Precise results for safe decisions How to better define and manage peanut allergy
Better risk assessment with allergen components How can you differentiate between true peanut allergy or symptoms caused by cross reactivity? Is there a risk of severe reactions for the patient? How can you best manage their peanut allergy? Who needs epinephrine? Who can undergo food challenge without too high risk? Who needs dietary advice?
Better differentiation of the peanut allergic patient Today, five ImmunoCAP peanut components are available; Ara h 1, Ara h 2, Ara h 3, Ara h 8 and Ara h 9. The presence of Specific IgE to Ara h 1, Ara h 2 and Ara h 3 is indicative of a true peanut allergy 1-3 Patients with true peanut allergy often have antibodies to Ara h 2. However, in rare cases sensitization to only Ara h 1 and/or Ara h 3 can occur 4 Sensitization to the cross-reactive allergen components Ara h 8 and Ara h 9 (present in pollen and plant foods) varies depending on local exposure 5-7 1. Astier C. et al. J Allergy Clin Immunol 2006; 118: 250-256 2. Flinterman AE. Et al. Clin Exp Allergy 2007; 37(8):1221-1228 3. Peeters KABM et al. Clin Exp Allergy 2007;37(1):108-115 4. Codreanu et al. Int.Arch.Allergy.Immunol 2011;154: 216-226 5. Mittag D et al. J Allergy Clin Immunol 2004;114: 1410-1417 6. Lauer I. et al. Clin Exp Allergy 2009;39: 1427-1437 7. Krause S. et al. J Allergy Clin Immunol 2009;124: 771-778
Who is at risk for severe reactions? Ara h 2 is the most important peanut allergen component but antibodies to Ara h 1 and/or Ara h 3 in addition increases the risk of severe reactions 8-10,11 The amount of Ara h 9 in a peanut is low and severe reactions in peanut allergy are not so well documented. However, sensitization to LTP is generally associated with severe reactions in addition to OAS 12,13 IgE antibodies to the Ara h 8 is seldom associated with systematic reactions but more often to local reactions like OAS 14,15 Sensitization to several peanut allergen components indicates increased risk for severe reactions 8-10 8. Astier C. et al. J Allergy Clin Immunol 2006; 118: 250-256 9. Flinterman AE. Et al. Clin Exp Allergy 2007; 37(8):1221-1228 10. Peeters KABM et al. Clin Exp Allergy 2007;37(1):108-115 11. Nicolaou N et al. J Allergy Clin Immunol 2010;125: 191-197 12. Lauer I. et al. Clin Exp Allergy 2009;39: 1427-1437 13. Krause S. et al. J Allergy Clin Immunol 2009;124: 771-778 14. Mittag D et al. J Allergy Clin Immunol 2004;114: 1410-1417 15. Asarnoj A. et al. Allergy 2010;65: 1189-1195
Suspicion of peanut allergy risk of severe reaction?
Risk assessment with ImmunoCAP Molecular Allergology All available peanut components are needed for a complete risk assessment
Protein Groups Storage Proteins: Ara h 1 Ara h 2 Ara h 3 - Associated with severe reactions - Stable to heat and digestion
Protein Groups PR-10 Proteins Ara h 8 - Associated with local reactions (e.g. OAS) - Labile to heat and digestion - Associated with allergy to birch and birch related tree pollens
Protein Groups LTP (Lipid Transfer Proteins) Ara h 9 - Associated with both severe and local reactions - Stable to heat and digestion - Associated with allergy to peach and peach related fruits
What difference does peanut component testing make? Increase confidence in management of your peanut allergic patients Evaluate your patients risk of severe reactions to peanut Ensure relevant dietary advice and avoid unnecessary elimination Define the optimal treatment for your patients Proper diagnosis of peanut allergic patients reduces the impact on daily life and improves quality of life
Conclusion All available ImmunoCAP peanut components are needed for a complete risk assessment of a suspected peanut allergy Sensitization to several peanut components is a stronger indication of more severe reactions than sensitization to only one of the components
Peanut Case #1: Caroline and Emma, 16 years old Similar clinical history Can component testing tell two different stories?
Background Previous symptoms Ezcema during infancy, outgrown at school age Rhinitis and conjunctivitis during pollen season, since school age Ongoing symptoms Nasal obstruction in combination with irritated, itchy eyes and sometimes local reaction in the mouth Family history None
Previous visit at 5 years Caroline Emma SPT results: Egg +1 Egg +1 Peanut +4 Peanut +4 Diagnosis: Peanut and egg allergy Peanut and egg allergy Treatment: Dietary restriction to Dietary restriction to peanut and egg peanut and egg
Current Visit Peanut Challenge outcome Caroline Emma Specific IgE results: Peanut 26 ku A /l Peanut 28 ku A /l Peanut Challenge: No symptoms Urticaria, rhinitis cough, tired Diagnosis: No peanut allergy Peanut allergy was confirmed Treatment: No dietary restriction Dietary restriction to peanut to peanut remains What would be the result of peanut component testing?
Current Visit ImmunoCAP Allergen components Caroline (ku A /l) Peanut (f13) 26 28 Ara h 1 <0.1 2.1 Ara h 2 <0.1 12.3 Ara h 3 <0.1 3.3 Ara h 8 33 10.3 Emma (ku A /l) Diagnosis: No peanut allergy Peanut allergy was confirmed Treatment: No dietary restriction Dietary restriction to peanut to peanut remains
Interpretation of the Allergen component test results Ara h 1, Ara h 2 and Ara h 3 Storage proteins The test results indicate an increased risk of severe reaction if eating peanuts, even small amounts = Emma s situation Ara h 8 PR-10 protein The test results indicate a pollen-related food allergy that might result in local reactions in the mouth when eating peanuts = Caroline s situation
Could testing with ImmunoCAP allergen components at an early age have changed their daily life? Yes, Caroline s quality of life could have been improved - No need of strict avoidance of peanut - No cause of stress in the family due to the risk of eating hidden peanuts Yes, Emma s well-being could have been improved - With ImmunoCAP peanut components, she could have received an adequate diagnosis at an early age, without the stress and risk associated with a peanut challenge
What difference does it make for the patient management? To differentiate between symptoms caused by true peanut allergy and symptoms caused by cross-reactivity in suspected peanut allergic patients To assess the clinical risk for reactions to peanut To select patients for food provocation, and to avoid food provocation if unneccessary
Peanut Case #2: Rudi, 8 years old
Background Previous symptoms Eczema since 6 months of age, outgrown at school age Asthma attacks during infections and exertion Rhinoconjunctivitis during tree pollen season Ongoing symptoms Asthma and rhinoconjunctivitis Itching in mouth Family history Mother, allergic to nuts Younger brother, allergic to egg, milk, peanut, tree pollen, cat and dog
Previous visit at 4 years SPT results Birch +3 Diagnosis: Treatment: Peanut +4 Hazelnut +1 Cat +4 Dog +1 Tree pollen, peanut, nuts and pets allergy Strict avoidance of peanut and nuts. Medication with antihistamine during tree pollen season. Symptomatic treatment with inhalant long-acting β2-agonists and corticosteroids
Previous visit - at 7 years SPT results ImmunoCAP test results (ku A /l) Birch 0 Birch 23.1 Peanut +4 Peanut 7.3 Hazelnut +2 Hazelnut 12.4 Cat +4 Cat 10.2 Dog +1 Dog 4.2 Diagnosis: No change in diagnosis Treatment: No change in treatment
Current visit ImmunoCAP Allergen components Test results (ku A /l) Peanut (f13) 7.3 Hazelnut (f17) 12.4 Ara h 1 0.2 Cor a 1 12.8 Ara h 2 4.3 Cor a 8 <0.1 Ara h 3 <0.1 Birch (t3) 23.1 Ara h 8 1.4 Ara h 9 <0.1
Interpretation of the Allergen component test results Ara h 2 Storage protein The test results indicate an increased risk of severe reaction if eating peanut, even small amounts Ara h 8 and Cor a 1 PR-10 protein The test results indicate a pollen-related food allergy that might result in local reactions in the mouth when eating peanuts and hazelnuts
Discussion and Consequences What will happen if eating peanuts? The test result of Ara h 2 indicates an increased risk for severe reactions if eating peanuts. Strict avoidance of peanut is therefore necessary What will happen if eating hazelnuts? The test result from Cor a 1 indicates that the itching in the mouth when eating hazelnuts may originate from the pollen-food allergy An open challenge with hazelnut might reduce the fear of severe reactions to hazelnut based on the family history What about the birch-pollen allergy? Sensitization to birch pollen is confirmed, continue with current medication