Soy Allergy Important protein source Sensitization frequency varies largely Prevalence of soy allergy % Symptoms –cuteaneous or gastrointestinal –respiratory and systemic reactions may occur Commonly used as additive in foods

Different types of soy allergy Genuine soy food allergy –Mostly in small children –Often resolves in childhood Soy allergy due to cross-reactivity –Mainly in adults –In birch-related tree pollen allergic patients –In legume allergic patients Occupational allergy

Doctor's challenges What kind of soy allergy is it? –Is it a genuine soy allergy or are the symptoms caused by cross-reactivity? Is there a risk for systemic reactions? Is strict avoidance necessary? What dietary advice should be given? Genuine or cross-reactive soy allergy?

Common clinical practice Patient At 4 years Anamnesis SPT to soy SPT to birch Diagnosis Advice Anna Eczema, Wheeze+2 Soy and birch allergy Avoid soy Oliver Eczema, Wheeze+2 Soy and birch allergy Avoid soy

Using components in clinical practice Improved diagnoses and altered advice Patient At 4 years Anamnesis SPT to soy SPT to birch At 8 years sIgE to soy Gly m 4 Gly m 5 Gly m 6 sIgE to birch Diagnosis Advice Anna Eczema, Wheeze Milk allergy outgrow kU A /l 15 < Pollen-associated soy allergy Birch pollen allergy No need for total avoidance Avoid large amounts of unprocessed soy Oliver Eczema, Wheeze Milk allergy outgrow+2 24 kU A /l Genuine soy allergy Birch pollen allergy Strict soy avoidance

Soy components

Latin name: Gly m - Glycine max Gly m 4 Gly m 5 Gly m 6 Soy components

Risk assessment of soy components

Gly m 4 A cross-reactivity marker, associated with allergy to birch and birch-related tree pollens A PR-10 protein, homologous to birch component Bet v 1 Labile protein - mainly causing local symptoms, e.g. OAS, but systemic reactions may occur

Cross reactivity - birch and soy Sensitization to soy Gly m 4 likely induced via sensitization to birch

Gly m 5 and Gly m 6 Are specific marker allergens for soy allergy Are storage proteins - proteins expressed in legumes, seeds and nuts Stable and heat resistant proteins that may cause systemic reactions

Peanut associated soy allergy Peanut (f13) 72.1 Ara h Ara h Ara h Ara h Ara h 9 <0.1 Boy 15 years old with confirmed peanut and birch allergies. Upon having a Japanese lunch he gets mouth itch. Soybean (f14) 1.5 Gly m Gly m 51.4 Gly m 62.2

In conclusion

What does Molecular Allergology add? Differentiation between genuine soy allergy and soy allergy due to cross-reactivity Enables assessment of the risk for systemic reactions Enables more precise dietary advice

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