Effective Biomarkers in the Diagnosis of Apple Allergy and Their Comparative Assessment

Objectives. To evaluate the diagnostic efficacy of the prick-test and the levels of tryptase, cations K+, NH4+ and Ca2+, peroxidase activity in the oral fluid (OF) as biomarkers of apple allergy and to comparatively assess them. Material and methods. We examined 35 patients with a history of allergic reactions to a fresh apple (the study group) and 29 healthy persons (the control group). All participants underwent the prick-test with 3 varieties of fresh apples and oral-pharyngeal provocative test (OPPT) with freshly prepared apple juice with the assessment of tryptase, peroxidase activity, K+, NH4+ and Ca2+ cations levels in the OF. Results. The prick-test was positive in 94% of patients. In 70% of patients after OPPT, there was a significant tryptase level increase in the OF compared with healthy persons (p=0.000003). After provocation, in the study group, in 74% of cases, a significant peroxidase activity level increase in the OF was revealed in comparison with the control group (p<0.0000001). A significant K+ level increase in the oral fluid was found in 81% of patients, in contrast to healthy persons after OPPT (p=0.02). In 67% of cases in the study group, a significant NH4+ level decrease after OPPT was found in comparison with the initial cation level in this group (p=0.039). Patients with a history of apple allergy after provocation showed a higher Ca2+ cations level in the OF than the control (p=0.02). Conclusions. Biomarkers of hypersensitivity to apples of the varieties Golden Delicious, Red Prince and Belarusian sweet were revealed: positive prick-test, an increase of tryptase, myeloperoxidase activity, K+ cations and a decrease of NH4+ level after OPPT. Biomarkers have a high diagnostic value and can be used both in combination and separately to identify systemic and local hypersensitivity and to diagnose food allergy to apples.