Allergen Profile, Cashew Nut, IgE With Component Reflex*

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Turnaround Time: 3-5 days
CPT Code:


Test Type: 1mL Serum


The measurement of specific immunoglobulin E (IgE) to components of an allergen, either purified native or recombinant, is referred to as component resolved diagnosis (CRD).1-5 This approach represents an improvement over traditional measurement of IgE to allergen extracts that contain a mixture of proteins. The pattern of specific IgE reactivity to component allergens can predict which patients are at higher risk for systemic allergic reactions versus those who are sensitized but clinically tolerant. CRD can also be used to predict which patients are at risk for more severe reactions and which patients are likely to have milder symptoms.

Allergies to plant-derived foods can occur as the result of sensitization to relatively stable proteins, such as the seed storage or lipid transfer proteins. Sensitization to this type of protein can be associated with more severe, systemic reactions and a higher risk for anaphylaxis. Alternatively, allergies to plant-derived foods may occur in pollen-sensitized individuals due to pollen allergens that cross-react with food allergens. Examples of pollen-associated allergens are the profilins or PR10 proteins that are homologues of the major white birch pollen antigen Bet v 1. Allergy to this family of proteins is associated with symptoms that are generally limited to the oropharyngeal area (commonly referred to as the oral allergy syndrome of pollen food allergy syndrome).

Component resolved diagnostics can help to1-5:

• Distinguish between allergy due to cross-reactivity and primary allergy.

• Improve risk assessment using allergen components.

• Improve management of allergic patients.

Cashew Allergy

• Cashew nut allergy is increasing as consumption increases. Snacking on cashew nuts has become more popular, and their use as a common ingredient in Asian foods, baked goods, nut butters, and pestos is growing.6,7

• Cashew nut allergic patients have high risk of experiencing severe allergic reactions; the risk has been reported to be even higher than for peanut allergic patients (74% vs. 30%).6-11

• Cashew nut allergy is potentially life-threatening, can start early in life, and is rarely outgrown.8,10,12

• Symptoms can be elicited on first known exposure, and the dose is often very low (eg, smelling, touching without eating).6,10,12

• Cashew nut allergy is increasing in parallel with increased consumption as it's becoming a popular snack, a common ingredient of Asian and processed foods, such as nut butters, baked goods, and pesto.6,7

• Cashew nut and pistachio are botanically closely related and show extensive cross-reactivity.7,13-16

Cashew Component

Ana o 3

• Ana o 3, a major cashew nut allergen, is a storage protein that serves as an energy source for the seed during growth of a new plant.7,17

• Sensitization to Ana o 3 indicates a primary cashew nut allergy.7,8,17

• Sensitization to 2S albumins, such as Ana o 3, is known to be associated with systemic food reactions.7,13,17-20

• Cashew nut allergic patients sensitized to Ana o 3 should avoid raw as well as roasted/heated cashew nuts.13,19

• Cashew nut allergic patients with sensitization to Ana o 3 should also be investigated for allergy to other nuts or seeds, such as pistachio, walnut and peanut, as coëxisting allergies may occur.7,13,19

• Positive whole cashew IgE with negative Ana o 3 results may be explained by sensitization to:

− Other cashew nut storage proteins or lipid transfer protein (LTP).

− Pollen proteins like profilin or PR10 proteins.

− CCD (cross-reacting carbohydrate determinants).

1. Chokshi NY, Sicherer SH. Interpreting IgE sensitization tests in food allergy. Expert Rev Clin Immunol. 2016 Apr; 12(4):389-403. PubMed 26666347

2. Canonica GW, Ansotegui IJ, Pawankar R, et al. A WAO - ARIA- GA2LEN consensus document on molecular-based allergy diagnostics. World Allergy Organ J. 2013 Oct 3; 6(1):17. PubMed 24090398

3. Incorvaia C, Rapetti A, Aliani M, et al. Food allergy as defined by component resolved diagnosis. Recent Pat Inflamm Allergy Drug Discov. 2014 Jan; 8(1):59-73. PubMed 24483212

4. Sampson HA, Aceves S, Bock SA, et al. Food allergy: A practice parameter update-2014. J Allergy Clin Immunol. 2014 Nov; 134(5):1016-1025. PubMed 25174862

5. Kattan JD, Sicherer SH. Optimizing the diagnosis of food allergy. Immunol Allergy Clin North Am. 2015 Feb; 35(1):61-76. PubMed 25459577

6. Clark AT, Anagnostou K, Ewan PW. Cashew nut causes more severe reactions than peanut: case-matched comparison in 141 children. Allergy. 2007 Aug; 62(8):913-916. PubMed 17620069

7. Robotham JM, Wang F, Seamon V, et al. Ana o 3, an important cashew nut (Anacardium occidentale L.) allergen of the 2S albumin family. J Allergy Clin Immunol. 2005 Jun; 115(6):1284-1290. PubMed 15940148

8. van der Valk JP, Dubois AE, Gerth van Wijk R, Wichers HJ, de Jong NW. Systematic review on cashew nut allergy. Allergy. 2014 Jun; 69(6):692-698. PubMed 24734868

9. de Silva IL, Mehr SS, Tey D, Tang ML. Paediatric anaphylaxis: A 5 year retrospective review. Allergy. 2008 Aug; 63(8):1071-1076. PubMed 18691309

10. Davoren M, Peake J. Cashew nut allergy is associated with a high risk of anaphylaxis. Arch Dis Child. 2005 Oct; 90(10):1084-1085. PubMed 16177166

11. Vetander M, Helander D, Flodström C, et al. Anaphylaxis and reactions to foods in children--a population-based case study of emergency department visits. Clin Exp Allergy. 2012 Apr; 42(4):568-577. PubMed 22417215

12. Wang F, Robotham JM, Teuber SS, Sathe SK, Roux KH. Ana o 2, a major cashew (Anacardium occidentale L.) nut allergen of the legumin family. Int Arch Allergy Immunol. 2003 Sep; 132(1):27-39. PubMed 14555856

13. Roux KH, Teuber SS, Sathe SK. Tree nut allergens. Int Arch Allergy Immunol. 2003 Aug; 131(4):234-244. PubMed 12915766

14. Hasegawa M, Inomata N, Yamazaki H, Morita A, Kirino M, Ikezawa Z. Clinical features of four cases with cashew nut allergy and cross-reactivity between cashew nut and pistachio. Allergol Int. 2009 Jun; 58(2):209-215. PubMed 19240380

15. Noorbakhsh R, Mortazavi SA, Sankian M, et al. Pistachio allergy-prevalence and in vitro cross-reactivity with other nuts. Allergol Int. 2011 Dec; 60(4):425-432. PubMed 21593580

16. Uotila R, Kukkonen AK, Pelkonen A, Mäkelä MJ. Cross-sensitization profiles of edible nuts in a birch-endemic area. Allergy. 2016 Apr; 71(4):514-521. PubMed 26706253

17. Savvatianos S, Konstantinopoulos AP, Borgå A, et al. Sensitization to cashew nut 2S albumin, Ana o 3, is highly predictive of cashew and pistachio allergy in Greek children. J Allergy Clin Immunol. 2015 Jul; 136(1):192-194. PubMed 25959668

18. Sastre J. Molecular diagnosis in allergy. Clin Exp Allergy. 2010 Oct; 40(10):1442-1460. PubMed 20682003

19. Masthoff LJ, Mattsson L, Zuidmeer-Jongejan L, et al. Sensitization to Cor a 9 and Cor a 14 is highly specific for a hazelnut allergy with objective symptoms in children and adults. J Allergy Clin Immunol. 2013 Aug; 132(2):393-399. PubMed 23582909

20. Pastorello EA, Farioli L, Pravettoni V, et al. Sensitization to the major allergen of Brazil nut is correlated with the clinical expression of allergy. J Allergy Clin Immunol. 1998 Dec; 102(6 Pt 1):1021-1027. PubMed 9847444

Collection Details:

Collection Instructions:

Red-top tube or gel-barrier tube.

Room Temperature.