Lymphocyte Blastogenic Responses to Inciting Food Allergens in Dogs with Food Hypersensitivity

Abstract

Lymphocyte blastogenic responses against food allergens in dogs with food hypersensitivity were evaluated in this study. Eleven dogs with food hypersensitivity, based on food elimination and oral food provocation tests and allergic responses to food allergens, were examined by various tests such as intradermal testing, antigen-specific IgE testing, and lymphocyte blastogenic responses. The number and kinds of food allergens identified as positive by these tests were compared with the offending food allergens that were found in an oral food provocation test. In 9 (82%) of the 11 dogs with food hypersensitivity, there was close agreement for positive allergens between the results of lymphocyte blastogenic responses and oral food provocation test; however, there was little agreement for intradermal and IgE testing of the positive allergens with those of the oral food provocation test (11% and 31%, respectively). In the 9 dogs, the stimulation indices of lymphocyte blastogenic responses increased to 2.0-10.1 upon food provocation but decreased significantly to 0.7-1.4 upon feeding the elimination diet until clinical signs disappeared. These results indicate that lymphocyte blastogenic responses may fluctuate because of exposure to offending food allergens in dogs with food hypersensitivity. Lymphocytes reactive to food allergens may play an important role in the pathogenesis of food hypersensitivity in dogs.

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

“…Results from a previous study showed that lymphocyte blastogenic responses to food allergens correlated well with those from food elimination and provocation trials: approximately 82% subject with FA diagnosed after a food elimination and provocation test also tested positive for a lymphocyte blastogenic response using a radioisotope [9]. This result indicates that type IV hypersensitivity against food allergens may be involved in the pathogenesis of FA in dogs.…”

“…Although a predisposition of certain dog breeds to FA has not yet been confirmed, the French bulldog and shih tzu are candidates for predisposition because they have been identified in another study on FA in dogs in Japan [9]. A larger number of clinical cases should be evaluated to confirm predisposed breeds.…”

“…The first onset of clinical signs occurred earlier than 1 year of age in 53.8% of the dogs with FA in this study, however, which supports the data in previous studies. One study conducted in Japan showed that 46% of dogs with FA began showing clinical signs between 1 and 3 years of age [9]. Studies in other countries have reported first onset of clinical signs earlier than 1 year of age in 37.5 % [3] and 46.5% [7] of dogs with FA.…”

“…Intradermal testing examines in vivo reactions mediated by the interaction between an allergen and antigen-specific IgE on mast cells in the skin; however, the test has proved unsuccessful for the identification of food allergens in dogs with FA [9,10,24]. Serum IgE tests that detect IgE against food allergens have also been found inappropriate because of their low sensitivity in detecting reactive allergens that were identified during food elimination and provocation [9,10]. Therefore, FA in dogs may be less associated with the pathogenesis of IgE-mediated allergic reactions and instead be caused by other factors.…”

The Antibody against Human CD25, ACT-1, Recognizes Canine T-lymphocytes in the G2/M and G0/G1 Phases of the Cell Cycle during Proliferation

“…Taken together, the present study confirmed the ability of ACT-1 to recognize proliferating T-lymphocytes in dogs, suggesting that flow cytometry using ACT-1 could be alternative to the assay with 3 H-thymidine incorporation for detection of canine lymphocyte proliferation. For instance, antigen-reactive lymphocytes are known to involve in the pathogenesis of canine food allergies, which has been examined with the 3 Hthymidine incorporation assay [5]; however, proliferation of T-lymphocytes against food antigens can be examined by assay using flow cytometry with ACT-1. Thus, the assay system comprised of flow cytometry with ACT-1 would be useful in investigation of CD4-positive T-lymphocyterelated allergic diseases in dogs, although further investigation is necessary to determine whether the antibody can recognize the canine CD25 molecule itself using its expressing cells or recombinant protein.…”