360 likes | 629 Views
Is it really soy allergy?. How to better define and manage soy allergic patients. Why is soy allergy complicated to identify?. IgE positivity to soy may be the result of different cross-reactivities, some without clinical reactions to soy 1,2
E N D
Is it really soy allergy? How to better define and manage soy allergic patients
Why is soy allergy complicated to identify? • IgE positivity to soy may be the result of different cross-reactivities, some without clinical reactions to soy1,2 • IgE-mediated allergy to soy might be the result of primary sensitization, but could also result from cross-reactivity to birch-related tree pollen and a variety of legumes3-7 • For patients sensitized to birch pollen with a suspicion of soy allergy, it is recommended to extend the testing with Gly m 4, which can be underrepresented in available tests based on extracts6-8 • Without components, it can be difficult to identify if your patient’s symptoms are actually due to soy 5. Ito K et al. J Allergy Clin Immunol. 2011 in press.6. Kleine-Tebbe J, J Allergy Clin Immunol 2002; 110:797-8047. Mittag D. J Allergy Clin Immunol 2004; 113:148-154.8. Ballmer-Weber B et al. Curr Opin Allergy Clin Immunol 2008;8:270-275 1. Sampson HA. J Allergy Clin Immunol. 2001;107:891-62. Matricardi et al. Clin Exp Allergy. 2008;38:493-5003. L’Hocine L, Boye J. Crit Rev Food Sci Nutr. 2007;47:127-1434. Holzhauser T, et al. J Allergy Clin Immunol. 2009;123(2):452-8
Better identification of the soy allergic patient… • The presence of specific IgE to the storage proteins Gly m 5 and Gly m 6 indicates real soy allergy and risk of severe reactions9-10 • Sensitization to Gly m 4, a PR-10 protein, is common in patients allergic to birch-related tree pollen and indicates risk of reactions to soy. The reactions are often local, but might also be systemic11-14 13. Ballmer-Weber B et al. Curr Opin Allergy Clin Immunol 2008;8:270-27514. Kosma P et al. Acta Peadiatrica 2011;100:305-307 9. Holzhauser T, et al. J Allergy Clin Immunol. 2009;123(2):452-810. Ito K et al. J Allergy Clin Immunol. 2011 in press.11. Kleine-Tebbe J, J Allergy Clin Immunol 2002; 110:797-80412. Mittag D. J Allergy Clin Immunol 2004; 113:148-154.
…results in improved patient management • Evaluate your patient’s risk of severe reactions to soy • Ensure relevant dietary advice and avoid unnecessary elimination • Define the optimal treatment for your patients • Proper diagnosis of patients with suspected soy allergy improves quality of life
Risk assessment of soy allergic patients All available soy components are needed for a complete risk assessment
Protein Groups Storage Proteins: • Gly m 5 • Gly m 6 - Associated with severe reactions - Stable to heat and digestion
Protein Groups PR-10 Proteins • Gly m 4 - Associated with local reactions (e.g. OAS)* - Labile to heat and digestion - Associated with allergy to birch and birch related tree pollens * Systemic reactions may occur, particularly in patients allergic to birch-related tree pollens when consuming high amounts of low-processed soy, e.g. soy milk.
What difference does soy component testing make? • Increase confidence in management of soy allergic patients • Differentiate between symptoms caused by real soy allergy or due to pollen-related soy allergy • Evaluate patients’ risk of severe reactions to soy • Ensure relevant dietary advice and avoid unnecessary elimination • Define the optimal treatment for patients • Proper diagnosis of soy allergic patients reduces the impact on daily life and improves quality of life
Soy Case #1: Robert, 18 years old Find the unexpected cause of a systemic reaction
Background Previous symptoms • Birch pollen allergy • No other known allergies Ongoing symptoms • Rhinoconjunctivitis during tree pollen season • OAS symptoms when eating apple Family history • None
Emergency treatment Robert receivesemergencytreatmentafterhaving a systemicreaction. Robert had the same daybeenexercising, eating a shrimp salad and drinking a soy drink. Symptoms • Coughing • Sweating • Dyspnoe • Swellingof lips • Tightnessofthroat
ImmunoCAP Allergen component test results ImmunoCAP test results (kUA/l) Egg <0.1 Shrimp <0.1 Soybean (f14) 4.2 Gly m 4 40,9 Gly m 5 <0.1 Gly m 6 <0.1 Birch (t3) 99,6
Interpretation of the Allergen component test results Gly m 4 – PR-10 protein • The test results indicate a clinically relevant cross-reaction between birch pollen and the PR-10 protein Gly m 4. IgE antibodies to Gly m 4 are often associated with local reactions. However, systemic reactions may occur, particularly when consuming high amounts of low processed soy. Robert’s reaction was most likely provoked by a high Gly m 4 content in the soy drink.
Diagnosis Birch allergy confirmed, pollen-related soy allergy Treatment • Avoid large amount of soy, e.g. soy milk • No strict dietary restrictions to soy and no stress due to the risk of eating ”hidden” soy • Medication with antihistamine and nasal steroids during pollen season
What difference does ImmunoCAP Allergen component testing make? • To find the underlying cause of a systemic reaction • To differentiate between symptoms caused by real soy allergy or due to pollen-related soy allergy • To assess the clinical risk for reactions to soy • To ensure relevant dietary advice
Could testing with ImmunoCAP Allergen components at an early age have changed Robert’s daily life? Yes, Robert could have avoided the experience of a systemic reaction • With ImmunoCAP® Allergen components and the knowledge about the pollen-related Gly m 4 (Bet v 1 homologue), Robert could have received an adequate diagnosis at an early age, without the stress and risk associated with a systemic reaction
Soy Case #2: Anna and Oliver, both 8 years old Better defineddiagnosis for improved quality of life
Background Previous symptoms • Milk allergy • Eczema during infancy, rhinitis Ongoing symptoms • Rhinoconjunctivitis during pollen season, dry skin Family history • None
Previous visit – at 4 years Anna Oliver SPT results: Egg 0 Egg 0 Milk 0 Milk 0 Soy +2 Soy +2 Wheat 0 Wheat 0 Fish 0 Fish 0 Birch +2 Birch +1 Grass 0 Grass 0 Diagnosis: Birch and Soy allergy Birch and Soy allergy Treatment: Dietary restriction to soy, Dietary restriction to soy, antihistamine during antihistamine during pollen season pollen season
ImmunoCAP allergen components at 8 years (4 years later) Anna (kUA/l) Oliver (kUA/l) Soybean (f14) 0,8 24 Gly m 4 15 2.5 Gly m 5 <0.1 16,2 Gly m 6 <0,1 6,7 Birch (t3) 58 20
Interpretation of the Allergen component test results Gly m 5, Gly m 6 – Storage proteins • The test results indicate an increased risk of severe reaction if eating soy, even small amounts = Oliver’s situation Gly m 4 – PR-10 protein • The test results indicate a clinically relevant cross-reaction between birch pollen and the PR-10 protein Gly m 4. IgE antibodies to Gly m 4 are often associated with local reactions. However, systemic reactions may occur, particularly when consuming high amounts of low processed soy, e.g. soy milk = Anna’s situation
Diagnosis and Treatment Diagnosis Anna Oliver Pollen-relatedsoyallergy, Soy and birchallergy birchallergywasconfirmedwasconfirmed Treatment Anna Oliver • Avoidlargeamountofsoy, Dietaryrestriction e.g. soy milk. However, no stricttosoyremains dietaryrestrictionstosoy and no stress dueto the risk ofeating ”hidden” soy
Could testing with ImmunoCAP Allergen components at an early age have changed their daily life? Yes, Anna’squalityoflifecouldhavebeenimproved • No needofstrictavoidanceofsoy • No cause of stress in the familydueto the risk ofeating ”hidden” soy
What difference does ImmunoCAP Allergen component testing make? • To differentiate between symptoms caused by real soy allergy or due to pollen-related soy allergy • To assess the clinical risk for reactions to soy • To ensure relevant dietary advice
Soy Case #3: John, 15 years old Is your peanut-allergic patient also at risk of severe reactions to soy?
Background Previous symptoms • Known peanut allergy, known birch allergy • No known issues with soy in the past • Complained of itching in the mouth and nasal congestion after eating a Japanese lunch • Suspicion of soy allergy Family history Father - rhinoconjunctivitis and asthma Concern • Is John at risk of severe reactions also to soy?
ImmunoCAP Allergen component test results ImmunoCAP test results (kUA/l) Soybean (f14) 1.5 Gly m4 1.9 Gly m5 1.4 Gly m6 2.2 Peanut (f13) 72.1 Ara h1 22.4 Ara h2 23.1 Ara h3 13.4 Ara h8 3.7 Ara h9 <0.1
Interpretation of Allergen component test results What happens if soy is ingested? Gly m 5, Gly m 6 – Storage proteins • The test results indicate an increased risk of severe reaction if soy is ingested, even small amounts. Strict avoidance of soy is therefore necessary. Gly m 4 – PR-10 protein • The test results indicate a clinically relevant cross-reaction between birch pollen and Gly m 4.
Interpretation of Allergen component test results Whathappensifpeanut is ingested? Ara h 1, Ara h 2, Ara h 3– Storage proteins • The test resultsindicate an increased risk ofseverereactionif peanuts areingested,even small amounts. The strictavoidanceofpeanutremains. Diagnosis: Soy and Peanutallergy Treatment: Strictdietaryrestrictiontobothsoy and peanut
What difference does ImmunoCAP Allergen component testing make? • To differentiate between symptoms caused by real soy allergy or due to pollen-related soy allergy • To assess the clinical risk for reactions to soy • To ensure relevant dietary advice