Evaluation of T-cell activation in the duodenum of dogs with cutaneous food hypersensitivity.

OBJECTIVE

To determine whether skin-related clinical signs in cutaneous food hypersensitivity (CFH) coincide with immune reactivity in the intestine in dogs.

ANIMALS: 11 dogs with CFH without intestinal clinical signs and 8 healthy control dogs.

PROCEDURES: After a provocation and elimination diet, the duodenal gene expression levels of Th1-, Th2- and Treg-related cytokines and transcription factors were investigated by means of quantitative PCR assay. The presence of CD3(+), CD8(+), CD4(+), CD1c(+), gammadelta T-cell receptor(+), and major histocompatibility complex II(+) cells in duodenal epithelium and lamina propria were determined.

RESULTS

The expression of Th1-, Th2-, and Treg-related genes in dogs with CFH and healthy control dogs was similar. Although clinical signs disappeared, there was no effect of the elimination diet on cytokines, transcription factors, or cellular phenotypes.

CONCLUSIONS AND CLINICAL RELEVANCE: No change in T-cell phenotypes or a distinct Th1, Th2, or Treg profile was detected in the duodenum of dogs with only cutaneous clinical signs of food hypersensitivity. This suggested that the intestinal mucosa is not the primary site of T-cell activation that eventually leads to cutaneous food hypersensitivity.