Clinical and Immunological Responses to Dermatophagoides farinae Allergen Immunotherapy in Dogs With Atopic Dermatitis.

BACKGROUND

Atopic dermatitis (AD) in dogs is a prevalent allergic disorder associated with environmental allergens, including the house dust mite Dermatophagoides farinae (Df).

HYPOTHESIS/

OBJECTIVES

To describe clinical and immunological changes over time in dogs with canine (c)AD sensitised to Df undergoing Df allergen-specific immunotherapy (ASIT) and to test the hypothesis that ASIT is associated with changes in Canine Atopic Dermatitis Extent and Severity Index, 4th iteration (CADESI-04), pruritus and medication scores and selected immunological markers.

MATERIALS AND

METHODS

Fifteen dogs with cAD sensitised to Df received ASIT for 12 months. Clinical evaluations included CADESI-04 and pruritus Visual Analog Scale (PVAS). Gene expression of interleukin (IL)-31, interferon-gamma (IFN-γ) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in peripheral blood mononuclear cells (PBMCs) was analysed using real-time PCR. Serum levels of Df-specific immunoglobulin (Ig)E, total IgG and IgG subclass 1 were measured using immunoassays. Evaluations were performed at 0, 6 and 12 months.

RESULTS

Significant reductions in pruritus scores and IL-31 expression were observed, while IFN-γ expression increased. CADESI-04 scores decreased, although the change was not statistically significant. A reduction in medication scores was observed over time. Serum analysis showed increased concentrations of IgG and IgG1, while Df-specific IgE remained elevated.

CONCLUSIONS AND CLINICAL RELEVANCE: Dermatophagoides farinae ASIT resulted in a reduction in pruritus and medication use over a 12 month period. Associated with this, PBMCs IL-31 was reduced and IFN-γ elevated. An increased serum IgG and IgG1 were measured, and Df-specific IgE remained elevated. These findings support an immunological effect of ASIT, yet further studies with a larger cohort are required to validate the findings.