P30: CLINICAL VALIDATION OF A COMPONENT‐BASED MULTI‐PARAMETER LINE BLOT TEST FOR PEANUT ALLERGY

Abstract

Assessing for peanut allergy is a challenging and difficult clinical problem. Skin or IgE testing with whole peanut extracts often yield false positive due to cross reactions with pollen allergy. The advent of peanut component testing has made available a useful tool for stratification of risk for peanut allergy. However multiple component testing with the available ImmunoCAP specific IgE (sIgE) platform or the ISAC allergen chip can be prohibitively expensive. Our Immunology service performed validation studies on the newly introduced Euroimmun line blot which contains 7 peanut components (rAra h 1, 2, 3, 5, 6, 7, 9) and rBet v 1. We compared the performance of the line blot using patient serum previously analysed and positive for rAra h 2, rAra h 6, PR10 and Profillin proteins by ImmunoCAP sIgE and one sample analysed by the ISAC allergen chip. Serum samples of patients with positive peanut oral food challenge (OFC) to peanut were also analysed with the peanut component line blot to determine retrospectively if they have unidentified IgE to peanut storage protein. There was perfect concordance of positive and negative results between patient serum samples previously analysed and positive for IgE to rAra h 2, rAra h 6, PR10 and Profillin proteins by ImmunoCAP sIgE and ISAC allergen chip. The peanut component line blot also picked up a new positive IgE to rAra h 1 in a patient who had a positive peanut OFC. There were two additional patients with positive peanut OFC with negative/low IgE to peanut that was also negative to all the peanut components on the peanut component line blot. The Euroimmune peanut component line blot performs well in comparison to the ImmunoCAP and ISAC tests. Preliminary testing suggests that it has promising clinical utility for assessing peanut allergy. However graded OFC is still necessary to confirm peanut tolerance in a patient with previous history of peanut allergy.