Birch pollen associated soy allergy – possibilities in diagnostic and clinical relevance1)

Birch pollen allergic individuals frequently suffer from food allergies in the form of an oral allergy syndrome after eating pome and stone fruits. These complaints are based on an immunological cross-reaction between pollen and food allergens. In the past, it has been shown that many birch pollen allergic patients are additionally not able to tolerate high protein soy products. Some severe immediate type reactions to soy have been observed. The cause for these immediate type reactions to soy is a Bet v 1 cross-reactive soy allergen called Gly m 4.Using a collective of 73 birch pollen allergic patients with associated food allergy in Leipzig as an example, the results of a standardized questioning, prick-to-prick test with a soy drink, determination of specific IgE against rGly m 4, and basophil activation test with Gly m 4 are presented.We showed that commercially available prick test extracts and determination of specific IgE against soy bean mix/f14 are not appropriate to diagnose birch pollen associated soy allergy. Generally, soy sensitization could be proven when a prick-to-prick-test with a soy drink and determination of specific IgE against rGly m 4 were done. A positive prick-to-prick test with a soy drink was found in 79% (55/70) of the birch pollen allergic patients with 89% (65/73) showing specific IgE for rGly m 4 (CAP>1). Although not every sensitization was clinically relevant, every third patient with a proven soy sensitization was diagnosed with a clinically relevant allergy to soy.