Background: Patients sensitized to birch pollen frequently suffer from a food allergy to plant foods such as celery, carrots, or hazelnut. Oneof the main manifestations of birch pollen-related food allergy is the oral allergy syndrome. Skin tests and allergen-specifi c immunoglobulin (Ig) E determinations are poor predictors of such reactions when assessed by double-blind placebo-controlled food challenge (DBPCFC).

Objective: To investigate whether a cellular test based on leukotriene release from basophils, the cellular antigen stimulation test in combination with enzyme-linked immunosorbent assay (CAST-ELISA), is predictive of pollen-related food allergy.

Methods: Birch pollen-sensitized patients with positive DBPCFC to celery (n = 21), hazelnut (n = 15), and carrot (n = 7) underwent skintests along with determination of specifi c IgE and CAST-ELISA for the respective allergens. The results were compared with those of 24 birch pollen-sensitized patients with negative open food challenge to celery, hazelnut, and carrot.

Results: While skin prick tests had a sensitivity of 85%, 80%, and 29% for commercial extracts of celery, hazelnut, and carrot, respectively, prick testing with self-prepared extracts yielded sensitivities of 100%, 80%, and 100%, respectively. For specifi c IgE determinations, sensitivities were 71%, 73%, and 57%, respectively, and the respective specifi cities were 67%, 73%, and 60%. For CAST-ELISA with various sources and doses of allergens, the sensitivity varied from 71% to 95% for celery, 73% to 80% for hazelnut, and 43% to 86% for carrot. The respective specifi cities were 67% to 92%, 75% to 88%, and 77% to 91%. Analysis of the predictive value of CAST-ELISA with receiver operating characteristic curves showed that the results of the tests were more predictive of pollen-related food allergy than quantitative allergen-specifi c IgE determinations.

Conclusions: CAST-ELISA is more specifi c than routine diagnostic tests for the diagnosis of pollen-related food allergy to celery, hazelnut, and carrot.

Key words: Cellular antigen stimulation test. Sulfi doleukotriene release. Pollen-associated food allergy. Oral allergy syndrome. Double-blind placebo-controlled food challenge. Hazelnut. Celery. Carrot.