The effectiveness of the measurement of total and specific IgE in diagnosis of cross allergy

Background: Some patients with birch pollinosis frequently develop hypersensitive reactions to certain plant food (i.e. apples, celery and carrots). This phenomenon is caused by cross-reactivity between inhalant and food allergens. Exposure to inhalant allergens causes hypersensitivity to the other allergens. The aim of this study was to investigate the diagnostic value of measurement total and specific IgE in diagnostic such kind of allergy.

Material and methods: Fifty eight patients at the age above 16 were included in the study.  The clinical history and the positive result of the skin prick test with the birch extract were the condition for qualifications. Patients were divided into two groups. Patients included in the first group were birch allergic without any symptoms after eating food (23 persons). Patients in the other group had birch pollen allergy and they reported clinical symptoms after eating foods such as: apple, celery, carrot, tomato, banana, peach, peanut and hazelnut (35 persons). IgE concentration (total and specific) were determined for all individuals.

Results: No difference in total IgE levels was found between the two groups (271,5+/-403,8 IU/ml vs 242,5+/- 340,9 IU/ml). Patients with birch allergy and hypersensitivity to food allergens showed significantly higher birch pollen specific IgE levels and it might be the predictive factor  of developing cross allergy to distinct plant food which may develop later (11,8 +/- 14,1 IU/ml vs 4,1 +/- 6,6 IU/ml). The measurement of total and specific IgE was characterized by the lowest effectiveness in diagnostic of allergy in comparison with skin tests (with commercial and native extracts of allergens).

Conclusions: The measurement of total and specific IgE seems to be the valuable method of verifying and supplementing other diagnostic tests in patients with food allergy. IgE may be an alternative in case of questionable or negative skin prick tests and when the SPT cannot be performed.