Flow Cytometric Analysis of Lymphocyte Proliferative Responses to Food Allergens in Dogs with Food Allergy

Abstract

ABSTRACT. Two different allergy tests, antigen-specific immunoglobulin E quantification (IgE test) and flow cytometric analysis of antigen-specific proliferation of peripheral lymphocytes (lymphocyte proliferation test), were performed to examine differences in allergic reactions to food allergens in dogs with food allergy (FA). Thirteen dogs were diagnosed as FA based on clinical findings and elimination diet trials. Seven dogs clinically diagnosed with canine atopic dermatitis (CAD) were used as a disease control group, and 5 healthy dogs were used as a negative control group. In the FA group, 19 and 33 allergen reactions were identified using the serum IgE test and the lymphocyte proliferation test, respectively. Likewise, in the CAD group, 12 and 6 allergen reactions and in the healthy dogs 3 and 0 allergen reactions were identified by each test, respectively. A significant difference was found between FA and healthy dogs in terms of positive allergen detection by the lymphocyte proliferation test, suggesting that the test can be useful to differentiate FA from healthy dogs but not from CAD. Both tests were repeated in 6 of the dogs with FA after a 1.5-to 5-month elimination diet trial. The IgE concentrations in 9 of 11 of the positive reactions decreased by 20-80%, whereas all the positive reactions in the lymphocyte proliferation test decreased to nearly zero (P<0.05), suggesting that lymphocytes against food allergens may be involved in the pathogenesis of canine FA.

Western blot analysis of sera from dogs with suspected food allergy

“…The diagnosis of AFRs is based on clinical improvement during an elimination diet (ED) trial, followed by relapse during a challenge with the previous or suspected diet . The ED is considered to be the gold standard for the diagnosis of AFR because other tests lack sensitivity and/or specificity …”

A randomized, double‐blinded crossover trial testing the benefit of two hydrolysed poultry‐based commercial diets for dogs with spontaneous pruritic chicken allergy

“…7 Additionally, peptides as small as 3-5 kDa could cross-link IgE antibodies in the form of haptens, or peptides as small as 0.5 kDa could activate lymphocytes in non-IgE-mediated CAFR. 8,[12][13][14][15][16] Ultamino (RCU), also known as "Anallergenic" (Royal Canin; Guelph, ON, Canada), is a commercially available hydrolysed poultry feather protein-based diet with purified cornstarch. The company provided analysis reports that more than 99% of peptides found in the final product are below 6 kDa, with larger peptides originating mostly from chicory root fibre.…”

Non-IgE-Related Diagnostic Methods (LST, Patch Test)

“…With respect to food allergies, the LST has been used mainly to evaluate the involvement of food antigens in the pathogenesis (especially delayed-type) of atopic dermatitis [1,13] . However, lymphocyte responses decrease significantly as a result of avoidance of offending foods, regardless of acquisition of immune tolerance, suggesting that the LST is not suitable for diagnosing immune tolerance [14] .…”