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Research article2008Peer reviewed

Allergen-specific IgE in Icelandic horses with insect bite hypersensitivity and healthy controls, assessed by FcɛR1α-based serology

Frey, Rebecka; Bergvall, Kerstin; Egenvall, Agneta

Abstract

Insect bite hypersensitivity (IBH) and atopy can both be causes of pruritus in horses and are associated with allergen-specific IgE to biting insects and environmental allergens respectively. Information with respect to differences in IgE levels in diseased and healthy animals is crucial in enabling an understanding of the clinical relevance of results of allergen-specific IgE tests.The aim of this study was (i) to evaluate and compare levels of allergen-specific IgE, using an ELISA method, in Icelandic horses, with and without IBH, Front Iceland and Sweden respectively; (ii) to investigate patterns of allergen-specific IgE to insects, pollens, moulds and mites in those groups of horses and (iii) to investigate the clinical significance of employing two different cutoff levels for the ELISA.The study compromised a total number of 99 horses from Iceland and Sweden, with and without IBH, divided in 5 groups. Sera from the horses were analysed blindly with the use of Allercept (TM), a non-competitive, solid-phase ELISA-test, designed to detect the presence of allergen-specific IgE in sera using the recombinant alphachain of the high-affinity IgE receptor (Fc epsilon FR1 alpha). The distribution of the ELISA values was shown for each insect, Mould. mite and pollen allergen, in the different groups using 10th, 50th and 90th percentiles. The use of two cut-off levels, 150 EA and 300 EA. did not eliminate the false positives. Horses with IBH had a higher number of positive reactions, counting all the 29 allergens, than healthy controls and this was borderline significant (P = 0.053).In this study it was shown that serological testing with in ELISA that uses the high-affinity IgE receptor (Fc epsilon R1 alpha) is presently not suitable as a tool for establishing a diagnosis of IBH or equine atopy. The importance of establishing a correct cut-off level for the ELISA for the different allergens is emphasised. (C) 2008 Elsevier B.V. All rights reserved.

Keywords

Horse; ELISA; Insect bite hypersensitivity; Atopy; Allergy

Published in

Veterinary Immunology and Immunopathology
2008, Volume: 126, number: 1-2, pages: 102–109