Lesional expression of thymus and activation-regulated chemokine in canine atopic dermatitis

In this study, we investigated the mRNA expression of a chemokine, thymus and activation-regulated chemokine (TARC), and cytokines including IL-1β, IL-4, IFN-γ and TNF-α in skin samples obtained from both dogs with atopic dermatitis (AD) and healthy dogs. TARC mRNA was found to be selectively expressed in lesional skin of the dogs with AD, but not in non-lesional skin of the dogs with AD or the normal skin of the healthy dogs. The expression levels of IL-1β, IFN-γ and TNF-α in the lesional skin were also significantly higher than those in the non-lesional skin of the dogs with AD. However, IL-4 mRNA was not detected in any of the skin samples in this study. The present results suggest that TARC and inflammatory cytokines such as IL-1β, IFN-γ and TNF-α may play roles in the pathogenesis of canine AD as well as that of human AD.