AAVN Webinar: Evaluation of a Direct Lymphocyte Proliferation Test for the Diagnosis of Delayed Food Allergies in Dogs

 In humans, food allergies (FA) are divided into those with an IgE-mediated (immediate FA), cell-mediated (delayed FA), or both mechanisms (mixed FA). In dogs, lymphocyte stimulation tests have the highest concordance with oral food challenges (OFC).

Nextmune isolated peripheral blood mononuclear cells (PBMCs) and automatically counted them before and after a 5-day culture with food allergens. Stimulation indices (SI) were then calculated (ratio of cell counts after allergen challenge versus saline controls). Food allergen-specific IgE was quantified using the Pet Allergy Xplorer (PAX). A cutoff SI value of 3.0 was chosen after doing this lymphocyte proliferation test (LPT) in ten healthy laboratory beagles. None of 25 healthy pet dogs had an SI greater than the chosen 3.0 cutoff, indicating a specificity of 100%. Of 55 dogs with FA diagnosed by veterinary dermatologists, 44 had a delayed FA (80%). Of these 44 dogs, an LPT was done in 28. All these 28 dogs had at least one positive lymphocyte stimulation to a food item causing delayed flares after OFC; the sensitivity of this test for the identification of delayed canine FA was thus 100%. The LPT correctly identified 57/68 food items that caused delayed flares after OFC (84%). The PAX was negative for food-specific IgE in 18/28 dogs (64%), as expected for delayed FAs. In three dogs (11%), PAX results overlapped with those of the LPT, suggesting a mixed FA. In conclusion, FAs with delayed reactions after OFC, those suspected of having a cell-mediated mechanism, seem to be the most common type of FA in dogs. The LPT is helpful in identifying such cases.

Thierry Olivry, DrVet, PhD, DipACVD, DipECVD graduated from the University of Toulouse, France, and completed a residency and PhD at the University of California Davis. He is a Diplomate of the ECVD and the ACVD. After 28 years as a clinician-scientist in veterinary dermatology and allergy at the NC State University College of Veterinary Medicine. Dr. Olivry left Academia and moved back to Europe to live in Riga, Latvia. In November 2022, he became Head of Research & Development at Nextmune, a multinational animal health company headquartered in Stockholm, Sweden. 

This webinar is free to all AAVN members.  The cost for non-members is $20.

Student Members - contact us at aavnexecutive@gmail.com to receive your promo code.