Pru p 3-specific IgE affinity is crucial in severe peach-allergy patients.

BACKGROUND: Peach allergy is common food allergen. Allergen components-specific antibodies of different isotypes in peach-allergy patients are poorly studied. Factors other than Pru p 3-sIgE levels may be related to severe symptoms.

OBJECTIVE: To evaluated peach component-specific-IgE, IgG1, and IgG4 characteristics in individuals with and without peach allergy, and Pru p 3-sIgE affinity in patients with different clinical symptoms.

METHODS: Fifteen healthy controls and 32 peach-allergy patients were enrolled. sIgE, sIgG1, and sIgG4 to 5 Escherichia coli- expressed peach-allergen components were determined by enzyme-linked immunosorbent assays. Pru p 3-sIgE affinity was measured in Pru p 3-sIgE-positive patients, using immunoadsorbance.

RESULTS: Patients were divided into oral allergy syndrome (OAS) and peach-induced anaphylaxis (PIA) groups. Serum Pru p 1-, Pru p 2-, Pru p 3-, Pru p 4-, and Pru p 7-sIgG1s were detected. Pru p 1- and Pru p 2-sIgG1 levels were higher in healthy controls, but Pru p 3-sIgG1 levels were significantly higher in peach-allergy patients. Pru p 1-, Pru p 3-, and Pru p 4-sIgG4-positivity was significantly greater among patients than among controls. Pru p 3 was the predominant allergen in peach-allergy patients. Allergen-sIgG1 and sIgG4 were similar between OAS and PIA patients. Pru p 3-sIgE levels were significantly higher in PIA patients, but Pru p 3-sIgE-positivity was similar in both groups. In Pru p 3-sIgE-positive patients, Pru p 3-sIgE affinity was significantly higher in PIA than OAS patients.

CONCLUSIONS: Allergen-sIgG1 was associated with allergen exposure. Both Pru p 3-sIgE levels and affinity are key factors in severe peach-allergy patients.