Immune responses in dogs with cutaneous adverse food reactions

Background: Adverse food reactions (AFR) in dogs are reactions to apparently harmless food antigens, with an unknown etiology i.e. immunopathogenesis. In the majority of dogs with AFR, the signs are only associated with the skin (CAFR). Despite the entry of food allergens via the intestinal tract, they do not generate clinical symptoms at that location. Tissue homeostasis (skin, intestine) is well maintained in general, involving many cells, cytokines and homing molecules. Aim of the research: The immunopathogenesis of CAFR in the intestine and/or the skin is unknown. The aim of the research presented in this thesis was to understand the pathogenesis of CAFR in dogs with and without clinical symptoms by investigating the T cell activity profile and immunoreactivity in the intestine, skin and blood separately and in conjunction. Conclusions: Cutaneous adverse food reactions (CAFR) are characterized by a mixed cutaneous Th2 and Treg gene expression profile and CD8+ T cell infiltrations in the skin. CAFR are not the result of intestinal T cell dysfunction and are paralleled by a decreased Th1 response in peripheral blood. No immunological relationship between intestine, blood and skin was found in CAFR dogs. In addition, the changes in observed clinical signs, induced by dietary tests, are not paralleled by changes in intestinal, blood and cutaneous T cell and cytokine profiles.