B-059 Allergen-specific IgE Measurement for Peanut Ara h 2*

Abstract

Abstract Background Legumes such as peanuts are a major source of food allergies among children and adults. Ingestion is the primary route of exposure, although inhalation may also trigger an allergic response in patients with known hypersensitivity. Allergic reactions to peanut can include atopic dermatitis, angioedema, vomiting, diarrhea, and anaphylaxis. Several allergenic peanut proteins have been identified and linked with variable severity of patient symptoms. Ara h 2 is one of the proteins uniquely associated with severe peanut allergy. In this study, we evaluate the analytical performance of the Ara h 2 allergen containing reagent for use in the IMMULITE® 2000 3gAllergy® Specific IgE assay. Methods Serum samples were collected from 13 patient samples with documented histories of tree nut or legume-related allergies. The samples were analyzed for specific IgE reactivity to a commercially available recombinant Ara h 2 (rAra h 2) using the IMMULITE 2000 3gAllergy Specific IgE assay (Siemens Healthcare Diagnostics Inc., Tarrytown, NY). Precision, linearity, limit of detection, and endogenous interference were assessed. Results Repeatability and within-lab precision at all levels tested were less than 10% over a 20-day study. Regression analysis was performed following linearity assessment and resulted in a slope 95% CI of 0.9251–1.0492 (range 0.3–24 kU/L). Limit of blank and limit of detection were 0.02 kU/L and 0.08 kU/L, respectively. Endogenous interference testing showed <10% difference when spiked with hemoglobin (1000 mg/dL), intralipid (3000 mg/dL), and unconjugated bilirubin (40 mg/dL). Conclusion rAra h 2 allergen containing reagent for use in the IMMULITE 2000 3gAllergy Specific IgE assay is sensitive and capable of quantitatively measuring IgE in patients with clinical history of nut allergy. *Assay under development. Not available for sale. Future availability cannot be guaranteed.