Investigation of the correlation of serum IL‐31 with severity of dermatitis in an experimental model of canine atopic dermatitis using beagle dogs

Background IL-31 is a cytokine that is believed to play an important role in atopic dermatitis (AD). IL-31 levels positively correlate with disease severity in children with AD. Currently, there is no study that has investigated such a correlation in atopic dogs. Hypothesis/objective The purpose of this study was to evaluate the correlation between IL-31 serum levels and severity of dermatitis. It was hypothesized that a positive correlation exists between severity of AD and circulating levels of IL-31. Animals Sixteen atopic beagles experimentally sensitized to house dust mites. Methods Atopic beagles were exposed to dust mites epicutaneously twice weekly for four weeks. Severity of dermatitis was scored by the Canine Atopic Dermatitis and Extent Severity Index, 3rd iteration (CADESI-03) on days 0 and 28. Blood samples were taken on days 0 and 28 to measure serum IL-31 using a commercially available ELISA. Results Correlation between CADESI-03 scores and serum IL-31 levels was not detected on day 0 (Pearson, r = −0.2609, P = 0.3291). After flare-up of dermatitis was induced with allergen exposure, a significant positive correlation was detected between serum IL-31 and CADESI-03 on Day 28 (r = 0.6738, P = 0.004). Conclusions and clinical importance Positive correlation was detected in active disease between severity of dermatitis and circulating levels of IL-31. Additional studies are needed to investigate this correlation in other breeds of dogs and to test whether circulating levels of IL-31 may predict clinical response to biological agents aimed at IL-31.