Scientists from the Division of Allergology, Department of Rheumatology, Clinical Immunology and Allergology, Inselspital University of Bern ADR-AC GmbH, Bern, Switzerland, and from the University Clinic of Respiratory and Allergic Diseases, Golnik, Slovenia, have carried out a study on people with birch pollen allergy with associated oral allergy syndrome (OAS) to apple.

Successful birch pollen immunotherapy does not consistently improve OAS symptoms, so the researchers determined whether regular apple consumption has an effect on OAS. Forty patients with birch pollen rhinoconjunctivitis and associated OAS to apple were included in an open, randomised controlled clinical trial. Twenty-seven patients consumed a daily defined amount of apple for 8 months, where the amount doubled every two to three weeks, and 13 remained untreated.

Questionnaires about cross-reactive food and pollen allergy symptoms were taken, as well as a conjunctival provocation test with birch pollen. The endpoint was the amount of patients who could tolerate 128g of apple. The results showed that 17 of the 27 could tolerate a whole apple after the intervention, but the observation of a relapse after regular apple consumption stopped, plus the absence of immunologic changes, suggest that induced tolerance is only temporary.

Source: Allergy: European Journal of Allergy and Clinical Immunology

First published in November 2011

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