) Fernandez-Rivas et al. 1997

Symptoms & Case Reports	References
systemic reactions anaphylaxis (7), exercise-induced anaphylaxis (5) cutaneous symptoms angioedema (1, 4, 11), urticaria (1, 6, 7, 11) gastrointestinal symptoms glottis edema (11), tongue edema (11), itching in mouth (1, 4, 8), itching in throat (1, 8), swelling of lips (8), tingling in mouth (1, 4), vomiting (11), oral allergy syndrome* (2, 3, 6, 7, 9, 10), in general (6) respiratory symptoms allergic rhinitis (1), asthma (4, 6, 11) * symptoms, which could be involved in oral allergy syndrome: local symptoms as intra-oral and lip-irritation, angioedema and systemic symptoms as rhino-conjunctivitis, urticaria-angioedema, asthma, and anaphylaxis (3)	(1) Kremser & Lindemayr 1983 (2) Pastorello et al. 1987 (3) Ortolani et al. 1988 (4) Ortolani et al. 1989 (5) Anibarro et al. 1994 (6) van Ree et al. 1995 (7) Fernandez-Rivas et al. 1997 (8) Möller et al. 1997 (9) Wüthrich 1997 (10) Wüthrich et al. 1997 (11) Sánchez-Monge et al. 1999
*Percentage of reactions* Oral allergy syndrome 82%, with additional systemic symptoms 17%, extra-oral symptoms 18% in 139 apple-allergic patients (1) Onset of symptoms within 5 min after food ingestion in > 50% of patients with oral allergy syndrome and within 30 min in > 90% (1) In 10 apple allergic patients without related pollinosis: 64% anaphylaxis, 27% oral allergy syndrome, and 18% urticaria (2)	(1) Ortolani et al. 1988 (2) Fernandez-Rivas et al. 1997

3 Diagnostic Features and Therapy of Apple Allergy

Parameters / Subjects Outcome References

IgE
birch pollen allergic patients
a) 24 with apple allergy, b) 9 apple tolerant Apple specific serum IgE (RAST):
a) 1.76 +/- 3.39 PRU/mL
b) 0.76 +/- 0.44 PRU/mL
no significant differences Pastorello et al. 1987

Histamine Release (HR)
40 birch pollen-allergic patients
a) with and b) without fruit allergy Dose-dependent HR in both groups:
apple peel = apple pulp > peach = cherry
(to significant higher extent of HR in b)
significant increase of basophil sensitivity to birch pollen in group b) Kleine-Tebbe et al. 1992

IgE and Clinical Relevance
patients with clinical apple allergy (a), birch pollen allergy (b), or other allergies (c) apple specific IgE > 0.35 kU/L in
a) 90% (in 85% >0.7 kU/L),
b) 44%, and
c) 5-10% of patients (RAST) Bjorksten et al. 1980

SPT, IgE and Clinical Relevance
apple-allergic patients positive reactions in 84% and 3.6% of patients with clinical apple allergy tested with fresh apples and commercial extracts, respectively (SPT)
apple specific IgE in 70% of patients with clinical apple allergy (RAST) Ortolani et al. 1988

a) RAST and Clinical Relevance
b) SPT and Clinical Relevance
44 patients with clinical history of apple allergy a) RAST (specific IgE > 0.7 kU/L):
positive results in 71%
positive preditive value 79%
negative preditive value 62%
b) SPT with commercial extracts and fresh food:
positive results in 2.3 % and 81%
positive preditive value 100% and 78%
negative preditive value 40% and 71% Ortolani et al. 1989

Birch Pollen spec. IgE
103 birch pollen-hypersensitive patients free of oral allergy syndrome (at begin of the followed-up study) Birch pollen specific serum IgE- levels in patients:
a) who developed Apiaceae sensitivity 15.5 AU/mL
b) who developed apple/hazelnut allergy only 8.5 AU/mL
c) who remained free of oral allergy syndrome 5 AU/mL
(median values, P < 0.05) Asero 1997

Birch Pollen Immunotherapy
20 birch pollen allergic patients 2 or 3 courses of immunotherapy in successive years:
fruit allergy improved in 9 patients
no improvement in 4 patients
fruit allergy developed in 3 patients
At the end of 3 years 16 patients were allergic to fruit, 13 of them to apple
IgE during immunotherapy:
birch and apple specific IgE increased temporary
IgG and IgG4 during immunotherapy:
increase of birch specific Ab only
histamine release:
sensitivity to birch pollen extract decreased significantly during immunotherapy, no significant changes to apple extract Herrmann et al. 1995

Birch Pollen Immunotherapy
49 birch pollen allergic patients with apple- induced oral allergy syndrome 12, 24, or 36 months of pollen- specific immunotherapy:
84 % improved (reported symptoms of OAS)
88 % improved (fresh apple, SPT)
IgE during immunotherapy:
significant decrease in birch pollen- specific IgE levels, apple- specific IgE reduction in 21%, no change in 43%, increase in 38% (RAST) Asero 1998

Oral Desentization
1 apple allergic patient A diluted food extract followed by increased pure food was administered following a standardized protocol, at the beginning pretreatment with oral sodium cromoglycate, length of therapy 3.5 months, after therapy apple was tolerated (maintenance dose: 1 apple twice a week) Patriarca et al. 1998

Parameters / Subjects	Outcome	References
*IgE* birch pollen allergic patients a) 24 with apple allergy, b) 9 apple tolerant	Apple specific serum IgE (RAST): a) 1.76 +/- 3.39 PRU/mL b) 0.76 +/- 0.44 PRU/mL no significant differences	Pastorello et al. 1987
*Histamine Release (HR)* 40 birch pollen-allergic patients a) with and b) without fruit allergy	Dose-dependent HR in both groups: apple peel = apple pulp > peach = cherry (to significant higher extent of HR in b) significant increase of basophil sensitivity to birch pollen in group b)	Kleine-Tebbe et al. 1992
*IgE and Clinical Relevance* patients with clinical apple allergy (a), birch pollen allergy (b), or other allergies (c)	apple specific IgE > 0.35 kU/L in a) 90% (in 85% >0.7 kU/L), b) 44%, and c) 5-10% of patients (RAST)	Bjorksten et al. 1980
*SPT, IgE and Clinical Relevance* apple-allergic patients	positive reactions in 84% and 3.6% of patients with clinical apple allergy tested with fresh apples and commercial extracts, respectively (SPT) apple specific IgE in 70% of patients with clinical apple allergy (RAST)	Ortolani et al. 1988
a) RAST and Clinical Relevance b) SPT and Clinical Relevance 44 patients with clinical history of apple allergy	a) RAST (specific IgE > 0.7 kU/L): positive results in 71% positive preditive value 79% negative preditive value 62% b) SPT with commercial extracts and fresh food: positive results in 2.3 % and 81% positive preditive value 100% and 78% negative preditive value 40% and 71%	Ortolani et al. 1989
*Birch Pollen spec. IgE* 103 birch pollen-hypersensitive patients free of oral allergy syndrome (at begin of the followed-up study)	Birch pollen specific serum IgE- levels in patients: a) who developed Apiaceae sensitivity 15.5 AU/mL b) who developed apple/hazelnut allergy only 8.5 AU/mL c) who remained free of oral allergy syndrome 5 AU/mL (median values, P < 0.05)	Asero 1997
*Birch Pollen Immunotherapy* 20 birch pollen allergic patients	2 or 3 courses of immunotherapy in successive years: fruit allergy improved in 9 patients no improvement in 4 patients fruit allergy developed in 3 patients At the end of 3 years 16 patients were allergic to fruit, 13 of them to apple IgE during immunotherapy: birch and apple specific IgE increased temporary IgG and IgG4 during immunotherapy: increase of birch specific Ab only histamine release: sensitivity to birch pollen extract decreased significantly during immunotherapy, no significant changes to apple extract	Herrmann et al. 1995
*Birch Pollen Immunotherapy* 49 birch pollen allergic patients with apple- induced oral allergy syndrome	12, 24, or 36 months of pollen- specific immunotherapy: 84 % improved (reported symptoms of OAS) 88 % improved (fresh apple, SPT) IgE during immunotherapy: significant decrease in birch pollen- specific IgE levels, apple- specific IgE reduction in 21%, no change in 43%, increase in 38% (RAST)	Asero 1998
*Oral Desentization* 1 apple allergic patient	A diluted food extract followed by increased pure food was administered following a standardized protocol, at the beginning pretreatment with oral sodium cromoglycate, length of therapy 3.5 months, after therapy apple was tolerated (maintenance dose: 1 apple twice a week)	Patriarca et al. 1998

4 Composition of Apple

5 Allergens of Apple

Proteins / Glycoproteins Allergen Nomenclature References

Bet v 1 - homolog Protein Mal d 1 Vieths et al. 1994

31-kDa-Allergen Hsieh et al. 1995

Lipid-transfer Protein Mal d 3 Sánchez-Monge et al. 1999

Profilin homolog Allergen: 14-15 kDa Vallier et al. 1992, Ebner et al. 1995

Art v 1 cross-reactive Allergen: 60 kDa Heiss et al. 1996, Grote et al. 1998

Allergen: 34-35 kDa Wellhausen et al. 1996

Allergens: 8-16, 18, 35, 50 kDa Vieths et al. 1992

Allergens: 13, 14, 16, 18, 31 kDa Hsieh et al. 1995

Allergens: 18 and 67-kDa Möller et al. 1997

5.1 Sensitization to Apple Allergens

Country / Subjects Sensitivity to References

Austria, Vienna
83 birch pollen allergic patients double band at 17 and 18 kDa in 97% (SDS-PAGE immunoblot) Ebner et al. 1991

Austria, Vienna
20 birch pollen allergic patients double band at 17 and 18 kDa in 95%
profilin-homologue 14 kDa allergen in 20 %
(SDS-PAGE immunoblot) Ebner et al. 1995

Germany, Berlin
23 (22) birch pollen and apple allergic patients Allergens from mature (and semi- mature) Golden Delicious:
50 kDa allergen in 13% (77%)
40-50 kDa allergens in 39% (68%)
35 kDa allergen in 4% (23%)
18 kDa allergen (Mal d 1) in 65% (9%)
16 kDa allergen in 26% (5%)
10-15 kDa allergens in 30% (36%)
allergens > 50 kDa in 9% (27%)
(SDS-PAGE / immunoblot) Vieths et al. 1993

Germany, Berlin
12 apple and celery allergic patients Carbohydrate epitopes on allergens > 30 kDa
(periodate treatment, immunoblot, EAST inhibition) Vieths et al. 1994b

Germany, Berlin
33 birch pollen and apple allergic patients Mal d 1 in 73 % and 76 % (purified allergen from Golden Delicious and Granny Smith) (SPT) Vieths et al. 1995

Spain, Madrid
10 apple and peach allergic patients Mal d 3 in 90 % (SDS-PAGE / immunoblot) Sánchez-Monge et al. 1999

USA, Rockville, MD
24 tree pollen and apple allergic patients 31 kDa allergen in 75 %
18 kDa allergen (Mal d 1) in 38 %
16 kDa allergen in 4 %
14 kDa allergen in 25 %
13 kDa allergen in 17 %
allergens > 38 kDa in 58 %
(SDS-PAGE / immunoblot) Hsieh et al. 1995

5.2 Bet v 1 - homologue Protein (Mal d 1)
5.3 31-kDa-Allergen
5.4 Lipid-transfer Protein (Mal d 3)

6 Isolation & Preparation

Extract / Purified Allergens Methods References

Protein extract Extraction of apple allergens in an active form, inhibition of reactions with phenolic compounds present in apple, chelators and solid PVPP in extraction medium Bjorksten et al. 1980

Protein extract Low temperature extraction method:
fresh fruit homogenized in acetone (-40°C), precipitates washed, filtered, lyophylized and water extracted Vieths et al. 1994c

Protein extract
(in vivo and in vitro- test solutions) Preparation of active extracts: application of inhibitors of cytoplasmic enzymes (phenol oxidases, peroxidases, proteases) during extraction, precipitation in organic solvents (diacetone alcohol) at -20°C and resolubilization in potassium phosphate buffer;
Storage of extract solutions at 4°C was most effective with PBS/glycerol and cysteine/sodium citrate/glycerol stabilizing additives Rudeschko et al. 1995a, 1995b

Protein extract Peeled apple pulp or powdered whole frozen apple were homogenized with extraction buffer (containing sucrose, polyvinylpyrrolidone, EDTA, and diethyldithiocarbamic acid, pH 9.5-10), filtered, centrifugated and stored at -20°C Hsieh et al. 1995

Protein extract Enhanced protein content of apple extracts after anion- exchange chromatography Martinez et al. 1997

Protein extract (apple peel)
(in vivo and in vitro- test solutions) Fresh peel (Granny Smith) homogenized with potassium phosphate buffer (pH 7.0, containing PVPP, EDTA, diethyldithiocarbamate and sodium azide), centrifuged, dialyzed, lyophylized and resuspended in saline plus phenol Asero et al. 1999

18-kDa allergen (Mal d 1) Isolation after modified low-temperature extraction: IEC followed by RP-HPLC Fahlbusch et al. 1995

18-kDa allergen (Mal d 1) Isolation after low-temperature extraction method by micropreparative SDS-PAGE followed by electroelution Vieths et al. 1995

Extract / Purified Allergens	Methods	References
Protein extract	Extraction of apple allergens in an active form, inhibition of reactions with phenolic compounds present in apple, chelators and solid PVPP in extraction medium	Bjorksten et al. 1980
Protein extract	Low temperature extraction method: fresh fruit homogenized in acetone (-40°C), precipitates washed, filtered, lyophylized and water extracted	Vieths et al. 1994c
Protein extract (in vivo and in vitro- test solutions)	Preparation of active extracts: application of inhibitors of cytoplasmic enzymes (phenol oxidases, peroxidases, proteases) during extraction, precipitation in organic solvents (diacetone alcohol) at -20°C and resolubilization in potassium phosphate buffer; Storage of extract solutions at 4°C was most effective with PBS/glycerol and cysteine/sodium citrate/glycerol stabilizing additives	Rudeschko et al. 1995a, 1995b
Protein extract	Peeled apple pulp or powdered whole frozen apple were homogenized with extraction buffer (containing sucrose, polyvinylpyrrolidone, EDTA, and diethyldithiocarbamic acid, pH 9.5-10), filtered, centrifugated and stored at -20°C	Hsieh et al. 1995
Protein extract	Enhanced protein content of apple extracts after anion- exchange chromatography	Martinez et al. 1997
Protein extract (apple peel) (in vivo and in vitro- test solutions)	Fresh peel (Granny Smith) homogenized with potassium phosphate buffer (pH 7.0, containing PVPP, EDTA, diethyldithiocarbamate and sodium azide), centrifuged, dialyzed, lyophylized and resuspended in saline plus phenol	Asero et al. 1999
18-kDa allergen (Mal d 1)	Isolation after modified low-temperature extraction: IEC followed by RP-HPLC	Fahlbusch et al. 1995
18-kDa allergen (Mal d 1)	Isolation after low-temperature extraction method by micropreparative SDS-PAGE followed by electroelution	Vieths et al. 1995

7 Cross-Reactivities


Cross-Reacting Allergens	Subjects / Methods	References
*Apple fruit* birch pollen	Apple allergic patients' serum pool: birch pollen inhibited IgE- binding to apple allergens (RAST-inhibition)	Bjorksten et al. 1980
*Apple fruit* significant associations: apple and cherry, apple and pear, apple and birch pollen *	262 fruit and/or vegetable allergic patients (clinical history, SPT, RAST)	Ortolani et al. 1988
*Apple allergen* (17 to 18 kDa) birch pollen	32 patients with birch pollen allergy (pooled serum) birch pollen inhibited IgE- binding to 17-18 kDa apple- allergen apple extract did not diminish binding to Bet v 1 (immunblot- inhibition)	Ebner et al. 1991
*Apple* (15 kDa) celery profilin (15 kDa)	Sera reactive to 15 kDa celery allergen: Inhibition of IgE and celery profilin specific rabbit-mAb binding to 15 kDa apple allergen by celery crude extract and by celery profilin, respectively (immunoblot inhibition)	Vallier et al. 1992
*Apple allergens* birch pollen	Apple and birch pollen allergic patients (immunoblot inhibition)	Vieths et al. 1992
*Apple* kiwi fruit	3 kiwi allergic patients (RAST inhibition)	Gall et al. 1994
*Apple* birch pollen (Bet v 1)	Depletion of birch-pollen extract for Bet v 1 removed approximately 95% of the IgE cross- reactivity between birch pollen and apple extract; Cross-reactive human IgE antibodies reacted with an epitope nonoverlapping with the epitope recognized by a mAb (1 patient, RAST inhibition, two-site RIA)	Akkerdaas et al. 1995
*Apple allergens* (17 kDa / Mal d 1) birch pollen (Bet v 1)	7 Bet v 1 and Bet v 2 sensitive patients (pooled serum): complete inhibition of IgE- binding by rBet v 1 to 17 kDa apple allergen, no inhibition of binding to 14 kDa allergen (immunoblot inhibition)	Ebner et al. 1995
*Apple allergens* (14 kDa) birch pollen (Bet v 2 profilin)	7 Bet v 1 and Bet v 2 sensitive patients (pooled serum): complete inhibition of IgE- binding by rBet v 2 to 14 kDa apple allergen, no inhibition of binding to 17 kDa allergen (immunoblot inhibition)	Ebner et al. 1995
*Apple allergens* (18 kDa / Mal d 1) birch pollen (Bet v 1)	3 birch pollen and apple allergic patients and pooled serum: Allergenic potencies: Bet v 1 > Mal d 1 (EAST inhibition)	Fahlbusch et al. 1995
*Apple* a) grass pollen (Lolium perenne) b) profilin (Lolium perenne) c) carbohydrate moieties (Lolium perenne)	a) Inhibition of IgE- binding to apple extract by grass pollen (Lolium perenne) in 8 of 9 patients (RAST inhibition) b) Decrease of IgE- binding to apple extract (41%) from anti-profilin- IgE-depleted serum (RAST) c) Inhibition of IgE- binding to apple extract by carbohydrate moieties in 1 patient (proteinase K digested grass pollen extract, RAST inhibition)	van Ree et al. 1995
*Apple allergens* (18 kDa / Mal d 1) birch pollen (Bet v 1)	2 birch pollen and apple allergic patients and pooled serum: Allergenic potencies: Bet v 1 > Mal d 1 (EAST inhibition, histamine release)	Vieths et al. 1995
*Apple* 60 kDa mugwort allergen (Art v 1)	Patients with food / pollen allergy (RAST inhibition)	Heiss et al. 1996
*Apple* tomato	Tomato allergic patients (EAST inhibition)	Petersen et al. 1996
*Apple* pear	Serum pool from 7 birch pollen allergic patients: inhibition of IgE- binding to pear allergens by apple extract from Golden Delicious (EAST inhibition)	Vieths et al. 1996
*Apple* (34-35 kDa) birch pollen allergen 35 kDa and Bet v 1	Sera from birch pollen allergic patients reactive to 35 kDa allergen: IgE binding to apple extract inhibited by 35 kDa allergen and Bet v 1 of birch pollen (EAST inhibition) 35 kDa allergen from birch pollen inhibited IgE binding to 34-35 kDa apple allergen (immunoblot inhibition)	Wellhausen et al. 1996
*Apple* a) peach, pear, mugwort pollen b) rye grass profilin *	a) Patients allergic to Rosaceae fruits Allergenic potencies: peach > apple > pear (RAST inhibition) b) Cross-reactivity in patients with apple and pollen allergy, no cross-reactivity to profilin in patients without pollinosis (RAST, histamine release)*	Fernandez-Rivas et al. 1997
*Apple* (18-kDa / Mal d 1) birch pollen, Bet v 1	7 apple / kiwi allergic patients (EAST inhibition, immunoblot inhibition)	Möller et al. 1997
*Apple* (67-kDa-Allergen) kiwi allergens (43, 67 kDa)	7 apple / kiwi allergic patients: max. inhibition of IgE-binding to apple extract: kiwi extract 27% (EAST inhibition, immunoblot inhibition)	Möller et al. 1997
*Apple* (18-kDa / Mal d 1) birch pollen, Bet v 1	13 birch pollen and apple sensitive patients 79% of Mal d 1-specific T-cell clones cross-reacted with Bet v 1; 44% Bet v 1-specific T-cell clones cross-reacted with Mal d 1; 6 cross-reactive T-cell epitopes from Bet v 1 Stimulating potencies: Bet v 1 > Mal d 1 (T-Cell proliferation, recombinant allergens)	Fritsch et al. 1998
*Apple pollen* birch pollen	Patients with birch pollen allergy and oral allergy to apple fruit; IgE binding inhibitory potency to birch pollen by apple pollen extract 1000-fold lower than homologous inhibition with birch pollen (RAST-inhibition)	Berrens et al. 1990
*Apple seeds* birch pollen	3 birch pollen-sensitive patients (RAST inhibition)	Lahti et al. 1980
*Birch pollen* (Bet v 1, Bet v 2 profilin) *	28 patients with oral allergy syndrome after ingestion of apples: 57% sensitive to rBet v 1 20 polysensitized patients with oral allergy syndrome after ingestion of apples: 20% sensitive to rBet v 2 (RAST)*	Rossi et al. 1996

* multiple sensitization (not proved by inhibition-tests)

8 Stability of Apple Allergens


Treatment / Ripening	Effects	References
*Apple* pulp	Apple-pulp allergens are unstable (skin test)	Lahti et al. 1980
*Apple slices* heating at 175°C for 0.5 h, storage at RT	allergenic activity: heat labile and decreased during storage at RT	Dreborg & Foucard 1983
*Apple* mature and unripe fruits	(1) Stronger IgE binding to allergens of mature Golden Delicious apple (SDS-PAGE immunoblot) (2) Higher relative amounts of 18-kDa allergen (Mal d 1) in mature apples than in unripe apples (Golden Delicious > Boskoop) (SDS-PAGE immunoblot, densitometry, EAST inhibition)	(1) Vieths et al. 1992 (2) Vieths et al. 1993
*Apple* a) store-purchased b) storage at 4°C c) different ripening stages of stored apples (controlled atmospheric conditions) d) sprayed to prevent microbial infection	a) Higher relative amounts of 18-kDa allergen (Mal d 1) as compared to fresh apple (Golden Delicious, Granny Smith) b) Increasing amounts of 18-kDa allergen (Mal d 1) after 3 weeks c) No clear correlation between ripening stages and amounts of 31- and 18-kDa allergens, reduction of 16-kDa allergen related to ripening d) Only 16-kDa allergen detected during regulated ripening conditions (see c) (SDS-PAGE immunoblot)	Hsieh et al. 1995
*Apple extracts* spiked with pesticides (chlorpropham, iprodione or thiram)	15 Apple allergic patients: a) SPT: in 40% - 73% inhibitory effect of pesticides (weaker skin reactions), in < 20% stronger skin reactions b) EAST / mediator release: dose- dependent decrease of spec. serum IgE and histamine release by chlorpropham spiked apple extracts, no influence on LTC4 release (mediator release from basophils, HPLC)	Vieluf et al. 1997
*Apple extracts* heat (30 min, 100°C)	Heating of the food reduced allergenic activity, while semipurified protein extracts from apple retained immunoreactivity of the major allergens	Vieths et al. 1998
*Apple Test Solutions* 4 commercial extracts 1 self-prepared peel extract	a) SPT: No reactivity using 3 commercial extracts, 14% sensitivity for 1 commercial extract, 91% sensitivity for peel extract b) RAST: 55% and 9% false negativ results for 1 commercial and for the peel extract, respectively (a) 35 and b) 11 birch- pollen allergic patients with OAS to apple and positive SPT to fresh apple)	Asero et al. 1999
*Apple Prick Test Solutions* 5 commercial prick test solutions	Only 1 solution showed weak allergenic activity as compared to highly active self-prepared apple extract (EAST)	Hoffman et al. 1999

9 Allergen Sources


Reported Adverse Reactions	References
*Food / Food additives* After ingestion of fresh fruits (1)	(1) see 2 Symptoms of Apple Allergy


Allergens in Apple Products	Content / Products	References
*Apple Allergens* tree pollen and apple allergic patients	trace ammounts of active allergens in canned apples (SDS-PAGE immunoblot)	Hsieh et al. 1995

10 Allergenicity of Different Apple Varieties


Varieties / Subjects	Differences	References
*16 Apple strains* patients allergic to birch pollen and apples	Relative amounts of 18-kDa allergen (Mal d 1): great variation in 16 apple strains Allergenicity of strains decreased in the following order: Golden Delicious > Boskoop > Jamba (corresponding to high, low, and very low 18-kDa allergen content) (SDS-PAGE / immunoblot / densitometry, EAST, histamine release, open challenge)	Vieths et al. 1994a
*4 Apple strains* patients allergic to tree pollen and apples	Relative amounts of 31-kDa allergen: Golden Delicious and Granny Smith > McIntosh and Red Delicious Relative amounts of 18-kDa allergen (Mal d 1): Golden Delicious > other strains (SDS-PAGE immunoblot)	Hsieh et al. 1995
*2 Apple strains* patients allergic to tree pollen	Granny Smith more positive skin reactions and a better agreement with clinical history than Golden Delicious	de Groot et al. 1996

Proteins / Glycoproteins	Allergen Nomenclature	References
Bet v 1 - homolog Protein	Mal d 1	Vieths et al. 1994
31-kDa-Allergen		Hsieh et al. 1995
Lipid-transfer Protein	Mal d 3	Sánchez-Monge et al. 1999
Profilin homolog Allergen: 14-15 kDa		Vallier et al. 1992, Ebner et al. 1995
Art v 1 cross-reactive Allergen: 60 kDa		Heiss et al. 1996, Grote et al. 1998
Allergen: 34-35 kDa		Wellhausen et al. 1996
Allergens: 8-16, 18, 35, 50 kDa		Vieths et al. 1992
Allergens: 13, 14, 16, 18, 31 kDa		Hsieh et al. 1995
Allergens: 18 and 67-kDa		Möller et al. 1997