Background The Pink peppercorn belongs to the same Anacardiaceae family as cashew and pistachio. However, the cross-reactivity of pink peppercorn with cashew and pistachio has yet to be studied. To date, there has been a single case report of anaphylaxis to pink peppercorn in a cashew and pistachio allergic individual. Objective We aim to demonstrate cross-sensitization to pink peppercorn in cashew and/or pistachio allergic children. Methods A small descriptive cohort study looking at cross-sensitization of pink peppercorn in cashew and/or pistachio allergic children was conducted. Children with a history of reaction to pistachio and/or cashew nut underwent skin prick tests to the pink peppercorn species Schinus terebinthifolius to determine cross-sensitization. Results Out of the 21 cashew and/or pistachio allergic subjects, 16 (76.2%) demonstrated cross-sensitization to pink peppercorn. None of the subjects had any knowledge of previous exposure or allergic reactions to pink peppercorn. Discussion This study demonstrates potential cross-reactivity between pink peppercorn and cashew and pistachio. While an oral food challenge to pink peppercorn would have been important in demonstrating clinical cross-reactivity, this was not performed due to ethical constraints. We hope to increase the awareness of pink peppercorn as a potential and hidden source of allergen and encourage further studies to demonstrate the clinical cross-reactivity and to better delineate the major allergen involved.

RATIONALE: Quantification of food allergens is increasingly important for dose assessments of food preparations used in oral immunotherapy (OIT), food allergy prevention, and monitoring safety in the food industry. Our aim was to develop and validate a multiplex immunoassay capable of simultaneously measuring eleven major food allergens from peanut, cow's milk, shellfish, egg, cashew, soy and hazelnut. METHODS: The multiplex array was developed on the Luminex xMAP system. Microspheres coupled to specific monoclonal antibodies were used for allergen capture. Biotinylated specific monoclonal or polyclonal antibodies were used for detection. Reference standards were formulated from natural or recombinant allergens, with purity established by mass spectrometry. A full method validation was performed to determine parameters of linearity, range, limits of quantification and detection, accuracy and precision of the multiplex food immunoassay. RESULTS: Full method validations were completed for the eleven major food allergens. The standard curves for all analytes allow for quantification over a broad dynamic range. The limits of detection (LLOD) were as low as 0.01ng/ml. Intra-and inter-assay accuracy and precision for three samples assayed in triplicate on four occasions passed acceptance criteria within the range of 70-130% recovery and a coefficient of variation of < _15%. CONCLUSIONS: A quantitative, accurate and precise multiplex immunoassay was validated for the simultaneous detection of eleven major food allergens. The multiplex array provides a sensitive and efficient tool for measuring specific food allergens, as opposed to generic food source proteins, with potential applications for risk assessment in the food industry and standardization of OIT products. J ALLERGY CLIN IMMUNOL FEBRUARY 2019 AB240 Abstracts MONDAY