Alterations in circulating concentrations of IL-17, IL-31 and total IgE in dogs with atopic dermatitis

Background The pathogenesis of canine atopic dermatitis (AD) is complex. Dysregulation of the cutaneous immune system is considered an important regulator of the allergic response. Exploration of association of interleukin-17 (IL-17), IL-31, IgE and leukogram attributes with canine AD could provide novel insights into its immunopathology. Hypothesis/Objectives To investigate possible associations of IL-17, IL-3, IgE and leukogram attributes of canine AD. Animals 17 dogs diagnosed with AD and six healthy dogs. Methods and materials Circulating concentrations of IL-17, IL-31 and total IgE from sera samples were determined using commercial canine-specific quantitative immunoassay kits. Complete blood cell counts were analysed by an automated haematology analyser. Statistical differences between the two groups were determined using an unpaired t-test. The degree of relationship between the IL-17, IL-31, IgE, total leukocyte count (TLC) values and clinical signs scores (Canine Atopic Dermatitis Lesion Index and pruritus Visual Analog Scale pVAS) was determined by Pearson's r correlation statistic. Results Dogs with AD had significantly (P < 0.0001) higher circulating concentrations of IL-17, IL-31 and total IgE compared with healthy dogs. Dogs with AD also had significantly higher TLC (P < 0.0002), absolute neutrophils (P < 0.0001) and absolute eosinophils (P < 0.0001) counts, and percentage of neutrophils (P < 0.03) and eosinophils (P < 0.0001) compared with healthy controls. A significant positive correlation (r(2) = 0.396; P < 0.007) between the pVAS and IL-31 was observed in dogs with AD. Conclusions and clinical importance Marked elevation in circulating IL-17, IL-31 and total IgE along with the abnormalities in leukogram may be associated with canine AD and could be possible targets in the therapeutic management of canine AD.